Caffeine Topical Gel Formulation

Abstract

Caffeine was used topically as one of many ingredients in various cosmetic preparations for reducing under-eye puffiness and dark circles. Gels containing 3% w/w caffeine as an active ingredient were prepared in this study. Suitable co-solvent systems and gel-forming concentrations were studied. Their effects on caffeine release from formulation were also studied. Suitable gel formulations consisted of carbopol Ultrez-21 as a gel-forming agent and propylene glycol (PG) as a co-solvent. The result showed that the increased concentration of Carbopol Ultrez-21, affected the formulation and thereby giving higher viscosity. However, all concentrations Carbopol Ultrez-21 studied (0.2%, 0.5%, 1%, 2% and 4%) did not affect caffeine release significantly. The percentage of PG in the formulation greatly affected caffeine release. Formulation containing 15% and 30% w/w PG gave release rate from Higuchi’s equation of 2.47 ± 0.26 mg/cm²/h½ and 2.37 ± 0.17 mg/cm²/h½, respectively which were lower when compared to release rate of 2.67 ± 0.07 mg/cm²/h½ from formulation containing 7.5% w/w PG. The best formulation of caffeine gel with good physical appearance and good release rate comprised of 3% caffeine, 0.5% carbopol Ultrez-21 and 7.5% PG.