Simvastatin and Captopril Combined Transdermal Delivery System for Controlling Blood Pressure and Fat: Design, Characterization, and In Vivo Pharmacokinetic Evaluation

We developed a sustained-release transdermal drug delivery system (TDDS) containing simvastatin (SIM) and captopril (CAP) to treat hypertension and hyperlipidemia and overcome treatment drawbacks, including significant liver first-pass effects, low bioavailability, and the short half-life of SIM and CAP oral tablets. We used a transdermal diffusion meter to preselect the formula of the SIM-CAP TDDS. Based on in vitro permeation experiments, we optimized the formula of the SIM-CAP TDDS to include 24% SIM, 24% CAP, 34% polyvinyl alcohol (PVA), 16% oleic acid (OA)–azone, and 2% polyacrylic acid resin II. We evaluated the optimized SIM-CAP TDDS formula by its appearance, stability, stickiness, drug content, in vivo pharmacokinetics, and skin irritation tests. The results indicated that the patch had good stability and stickiness. The SIM and CAP contents were 5.02 ± 0.41 mg/cm2 in the 1 cm2 SIM-CAP TDDS. The pharmacokinetic results indicated that the system continuously released SIM and CAP for 24 h and significantly enhanced their bioavailability, with a higher area under the curve. The SIM-CAP TDDS exhibits a sustained-release effect with good characteristics and pharmacokinetics. And it is safe and has no irritating effects on the skin; therefore, it is an ideal formulation.