Abstract
As an approach to an understanding of the membrane action of phenothiazines, the adsorption from solution was investigated using such adsorbents as carbon black (CB), graphite (GP), silica gel (SG) and polyethylene (PE), and relating the results with other physico-chemical and biological activities of the drugs. The adsorption isotherms by CB and GP were in accordance with Langmuir equation. In the case of SG, the phenomenon looked like a multilayer adsorption. Phenothiazines were considered to be classified into three groups according to the adsorbability by PE. The adsorbed amount was influenced by the molecular volume of R10'N at 9-position, sulfoxide group at 5-position, and the bulkiness of substituent at 2-position. The adsorbed amount increased with pH of buffer solution between 5 and 8, and it was considered that pH had influence on the hydrophobic and hydrophilic balance of the molecule. The decrease in adsorption with addition of urea demonstrated that the adsorption of phenothiazines proceeded on the hydrophobic interaction. The adsorbability of phenothiazines by CB increased with the surface tension lowering of solution and also with the partition coefficient in CHCl3-0.2N HCl. It was shown that the adsorbability have relation to the neuroleptic and the haemolytic activities.
