Design and Characterization of Polymer-Based Nasal In Situ Gelling Systems for Sustained Release of an Antihypertensive Drug

ABSTRACTThe present study aimed to develop and characterize a polymer-based nasal in situ gelling system forsustained delivery of Propranolol Hydrochloride, an antihypertensive drug associated with extensivefirst-pass metabolism, low oral bioavailability, and a relatively short biological half-life. Fiveformulations (F1–F5) were prepared using thermosensitive polymers, Poloxamer 407 and Poloxamer188, in combination with the mucoadhesive polymers Carbopol 934 and HPMC K100M. Theformulations were evaluated for appearance, pH, drug content, gelation temperature, gelation time,viscosity, mucoadhesive strength, in vitro drug release, drug–excipient compatibility, and morphology.All formulations were clear and showed pH values within the nasal physiological range. Increasingpolymer concentration decreased gelation temperature and increased viscosity and mucoadhesivestrength. The optimized formulation F5 exhibited gelation at 32.8 ± 0.2°C within 20 ± 1 seconds, drugcontent of 98.1 ± 0.3%, and the highest mucoadhesive strength (1320 ± 20 dynes/cm²). F5 alsoprovided controlled drug release, with 93.5% cumulative release over 12 hours. Release kineticanalysis indicated predominately diffusion-controlled behavior, with the Higuchi model providing thebest fit. FTIR analysis indicated no significant drug–excipient incompatibility, while SEMdemonstrated a uniform porous polymeric network. These findings indicate that the optimizedpolymer-based nasal in situ gel may provide a promising platform for sustained intranasal delivery ofPropranolol Hydrochloride.