Search results for: SVR (sustained virologic response)

Authors: Tabassum Yasmin, Hamid Pahlevan

Abstract:

HIV/Hepatitis C co-infection treatments have evolved substantially and they have similar sustained virologic response rates as those of Hepatitis C monoinfected population. There are a few studies on therapy of patients with dual genotypes, especially in HIV/Hepatic C coinfected group. Most studies portrayed case reports of dual genotype chronic Hepatitis C coinfection treatment with Sofosbuvir/Ledipasvir and Ribavirin. A 79-year-old male with a history of HIV on Truvada and Isentress had chronic Hepatitis C with 1a and 2 genotypes. The patient has a history of alcohol intake for 40 years but recently stopped drinking alcohol. He has a history of intravenous drug use in the past and currently is not using any recreational drugs. Patient has Fibro score of 0.7 with Metavir score F2 to F4. AFP is 3.2. The HCV RNA is 493,034 IU/ML. The HBV viral DNA is < 1.30 (not detected). The CD4 is 687CU/MM. The FIB 4 is 3.34 with APRI index 0.717. The HIV viral load is 101 copies/ML. MRI abdomen did not show any liver abnormality. Fixed dose Sofosbuvir/Ledipasvir was used for therapy without Ribavirin. He tolerated medication except for some minor gastrointestinal side effects like abdominal bloating. He demonstrated 100% adherence rate. Patient completed 12 weeks of therapy. HCV RNA was undetectable at 4 and 12 weeks. He achieved SVR at week 12 and subsequently had undetectable RNA for 2 years. Dual genotype prevalence in chronic hepatitis C population is rare, especially in HIV/hepatic coinfection. Our case demonstrates that dual genotypic cases can still be successfully treated with Direct Acting Antiviral agents. The newer agents for therapy for pan genotypes were not available at the time the patient was being treated. We demonstrated that dual agent therapy was still able to maintain SVR in our patient.

Keywords: HIV/Hepatitis C, SVR (sustained virologic response), DAA (direct active antiviral agents, dual genotype

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Authors: Ali Kassem, Ehab Fawzy, Mahmoud Sef el-eslam, Fatma Salah- Eldeen, El zahraa Mohamed

Abstract:

Introduction: The combination of interferon (INF) and ribavirin is the preferred treatment for chronic hepatitis C viral (HCV) infection. However, nonresponse to this therapy remains common and is associated with several factors such as HCV genotype and HCV viral load in addition to host factors such as sex, HLA type and cytokine polymorphisms. Aim of the work: The aim of this study was to determine predictors of response to (INF) therapy in chronic HCV infected patients treated with INF alpha and ribavirin combination therapy. Patients and Methods: The present study included 110 patients (62 males, 48 females) with chronic HCV infection. Their ages ranged from 20-59 years. Inclusion criteria were organized according to the protocol of the Egyptian National Committee for control of viral hepatitis. Patients included in this study were recruited to receive INF ribavirin combination therapy; 54 patients received pegylated NF α-2a (180 μg) and weight based ribavirin therapy (1000 mg if < 75 kg, 1200 mg if > 75 kg) for 48 weeks and 53 patients received pegylated INF α-2b (1.5 ug/kg/week) and weight based ribavirin therapy (800 mg if < 65 kg, 1000 mg if 65-75 kg and 1200 mg if > 75kg). One hundred and seven liver biopsies were included in the study and submitted to histopathological examination. Hematoxylin and eosin (H&E) stained sections were done to assess both the grade and the stage of chronic viral hepatitis, in addition to the degree of steatosis. Modified hepatic activity index (HAI) grading, modified Ishak staging and Metavir grading and staging systems were used. Laboratory follow up including: HCV PCR at the 12th week to assess the early virologic response (EVR) and at the 24th week were done. At the end of the course: HCV PCR was done at the end of the course and tested 6 months later to document end virologic response (ETR) and sustained virologic response (SVR) respectively. Results One hundred seven patients; 62 males (57.9 %) and 45 females (42.1%) completed the course and included in this study. The age of patients ranged from 20-59 years with a mean of 40.39±10.03 years. Six months after the end of treatment patients were categorized into two groups: Group (1): patients who achieved sustained virological response (SVR). Group (2): patients who didn't achieve sustained virological response (non SVR) including non-responders, breakthrough and relapsers. In our study, 58 (54.2%) patients showed SVR, 18 (16.8%) patients were non-responders, 15 (14%) patients showed break-through and 16 (15 %) patients were relapsers. Univariate binary regression analysis of the possible risk factors of non SVR showed that the significant factors were higher age, higher fasting insulin level, higher Metavir stage and higher grade of hepatic steatosis. Multivariate binary regression analysis showed that the only independent risk factor for non SVR was high fasting insulin level. Conclusion: Younger age, lower Metavir stage, lower steatosis grade and lower fasting insulin level are good predictors of SVR and could be used in predicting the treatment response of pegylated interferon/ribavirin therapy.

Keywords: chronic HCV infection, interferon ribavirin combination therapy, predictors to antiviral therapy, treatment response

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Authors: Ananya Pal, Neelakshi Sarkar, Debraj Saha, Dipanwita Das, Subhashish Kamal Guha, Bibhuti Saha, Runu Chakravarty

Abstract:

