La. Martinez et al., SINGLET OXYGEN (O-2((1)DELTA(G))) PRODUCTION BY PHOTOSENSITIZING DRUGS IN MICROHETEROGENEOUS SYSTEMS, Journal of information recording, 24(3-4), 1998, pp. 179-183
Photosensitization is a relatively common side-effect induced by some
drugs. Non steroidal antiinflammatory drugs (NSAID) deserve special at
tention because of various reasons: 1) these drugs are currently used
to treat several human diseases, 2) their photosensitizing behaviour i
n vivo is a well-documented phenomenon and 3) short-lived species, amo
ng them singlet oxygen(O-1(2)), have been claimed to be involved in th
e development of this side-effect [1]. We have measured the quantum yi
eld of singlet oxygen production (Phi(Delta)) in anionic microemulsion
s by a series of NSAID which have been found to behave as photosensiti
zing agents in several in vitro and in vivo models. Microemulsions hav
e been chosen as reaction media, because they may be considered as sim
plest models to mimic organized microenvironments (ie., cellular membr
anes) [2]. By monitoring the O-1(2) luminescence at 1270 nm upon irrad
iation of the drugs, it has been possible to establish that NSAID are
efficient O-1(2) sensitizers in microheterogeneous systems, some of th
em exhibiting rather high Phi(Delta)(app) (0.86 for tiaprofenic acid).
Although extrapolation of the data to more complicated systems is ext
remely complex, we have found that NSAID are able to produce O-1(2) in
microheterogeneous systems composed of hydrophobic and hydrophilic mi
crodomains with a higher efficiency than in homogeneous aqueous soluti
on.