Avaliação da permeação cutânea do fármaco Ibuprofeno utilizando o óleo de copaíba como promotor de absorção em modelos experimentais "in vitro" e "in vivo"

Abstract

The administration of medications on the skin through transcutaneous routeis a practice that has been used by mankind for millennia. The non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to be a class of drugs of interest for transcutaneous formulation development, since they present severe gastro-intestinal effects when used for treatment of chronic diseases such as rheumatoid arthritis. Among drugs of this class, Ibuprofen (IBU) is considered a good candidate for skin permeation, since it has a low molecular weight (206.28), partition coefficient (log P) lower than 4 and short plasma half-life. Therefore, an effective strategy to facilitate the drug diffusion through the skin is the use of permeation enhancers. Recently, some studies have been reporting the use of terpenes and natural oils rich in terpenes and their roles in promoting cutaneous drug penetration. Copaiba oil, due to its rich content of terpenes, presents itself as a great choice of penetration enhancer for drugs administered on the skin. In this study, two cream formulations containing 5% of IBU were developed: IBOC5 with 5% of Copaiba oil and IBOC10 with 10% of the same oil. In vitro cutaneous penetration/permeation studies of IBU were performed using pig ear skin as biological membrane in the Franz-type diffusion cells. In vivo permeation tests were also performed through anti-inflammatory activity evaluation using Croton oil-induced mouse ear edema test. The permeation flux (J) of IBU samples, IBOC5 (35.72 + 6.35) and IBOC10 (29.78 + 2.41) were significantly higher (p < 0.01 and p < 0.05, respectively) when compared to control cream, without Copaiba oil (10.32 + 1.52) and to commercial product (14.44 + 2.39). In the penetration analysis, the amount of IBU found in the samples IBOC5 and IBOC10 was higher (p < 0.01 and p < 0.05, respectively) in dermis than epidermis. In vivo tests showed that samples IBOC5 and IBOC10 decreased (p < 0.05 e p < 0,001, respectively) inflammatory process when it was compared to the negative control, however they weren’t considered statistically different (p > 0.05) of positive control. Concluding, Copaiba oil showed a significant capability to promote skin penetration and permeation of ibuprofen when it was added into the cream samples, according to the in vitro diffusion cells test results. On the other hand, the results obtained from the in vivo method weren’t enough satisfactory considering the analyzed samples.