Influence of Ultraviolet Irradiation on the Surface Activity of Phenothiazine Drugs

Phospholipid Spherules as a Model to Assess Photosensitizing Properties of Drugs

“…However, the possibility cannot be eliminated that the N-oxide and hydroxy derivatives of chlorpromazine, which were also identified by Huang and Sands (12) as photoproducts, may be responsible to some degree for the observed effects. These products, resulting from the UV irradiation of chlorpromazine, have been shown to be more surface active than chlorpromazine itself (13) and thus more likely to penetrate and disrupt phospholipid membranes.…”

The effect of the photodecomposition of chlorpromazine on lecithin monolayers

“…Chlorpromazine sulphoxide is less surface active than the HCI (Zografi & Auslander, 1964) and in the amounts formed would not therefore be expected to contribute to the expansion that was observed when the lecithin films on cpz HCl were irradiated (Figs 2, 5). Felmeister & Schaubman (1969) suggested that the expansion might be due to the production of dimers or polymers of cpz; but none could be detected in this work. Since in the absence of cpz the lecithin films appeared to be unaffected by ultraviolet light, it is concluded that the expansion was due primarily to the second reaction product, 2-hydroxypromazine, the presence of which in these irradiated systems was also noted by Grant (1974).…”

“…lecithin as a monolayer on the surface of an aqueous solution of the drug and irradiate the system with light of appropriate wavelength (Davies & Rideal, 1963;Pilpel & Hunter, 1970). This technique was used by Felmeister & Schaubman (1968, 1969 who calculated so-called phototoxic indices for five different phenothiazine drugs. Although they assumed that the observed expansion of the monolayer was due to a polymerization process, they were unable to identify the products of the reaction.…”