PubMed · 301803
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
P M Catalano, D D Fulghum. 1977. A water-resistant sunscreen.. https://doi.org/10.1111/j.1365-2230.1977.tb01555.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
N-Acetyltransferase activities associated with erythrocytes from 20 individuals have been determined with p-aminobenzoic acid as substrate. A three-fold variation in Vmax is found. The N-acetyltransferase genotype of the individuals has been determined and there is no correlation between the extent of acetylation measured in the individuals' erythrocytes and the inheritance of alleles at the polymorphic NAT locus. Folate is confirmed to be an inhibitor of arylamine N-acetyltransferase activity measured in erythrocytes. The content of folate in erythrocytes of individuals also varies. The individual with the maximum folate content has the minimum N-acetyltransferase activity. The monomorphic N-acetyltransferase gene from individuals spanning the range of N-acetyltransferase activity have been amplified, using the polymerase chain reaction. The pattern of restriction enzyme digestion of the monomorphic N-acetyltransferase gene with a series of eight restriction enzymes is the same for individuals spanning the activity range of arylamine N-acetyltransferase in their erythrocytes.
To study the effects of para-aminobenzoate on the dermis, fibroblast cell lines derived from lesions of lichen sclerosus et atrophicus, from morphoea and from normal skin were incubated with Potaba in vitro. Monolayer cultures containing Potaba showed a dose-dependent inhibition of proliferation beginning at 1,000 micrograms/ml with total inhibition at 10,000 micrograms/ml. Mean ID50 values for the three groups were not significantly different. There was a similar dose dependent inhibition of glycosaminoglycan secretion in all 3 groups, except at 10,000 micrograms/ml where secretion by lichen sclerosus et atrophicus and morphoea fibroblasts was significantly more inhibited than normal lines. Inhibition of the glycosaminoglycan secretion at 10-1,000 micrograms/ml was a direct effect of the drug rather than an indirect effect of changes in cell density, and lichen sclerosus et atrophicus fibroblasts produced about 40% more GAG than the morphoea or normal lines growing at similar densities. Collagen synthesis was increased in both lichen sclerosus et atrophicus and morphoea cell lines, with increased non-collagenous protein in morphoea lines. These results confirm that there are differences between lichen sclerosus et atrophicus and morphoea, and suggest glycosaminoglycan secretion as a possible target for the therapeutic action of Potaba.
A series of 8 p-aminobenzoate esters were selected as model drugs to study the effect of molecular volume and partition coefficient on percutaneous absorption. The octanol/water partition coefficient and solubility of these compounds were determined and their penetration rate through rat skin in vitro was measured using a Keshany-Chien diffusion cell. The results showed that when the molecular volume was increased the permeation coefficient was decreased. However, when the partition coefficient was increased, the permeation coefficient was increased at first and then reached a plateau. The mathematical formula has been derived from a bi-layer diffusion model to show how the molecular volume and the partition coefficient influence the permeation coefficient. The formula could be used to estimate the permeation coefficient of drug through skin.