In vitro comparative evaluation of co-trimoxazole tablet products obtained from drug retail outlets in Addis Ababa

  • Haymanot Assefa
  • Seid Ibrahim
  • Tsige Gebre-Mariam Department of Pharmaceutics, School of Pharmacy, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia


Bacterial resistance to trimethoprim-sulphamethoxazole is a rapidly increasing problem and is exacerbated by use of substandard products. In this work, it is aimed to evaluate the physical properties and the dissolution profiles of trimethoprim-sulphamethoxazole tablets which were obtained from drug retail outlets in Addis Ababa and produced by ten different manufacturers. Accordingly, the different tablets were evaluated for physical properties (diameter, thickness, hardness, and friability and disintegration time) and their dissolution profiles were compared by the USP XXVI paddle method. The very long t90% values of Cotreich and Cotrimol (60 & 45 min, respectively) for trimethoprim, the very long t50% & t90% values of Cotreich (38 and >60 min, respectively) for trimethoprim and sulphamethoxazole, and the very long t90% values of Cotreich, Cotrimol and Kanprim (>60 min) for sulphamethoxazole indicate that these products could result in lower rate and extent of bioavailability in the body. Similar problems could be encountered with the relatively long t90% values of cotrimoxazole (45 min) and Oriprim (40 min) for sulphamethoxazole. The smaller amount of sulphamethoxazole and trimethoprim released from products with delayed release could compromise the in vivo efficacy of these tablets.

Keywords: co-trimoxazole, tablet, dissolution, formulation parameters, process parameters

Ethiopian Pharmaceutical Journal Vol. 24, 2006: 31-40

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eISSN: 1029-5933