Presently, tenofovir disoproxil fumurate (TDF) is the most effective anti-viral agent for the treatment of hepatitis B virus (HBV) in individuals co-infected with HIV and HBV as TDF has activity to suppress both wild-type and lamivudine (3TC)-resistant HBV. However, suboptimal response to TDF was reported in HIV-HBV co-infected individuals with prior 3TC therapy from different countries recently. The incidence of 3TC-resistant HBV strains is quite high in HIV-HBV co-infected patients experiencing long-term anti-retroviral therapy (ART) in eastern India. In spite of this risk, most of the patients with long-term 3TC treatment are continued with the same anti-viral agent in this country. Only a few have received TDF in addition to 3TC in the ART regimen since TDF has been available in India for the treatment of HIV-infected patients in 2012. In this preliminary study, we investigated the virologic and biochemical parameters among HIV-HBV co-infected patients who are non-responders to 3TC treatment during the continuation of 3TC or TDF add-on to 3TC in their ART regimen. Fifteen HIV-HBV co-infected patients who experienced long-term 3TC (mean duration months 36.87 ± 24.08 months) were identified with high HBV viremia ( > 20,000 IU/ml) or harbouring 3TC-resistant HBV. These patients receiving ART from School of Tropical Medicine Kolkata, the main ART centre in eastern India were followed-up semi-annually for next three visits. Different virologic parameters including quantification of plasma HBV load by real-time PCR, detection of hepatitis B e antigen (HBeAg) by commercial ELISA and anti-viral resistant mutations by sequencing were studied. During three follow-up among study subjects, 86%, 47%, and 43% had 3TC-mono-therapy (mean treatment-duration 41.54±18.84, 49.67±11.67, 54.17±12.37 months respectively) whereas 14%, 53%, and 57% experienced TDF in addition to 3TC (mean treatment duration 4.5±2.12, 16.56±11.06, and 23±4.07 months respectively). Mean CD4 cell-count in patients receiving 3TC was tended to be lower during third follow-up as compared to the first and the second [520.67±380.30 (1st), 454.8±196.90 (2nd), and 397.5±189.24 (3rd) cells/mm3) and similar trend was seen in patients experiencing TDF in addition to 3TC [334.5±330.218 (1st), 476.5±194.25 (2nd), and 461.17±269.89 (3rd) cells/mm3]. Serum HBV load was increased during successive follow-up of patients with 3TC-mono-therapy. Initiation of TDF lowered serum HBV-load among 3TC-non-responders at the time of second visit ( < 2,000 IU/ml), interestingly during third follow-up, mean HBV viremia increased >1 log IU/ml (mean 3.56±2.84 log IU/ml). Persistence of 3TC-resistant double and triple mutations was also observed in both the treatment regimens. Mean serum alanine aminotransferase remained elevated in these patients during this follow-up study. Persistence of high HBV viraemia and 3TC-resistant mutation in HBV during the continuation of 3TC might lead to major public health threat in India. The inclusion of TDF in the ART regimen of 3TC non-responder HIV-HBV co-infected patients showed adverse treatment response in terms of virologic and biochemical parameters. Therefore, serious attention is necessary for proper management of long-term 3TC experienced HIV-HBV co-infected patients with high HBV viraemia or 3TC-resistant HBV mutants in India.

Keywords: HBV, HIV, TDF, 3TC-resistant

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Authors: Heiko Jessen, Laura Tanus, Slobodan Ruzicic

Abstract:

Objectives: The efficacy of Stribild®, an integrase strand transfer inhibitor (INSTI) -based STR, has been evaluated in randomized clinical trials and it has demonstrated durable capability in terms of achieving sustained suppression of HIV-1 RNA-levels. However, differences in monitoring frequency, existing selection bias and profile of patients enrolled in the trials, may all result in divergent efficacy of this regimen in routine clinical settings. The aim of this study was to assess the virologic outcomes, safety and tolerability profile of Stribild® in a routine clinical setting. Methods: This was a retrospective monocentric analysis on HIV-1-infected patients, who started with or were switched to Stribild®. Virological failure (VF) was defined as confirmed HIV-RNA>50 copies/ml. The minimum time of follow-up was 24 weeks. The percentage of patients remaining free of therapeutic failure was estimated using the time-to-loss-of-virologic-response (TLOVR) algorithm, by intent-to-treat analysis. Results: We analyzed the data of 197 patients (56 ART-naïve and 141 treatment-experienced patients), who fulfilled the inclusion criteria. Majority (95.9%) of patients were male. The median time of HIV-infection at baseline was 2 months in treatment-naïve and 70 months in treatment-experienced patients. Median time [IQR] under ART in treatment-experienced patients was 37 months. Among the treatment-experienced patients 27.0% had already been treated with a regimen consisting of two NRTIs and one INSTI, whereas 18.4% of them experienced a VF. The median time [IQR] of virological suppression prior to therapy with Stribild® in the treatment-experienced patients was 10 months [0-27]. At the end of follow-up (median 33 months), 87.3% (95% CI, 83.5-91.2) of treatment-naïve and 80.3% (95% CI, 75.8-84.8) of treatment-experienced patients remained free of therapeutic failure. Considering only treatment-experienced patients with baseline VL<50 copies/ml, 83.0% (95% CI, 78.5-87.5) remained free of therapeutic failure. A total of 17 patients stopped treatment with Stribild®, 5.4% (3/56) of them were treatment-naïve and 9.9% (14/141) were treatment-experienced patients. The Stribild® therapy was discontinued in 2 (1.0%) because of VF, loss to follow-up in 4 (2.0%), and drug-drug interactions in 2 (1.0%) patients. Adverse events were in 7 (3.6%) patients the reason to switch from therapy with Stribild® and further 2 (1.0%) patients decided personally to switch. The most frequently observed adverse events were gastrointestinal side effects (20.0%), headache (8%), rash events (7%) and dizziness (6%). In two patients we observed an emergence of novel resistances in integrase-gene. The N155H evolved in one patient and resulted in VF. In another patient S119R evolved either during or shortly upon switch from therapy with Stribild®. In one further patient with VF two novel mutations in the RT-gene were observed when compared to historical genotypic test result (V106I/M and M184V), whereby it is not clear whether they evolved during or already before the switch to Stribild®. Conclusions: Effectiveness of Stribild® for treatment-naïve patients was consistent with data obtained in clinical trials. The safety and tolerability profile as well as resistance development confirmed clinical efficacy of Stribild® in a daily practice setting.

Keywords: ART, HIV, integrase inhibitor, stribild

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Authors: Kuan-Wei Chen, Chien-Wei Chen, Tai-Ling Chang, Nan-Cheng Chen, Ching-Lin Hsieh, Gong-Hong Lin

Abstract:

Background and Purposes: Deficits in sustained attention are common in patients with schizophrenia. Such impairment can limit patients to effectively execute daily activities and affect the efficacy of rehabilitation. The aims of this study were to examine the test-retest agreement, random measurement error, and practice effect of the Continuous Performance Test-Identical Pairs (CPT-IP) (a commonly used sustained attention test) in patients with schizophrenia. The results can provide empirical evidence for clinicians and researchers to apply a sustained attention test with sound psychometric properties in schizophrenia patients. Methods: We recruited patients with chronic schizophrenia to be assessed twice with 1 week interval using CPT-IP. The intra-class correlation coefficient (ICC) was used to examine the test-retest agreement. The percentage of minimal detectable change (MDC%) was used to examine the random measurement error. Moreover, the standardized response mean (SRM) was used to examine the practice effect. Results: A total of 56 patients participated in this study. Our results showed that the ICC was 0.82, MDC% was 47.4%, and SRMs were 0.36 for the CPT-IP. Conclusion: Our results indicate that CPT-IP has acceptable test-retests agreement, substantial random measurement error, and small practice effect in patients with schizophrenia. Therefore, to avoid overestimating patients’ changes in sustained attention, we suggest that clinicians interpret the change scores of CPT-IP conservatively in their routine repeated assessments.

