Assessment of skin permeability to topically applied drugs by skin impedance and admittance.

Objective: Pharmacokinetic and pharmacodynamic studies of topically applied drugs are commonly performed by sampling of interstitial fluid with dermal open flow microperfusion and subsequent analysis of the samples. However, the reliability of results from the measured concentration-time profile of the penetrating drug suffers from highly variable skin permeability to topically applied drugs that is mainly caused by inter- and intra-subject variations of the stratum corneum. Thus, statistically significant results can only be achieved by performing high numbers of experiments.

Open Flow Microperfusion as a Dermal Pharmacokinetic Approach to Evaluate Topical Bioequivalence.

Background: The availability of generic topical dermatological drug products is constrained by the limited methods established to assess topical bioequivalence (BE). A novel cutaneous pharmacokinetic approach, dermal open-flow microperfusion (dOFM), can continuously assess the rate and extent to which a topical drug becomes available in the dermis, to compare in vivo dermal bioavailability (BA) and support BE evaluations for topical products.

Objective: To evaluate whether dOFM is an accurate, sensitive, and reproducible in vivo method to characterize the intradermal BA of acyclovir from 5 % acyclovir creams, comparing a reference (R) product either to itself or to a different test (T) product.

Kinetics of Clobetasol-17-Propionate in Psoriatic Lesional and Non-Lesional Skin Assessed by Dermal Open Flow Microperfusion with Time and Space Resolution.

Purpose: To evaluate the kinetics of topically applied clobetasol-17-propionate (CP-17) in lesional and non-lesional psoriatic skin when released from a commercially available low-strength cream using in vivo dermal open-flow microperfusion (dOFM).

Methods: Twelve patients received Dermovate® cream (CP-17, 0.05%) on small lesional and non-lesional skin test sites for 14 days, once daily.