Influence of hydroxypropyl-beta-cyclodextrin on photo-induced free radical production by the sunscreen agent, butyl-methoxydibenzoylmethane.
The aim of the study was to investigate the effect of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on the photo-induced production of free radicals by the sunscreen agent, butyl-methoxydibenzoylmethane (BMDBM). Spin-trapping/electron paramagnetic resonance spectroscopy was used to evaluate the formation of radicals and the extent of BMDBM photodegradation was measured by high-performance liquid chromatography. The stable 2,2,6,6-tetramethylpiperidine-1-oxyl, nitroxide radical (TEMPO) was used as spin-trap. Any free radicals generated during irradiation of the sunscreen agent will couple with the TEMPO radicals giving diamagnetic species and thus a decrease of the signal intensity in the electron paramagnetic resonance spectrum. Following 2-h illumination with simulated sunlight, the solution containing free BMDBM exhibited a 93.9% decrease of the intensity of the TEMPO signal. Under the same irradiation conditions, only a 12.2% reduction of the TEMPO concentration was measured in the sample containing BMDBM complexed with HP-beta-CD. Moreover, the decrease of the spin-trap level observed for the HP-beta-CD/BMDBM complex was not significantly different from that produced when solutions containing TEMPO only or TEMPO in the presence of HP-beta-CD alone were subjected to irradiation. In addition, the photodegradation of the sunscreen agent was reduced by complexation with HP-beta-CD (the extent of degradation was 27.6% for the complex compared with 63.1% for free BMDBM). The results obtained indicate that the free radicals generated by BMDBM when exposed to simulated sunlight are effectively scavenged by inclusion complexation of the sunscreen agent with HP-beta-CD.
Scalia
Santo
S
Department of Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 17, 44100 Ferrara, Italy. sls@unife.it
Simeoni
Silvia
S
Barbieri
Andrea
A
Sostero
Silvana
S
D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000473:Alkanes / Q000737:chemistry* / Q000528:radiation effects; D001565:Benzoates / Q000737:chemistry* / Q000528:radiation effects; D047188:Chalcones; D002851:Chromatography, High Pressure Liquid; D003505:Cyclodextrins / Q000737:chemistry*; D004055:Differential Thermal Analysis; D004355:Drug Stability; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D011427:Propiophenones; D013056:Spectrophotometry, Ultraviolet; D013473:Sunscreening Agents / Q000737:chemistry* / Q000528:radiation effects; D013997:Time Factors; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction; D047392:beta-Cyclodextrins
D000473:Alkanes; D001565:Benzoates; D047188:Chalcones; D003505:Cyclodextrins; D005609:Free Radicals; D011427:Propiophenones; D013473:Sunscreening Agents; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; C049935:avobenzone