Keywords: schizophrenia, sustained attention, CPT-IP, reliability

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Authors: Luciano Tarantino, Emanuele Balzano, Aurelio Nasto

Abstract:

S.R. 53 years. January 2009: HCV-related cirrhosis, Child-Pugh A5 class, EGDS no aesophageal Varices. No important comorbidities. Treated with PEG-IFN+Ribavirin (march-november 2009) with subsequent sustained virologic response. HCVRNA absent overtime. October 2016 :CT detected small HCC nodule in the VIII segment (diam.=12 mm). Treated with US guided RF-ablation. November 2016 CT: complete necrosis. Unfortunately, the patient dropped out US and CT follow-up controls.September 2018: asthenia and weight loss. CT showed a large tumor infiltrating V-VII-VI segments and complete PVTT of right portal vein and its branches . Surgical Consultation excluded indication to Liver resection and OLT . 23 october 2018: ECT of a large peri-hilar area of the tumor including the PVTT. 1 and 3 months post-treatment CT showed complete necrosis and retraction of the thrombus and residual viable tumor in the peripheral portion of the right lobe . Therefor, the patient was reevaluated for OLT and considered eligible in waiting list . March 2019: CT showed no perihilar or portal vein recurrence and distant progression in the right lobe . March 2019 : Trans-arterial-Radio-therapy (TARE) of the right lobe. Post-treatment CT demonstrated no perihilar or portal vein recurrence and extensive necrosis of the residual tumor . December 2019: CT demonstrated several recurrences of HCC infiltrating the VI and VII segment . Howewer no recurrence was observed at hepatic hilum and in portal vessels . Therefore, on February 2020 the patient received OLT. At 44 months follow-up, no complication or recurrence or liver disfunction have been observed.

Keywords: hepatocellular carcinoma, portal vein tumor thrombosis, interventional ultrasound, liver tumor ablation, liver transplantation

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Authors: Khaoula Azraiel, Mohamed Mehdi Abassi, Amel Sadraoui, Walid Hammami, Azouz Msaddek, Imed Cheikh, Maria Mancebo, Elisabet Perez-Navarro, Antonio Caruz, Henda Triki, Ahlem Djebbi

Abstract:

IL28B rs12979860 genotype is confirmed as an important predictor of response to peginterferon/ribavirin therapy in patients with chronic hepatitis C (CHC). IFNL4 ss469415590 is a newly discovered polymorphism that could also affect the sustained virological response (SVR). The aim of this study was to evaluate the association of IL28B and IFNL4 genotypes with peginterferon/ribavirin treatment response in Tunisians patients with CHC and to determine which of these SNPs, was the stronger marker. A total of 120 patients were genotyped for both rs12979860 and ss469415590 polymorphisms. The association of each genetic marker with SVR was analyzed and comparison between the two SNPs was calculated by logistic regression models. For rs12979860, 69.6% of patients with CC, 41.8% with CT and 42.8% with TT achieved SVR (p = 0.003). Regarding ss469415590, 70.4% of patients with TT/TT genotype achieved SVR compared to 42.8% with TT/ΔG and 37.5% with ΔG /ΔG (p = 0.002). The presence of CC and TT/TT genotypes was independently associated with treatment response with an OR of 3.86 for each. In conclusion, both IL28B rs12979860 and IFNL4 ss469415590 variants were associated with response to pegIFN/RBV in Tunisian patients, without any additional benefit in performance for IFNL4. Our results are different from those detected in Sub-Saharan Africa countries.

Keywords: Hepatitis C virus, IFNL4, IL28B, Peginterferon/ribavirin, polymorphism

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Authors: Adewusi Adeoluwawale, Oronti Iyabosola Busola, Akinola Iretiayo, Komolafe Olusola Aderibigbe

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The complex and radial structure of the low voltage distribution network (415V) makes it vulnerable to faults which are due to system and the environmental related factors. Besides these, the protective scheme employed on the low voltage network which is the fuse cannot be monitored remotely such that in the event of sustained fault, the utility will have to rely solely on the complaint brought by customers for loss of supply and this tends to increase the length of outages. A microcontroller based fault detection scheme is hereby developed to detect low voltage and high voltage fault conditions which are common faults on this network. Voltages below 198V and above 242V on the distribution feeders are classified and detected as low voltage and high voltages respectively. Results shows that the developed scheme produced a good response time in the detection of these faults.

Keywords: fault detection, low voltage distribution feeders, outage times, sustained faults

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Authors: Aisling Davies, Ciara Greene

Abstract:

Over the past decade the phenomenon of mind-wandering in cognitive tasks has attracted widespread scientific attention. Research indicates that mind-wandering occurrences can be detected through behavioural responses in the Sustained Attention to Response Task (SART) and several studies have attributed a specific pattern of responding around an error in this task to an observable effect of a mind-wandering state. SART behavioural responses are also widely accepted as indices of sustained attention and of general attention lapses. However, evidence suggests that these same patterns of responding may be attributable to other factors associated with more focused states and that it may also be possible to distinguish the two states within the same task. To use behavioural responses in the SART to study mind-wandering, it is essential to establish both the SART parameters that would increase the likelihood of errors due to mind-wandering, and exactly what type of responses are indicative of mind-wandering, neither of which have yet been determined. The aims of this study were to compare different versions of the SART to establish which task would induce the most mind-wandering episodes and to determine whether mind-wandering related errors can be distinguished from errors during periods of focus, by behavioural responses in the SART. To achieve these objectives, 25 Participants completed four modified versions of the SART that differed from the classic paradigm in several ways so to capture more instances of mind-wandering. The duration that trials were presented for was increased proportionately across each of the four versions of the task; Standard, Medium Slow, Slow, and Very Slow and participants intermittently responded to thought probes assessing their level of focus and degree of mind-wandering throughout. Error rates, reaction times and variability in reaction times decreased in proportion to the decrease in trial duration rate and the proportion of mind-wandering related errors increased, until the Very Slow condition where the extra decrease in duration no longer had an effect. Distinct reaction time patterns around an error, dependent on level of focus (high/low) and level of mind-wandering (high/low) were also observed indicating four separate attention states occurring within the SART. This study establishes the optimal duration of trial presentation for inducing mind-wandering in the SART, provides evidence supporting the idea that different attention states can be observed within the SART and highlights the importance of addressing other factors contributing to behavioural responses when studying mind-wandering during this task. A notable finding in relation to the standard SART, was that while more errors were observed in this version of the task, most of these errors were during periods of focus, raising significant questions about our current understanding of mind-wandering and associated failures of attention.

