Studies on the Efficacy of Methyl Esters of N-Alkyl Fatty Acids as Penetration Enhancers

In 1989, a study was conducted to assess the effectiveness of methyl esters of medium chain n-alkyl fatty acids, particularly methyl nonanoate and methyl caprate, as skin penetration enhancers for drugs, using minoxidil as a test drug. The study found that a 10% concentration of these esters significantly increased the absorption of a 2% minoxidil solution through animal and human skin, by 5-8 times compared to a control solution. Methyl caprate was effective across various skin types and with different substances, including vitamin D3, erythromycin, and testosterone. The study concluded that methyl caprate is an ideal penetration enhancer due to its effectiveness at low concentrations, non-irritating nature, and pharmacological inertness. It was also found to be more effective than other enhancers like Azone, DMSO, and DEET. The mechanism is believed to involve the disruption of lipid layers in the skin, facilitating drug penetration.