Vesicles drug transport studies

Many studies have employed phospholipids as liposomes (vesicles) to transport drugs into and through human skin. However, a few investigations have also employed phospholipids in a nonvesicular form as penetration enhancers. For example, 1% phosphatidylcholine in PG, a concentration at which liposomes would not form, enhanced theophylline penetration through hairless mouse skin [64]. Similarly, indomethacin flux was enhanced through rat skin by the same phospholipid and hydrogenated soybean phospholipids increased diclofenac permeation through rat skin in vivo. 

It has been demonstrated that cis- (76) and frarcs-flupentixol (75) (see Fig. 5) inhibited the photo affinity labeling of P-gp by substrate analogues [173] Binding of several MDR modulators, among them TFP (5), to P-gp was shown by means of fluorescence quenching of the MIANS probe [174] or P-gp tryptophan fluorescence [175]. CPZ (9) is likely a P-gp substrate, as was shown in studies of its transport in membrane vesicles obtained from multidrug-resistant CCRF-CEM cells [176], and therefore it was used as a competitive inhibitor of drug transport mediated by P-gp [177]. 

A third method to increase the skin transport is encapsulation of drugs in vesicles. Although several studies have been performed, the interactions between vesicles and skin is still largely unknown. In this chapter a review will be given on the state of the an in skin vesicle rese ch. 

Glavinas H, Mehn D, Jani M, Oosterhuis B, Heredi-Szabo K, Krajcsi P (2008) Utilization of membrane vesicle preparations to study drug-ABC transporter interactions. Expert Opin Drug Metab Toxicol 4 721-732. 

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