Topical Pentravan® Based Compositions with Naproxen and Its Proline Ester Derivative—A Comparative Study of Physical Properties and Permeation of Naproxen Through the Human Skin

The compositions based on Pentravan® vehicle were prepared with (S)-naproxen, and its salt —(S)-naproxenate of L-prolinium isopropyl ester as active pharmaceutical ingredients, and two penetration enhancers from the group of sensates—menthol and Capsicum Tincture. Thermophysical properties of the mixtures of each naproxen form with enhancers were determined by DSC method. The stability of the prepared compositions after one- and three-month storage and the rheological properties were investigated. The permeation of active ingredients through the human skin was evaluated based on the in vitro study in Franz diffusion cells using the prepared compositions with each naproxen form. Increase in the permeability of the naproxen salt, especially in the presence of Capsicum Tincture, provides much faster and greater penetration of the skin by the drug. It seems to be promising the use of the developed composition in the form of pain relief and anti-inflammatory creams, occlusive compresses or topical patches. Moreover, the developed compositions can be crucial for the topical compositions made in compounding pharmacies by physicians’ recipes in individual pain pharmacotherapy.