Ij. Bosman et al., NOVEL DIFFUSION CELL FOR IN-VITRO TRANSDERMAL PERMEATION, COMPATIBLE WITH AUTOMATED DYNAMIC SAMPLING, Journal of pharmaceutical and biomedical analysis, 14(8-10), 1996, pp. 1015-1023
The development of a new diffusion cell for in vitro transdermal perme
ation is described. The so-called Kelder cells were used in combinatio
n with the ASPEC system (Automatic Sample Preparation with Extraction
Columns), which is designed for the automation of solid-phase extracti
ons (SPE). Instead of SPE columns, 20 Kelder cells were placed in the
racks. This allowed automatic sampling of up to 20 cells for 24 h in a
dynamic mode. The cells consist of an inlet compartment, a donor comp
artment and a receptor compartment. The size and the depth of the inle
t compartment were important to avoid entrapment of air bubbles in the
receptor compartment. The Kelder cells mimic blood flow beneath the s
kin by replacement of the permeating drug every 2 min. Hence sink cond
itions are more easily maintained than with the static Franz diffusion
cell. The performance of the cells was tested with permeation experim
ents using atropine as a model drug permeating through an artificial m
embrane (Silastic). The use of this skin model minimized the variabili
ty in permeation of atropine as compared with human skin.