Gelatin-based microspheres crosslinked with glutaraldehyde and rutin oriented to cosmetics

ABSTRACT Glutaraldehyde (GTA) has been extensively used as a gelatin crosslinking agent, however, new natural ones have been suggested as more biocompatible. Polyphenols are possible candidates and the flavonols, such as rutin (RUT), also exhibit potential synergism with sunscreens and antioxidant agents used in cosmetics. In this work, gelatin microspheres (M0) were obtained and crosslinked with GTA 10 mM (MG) or RUT 10 mM (MR), dissolved in acetone:NaOH 0,01M (70:30 v/v). MG exhibited crosslinking extent of 54.4%. Gelatin, M0, MG and MR did not elicit any signs of skin damage, regarding the formation of erythema, the barrier function disruption and negative interference in the stratum corneum hydration. Oily dispersions containing M0, MG or MR, isolated or combined with benzophenone-3 or octyl methoxycinnamate, suggested that the microspheres, at a 5.0% w/w, had no additional chemical or physical photoprotective effect in vitro. Crosslinking with RUT had occurred, but in a lower degree than GTA. Microspheres had not improved sun protection parameters, although, non-treated gelatin interfered positively with the SPF for both UV filters. The in vivo studies demonstrated that these materials had very good skin compatibility.

Use of Curcuma longa in cosmetics: extraction of curcuminoid pigments, development of formulations, and in vitro skin permeation studies

Curcuma longa is a ginger family aromatic herb (Zingiberaceae) whose rhizomes contain curcuminoid pigments, including curcumin, a compound known for its anti-inflammatory effects. The objective of this study was to obtain curcuminoid-rich extracts, develop topical formulations thereof, and assess the stability and skin permeation of these formulations. Curcuma longa extracts were obtained and used to develop formulations. Skin permeation studies were conducted in a modified Franz diffusion cell system, and skin retention of curcuminoid pigments was quantified in pig ear membrane. Prepared urea-containing gel-cream formulations were unstable, whereas all others had satisfactory stability and pseudoplastic rheological behavior. The amount of curcuminoid pigments recovered from the receptor solution was negligible. The skin concentration of curcuminoid pigments retained was positive (>20 µg/g of skin, mostly in the stratum corneum), considering the low skin permeability of curcumin. We conclude that development of topical formulations containing curcumin or Curcuma longa extract is feasible, as long as adjuvants are added to improve preservation and durability. The formulations developed in this study enabled penetration of curcumin limited to the superficial layers of the skin and then possibly without a risk of systemic action, thus permitting local use as a topical anti-inflammatory.

Curcuma longa é uma erva aromática, pertencente à família Zingiberaceae e seus rizomas contêm pigmentos curcuminoides, dentre eles a curcumina, conhecida por seu efeito anti-inflamatório. O objetivo deste trabalho foi obter extratos ricos nestes pigmentos, desenvolver e avaliar a estabilidade de formulações tópicas e realizar o estudo da penetração cutânea. Extratos de Curcuma longa foram obtidos e utilizados no desenvolvimento de formulações. A penetração e retenção cutâneas de pigmentos curcuminoides foi avaliada em pele de orelha de porco, utilizando célula de difusão de Franz modificada. As formulações de gel creme preparadas que continham ureia foram instáveis e as demais apresentaram estabilidade satisfatória e comportamento reológico pseudoplástico. A quantidade de pigmentos curcuminoides encontrada na solução receptora foi insignificante, enquanto que a quantidade retida na pele foi superior a 20 µg/g de pele. Concluiu-se como possível o desenvolvimento de formulações tópicas contendo curcumina ou extrato de Curcuma longa, conciliando a adição de adjuvantes para a preservação e maior durabilidade da mesma. As formulações promoveram a penetração da curcumina limitada às camadas superiores da pele, possivelmente sem o risco de ocorrência de ação sistêmica sendo possível a sua utilização para ação local com atividade anti-inflamatória.