Microencapsulation of Diclofenac Sodium by Nonsolvent Addition Technique

Purpose: To prepare, using non-solvent addition technique, diclofenac sodium-ethylcellulose microparticles with modified drug release properties.Methods: Microparticles were prepared by non-solvent addition phase separation method and characterized by micromeritics, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), dissolution test and thermal analysis.Results: The microparticles were whitish, irregular, aggregated, and in the size range of 390 - 442 μm size. Drug embedment efficiency was 89 - 91 %. Characterisation studies indicate that there was no strong chemical interaction between the drug and the polymer in the microparticles. Polymer concentration and sustained release behavior were directly proportional.Conclusion: Non-solvent addition phase separation is a suitable method for preparing diclofenac sodium-ethylcellulose multi-unit controlled release drug delivery system.Keywords: Phase separation, Diclofenac sodium, Ethylcellulose, Non-solvent addition, Characterisation

Transcranial direct current stimulation and stroke recovery: opportunities and challenges

Transcranial direct current stimulation (tDCS) is one type of neuromodulation, which is an emerging technology that holds promise for the future studies on therapeutic and diagnosis applications in treatment of neurological and psychiatric diseases. However, there is a serious question among developing countries with limited financial and human resources, about the potential returns of an investment in this field and regarding the best time to transfer this technology from controlled experimental settings to health systems in the public and private sectors. This article reviews the tDCS as tools of neuromodulation for stroke and discusses the opportunities and challenges available for clinicians and researchers interested in advancing neuromodulation therapy. The aim of this review is to highlight the usefulness of tDCS and to generate an interest that will lead to appropriate studies that assess the true clinical value of tDCS for brain diseases in developing countries. Methods: Literature review was done on PubMed from 2016 on neuromodulation in under-developed countries (UDCs) by non-invasive brain stimulation methods, using the key words “stroke”, “rehabilitation”, and “tDCS”. Results: We first identified articles and websites, of which were further selected for extensive analysis mainly based on clinical relevance, study quality and reliability, and date of publication. Conclusion: Despite the promising results obtained with tDCS in basic and clinical neuroscience, further progress has been impeded by a lack of clarity to use in mostly UDCs

Pharmacokinetic Study of Nifedipine in Healthy Adult Male Human Volunteers

Purpose: To evaluate the pharmacokinetics of nifedipine in healthy adult Pakistani subjects. Methods: Each of six fasting volunteers received 20 mg nifedipine (2 x Adalat® 10 mg capsules) orally once and then another one week later. Their blood samples were obtained at regular time intervals and analysed by HPLC. Using the non-compartmental approach, plasma levels of nifedipine were employed to compute their individual disposition kinetics, including Cmax (maximum plasma concentration), Tmax(time to reach maximum plasma concentration), MRT (mean residence time), AUC0-∞ (area under curve), AUMC0-∞ (area under first moment curve) and Ka (absorption rate constant). Results: The suggested therapeutic level of nifedipine for the treatment of hypertension (15-35 ng.mL-1) was achieved in all six volunteers within 0.25 h after dose administration, and maintained for more than 6 h. Tmax was 1.58 h and Cmax varied from 140 – 300 ng.mL-1. Mean absorption rate constant was 2.22 h-1 while mean absorption half-life was 0.43 h. The mean elimination rate constant was 0.16 h-1 while 5.7 h was recorded for terminal half-life. AUC0-¥, AUMC0-¥ and MRT were 1879.86 ng.h.mL-1, 8244.04ng.h2.mL-1 and 4.2 h, respectively. Conclusion: This study confirms the rapid absorption of nifedipine in humans. AUC was similar to thatpreviously reported for Nigerians but slightly lower than that stated in the literature for other south Asian races. Further studies on large segments of the local population using the non-compartmental model forkinetic analysis is recommended

Pharmacokinetic Studies on Metoprolol - Eudragit Matrix Tablets and Bioequivalence Consideration with Mepressor®