Keywords: attention, mind-wandering, trial duration rate, Sustained Attention to Response Task (SART)

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Authors: Sila Akhan, Muge Toygar, Murat Sayan, Simge Fidan

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Chronic viral hepatitis B, C, and D can cause hepatocellular carcinoma (HCC), cirrhosis and death. The proper treatment reduce the risk of development of HCC importantly, but not to zero point. Materials and Methods: We analysed retrospectively our chronic viral hepatitis B, C and D patients who attended to our Infectious Diseases policlinic between 2004-2018. From 589 biopsy-proven chronic hepatitis patients 3 have hepatocellular carcinoma on our follow up. First case is 74 years old patient. His HCV infection diagnosis was made 8 years ago. First treatment was pegylated interferon plus ribavirin only 28 weeks, because of HCV RNA breakthrough under treatment. In 2013 he was retreated with telaprevir, pegylated interferon plus ribavirin 24 weeks. But at the end of the therapy HCV RNA was found 1.290.000 IU/mL. He has abdominal ultrasonography (US) controls and alpha-fetoprotein (AFP) at 6 months intervals. All seemed normal until 2015 then he has an abdominal magnetic resonance imaging (MRI) and found HCC by chance. His treatment began in Oncology Clinic after verified with biopsy of HCC. And then sofosbuvir/ledipasvir was given to him for HCV 24 weeks. Sustained virologic response (SVR) was obtained. He is on cure for HCV infection and under control of Oncology for HCC. Second patient is 36 years old man. He knows his HBV infection since 2008. HBsAg and HBeAg positive; HDV RNA negative. Liver biopsy revealed grade:4, stage 3-4 according modified Knodell scoring system. In 2010 tenofovir treatment was began. His abdominal US and AFP were normal. His controls took place at 6 months intervals and HBV DNA negative, US, and AFP were normal until 2016 continuously. AFP found 37 above the normal range and then HCC was found in MRI. Third patient is 57 years old man. As hepatitis B infection was first diagnosed; he has cirrhosis and was began tenofovir as treatment. In short time he has HCC despite normal AFP values. Conclusion: In Mediterranian countries including Turkey naturally occurring pre-S/S variants are more than 75% of all chronic hepatitis B patients. This variants may contribute to the development of progressive liver damage and hepatocarcinogenesis. HCV-induced development of HCC is a gradual process and is affected by the duration of disease and viral genotype. All the chronic viral hepatitis patients should be followed up in 6 months intervals not only with US and AFP for HCC. Despite they have proper treatment there is always the risk development of HCC. Chronic hepatitis patients cannot be dropped from follow up even treated well.

Keywords: HCC, HCV, HBV, DAA

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Authors: Nagasamy Venkatesh Dhandapani

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The objective of the present study was to develop sustained release oral matrix tablets of anti epileptic drug levetiracetam. The sustained release matrix tablets of levetiracetam were prepared using hydrophilic matrix hydroxypropyl methylcellulose (HPMC) as a release retarding polymer by wet granulation method. Prior to compression, FTIR studies were performed to understand the compatibility between the drug and excipients. The study revealed that there was no chemical interaction between drug and excipients used in the study. The tablets were characterized by physical and chemical parameters and results were found in acceptable limits. In vitro release study was carried out for the tablets using 0.1 N HCl for 2 hours and in phosphate buffer pH 7.4 for remaining time up to 12 hours. The effect of polymer concentration was studied. Different dissolution models were applied to drug release data in order to evaluate release mechanisms and kinetics. The drug release data fit well to zero order kinetics. Drug release mechanism was found as a complex mixture of diffusion, swelling and erosion.

Keywords: levetiracetam, sustained-release, hydrophilic matrix tablet, HPMC grade K 100 MCR, wet granulation, zero order release kinetics

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Authors: Anoff Anim, Lila Mahmoud, Maria Katsikogianni, Sanjit Nayak

Abstract:

Sustained and controlled delivery of antimicrobial drugs have been largely studied recently using metal organic frameworks (MOFs)and different polymers. However, much attention has not been given to combining both MOFs and biodegradable polymers, which would be a good strategy in providing a sustained gradual release of the drugs. Herein, we report a comparative study of the sustained and controlled release of widely used antibacterial drugs, cephalexin and metronidazole, from zinc-based MOF-5 incorporated in biodegradable polycaprolactone (PCL) and poly-lactic glycolic acid (PLGA) membranes. Cephalexin and metronidazole were separately incorporated in MOF-5 post-synthetically, followed by their integration into biodegradable PLGA and PCL membranes. The pristine MOF-5 and the loaded MOFs were thoroughly characterized by FT-IR, SEM, TGA and PXRD. Drug release studies were carried out to assess the release rate of the drugs in PBS and distilled water for up to 48 hours using UV-Vis Spectroscopy. Four bacterial strains from both the Gram-positive and Gram-negative types, Staphylococus aureus, Staphylococuss epidermidis, Escherichia coli, Acinetobacter baumanii, were tested against the pristine MOF, pure drugs, loaded MOFs and the drug-loaded MOF-polymer composites. Metronidazole-loaded MOF-5 composite of PLGA (PLGA-Met@MOF-5) was found to show highest efficiency to inhibit the growth of S. epidermidis compared to the other bacteria strains while maintaining a sustained minimum inhibitory concentration (MIC). This study demonstrates that the combination of biodegradable MOF-polymer composites can provide an efficient platform for sustained and controlled release of antimicrobial drugs and can be a potential strategy to integrate them in biomedical devices.

Keywords: antimicrobial resistance, biodegradable polymers, cephalexin, drug release metronidazole, MOF-5, PCL, PLGA

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Authors: Shahana Sharmin

Abstract:

In the present study, the effect of cellulose polymers Ethyl Cellulose and Hydroxy Propyl Methyl Cellulose was evaluated on the release profile of drug from sustained release pellet. Diltiazem Hydrochloride, an antihypertensive, cardio-protective agent and slow channel blocker were used as a model drug to evaluate its release characteristics from different pellets formulations. Diltiazem Hydrochloride sustained release pellets were prepared by drug loading (drug binder suspension) on neutral pellets followed by different percentages of spraying, i.e. 2%,4%, 6%, 8% and 10% coating suspension using ethyl cellulose and hydroxy-propyl methyl cellulose polymer in a fixed 85:15 ratios respectively. The in vitro dissolution studies of Diltiazem Hydrochloride from these sustained release pellets were carried out in pH 7.2 phosphate buffer for 1, 2, 3, 4, 5, 6, 7, and 8 hrs using USP-I method. Statistically, significant differences were found among the drug release profile from different formulations. Polymer content with the highest concentration of Ethyl cellulose on the pellets shows the highest release retarding rate of the drug. The retarding capacity decreases with the decreased concentration of ethyl cellulose. The release mechanism was explored and explained with zero order, first order, Higuchi and Korsmeyer’s equations. Finally, the study showed that the profile and kinetics of drug release were functions of polymer type, polymer concentration & the physico-chemical properties of the drug.

