Formulation and in-vitro Evaluation of Nanosponge Loaded Extended Release Tablets of Trimethoprim

Abstract

Trimethoprim is an antibiotic primarily used in the treatment of bladder infections and urinary tract infections. Its low aqueous solubility leads to the poor oral bioavailability. In order to enhance its solubility, we prepared Trimethoprim Nanosponges loaded extended release tablets to delay the drug release at urinary tract. Nanosponges are tiny sponges with an average diameter below 1 μm and consist of cavities filled with drug molecules. Initially eight formulations of trimethoprim nanosponges were prepared by using ethyl cellulose as entrapping agent, dichloromethane as cross linking agent in various proportions and evaluated for powder flow properties, % yield, entrapment efficiency, morphology, zeta potential, particle size and in-vitro drug release characteristics. Based on the evaluation results, formulation F4 was selected to prepare six extended release tablet formulations by using HPMC K100M and HPMC K15M as extended release polymers. All six formulations were evaluated for thickness, hardness, friability, % drug content and in-vitro drug release. From the results, it was found that all the evaluation results are within IP limits and all formulations showed maximum drug release of 98.43 ± 0.1% at the end of 10 h. From this study, we concluded that nanosponge loaded extended release tablets of trimethoprim showed delayed drug release upto 10 h with enhanced solubility and dissolution. Hence, nanosponge technique will be a challenging approach for enhancing the solubility of poorly soluble drugs.