Purpose: To investigate the pharmacokinetics of of a developed metoprolol and a reference standard (Mepressor®).Methods: Metoprolol tartrate-loaded Eudragit® FS microparticles were formulated and compressed into tablets. The tablets were tested for their physicochemical properties according to United States Pharmacopoeia (USP) criteria. In vivo studies of the formulations were carried out in 28 young healthy fasting male volunteers based on a randomized open label 4×4 crossover study design with a washout period of 7 days.Results: In vitro tests showed that the developed and reference standard of metoprolol tablets met compendia (USP) requirements. Zero order release of drug was observed from all the tablets. In vivo data demonstrated that there were significant (p < 0.05) differences in tmax, Cmax, MRT, AUC0−t, and AUC0–∞ between the reference and test (developed) formulations. However, the 90 % class interval for the mean ratios of the ln-transformed Cmax, AUC0-t and AUC0-α for the reference, T1, T2, and T3 lied in the bioequivalence range (80 to 125 %) indicating bioequivalence between the compared formulations.                  Conclusion: It can be concluded from this single-dose study that the reference and test (developed) formulations met the predetermined criteria for bioequivalence in young healthy fasting male human subjects as the bioequivalence factor lie in the pre-determined limits for bioequivalence. Thus, the two formulations can be considered bioequivalent.Keywords: Metoprolol tartrate, Eudragit® FS, Microparticles, Bioavailability, Pharmacokinetics

Effect of compost addition on arsenic uptake, morphological and physiological attributes of maize plants grown in contrasting soils

Contamination of soils with arsenic (As) represents a global environmental and health issue considering the entrance of toxic As in the human food chain. Although partially understood, addition of compost for the remediation of As-contaminated soils may result in distinct effects on plant growth and physiological attributes depending on compost-mediated potential mobility/sequestration of As in soils. This study explores the role of compost addition (C; 0, 1 and 2.5%) on morphological and gas exchange attributes and photosynthetic pigments (chlorophyll contents) of maize plants under As stress (0, 40, 80, 120 mg kg− 1), as well as soil As immobilization/mobilization in a pot experiment, using two contrasting soils. Results revealed that, in Narwala (sandy loam) soil, the addition of compost decreased shoot As concentration of maize plants (p < 0.05; 4.01–13.7 mg kg− 1 dry weight (DW)), notably at C2.5 treatment, with significant improvement in shoot dry biomass, gas exchange attributes and chlorophyll (a and b) contents, i.e., 1.33–1.82, 1.20–2.65 and 1.34–1.66 times higher, respectively, over C0 at all As levels. Contrastingly, in Shahkot (clay loam) soil, C2.5 treatment increased shoot As concentration (p < 0.05; 7.02–17.3 mg kg− 1 DW), and as such reduced the shoot dry biomass, gas exchange attributes and chlorophyll contents, compared to the control – rather C1 treatment was more effective and exhibited positive effect than C2.5. Considerably, at C2.5 treatment, phosphate extractable (bioavailable) soil As concentration was also found to be greater in the (post-experiment) Shahkot soil than that of Narwala soil (0.40–3.82 vs. 0.19–1.51 mg kg− 1, respectively). This study advanced our understanding to resolve the complex compost-As interactions in As-contaminated soils, which are imperative to understand for developing the effective and soil-specific remediation strategies

Structural and magnetic properties of co-nd substituted znfe2o4 ferrites synthesized by co-precipitation technique

A series of Zn1-xCoxNdyFe2-yO4 spinel ferrites (x=0,0-0.5, y=0.00-0.10) was synthesized using the co-precipitation method sintered at 1000oC. Synthesized Ferrites were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometery (VSM). The diffraction patterns show the formation of the spinel phase along with some traces of second phase Nd2O3. The lattice constant decreases with increasing Co-Nd ions because of the solubility of Nd3+ into the spinel lattice. SEM shows the decrease of the grain size with the increase of Co-Nd contents due to the fact that the second phase inhibits the growth of grain. VSM results show increasing trends of remanence and saturation magnetization due to the strengthening of the A-B sublattice interactions. The coercivity shows an increasing behaviour with the increase of co-substitutent contents

