Photochemical and Photophysical Properties of Indoprofen¶

Abstract

The photophysical properties and photochemistry of indoprofen (INP) have been investigated. Absorption and emission spectroscopies in phosphate buffer, ethanol and ether show that INP photophysics is dominated by a singlet-singlet transition of pipi* character. INP fluoresces at room temperature, with a quantum yield approximately 0.04. Flash photolysis experiments together with the lack of phosphorescence at room temperature point to a very weak intersystem crossing. The photoreactivity of INP is centered on the propionic acid chain and gives rise to photoproducts similar to those obtained with other arylpropionic acids (ethyl, hydroxyethyl and acetyl derivatives). Thus, irradiation of INP in aqueous buffer results in photodecarboxylation and leads mainly to oxidative compounds whose proportions increase with increasing oxygen concentration. These data suggest a photoreactivity occurring from the excited singlet state.

Development of an RPLC‐based Method for Measurement of Indoprofen Stability and Validation of the Method

“…The key intermediates are likely to be a benzylic carbanion, a benzylic radical, and a hydroperoxy radical arising from benzylic radical via oxygen trapping (Scheme 2). 15 The results are consistent with the hypothesis that the photodegradation of INP proceeds via a free radical process, which excludes the possibility of an ionic mechanism.…”

“…Because stability studies are needed at the pre-formulation stage of development of dosage-forms, establishment of a stability-indicating assay suitable for identification of potentially critical factors has become an important goal. [12][13][14] In 2003, Trzcionka and colleagues 15 examined the photochemical and photophysical properties of INP and found the agent unstable in the presence of light. They also found that a photoproduct of INP was proposed to serve as a photosensitizer of DNA.…”

Drug-biomolecule interactions in the excited states

“…These damages are obtained via a triplet-triplet (T-T) energy transfer from the excited drug to thymine and require that the populated triplet of the photosensitizer be higher in energy than that of the nucleobase. This condition seems to be fulfilled for the [23]. In the latter case, an interesting hypothesis is that one of the INP photoproducts is in the origin of the photosensitization mechanism.…”

Synthesis and fluorescence properties of isoindoline–benzazole-based boron difluoride complexes

“…Starting materials (1-6) were synthesized according to the reported literatures. 12 By reacting 1-6 with boron trifluoride etherate in the presence of triethylamine in dichloroethane or dichloromethane, BF 2 dyes (7)(8)(9)(10)(11)(12) were obtained in good yields (46-86%). All dyes were stable in air and could be purified by recrystallization or silica-gel column chromatography.…”

“…All dyes were stable in air and could be purified by recrystallization or silica-gel column chromatography. All six new compounds were characterized by 1 H, 11 B NMR spectroscopy, ESI-MS and elemental analysis (ESI †). Except for 9, the other compounds were structurally characterized by X-ray crystallography (Fig.…”