Analysis of in vitro skin penetration of acyclovir prodrugs based on a diffusion model with a metabolic process

In Vitro Metabolism of 5-ALA Esters Derivatives in Hairless Mice Skin Homogenate and in Vivo PpIX Accumulation Studies

“…In studies on metabolism, more commonly purified enzymes are used. However, in skin metabolism mediated by several enzymes with overlapping metabolic activities, the method of using homogenized skin is more convenient and reflects presumably the real metabolism of a drug during its penetration process through the skin more exactly (24,25). 5-ALA esters are degraded rapidly following administration skin homogenates.…”

Incidence of low bioavailability of leuprolide acetate after percutaneous administration to rats by dissolving microneedles

“…On the other hand, LA is stable in water as reported by (Hall et al, 1999), where more than 90% of LA was remained unchanged after being incubated for 1 year at 37 • C. The main metabolic pathway of LA is hydrolysis. In the epidermal region of the skin, there are many enzymes such as peptidases and P-450 (Hayashi et al, 1997;Bando et al, 1996Bando et al, , 1997. Therefore, the degradation of LA in the skin tissue homogenate was ascribed to the hydrolysis by the enzymes there.…”

Analysis of in Vitro Skin Permeation of 22-Oxacalcitriol Having a Complicated Metabolic Pathway

“…This simulation study indicates that not only the metabolic rate, but also diffusivity in skin, would affect the bioconversion ratio of a drug. Bando et al (8) reported that the metabolic rate of acyclovir isovalerate was 0.156 h j1 and the permeated amount of regenerated acyclovir was less than that of acyclovir isovalerate. On the other hand, OCT, the metabolic rate of which was the same as acyclovir isovalerate, mainly permeated through skin in a metabolized form.…”

“…A two-layer skin model including metabolic processes (8,11,13) was employed to express in vitro skin permeation of a drug. A schematic representation of the model is shown in Fig.…”