Pharmaceutical Evaluation and Microbiological Properties of Three Brands of Tobramycin Eye Drops Marketed in Retail Pharmacies of Al-Bayda, Libya

Background: Tobramycin (TBM) is a water-soluble aminoglycoside antibiotic in various formulations, including ophthalmic solutions. It has been demonstrated to be effective against numerous ocular pathogens. Objectives: This study aimed to determine the pharmaceutical and microbiological efficiency of three brands of tobramycin eye drops sold in retail pharmacies in Al-Bayda, Libya. Materials and Methods: Three sterile eye drops from different tobramycin brands sourced from the Al-Bayda market in Libya were analyzed. The physical appearance of each brand was assessed for packaging and closure integrity. Pharmaceutical analyses (color and clarity evaluation, pH), sterility testing, antibacterial activity, and antimicrobial effectiveness were conducted by inoculating nutrient agar and Sabouraud dextrose medium with each eye drop brand. Results: The findings showed that all brand packaging adheres to proper sealing standards with intact container closures. The labels complied with FIP guidelines for prescribed medicines. All brands were transparent and particle-free when examined against white and black backgrounds, respectively. The pH values for brands A, B, and C were 6.88, 6.91, and 6.90, respectively, matching the tear fluid's physiological pH. The refractive indices were 1.335, 1.334, and 1.334 for brands A, B, and C, respectively, consistent with tear fluid. Sterility tests indicated no microbial growth, and the preservatives were effective against Escherichia coli, Staphylococcus aureus, and Candida albicans. Conclusion: This preservative system confers resistance to microbial contamination during its utilization. Further clinical investigations are necessary to assess the safety and long-term effectiveness of these pharmaceutical agents.