Impact of Menthol Concentration on Ketoprofen Permeation and Photostability in Compounded Topical Preparations in a Pentravan Base.

BACKGROUND

Topical nonsteroidal anti-inflammatory drugs provide localized pain relief while reducing the risk of systemic adverse effects. Menthol is frequently used in topical formulations both as an analgesic agent and as a penetration enhancer.

OBJECTIVE

This study evaluated the effect of menthol concentration on ketoprofen permeation through Strat-M membranes and photostability in compounded topical formulations based on a Pentravan vehicle.

RESEARCH DESIGN AND

METHODS

Semisolid formulations containing ketoprofen, lidocaine hydrochloride, and increasing concentrations of menthol were prepared using the Pentravan base. In vitro permeation experiments were performed using Franz diffusion cells with Strat-M membranes as a screening model. Ketoprofen concentrations were determined using UHPLC analysis. Photostability under UVA exposure (0-200 Wh/m2) was also assessed.

RESULTS

Ketoprofen permeation increased with increasing menthol concentration. After 12 h, the cumulative amount detected in the acceptor phase ranged from 194.9 μg for the menthol-free formulation to 475.9 μg for the formulation containing 10% menthol. Photostability studies showed formulation-dependent degradation profiles. The menthol-free formulation retained the highest proportion of ketoprofen during UVA exposure, whereas the menthol-containing formulation and the commercial product showed more pronounced drug degradation.

CONCLUSION

Menthol enhanced ketoprofen permeation in the applied in vitro model while also influencing the drug's photodegradation behavior under UVA exposure, highlighting the importance of formulation composition in compounded topical preparations.