Formulation and Characterization of pH Induced in situ Gels Containing Sulfacetamide Sodium for Ocular Drug Delivery: A Combination of Carbopol®/ HPMC Polymer

Introduction: Topical delivery of eye drops which currently accounts to 90% of available ocular dosage forms are ideal for the treatment of eye diseases but having limitations of poor therapeutic response and low bioavailability. Objectives: The objectives of present research was to develop and characterize sustained release in situ ocular gels containing sufacetamide sodium using pH induced gelling polymers for improved therapeutic response and patient compliance. Methods: In situ gel formulations prepared by dispersion method using Carbopol® 940/Carbopol® 934 alone or in combination with hydroxypropyl methylcellulose (HPMC E4M). Formultaions were evaluated for appearance, pH, viscosity, gelling capacity, drug content and in vitro drug release. The optimized formulation was assessed for sterility and antimicrobial efficacy using disk diffusion technique in comparison to commercial eye drops (Albucid® 10%). Results: The appearance of in situ gels were clear and free flowing in nature however, a viscous clear solution with no flow was produced for formulations consisting of 0.8% w/v Carbopol® 940/Carbopol® 934 and 2% w/v HPMC E4M. pH of all the formulations was within the range of 5.9 to 6.7. In situ gels with Carbopol® 940 demonstrated higher viscosity compared to Carbopol® 934 and drug release was sustained over a period of 8 hr. The selected formulation containing 0.8% w/v Carbopol® 940 and 1.5% w/v HPMC E4M passed sterility test and demonstrated similar antimicrobial efficiency compared to commercial product. Conclusion: Carbopol® /HPMC-based in situ gels have potential to improve patient’s compliance by reducing the dosing frequency and could be a viable alternative to commercial product.