IN VITRO SKIN PERMEATION OF SUNSCREEN AGENTS FROM O/W EMULSIONS

Les effets d’e´mulsifiants diffe´rents teste´s in vitro surla perme´abilite´ de la peau humaine de deux agentsde protection solaire [octylmethoxycinnamate(OMC) et butylmethoxydibenzoylmethane (BMBM)]ont e´te´ soumis a` une recherche a` partir d’e´mulsionO/W. Les e´chantillons teste´s ont e´te´ pre´pare´ enutilisant la meˆme huile et les meˆme ingre´dients dephase aqueuse avec les syste´mes d’e´mulsifiants etcoe´mulsifiants suivants: Emulgade SE (ceteareth-12 and ceteareth-20 and cetearyl alcohol andcetyl palmitate) et glycerylmonostearate (e´mulsion1); Brij 72 (steareth-2), Brij 721 (steareth-21)et cetearyl alcohol (e´mulsion 2); Phytocream(Potassium palmitoyl-hydrolised wheat protein andglyceryl stearate and cetearyl alcohol) et glycerylmonostearate(e´mulsion 3); Montanov 68(cetearyl glucoside and cetearyl alcohol) (e´mulsion4); Xalifin-15 (C15-20 acid PEG-8 ester) etcetearyl alcohol (e´mulsion 5). La quantite´ cumulatived’OMC qui a pe´ne´tre´, in vitro, la peauhumaine apre´s 22h, a` partir des e´chantillonsteste´s a baisse´, de l’ordre de 3 > 1 @ 4 > 5 > 2 ete´tait environ 9 fois plus grande pour l’e´mulsion 3compare´e a` l’e´mulsion 2. En ce qui concerne le BMBM, aucune diffe´rence significative n’a e´te´observe´e pour la perme´abilite´ de la peau pourl’e´mulsion 1, 3, 4 et 5 alors que l’e´chantillon 2 amontre´ une baisse significative de la quantite´ deBMBM qui pe´ne´tre la peau. Les expe´riences derelaˆchement in vitro d’OMC et BMBM des e´mulsions1 a` 6 sur des membranes de cellulose ontmontre´ que seules les e´mulsions 4 et 5 ont re´agiavec un relaˆchement de pseudo premier ordre seulementpour l’OMC. Les re´sultats de ces expe´rimentationssugge´rent que le type de syste´med’e´mulsifiant utilise´ pour pre´pare´ une e´mulsion O/W peut affecter fortement la perme´abilite´ desagents de protection solaire de ces e´chantillons.Par conse´quence, les effets des ve´hicule´s devraienteˆtre soigneusement re´fle´chis pris en compte pourla production de cre´me de protections solaires.

The effects of different emulsifiers on the in vitropermeation through human skin of two sunscreenagents [octylmethoxycinnamate (OMC) and butylmethoxydibenzoylmethane(BMBM)] were investigatedfrom O/W emulsions. The test formulationswere prepared using the same oil and aqueousphase ingredients and the following emulsifier andcoemulsifier systems: Emulgade SE (ceteareth-12and ceteareth-20 and cetearyl alcohol and cetylpalmitate) and glycerylmonostearate (emulsion 1);Brij 72 (steareth-2), Brij 721 (steareth-21) andcetearyl alcohol (emulsion 2); Phytocream (potassiumpalmitoyl-hydrolysed wheat protein and glycerylstearate and cetearyl alcohol) andglycerylmonostearate (emulsion 3); Montanov 68(cetearyl glucoside and cetearyl alcohol) (emulsion4); Xalifin-15 (C15–20 acid PEG-8 ester) and cetearylalcohol (emulsion 5). The cumulative amountof OMC that permeated in vitro through humanskin after 22 h from the formulations being testeddecreased in the order 3 > 1 @ 4 > 5 > 2 and wasabout nine-fold higher from emulsion 3 comparedwith that from emulsion 2. As regards BMBM, nosignificant difference was observed as regards itsskin permeation from emulsions 1, 3, 4 and 5,whereas formulation 2 allowed significantly loweramounts of BMBM to permeate the skin. In vitrorelease experiments of OMC and BMBM from emulsions1–6 through cellulose acetate membranesshowed that only emulsions 4 and 5 providedpseudo-first-order release rates only for OMC. Theresults of this study suggest that the type of emulsifyingsystems used to prepare an O/W emulsionmay strongly affect sunscreen skin permeationfrom these formulations. Therefore, the vehicleeffects should be carefully considered in the formulationof sunscreen products.