Phospholipid Spherules as a Model to Assess Photosensitizing Properties of Drugs

Felmeister, Alvin; Tolat, Shrilekha V.

doi:10.1002/jps.2600590632

Cited by 2 publications

(1 citation statement)

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“…Our results differ from those of Felmeister and Tolat (1970). They found that liposomes (which contained egg lecithin and no cholesterol) released chromate marker in the presence of UV irradiated chlorpromazine and prochlorperazine.…”

Section: Discussioncontrasting

confidence: 99%

Light‐induced Leakage of Spin Label Marker From Liposomes in the Presence of Phototoxic Phenothiazines

Copeland

Alving

Grenan

1976

Photochem & Photobiology

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Abstract— Liposomes prepared from dipalmitoyl lecithin, cholesterol and dicetyl phosphate and containing a trapped spin label marker were exposed to long wavelength UV light in the presence of a series of phenothiazine tranquilizers. EPR spectroscopy was used to detect spin label marker released from liposomes, taking advantage of the disappearance of line broadening from electron spin exchange which occurred on spin label release. The minimum effective phototoxic dose in mice of these phenothiazines was also determined. Kinetic studies of light‐induced spin label release from phenothiazine‐sensitized liposomes showed that membrane damage was rapidly induced and that the damaging species were short‐lived. The damage process was oxygen dependent and could be temporarily prevented by cysteamine or α‐tocopherol added immediately before irradiation. Only those phenothiazines which mediated light‐dependent liposomal membrane damage had phototoxic activity in mice and the degree of photosensitization was parallel in the two systems. In both photosensitization phenomena, the nature of the substituent at the phenothiazine 2‐position was more important than the phenothiazine side chain.

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Section: Discussioncontrasting

confidence: 99%