Penetration Enhancement of Topical Formulations

The special issue titled "Penetration Enhancement of Topical Formulations" presents research on overcoming the challenges of drug delivery through human skin, focusing on the stratum corneum as the primary barrier. Small, moderately lipophilic molecules penetrate the skin well, while other drugs may require penetration enhancers, such as chemical or physical methods, to improve efficacy. One study by Martin et al. evaluated topical gabapentin formulations with various chemical penetration enhancers, finding that a proprietary Lipoderm® base was the most clinically relevant. Another study by Abd et al. investigated targeted delivery of minoxidil for hair loss treatment using nanoemulsions with oleic acid and eucalyptol as penetration enhancers, showing significant retention in skin layers and hair follicles. Conversely, Montenegro et al. highlighted the need for careful selection of excipients in sunscreen formulations to limit skin penetration and avoid toxicity. The issue emphasizes the importance of tailoring topical formulations to their specific applications and the potential of these insights to benefit those working with other biological barriers.