The surface activity of phenothiazine derivatives at the air-solution interface

The surface activity of triflupromazine, chlorpromazine, promazine, promethazine, and chlorpromazine sulfoxide has been determined at the air-solution interface by the drop-volume method to measure surface tension. Differences in the abilities of the various phenothiazines employed to affect surface pressure development seem correlated with their relative nonpolarities. Anionic buffer ingredients appear to have an affect on surface activity at pH 5.0. Increasing concentrations of phthalate, citrate, and succinate buffers tend to increase surface activity, while increasing the concentration of the acetate buffer has the opposite effect. Raising the pH greatly increases surface activity of chlorpromazine and its sulfoxide, but the low solubility of the un-ionized form of chlorpromazine prevents it from exhibiting surface activity unless a significant amount of protonated form is also present. The un-ionized form of chlorpromazine sulfoxide is more soluble than chlorpromazine, and it exhibits marked surface activity at high pH.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33453/1/0000856.pd