Formulation and characterization of modified release tablets containing ionizid using swellable polymers

The aim of this work was to develop swellable modified release (MR) isoniazid tablets using different combinations of polyvinyl acetate (PVAc) and sodium-carboxymethylcellulose (Na-CMC). Granules were prepared by moist granulation technique and then compressed into tablets. In vitro release studies for 12 hr were carried out in dissolution media of varying pH i.e. pH 1.2, 4.5, 7.0 and 7.5. Tablets of all formulations were found to be of good physical quality with respect to appearance (width and thickness), content uniformity, hardness, weight variation and friability. In vitro release data showed that increasing total polymer content resulted in more retarding effect. Formulation with 35% polymer content exhibited zero order release profile and it released 35% of the drug in first hr, later on, controlled drug release was observed upto the 12th hour. Formulations with PVAc to Na-CMC ratio 20:80 exhibited zero order release pattern at levels of studied concentrations, which suggested that this combination can be used to formulate zero order release tablets of water soluble drugs like isoniazid. Korsmeyer-Peppas modeling of drug release showed that non-Fickian transport is the primary mechanism of isoniazid release from PVAc and Na-CMC based tablets. The value of mean dissolution time decreased with the increase in the release rate of drug clearly showing the retarding behavior of the swellable polymers. The application of a mixture of PVAc to Na-CMC in a specific ratio may be feasible to formulate zero order release tablets of water soluble drugs like isoniazid.Keywords: Isoniazid, Polyvinyl acetate, Sodium-carboxymethylcellulose, Modified release tablets

Development of a single combined microencapsulated formulation of allopurinol and nimesulide and investigation of their release behaviours

The aim of this study was to develop a single combined once-daily sustained release microencapsulated dosage form of Allopurinol and Nimesulide using Ethyl cellulose as release controlling factor and to evaluate drug release parameters as per various release kinetic models. In order to achieve required sustained release profile, microparticles were prepared using coacervation thermal change technique. The formulated microparticles were also characterized by physical and chemical parameters and results were found in acceptable limits. Different dissolution models were applied to drug release data in order to evaluate release mechanisms and kinetics. The drug release data fit well to the Higuchi expression. Drug release mechanism was found as a complex anomalous one

Role of a probiotic (Saccharomyces boulardii) in management and prevention of diarrhoea

AIM: To assess the efficacy and safety of Saccharomyces boulardii (S. boulardii) in acute watery diarrhoea and its role in reducing the frequency of episodes of diarrhoea in subsequent two months.Methods: Children from 2 mo to 12 years of age, with acute diarrhoea were selected according to inclusion criteria and randomised in S. boulardii group (treated with ORS, nutritional support and S. boulardii, 250 mg bid) and in control group (treated with ORS and nutritional support only). Active treatment phase was 5 d and each child was followed for two months afterwards. Frequency and consistency of stools as well as safety of drug was assessed on every visit. A comparison of two groups was done in terms of number of diarrhoeal episode in subsequent two months.Results: There were fifty patients in each group. Baseline characteristics such as mean age and the average frequency of stools were comparable in S. boulardii and control group at the time of inclusion in the trial. By d 3 it reduced to 2.7 and 4.2 stools per d respectively and by d 6 it reduced to 1.6 (S. boulardii Group) and 3.3 (control group). The duration of diarrhoea was 3.6 d in S. boulardii group whereas it was 4.8 d in control group (P = 0.001). In the following two months, S. boulardii group had a significantly lower frequency of 0.54 episodes as compared to 1.08 episodes in control group. The drug was well accepted and tolerated. There were no reports of the side effects during treatment period.Conclusion: S. boulardii significantly reduces the frequency and duration of acute diarrhoea. The consistency of stool also improves. The drug is well-tolerated