Keywords: diltiazem hydrochloride, ethyl cellulose, hydroxy propyl methyl cellulose, release kinetics, sustained release pellets

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Authors: Anoff Anim, Lila A. M. Mahmoud, Maria Katsikogianni, Sanjit Nayak

Abstract:

Sustained and controlled delivery of antimicrobial drugs have been largely studied recently using metal organic frameworks (MOFs)and different polymers. However, much attention has not been given to combining both MOFs and biodegradable polymers, which would be a good strategy in providing a sustained gradual release of the drugs. Herein, we report a comparative study of the sustained and controlled release of widely used antibacterial drugs, cephalexin and metronidazole, from zinc-based MOF-5 incorporated in biodegradable polycaprolactone (PCL) and poly-lactic glycolic acid (PLGA) membranes. Cephalexin and metronidazole were separately incorporated in MOF-5 post-synthetically, followed by their integration into biodegradable PLGA and PCL membranes. The pristine MOF-5 and the loaded MOFs were thoroughly characterized by FT-IR, SEM, TGA and PXRD. Drug release studies were carried out to assess the release rate of the drugs in PBS and distilled water for up to 48 hours using UV-Vis Spectroscopy. Four bacterial strains from both the Gram-positive and Gram-negative types, Staphylococus aureus, Staphylococuss epidermidis, Escherichia coli, Acinetobacter baumanii, were tested against the pristine MOF, pure drugs, loaded MOFs and the drug-loaded MOF-polymer composites. Metronidazole-loaded MOF-5 composite of PLGA (PLGA-Met@MOF-5) was found to show highest efficiency to inhibit the growth of S. epidermidis compared to the other bacteria strains while maintaining a sustained minimum inhibitory concentration (MIC). This study demonstrates that the combination of biodegradable MOF-polymer composites can provide an efficient platform for sustained and controlled release of antimicrobial drugs and can be a potential strategy to integrate them in biomedical devices.

Keywords: antimicrobial resistance, biodegradable polymers, cephalexin, drug release metronidazole, MOF-5, PCL, PLGA

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Authors: N. M. Sani, E. D. Jatau, O. S. Olonitola, M. Y. Gwarzo, P. Moodley, N. S. Mujahid

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Haemoglobin (HB) indicates anaemia level and by extension may reflect the nutritional level and perhaps the immunity of an individual. Some antiretroviral drugs like zidovudine are known to cause anaemia in People living with HIV/AIDS (PLWHA). A cross-sectional study using demographic data and blood specimen from 218 female commercial sex workers attending antiretroviral therapy (ART) clinics was conducted between December 2009 and July 2011 to assess the effect of zidovudine on haematologic and RNA viral load of female sex workers receiving antiretroviral treatment in north-western Nigeria. Anaemia is a common and serious complication of both HIV infection and its treatment. In the setting of HIV infection, anaemia has been associated with decreased quality of life, functional status, and survival. Antiretroviral therapy, particularly the highly active antiretroviral therapy (HAART), has been associated with a decrease in the incidence and severity of anaemia in HIV-infected patients who have received a HAART regimen for at least 1 year. In this study, result has shown that out of 218 patients, 26 with haemoglobin count between 5.1–10 g/dl were observed to have the highest viral load count of 300,000–350,000 copies/ml. It was also observed that most patients (190) with HB of 10.1–15.0 g/dl had viral load count of 200,000–250,000 copies/ml. An inverse relationship therefore exists, i.e. the lower the haemoglobin level, the higher the viral load count, even though the test statistics did not show any significance between the two (P=0.206). This shows that multivariate logistic regression analysis demonstrated that anaemia was associated with a CD4+ cell count below 50/µL in female sex workers with a viral load above 100,000 copies/mL who use zidovudine. Severe anaemia was less prevalent in this study population than in historical comparators; however, mild to moderate anaemia rates remain high. The study, therefore, recommends that hematological and virologic parameters be monitored closely in patients receiving first line ART regimen.

Keywords: anaemia, female sex worker, haemoglobin, Zidovudine

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Authors: Anoff Anim, Lila Mahmound, Maria Katsikogianni, Sanjit Nayak

Abstract:

Sustained and controlled delivery of antimicrobial drugs have been largely studied recently using metal organic frameworks (MOFs)and different polymers. However, much attention has not been given to combining both MOFs and biodegradable polymers which would be a good strategy in providing a sustained gradual release of the drugs. Herein, we report a comparative study of the sustained and controlled release of widely used antibacterial drugs, cephalexin and metronidazole, from zinc-based MOF-5 incorporated in biodegradable polycaprolactone (PCL) and poly-lactic glycolic acid (PLGA) membranes. Cephalexin and metronidazole were separately incorporated in MOF-5 post-synthetically, followed by their integration into biodegradable PLGA and PCL membranes. The pristine MOF-5 and the loaded MOFs were thoroughly characterized by FT-IR, SEM, TGA and PXRD. Drug release studies were carried out to assess the release rate of the drugs in PBS and distilled water for up to 48 hours using UV-Vis Spectroscopy. Four bacterial strains from both the Gram-positive and Gram-negative types, Staphylococus aureus, Staphylococuss epidermidis, Escherichia coli, Acinetobacter baumanii, were tested against the pristine MOF, pure drugs, loaded MOFs and the drug-loaded MOF-polymer composites. Metronidazole-loaded MOF-5 composite of PLGA (PLGA-Met@MOF-5) was found to show highest efficiency to inhibit the growth of S. epidermidis compared to the other bacteria strains while maintaining a sustained minimum inhibitory concentration (MIC). This study demonstrates that the combination of biodegradable MOF-polymer composites can provide an efficient platform for sustained and controlled release of antimicrobial drugs, and can be a potential strategy to integrate them in biomedical devices.

