Antibacterial effects of nine brands of ciprofloxacin tablets available in Dar es Salaam

Abstract

Nine brands of ciprofloxacin tablets available in Dar es Salaam City were assayed for antibacterial effects against three strains of bacteria namely Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli using the Kirby-Bauer disc diffusion method. The ciprofloxacin brands were randomly coded with letters A to I for commercial protection. The sampled tablets were pulverized and dissolved in 0.1M HCl. At 0, 15, 30, 45 and 90 min, and 24 h, 20 μl aliquots were drawn and embedded onto 5 mm diameter Whatman filter papers. Equal volume of 0.1M HCl and commercially available ciprofloxacin disc (1 μg) were used as negative and positive controls, respectively. Results of the zones of inhibition at time 0 showed that none of the brands had comparable antibacterial effects as the positive control. The zones of inhibition produced by 3 brands (D, H and I) against E. coli were below specified limits (30-40 mm) at all assay times. The antibacterial effects of ciprofloxacin brands against S. aureus were only significant at 24 h. Brand A, which was the most expensive, exhibited the most potent antibacterial effect against test bacteria. Positive correlation between antibacterial effect and price was observed (R = 0.119; p = 0.290). High prevalence (44.4%) of poor quality ciprofloxacin tablets was observed. We recommend enforcement of post-market surveillance of medicines and more stern measures be imposed to prevent entry of poor quality drugs into Tanzania.

Keywords: Antibacterial effect, inhibition zone, poor quality drugs