Formulation and characterization of agar based aerogels as potential implantable controlled drug delivery system.

Introduction: Agar-based aerogels have emerged as promising candidates for implantable drug delivery systems due to their tunable porosity, mechanical properties, and biocompatibility. Methods: Agar aerogels were prepared at varying concentrations (2, 2.5, 3, and 3.5% w/v) and loaded with caffeine as a model drug using preloading and post-loading techniques. The formulations were characterized for mechanical strength, porosity, swelling behavior, drug content distribution, and in vitro release profiles. Raman mapping and HPLC analysis were employed to evaluate drug distribution and quantification. Results: Increasing agar concentration significantly enhanced mechanical strength while reducing porosity and swelling capacity. Preloaded aerogels demonstrated improved mechanical stability, whereas post-loaded aerogels exhibited reduced strength with increasing loading volume. Drug distribution was more homogeneous at lower agar concentrations and moderate drug loadings. All formulations exhibited biphasic release profiles, with an initial burst release followed by sustained release, influenced by agar concentration, drug loading, and loading method. Discussion: Optimized formulations, particularly preloaded aerogels with 5% caffeine and post-loaded aerogels with 1% caffeine at controlled volumes, demonstrated desirable mechanical and release characteristics. These findings highlight the potential of agar-based aerogels as versatile and tunable systems for localized controlled drug delivery.