Scopolamine permation through human skin in vitro

Abstract

The sorption and rate of permeation of scopolamine base in human skin have been measured as a function of drug concentration in aqueous solution contacting the stratum corneum surface of the skin. The sorption isotherm is nonlinear, and the apparent penetrant diffusivity computed from steady state permeation data is greater than that estimated from unsteady state (time lag) measurements. By assuming that sorption occurs by both ordinary dissolution and binding of penetrant to immobile sites in the membrane, the experimental sorption isotherm can be predicted, and the disparity between steady state and time lag diffusivities can be reconciled.

Multiscale Modeling Framework of Transdermal Drug Delivery

“…Both transport through the device and through the skin are generally considered to follow Fickian diffusion through a simple homogeneous membrane. The studies on transport of compounds through the skin may be divided into two large categories: those that deal with the skin as a whole 11,25,26,34 and those that concentrate on the stratum corneum as a separate layer. 11,18,27,30 Here, we take the second approach, by explicitly considering the biphasic microstructure of the stratum corneum.…”

Modeling and Numerical Computation of Drug Transport in Laminates: Model Case Evaluation of Transdermal Delivery System

“…Tz I r I y (22) where y is chosen slightly smaller than r3. Therefore, C(0,r) exactly fulfills the boundary condition stated by eqs.…”

Prediction of Drug Disposition Kinetics in Skin and Plasma Following Topical Administration

“…then suitable corrections can be applied to (Eq. 4) where VI -V4 correspond to the volumes of compartments I -4, respectively. Manipulation of the equations to obtain an expression for the amount of drug appearing in the urine as a function of time has been presented prcviously (27).…”

“…The heightened interest in percutaneous absorption encompasses many aspects: (a) the development of new delivery systems (4)(5)(6), (b) the search for agents capable of enhancing penetration (7-1 I), and (c) the continuing effort to understand skin absorption rate and extent in terms of accepted biological facts and penetrant physicochemical properties (12)(13)(14)(15)(16)(17)(18)(19)(20). In the first group, one may cite the appearance of transdermal therapeutic systems containing nitroglycerin for the treatment of angina pectoris (21) and the surprising suggestion that topically applied liposomes are able to exert an influence on the local and systemic distribution of an encapsulated drug (22,23).…”