Formulation and Evaluation of Depot Parenteral Preparations for a Combination of Norfloxacin and Tinidazole

Norfloxacin and tinidazole in combination are used as antibacterial and antidiarrhoeal agents, respectively. In the treatment of bacterial infections, factors of paramount importance are to maintain the therapeutically optimum drug concentration in the plasma and eliminate the need for frequent dose administration. In the present investigation, an attempt was made to design microspheres loaded with norfloxacin and tinidazole intended for parenteral administration. Biodegradable, non-toxic polymers viz., bovine serum albumin (BSA) and chitosan were used to form microspheres. Microspheres were prepared using the chemical cross-linking method. Glutaraldehyde-saturated toluene (GST) was employed as the crosslinking agent. Various process parameters, like drug:polymer ratio, did not effect the mean particle size or particle size distribution to a significant extent and relatively a narrow particle size distribution was obtained. Entrapment efficiency of the albumin microspheres for both the drugs was more than the corresponding chitosan microspheres. Results of in vitro release studies indicate a biphasic release pattern characterized by a initial burst-effect followed by a slow release over a period of 12 to 24 h.