RESUMEN
<p><b>AIM</b>To prepare capsaicin transfersomes and evaluate them in vitro and in vivo.</p><p><b>METHODS</b>Capsaicin transfersomes were prepared by high shear dispersing machine and evaluated by entrapment efficiency, release rate, in vitro skin permeation and distribution in different tissues in vivo.</p><p><b>RESULTS</b>Capsaicin transfersomes were composed of single unilamellar vesicles with an average diameter of 150.6 nm. Capsaicin entrapment efficiency increased distinctly with increasing of concentration of lecithin and entrapment efficiency is 96.7% while concentration of lecithin to 8%. Cumulative release amount of capsaicin is in direct proportion to the ethanol concentration in the receptor medium. In vitro capsaicin cumulative penetration amount showed higher levels in transfersomes than cream and suspension in rat abdominal skin. Abdominal skin cumulative penetration amount in vitro of capsaicin transfersomes in mouse was significantly higher than that from rat and men. In the same way, abdominal skin epidermal membrane cumulative penetration amount in vitro of capsaicin transfersomes was significantly higher than that from derma and full skin in human abdominal skin. The capsaicin tissue distribution of capsaicin injection by multiple celiac injections in rats is different: bone > plasma > skin > muscle. There is a similar result by multiple thigh topical application of capsaicin transfersomes: bone > skin > plasma > muscle.</p><p><b>CONCLUSION</b>Entrapment efficiency of capsaicin transfersomes reached the criterion of China Pharmacopoeia (> 80%) and capsaicin skin penetration can be increased by capsaicin transfersomes. It should be noted that the diverse characters and levels of skin may probably affect the permeating capability of capsaicin. Capsaicin tissue distribution in bone and muscle is similar and is different in plasma and skin by multiple injections and topical skin apply.</p>