Keywords: antimicrobial resistance, biodegradable polymers, cephalexin, drug release metronidazole, MOF-5, PCL, PLGA

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Authors: Saad Khalid Niaz, Arif Mahmood Siddiqui, Afzal Haqi

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Background: Estimated prevalence of Hepatitis C in Pakistan is 5% of which 78 % are Genotype 3, in which Response to conventional interferon is reported to be 70%. Objective: To determine the efficacy of pegylated interferon 20 kDa (Unipeg) plus ribavirin (Ribazole) in HCV genotype 3 patients who relapsed to conventional interferon. Methods: This is an ongoing study of 20 enrolled patients. Pegylated interferon alfa-2a 20 kDa 180 mcg weekly with ribavirin, were administered for a period of 24 weeks. Virological Responses were measured by Qualitative HCV RNA at weeks 4, 12, 24 and 48 to determine Rapid Virological Response (RVR), Early Virological Response (EVR), End of Treatment (ETR) and Sustained Virological Response (SVR), respectively. EVR was done for those who didn’t achieve RVR. Results: Males were 12 (60%) and mean age was 38.5 ±7.62 years. Out of 20 recruited patients, all completed 4 weeks therapy; RVR was achieved in 8 (40%) patients. One patient was lost to follow up and one yet to visit at 12 weeks. From 10 patients, 8 (80%) patients achieved EVR. Out of intent-to-treat patients, 15 completed 24 weeks therapy, ETR was achieved in 14 (93%) patients and 9 patients completed post therapy follow-up, of which, 8 (89%) patients achieved SVR. Conclusion: Our interim data demonstrates that Pegylated Interferon alfa-2a 20 kDa 180 mcg (Unipeg) in combination with Ribavirin (Ribazole) has shown promising results in treating HCV Genotype 3 patients who relapsed to conventional interferon. We recommend use of Pegylated Interferon in Relapsers with Genotype 3 when financial constraints limit the use of oral antivirals.

Keywords: pegylated interferon (unipeg), hepatitis c, relapsers, Pakistan

Procedia PDF Downloads 273

Authors: Sultan Daud, John P. Forth, Nikolaos Nikitas

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The current study aims to highlight the loading characteristics impact on the time evolution (focusing particularly on long term effects) of the deformation of realized reinforced concrete beams. Namely the tension stiffening code provisions (i.e. within Eurocode 2) are reviewed with a clear intention to reassess their operational value and predicting capacity. In what follows the experimental programme adopted along with some preliminary findings and numerical modelling attempts are presented. For a range of long slender reinforced concrete simply supported beams (4200 mm) constant static sustained and repeated cyclic loadings were applied mapping the time evolution of deformation. All experiments were carried out at the Heavy Structures Lab of the University of Leeds. During tests the mid-span deflection, creep coefficient and shrinkage strains were monitored for duration of 90 days. The obtained results are set against the values predicted by Eurocode 2 and the tools within an FE commercial package (i.e. Midas FEA) to yield that existing knowledge and practise is at times over-conservative.

Keywords: Eurocode2, midas fea, repeated, sustained loading.

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Authors: Sunil Kamboj, Vipin Saini, Suman Bala, Gaurav Sharma

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The main aim of the present research was to encapsulate mefenamic acid in niosomes and incorporate the prepared niosomes in the carbopol gel base for sustained therapeutic action. Mefenamic acid loaded niosomes were prepared by thin film hydration technique and evaluated for entrapment efficiency, vesicular size and zeta potential. The entrapment efficiency of the prepared niosomes was found to increase with decreasing the HLB values of surfactants and vesicle size was found to increase with increasing the cholesterol concentration. Niosomal vesicles with good entrapment efficiencies were incorporated in carbopol gel base to form the niosomal gel. The prepared niosomal gel was evaluated for pH, viscosity, spreadability, extrudability and skin permeation study across the rat skin.The results of permeation study revealed that the gel formulated with span 60 niosomes sustained the drug release for 12 h. Further the in vivo study showed the good inhibition of inflammation by the gel prepared with span 60 niosomes.

Keywords: mefenamic acid, niosomal gel, nonionic surfactants, sustained release

Procedia PDF Downloads 373

Authors: Malay K. Das, Bhupen Kalita

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The poor oral bioavailability of resveratrol (RSV) due to presystemic metabolism can be avoided via dermal route of administration. The hydrophilic-lipophilic nature of resveratrol-phospholipid complex (RSVPs) favors the delivery of resveratrol via the skin. The RSVPs embedded polymeric patch with moderate adhesiveness was developed for dermal application for sustained anti-inflammatory effect. The prepared patches were evaluated for various physicochemical properties, surface morphology by SEM, TEM, and compatibility of patch components by FT-IR and DSC studies. The dermal flux of the optimized patch formulation was found to be at 4.28 ± 0.48 mg/cm2/24 h. The analysis of skin extract after permeation study revealed the presence of resveratrol, which confirmed the localization of RSVPs in the skin. The stability of RSVPs in the polymeric patch and the physiologic environment was confirmed by FE-SEM studies on the patches after drug release and skin permeation studies. The RSVPs particles released from the polymer matrix maintaining the structural integrity and permeate the keratinized horney layer of skin. The optimized patch formulation showed sustained anti-inflammatory effect (84.10% inhibition of inflammation at 24 h) in carrageenan-induced rat paw edema model compared to marketed diclofenac sodium gel (39.58% inhibition of inflammation at 24 h). The CLSM study confirmed the localization of RSVPs for a longer period, thus enabling drug targeting to the dermis for sustained anti-inflammatory effect. Histological studies with phase contrast trinocular microscope suggested no alteration of skin integrity and no evidence of the presence of inflammatory cells after exposure to the permeants. The patch was found to be safe for skin application as evaluated by Draize method for skin irritation scoring in a rabbit model. These results suggest the therapeutic efficacy of the developed patch in both acute and chronic inflammatory diseases.

