ABSTRACT
Objective: To evaluate the antibacterial effectiveness of 34 competitive Ofloxacin products representing 31 manufacturers available in the local market, on 3 standard Quinolone-sensitive American Type Culture Collection [ATCC] bacterial cultures of E.coli, Proteus vulgaris and Staphylococcus aureus
Design: A blind assessment of 29 Ofloxacin brands in tablet form, and 5 in pre-mixed injectable solution collected by The Network for Consumer Protection in Pakistan, Islamabad, with trade and manufacturers names of the products veiled by blanking
Setting: The appraisal was conducted in Karachi at the Department of Microbiology, Jinnah University for Women, and Dr. Essa's Lab and Diagnostic Centre, in March 2003
Method: Direct aqueous suspensions along with 3 additional serial dilutions of each product were used to challenge the 3 target bacteria by the disc-diffusion method. The resultant inhibition-zone diameters were recorded for comparison of antibacterial activity
Results: Comparatively effective but varying antibacterial results were seen using Proteus and Staph aureus; however, alarming differences were recorded when E.coli was targeted. With this organism, excellent inhibition zone diameters were observed with Eracin [CCL], Ofloxacin [Shin Poong], Oflobid [Hilton] and Oflobiotic [Zafa]; others gave good, moderate or poor zones, while 4 shockingly exerted no visible effect: these included 3 single-vial injectable suspensions purported to represent Brookes [Quinon], Bosch [Tariflox] and Hoechst/Aventis [Tarivid], and the GlaxoSmithKlein's tablet Floxy
Conclusion: A significant variation in antibacterial activity of marketed Ofloxacin brands, some representing pharmaceutical giants, demonstrated by simple disc diffusion zone diameter comparison raises serious questions whether the less effective ones obtained in Islamabad and also purchased in Karachi for comparison were flawed, counterfeit or sub-standard preparations