The 3-D structures were generated and optimized for minimum energy. Molecular descriptors were generated using the previously mentioned software, and property predictions were made using robust QSPR models already developed. For each property within the acceptable range, the score of the molecule was incremented by a value of one. Thus, a summary numerical score is assigned to each of the molecules generated. Molecules that passed all the screening KU-60019 mw
tests and had a fitness score value of eight were accepted as potential CPEs. Figure?5 summarizes the scoring of the molecules in each generation. Molecules that have high log Kp values have higher skin penetration ability. Hence, the screened molecules are sorted according to their log Kp value, and the top 10% of the molecules were retained and added to the parent molecule set to be used in the next generation. Approximately 1000 molecules were generated in each generation run, and this procedure was repeated for five generations. Table?2 summarizes the results of the five generation runs. In general, slightly <20% of the molecules generated were considered candidate for further evaluation as CPEs. The molecules, thus, identified <a href="http://en.wikipedia.org/wiki/IκBα
">Bay 11-7085 were further validated for skin permeation and skin irritation using carefully designed experiments. The experimental work was performed by members of the OSU Chemical Design Research Group and is disseminated elsewhere (12�C15); nevertheless, a brief discussion of the experimental work is provided for completeness. Molecules Doramapimod
with a score of 8 and with high log Kp values in each generation were selected for experimental validation. In this work, insulin was the targeted drug to be delivered transdermally; hence, the CPEs were experimentally validated for penetration enhancement of insulin. The skin permeation experimental procedures were validated by performing permeability measurements on four known CPEs. These validations used a Franz Cell with porcine skin and high-performance liquid chromatography (HPLC) analysis. The resistance factor (RF) and the insulin flux obtained using the Franz cell and the HPLC method, respectively, for the experimentally validated molecules are presented in Table?3. Chemical compounds with high RF and insulin flux values are considered effective in transdermal penetration. The toxic effects of these enhancers were also studied on (i) human foreskin fibroblasts with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-formazan assays at two different concentrations and (ii) porcine abdominal skin using histology and haemotoxylin/eosin (H/E) staining at the end of a 24-h exposure period. A detailed discussion of the experimental procedures is beyond the scope of this paper and is given elsewhere (12�C15). Eighteen of the potential CPEs identified by the virtual design algorithm were validated experimentally for skin permeation and toxicity.