Keywords: resveratrol-phospholipid complex, skin delivery, sustained anti-inflammatory effect, inflammatory diseases, dermal patch

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Authors: Mohammad Najmol Haque, Takeshi Maki, Jun Sasaki

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Headed stud shear connections are widely used in the junction or embedded zone of hybrid girder to achieve whole composite action with continuity that can sustain steel-concrete interfacial tensile and shear forces. In Japan, Japan Road Association (JRA) specifications are used for hybrid girder design that utilizes very low level of stud capacity than those of American Institute of Steel Construction (AISC) specifications, Japan Society of Civil Engineers (JSCE) specifications and EURO code. As low design shear strength is considered in design of connections, the time dependent shear behavior due to sustained external loading is not considered, even not fully studied. In this study, a finite element approach was used to evaluate the time dependent shear behavior for headed studs used as connections at the junction. This study clarified, how the sustained loading distinctively impacted on changing the interfacial shear of connections with time which was sensitive to lodging history, positions of flanges, neighboring studs, position of prestress bar and reinforcing bar, concrete strength, etc. and also identified a shear influence area. Stud strength was also confirmed through pushout tests. The outcome obtained from the study may provide an important basis and reference data in designing connections of hybrid girders with enhanced stud capacity with due consideration of their long-term shear behavior.

Keywords: finite element, hybrid girder, shear connections, sustained loading, time dependent behavior

Procedia PDF Downloads 99

Authors: Daniela Istrati, Alina Morosan, Maria Stanca, Bogdan Purcareanu, Adrian Fudulu, Laura Olariu, Alice Buteica, Ion Mindrila, Rodica Cristescu, Dan Eduard Mihaiescu

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Our present work is related to the synthesis, characterization and applications of new nanocomposite materials based on silica mesoporous nanocompozites systems. The nanocomposite support was obtained by using a specific step–by–step multilayer structure buildup synthetic route, characterized by XRD (X-Ray Difraction), TEM (Transmission Electron Microscopy), FT-IR (Fourier Transform-Infra Red Spectrometry), BET (Brunauer–Emmett–Teller method) and loaded with Salvia officinalis plant extract obtained by a hydro-alcoholic extraction route. The sustained release of the target compounds was studied by a modified LC method, proving low release profiles, as expected for the high specific surface area support. The obtained results were further correlated with the in vitro / in vivo behavior of the nanocomposite material and recommending the silica mesoporous nanocomposites as good candidates for biomedical applications. Acknowledgements: This study has been funded by the Research Project PN-III-P2-2.1-PTE-2016-0160, 49-PTE / 2016 (PROZECHIMED) and Project Number PN-III-P4-ID-PCE-2016-0884 / 2017.

Keywords: biomedical, mesoporous, nanocomposites, natural products, sustained release

Procedia PDF Downloads 183

Authors: Camille Charlebois-Plante, Marie-Ève Bourassa, Gaelle Dumel, Meriem Sabir, Louis De Beaumont

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To the extent of our knowledge, there has been little interest in the chronic effects of mild traumatic brain injury (mTBI) on cognition during normal aging. This is rather surprising considering the impacts on daily and social functioning. In addition, sustaining a mTBI during late adulthood may increase the effect of normal biological aging in individuals who consider themselves normal and healthy. The objective of this study was to characterize the persistent neuropsychological repercussions of mTBI sustained during late adulthood, on average 12 months prior to testing. To this end, 35 mTBI patients and 42 controls between the ages of 50 and 69 completed an exhaustive neuropsychological assessment lasting three hours. All mTBI patients were asymptomatic and all participants had a score ≥ 27 at the MoCA. The evaluation consisted of 20 standardized neuropsychological tests measuring memory, attention, executive and language functions, as well as information processing speed. Performance on tests of visual (Brief Visuospatial Memory Test Revised) and verbal memory (Rey Auditory Verbal Learning Test and WMS-IV Logical Memory subtest), lexical access (Boston Naming Test) and response inhibition (Stroop) revealed to be significantly lower in the mTBI group. These findings suggest that a mTBI sustained during late adulthood induces lasting effects on cognitive function. Episodic memory and executive functions seem to be particularly vulnerable to enduring mTBI effects.

Keywords: cognitive function, late adulthood, mild traumatic brain injury, neuropsychology

Procedia PDF Downloads 143

Authors: Wee Tong Liaw, Elaine Wong Yee Sing

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Since 2001, many companies in Singapore have voluntarily participated in the bi-annual Singapore HEALTH Award initiated by the Health Promotion Board of Singapore (HPB). The Singapore HEALTH Award (SHA), is an industry wide award and assessment process. SHA assesses and recognizes employers in Singapore for implementing a comprehensive and sustainable health promotion programme at their workplaces. The rationale for implementing a sustained health promoting workplace and participating in SHA is obvious when company management is convinced that healthier employees, business productivity, and profitability are positively correlated. However, performing research or empirical studies on the impact of a sustained health promoting workplace on stock returns are not likely to yield any interests in the absence of a systematic and independent assessment on the comprehensiveness and sustainability of a health promoting workplace in most developed economies. The principles of diversification and mean-variance efficient portfolio in Modern Portfolio Theory developed by Markowitz (1952) laid the foundation for the works of many financial economists and researchers, and among others, the development of the Capital Asset Pricing Model from the work of Sharpe (1964), Lintner (1965) and Mossin (1966), and the Fama-French Three-Factor Model of Fama and French (1992). This research seeks to support the rationale by studying whether there is a significant relationship or impact of a sustained health promoting workplace on the performance of companies listed on the SGX. The research shall form and test hypotheses pertaining to the impact of a sustained health promoting workplace on company’s performances, including stock returns, of companies that participated in the SHA and companies that did not participate in the SHA. In doing so, the research would be able to determine whether corporate and fund manager should consider the significance of a sustained health promoting workplace as a risk factor to explain the stock returns of companies listed on the SGX. With respect to Singapore’s stock market, this research will test the significance and relevance of a health promoting workplace using the Singapore Health Award as a proxy for non-diversifiable risk factor to explain stock returns. This study will examine the significance of a health promoting workplace on a company’s performance and study its impact on stock price performance and beta and examine if it has higher explanatory power than the traditional single factor asset pricing model CAPM (Capital Asset Pricing Model). To study the significance there are three key questions pertinent to the research study. I) Given a choice, would an investor be better off investing in a listed company with a sustained health promoting workplace i.e. a Singapore Health Award’s recipient? II) The Singapore Health Award has four levels of award starting from Bronze, Silver, Gold to Platinum. Would an investor be indifferent to the level of award when investing in a listed company who is a Singapore Health Award’s recipient? III) Would an asset pricing model combining FAMA-French Three Factor Model and ‘Singapore Health Award’ factor be more accurate than single factor Capital Asset Pricing Model and the Three Factor Model itself?

