| Abstrakt: |
A hypothesis, namely, that the site of action of surfactants is in the biological membranes, was investigated with an indirect method. One representative member from each of 3 major types of nonionic surfactants was tested. Sorbitan trioleate, polysorbate 85, and polyoxyethylene ether 96 were incorporated, 10 percent in concentration, in white petrolatum and applied to rabbit skin daily. Measurements of lipid phosphorus indicated a considerable increase in the phospholipid content of the 0.1mm. thick skin samples representing mainly the epidermis. Two reference standards were used: the wet weight and the deoxyribonucleic acid (DNA) content. After 4days of treatment with polysorbate 85, sorbitan trioleate, and polyoxyethylene ether 96 preparations, the increase in phosphorus was found to be 23–56 percent, 28–73 percent, and 46–90 percent, respectively, on the basis of wet weight and 26–53 percent, 27–58 percent, and 47–81 percent, respectively, if DNA content was used as the reference standard. After 10days of treatment, the increase in phosphorus was considerably smaller if calculated on the basis of DNA present in the sample, but did not differ much if wet weight was used as the reference. A comparison of the two reference standards demonstrated that the DNA content also increased after 10days of treatment. The smaller spread in results indicated that DNA content may be more reliable as a reference standard, but the wet weight still can be used as a practical and useful standard of reference especially if the DNA content is also influenced by the test. |
Plný text