By Arunprasad Sivaraman and Ajay K. Banga
Transdermal patches play a major role in dermatological drug delivery. The route of transdermal delivery is the most sought after the oral and parenteral routes. Although the active transdermal techniques are looming, the transdermal patches with their already established regulatory pathway are a major player with a larger margin of profit than other transdermal dosage forms. The use of matrix-based transdermal patches is expanding—unlike that of reservoir transdermal patches—because of their simplicity in preparation and acceptability by the patients.
Individuals who have difficulty taking oral medications or do not have intravenous access can benefit from transdermal patches. Chronic pain, which can persist for weeks, months, and even years, affects around 100 million Americans. In our research, we tested a semi-synthetic opioid that can treat moderate to severe pain but undergoes extensive first-pass hepatic metabolism; hence the drug has very low oral bioavailability. In our lab, we developed a 72 hour matrix transdermal patch using a novel dissolved-drug-dispersion (DDD) technique and evaluated the permeation of the drug using human dermatomed skin.
Generally, increased drug loading in the adhesive matrix of the transdermal patch is an essential requirement to provide sustained drug delivery. In our study, the drug couldn’t be dissolved in the silicone adhesive, which was the preferred adhesive to use especially in our study. The novel DDD technique used here allowed the drug to be in the dissolved state in the silicone matrix with the use of amphiphilic solvent and provided sustained drug delivery. The drug was dissolved in the amphiphilic solvent, and the drug-loaded solvent was dispersed evenly in the silicone adhesive matrix. The prepared matrix transdermal patch showed the formation of emulsion where the amphiphilic solvent with the dissolved drug was dispersed evenly in the silicone matrix. The developed matrix transdermal patch using the novel DDD technique allowed the drug in dissolved state within the silicone matrix by use of amphiphilic solvent and provided sustained drug delivery for 72 hours. This novel technique may provide an alternative way to develop a matrix transdermal patch and eliminate the solubility issue for drugs that cannot be solubilized in the silicone adhesive.
This work was presented and awarded both at the 34th Annual Graduate Research Association of Students in Pharmacy (GRASP) and at the 2015 AAPS Annual Meeting and Exposition.