LC-MS/MS determination in rabbit plasma of the main photoproduct of RLP068/Cl, a cationic sensitizer proposed for photodynamic therapy (PDT) of microbial infections.

The clinical development of a sensitizer for photodynamic therapy (PDT) requires the structural identification of the photoproducts and their quantification in biological fluids and tissues. We describe the LC-MS identification of the most important photoproducts of a cationic phthalocyanine sensitizer (RLP068/Cl) and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of the main photoproduct (the cationic phthalimide derivative 3-[(1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)oxy]-N,N,N-trimethylbenzenaminium chloride) in rabbit plasma. The tri-deuterated product was used as co-eluting internal standard.

Determination of tetracationic zinc(II) phthalocyanine derivative RLP068 in rabbit serum by liquid chromatography-tandem mass spectrometry.

The development and validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of the tetracationic zinc(II) phthalocyanine derivative RLP068 in rabbit serum is described. The dodecadeuterated product (RLP068-D12) was used as co-eluting internal standard. RLP068 was isolated from serum samples by solid-phase extraction using weak cationic exchange cartridges (WCX).

Selective ring contraction of 5-spirocyclopropane isoxazolidines mediated by acids.

Thermolysis of 3,4-cis ring-fused 5-spirocyclopropane isoxazolidines 16, 18-21, 33, 34, 38a, and 61, in the presence of a protic acid at 70-110 degrees C, yielded 3,4-cis ring-fused azetidin-2-ones 22-26,41, 42, 46, and 62 with concomitant extrusion of ethylene, in good yields. So far, the collected evidences strongly support a mechanism started by a homolytic cleavage of the protonated N-O bond for the rearrangement of 5-spirocyclopropane isoxazolidines to beta-lactams. Some different competitive pathways can then follow depending on the stability or the stereoelectronic properties of cationic diradical intermediates.

[Study of 241 epitheliomas of uterine cervix (T1-T2) treated by radio-surgical procedure (author's transl)].

A casuistic study of 241 epidermoid cancers of the uterine cervix treated at the Cancer Center in Nice is analysed depending upon various protocols. The cases are studied according to the stage and type of treatment, with indication of the incidence of lymph node involvement. Surgical or radiological procedure, pelvic-node-vaginal recurrence, modalities of death and survival control at five years are detailed.