Formulation and in vitro penetration study of transfersomes gel containing gotu kola leaves extract (Centella Asiatica L. Urban)

Objective: Asiaticoside from gotu kola leaves extract (Centella asiatica L. Urban) could be used for anti-aging cosmetics. Nevertheless, its skin penetration is difficult, since it has a high molecular weight. Transfersome is a suitable carrier system that can enhance the penetration of active substances. The aims of this study were to prepare and characterize transfersomes of gotu kola leaves extract and formulated them into a gel, a control gel was also prepared without transfersome. Methods: Transfersomes were formulated with different concentrations of active substance, which was equal to asiaticoside 0.3% (F1), 0.5% (F2) and 0.7% (F3). The obtained transfersomes were evaluated for entrapment efficiency, particles morphology, particles size, polydispersity index, zeta potensial, deformability index, and penetration study using Franz diffusion cells. The best transfersomes was formulated into a gel dosage form, and then evaluated. Results: The results showed that the F1 transfersomes was the best transfersomes, hence it was incorporated into gel dosage form. The F1 transfersomes had spherical morphology with the highest entrapment efficiency of 85.80%, ninety percent of the particle size distribution (D_V90) was below 204.3 nm, polydispersity index of 0.125, zeta potensial of -36.3 mV and deformability index of 1.12. The cumulative amount of penetrated asiaticoside was 1050.85 ± 19.82 μg/cm² for transfersomes gel and 540.21 ± 12.28 μg/cm² for control gel. The cumulative percentage of penetrated asiaticoside for transfersomes gel and control gel were 51.80 and 26.63%, respectively. The flux of transfersomes gel containing asiaticoside and control gel were respectively 47.92 and 26.57 μg/cm²/h. Conclusion: The subcutaneous penetration of asiaticoside from the transfersomes gel containing gotu kola leaves extract increased compared to the control gel without transfersomes.