COMPARATIVE IN VITRO EVALUATION OF DIFFERENT BRANDS OF NIFEDIPINE 20mg RETARD TABLET PRODUCTS MARKETED IN ADDIS ABABA, ETHIOPIA

Nifedipine has been formulated and marketed as extended-release-film coated tablet. A certain degree of success has been achieved in reducing the incidence of adverse effects by the use of slow-release formulations such as nifedipine retard. The aim of the present study was to evaluate the physicochemical quality attributes and in vitro equivalence of six brands of nifedipine retard tablets available in different retail outlets in Addis Ababa, Ethiopia. After constructing the calibration curve, the in vitro drug release studies were carried out using USP type I dissolution apparatus at 100 rpm. The dissolution was done in a medium of 0.1N HCl containing 0.5% sodium lauryl sulfate for 12 hrs. All the tablets met the requirement for tablet weight uniformity. The mean crushing strengths of sample tablets ranged from 49.2 to 111.2 N. All the brands  studied released more than 80% within 12 hours which is within the tolerance limit.  However the release profile revealed that five of the brands showed over 15% drug release at 1st hour except product F which released only 14.32%. In conclusion, all the brands of tablets had uniform thickness and good hardness. Despite all the brands could sustained the release for over 12 hours recommended for such formulations, five of them showed higher release in the first hour which may affect their in vivo performance.†Keywords: nifedipine, retard tablets, physicochemical properties, crushing strengths, in vitro drug releas

COMPARATIVE IN VITRO EVALUATION OF BRANDS OF CLOTRIMAZOLE CREAM FORMULATIONS MARKETED IN ETHIOPIA

The aim of present work was to undertake comparative in vitro quality evaluation of six marketed clotrimazole cream formulations in Ethiopia with respect to physico-chemical properties like viscosity, spreadability, extrudability, pH and drug content. In vitro clotrimazole release from cream formulations was also studied using synthetic cellulose acetate membrane at 37 ºC in a solvent containing methanol and PBS 7.4 in the ratio of 75:25 as receiver medium. The cumulative amounts of the drug released over 12 h (µg mm-2) were analyzed. All clotrimazole cream formulations showed good and smooth homogeneous appearance with white color. The pH of clotrimazole cream formulations ranged from 4-7, which is a physiologically acceptable pH range and in principle devoid of any skin irritation. Clotrimazole content ranged from 90-110%, ensuring the uniformity of the drug content in all formulations. The increase in diameter of clotrimazole cream formulations following the spreadability test was found to range from 4-6 cm. Cream formulation D (Clotri-Denk) exhibited highest viscosity values than other formulations, whereas formulation E (Chinese Clotrimazole BP) showed lowest viscosity value. Cream formulation F (Mycoril) showed better extrudability and spreadability as compared to other formulations. Drug release from all formulations was slow in the first 6 hrs. After the 6th hr, steady drug release continued for formulation D and E. Fast drug release was observed in formulations A (Candid) and B (Candigen), whereas for the formulations C (Canesten), D and E, steady drug release pattern was observed after the 6th hr. It can be concluded that all clotrimazole cream formulations fulfilled the quality criteria of in-house and pharmacopeias specifications. Keywords: In Vitro Evaluation, Clotrimazole, Cream, Spreadability, Extrudability, Ethiopi