Incorporation in Lipid Microparticles of the UVA Filter, Butyl Methoxydibenzoylmethane Combined with the UVB Filter, Octocrylene: Effect on Photostability

Abstract

Abstract. The aim of this study was to reduce the photoinstability of butyl methoxydibenzoylmethane (BMDBM), the most widely used UVA filter, by incorporating it in lipid microparticles (LMs) alone or together with the UVB filter octocrylene (OCR), acting also as photostabilizer. Microparticles loaded with BMDBM or with combined BMDBM and OCR were produced by the hot emulsion technique, using glyceryl behenate as lipid material and poloxamer 188 as surfactant. The LMs were characterized by release studies, scanning electron microscopy, and powder X-ray diffractometry. The BMDBM and OCR loading was 15.2% and 10.6%, respectively. In order to reproduce the conditions prevalent in commercial sunscreen products, the photoprotective efficacy of the LMs was evaluated after their introduction in a model cream (oil-in-water emulsion) containing a mixture of UVA and UVB filters. A small but statistically significant decrease in BMDBM photodegradation was obtained when the UVA filter was encapsulated alone into the LMs (the extent of degradation was 28.6% ±2.4 for nonencapsulated BMDBM and 26.0% ±2.5 for BMDBM-loaded microparticles). On the other hand, the coloading of OCR in the LMs produced a more marked reduction in the light-induced decomposition of microencapsulated BMDBM (the UVA filter loss was 21.5% ±2.2). Therefore, incorporation in lipid microparticles of BMDBM together with the sunscreen OCR is more effective in enhancing the UVA filter photostability than LMs loaded with BMDBM alone.

Encapsulation of the UV Filters Ethylhexyl Methoxycinnamate and Butyl Methoxydibenzoylmethane in Lipid Microparticles: Effect on in vivo Human Skin Permeation

“…Sample injections were effected with a Model 701 syringe (10 l; Hamilton, Bonaduz, Switzerland). Separations were performed according to a previously published method [11] , with minor modifications. A 5-m Zorbax SB-CN column (150 mm !…”

“…Unloaded LMs were prepared according to Scalia and Mezzena [11] , by emulsifying the melted lipid phase (3.5 g) at 75-85 ° C with hot water (50 ml) containing 1% (w/w) hydrogenated soybean phosphatidylcholine. The samples were mixed (17,500 rpm for 2 min) with an Ultra-Turrax T25 (IKA-Werk, Staufen, Germany) and then rapidly cooled at room temperature under magnetic stirring.…”

“…For the preparation of the LMs loaded with high amounts of BMDBM or EHMC, a melt emulsification technique which avoids the use of organic solvents was employed [11] . Different lipid materials (tristearin, glyceryl behenate, stearic acid) were utilized in conjunction with hydrogenated phosphatidylcholine, which was selected as the surfactant due to its biocompatibility.…”

“…In particular lipid microparticles (LMs) represent an appropriate carrier for sunscreen agents [10,11] . These micrometer-sized particles, consisting of a solid lipid core (i.e.…”

Occurrence of eight UV filters in beaches of Gran Canaria (Canary Islands). An approach to environmental risk assessment

“…For this reason, BMDBM is usually employed with OC to prevent its quick degradation. In fact, OC presents a moderate extinction coefficient and it is fundamentally used as BMDBM photostabilizer (Scalia and Mezzena, 2009). This joint use and similar log K ow values are consistent with the strongest correlation found between concentration levels of compound pair (Pearson correlation coefficient % 0.88).…”