Formulation and Evaluation of Microspheres Based on Gelatin-Mucin Admixtures for the Rectal Delivery of Cefuroxime Sodium

Purpose: Swellable microspheres based on polymers or their admixtures are frequently employed as drug delivery systems to achieve a controlled release and site-specific targeting of the incorporated drug. The objective of the present study was to enhance the rectal delivery of cefuroxime sodium by entrapping it into water-swellable gelatin-mucin microspheres. Method: Cefuroxime sodium-loaded microspheres containing admixtures of gelatin and porcine mucin were prepared via an emulsification-crosslinking technique. The drug entrapment efficiency of the microspheres was evaluated in citrate/phosphate buffer (pH 7.4) while the swelling properties was evaluated in both simulated gastric fluid (SGF) without pepsin and simulated intestinal fluid (SIF) without pancreatin (pH 1.2). Release of cefuroxime sodium from the microspheres was evaluated in vitro in SIF and further evaluated in vivo after rectal administration to male Wistar rats. Result: Results obtained showed that a high entrapment efficiency, most notably manifested in microspheres formulated with equal portions of gelatin and mucin, led to a high release (up to 85 %) and also a high bioavailability of the incorporated drug. Formulations based on varying portions of gelatin and mucin also showed high drug loading efficiency which also resulted in high drug release in SIF within 3 h. Drug release from the different formulations was observed to be rapid and generally showed a biphasic pattern. The mean AUC was shown to be formulation-dependent with values of 168±1.93μg.h/ml for the control, 262±3.47 μg.h/ml for microspheres based on gelatine only and 328±2.55 μg.h/ml for microspheres formulated with equal parts of gelatin and mucin. Conclusion: The inclusion of S-mucin in the composition of the microspheres has an enhancer effect on the release and rectal bioavailability of cefuroxime sodium which may be exploited in the design of a rectal delivery system of the drug.