Keywords: asset pricing model, company's performance, stock prices, sustained health promoting workplace

Procedia PDF Downloads 341

Authors: Aneesha Fonseca, Arij Daas, Muhammed Abdulkader

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Transient intraocular pressure (IOP) rise is a common occurrence after glaucoma laser procedures. However, this pressure spike usually lasts only a few days. We describe a case of a 60-year-old Caucasian gentleman who underwent selective laser trabeculoplasty (SLT) in both eyes for ocular hypertension previously treated with Bimatoprost and Timolol and developed a sustained raised IOP. His IOP rose from 34 and 33 mmHg pre-laser to 48 and 42 mmHg after SLT in the right and left eye, respectively. Even after maximum medical therapy (Bimatoprost, Timolol, Brinzolamide Apraclonidine, and oral Acetozolamide), his IOP remained at 32 and 28mmHg. A provisional diagnosis of trabeculitis was made, and topical Ketorolac was commenced in addition to the IOP-lowering medications. Within a week, his IOP came down to 21 and 18mmHg in the right and left eye, respectively.

Keywords: complications, selective laser trabeculoplasty, sustained pressure rise, trabeculitis

Procedia PDF Downloads 67

Authors: Sulaiman Yunus

Abstract:

The need for modeling response to urban fire disaster cannot be over emphasized, as recurrent fire outbreaks have gutted most cities of the world. This necessitated the need for a prompt and efficient response system in order to mitigate the impact of the disaster. Promptness, as a function of time, is seen to be the fundamental determinant for efficiency of a response system and magnitude of a fire disaster. Delay, as a result of several factors, is one of the major determinants of promptgness of a response system and also the magnitude of a fire disaster. Response Delay Model (RDM) intends to bridge the gap in urban fire disaster response system through incorporating and synchronizing the delay moments in measuring the overall efficiency of a response system and determining the magnitude of a fire disaster. The model identified two delay moments (pre-notification and Intra-reflex sequence delay) that can be elastic and collectively plays a significant role in influencing the efficiency of a response system. Due to variation in the elasticity of the delay moments, the model provides for measuring the length of delays in order to arrive at a standard average delay moment for different parts of the world, putting into consideration geographic location, level of preparedness and awareness, technological advancement, socio-economic and environmental factors. It is recommended that participatory researches should be embarked on locally and globally to determine standard average delay moments within each phase of the system so as to enable determining the efficiency of response systems and predicting fire disaster magnitudes.

Keywords: delay moment, fire disaster, reflex sequence, response, response delay moment

Procedia PDF Downloads 177

Authors: Yu-Chen Chang, Yen-Ping Peng, Wei-Yu Chen, Ku-Fan Chen

Abstract:

Contamination of soil and groundwater has become a serious and widespread environmental problem. In this study, sustained-release persulfate tablets were developed using persulfate powder and a modified cellulose binder for organic-contaminated groundwater remediation. Conventional cement-based persulfate-releasing materials were also synthesized for the comparison. The main objectives of this study were to: (1) evaluate the release rates of the remedial tablets; (2) obtain the optimal formulas of the tablets; and (3) evaluate the effects of the tablets on the subsurface environment. The results of batch experiments show that the optimal parameter for the preparation of the persulfate-releasing tablet was persulfate:cellulose = 1:1 (wt:wt) with a 5,000 kg F/cm2 of pressure application. The cellulose-based persulfate tablet was able to release 2,030 mg/L of persulfate per day for 10 days. Compared to cement-based persulfate-releasing materials, the persulfate release rates of the cellulose-based persulfate tablets were much more stable. Moreover, since the tablets are soluble in water, no waste will be produced in the subsurface. The results of column tests show that groundwater flow would shorten the release time of the tablets. This study successfully developed unique persulfate tablets based on green remediation perspective. The efficacy of the persulfate-releasing tablets on the removal of organic pollutants needs to be further evaluated. The persulfate tablets are expected to be applied for site remediation in the future.

Keywords: sustained-release persulfate tablet, modified cellulose, green remediation, groundwater

Procedia PDF Downloads 249

Authors: Rohan V. Ambekar, Shrirang N. Tande

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The present study estimates the seismic response reduction factor (R) of reinforced concrete special moment resisting frame (SMRF) with and without shear wall using static nonlinear (pushover) analysis. Calculation of response reduction factor (R) is done as per the new formulation of response reduction factor (R) given by Applied Technology Council (ATC)-19 which is the product of strength factor (Rs), ductility factor (Rµ) and redundancy factor (RR). The analysis revealed that these three factors affect the actual value of response reduction factor (R) and therefore they must be taken into consideration while determining the appropriate response reduction factor to be used during the seismic design process. The actual values required for determination of response reduction factor (R) is worked out on the basis of pushover curve which is a plot of base shear verses roof displacement. Finally, the calculated values of response reduction factor (R) of reinforced concrete special moment resisting frame (SMRF) with and without shear wall are compared with the codal values.

Keywords: response reduction factor, ductility ratio, base shear, special moment resisting frames

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Authors: Huai-Feng Wang, Meng-Lin Lou, Ru-Lin Zhang

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One good analysis method in seismic response analysis is direct time integration, which widely adopts Rayleigh damping. An approach is presented for selection of Rayleigh damping coefficients to be used in seismic analyses to produce a response that is consistent with Modal damping response. In the presented approach, the expression of the error of peak response, acquired through complete quadratic combination method, and Rayleigh damping coefficients was set up and then the coefficients were produced by minimizing the error. Two finite element modes of soil layers, excited by 28 seismic waves, were used to demonstrate the feasibility and validity.

Keywords: Rayleigh damping, modal damping, damping coefficients, seismic response analysis

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Authors: Krutika K. Sawant, Anil Solanki

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The present study deals with the preparation and optimization of ethyl cellulose-containing disopyramide phosphate loaded microspheres using solvent evaporation technique. A central composite design consisting of a two-level full factorial design superimposed on a star design was employed for optimizing the preparation microspheres. The drug:polymer ratio (X1) and speed of the stirrer (X2) were chosen as the independent variables. The cumulative release of the drug at a different time (2, 6, 10, 14, and 18 hr) was selected as the dependent variable. An optimum polynomial equation was generated for the prediction of the response variable at time 10 hr. Based on the results of multiple linear regression analysis and F statistics, it was concluded that sustained action can be obtained when X1 and X2 are kept at high levels. The X1X2 interaction was found to be statistically significant. The drug release pattern fitted the Higuchi model well. The data of a selected batch were subjected to an optimization study using Box-Behnken design, and an optimal formulation was fabricated. Good agreement was observed between the predicted and the observed dissolution profiles of the optimal formulation.

Keywords: disopyramide phosphate, ethyl cellulose, microspheres, controlled release, Box-Behnken design, factorial design

Procedia PDF Downloads 426