Effect of various formulation factors on spreadability and release properties of caffeine from carbopol gels

The objective of this study was to prepare acceptable carbopol gels and to evaluate the factors influencing the spreadability and release properties of a model hydrophilic compound (caffeine). Results were analyzed statistically using student t-test. The gels were transparent at 1 and at 2% caffeine (with alcohol). Spreadability was decreased when carbopol was increased and when caffeine quantity was changed (except at 2% carbopol). Spreadability was affected statistically with change of cosolvent. Released caffeine quantity (%) was increased with decreasing of carbopol quantity and increasing of caffeine quantity introduced in the formula. Total caffeine quantity (%) was decreased with alcohol presence. Caffeine release followed Higuchi pattern, e.g. diffusion was the principal mechanism of caffeine release from these formulas.