Curcumin-laden amphiphilic chitosan microemulsion with enhanced transdermal delivery, skin compatibility and anti-arthritic activity

Transdermal administration can avoid the first-pass effect of liver, improve the bioavailability of drugs and the adaptability of patients. However, there are still many problems, such as low load efficiency, short drug half-life, unfavorable transdermal efficiency, poor skin compatibility, which hinder the development of transdermal administration. In order to solve the above problems, amphiphilic chitosan microemulsion (AC-ME) is developed by using chitosan with hydrophilic carboxyl groups and hydrophobic long alkane chains as surfactant. AC-ME is efficient for drug loading and transdermal delivery , which is demonstrated by extremely high drug loading, improved drug stability and excellent transdermal efficiency. Specifically, the loading amount of curcumin (Cur) can reach up to 3.41 ± 0.13 mg/mL, an increase of approximately 30,000 times compared to its water solution. The light stability of Cur is improved from 43% to 75%. The transdermal process and skin retention of Cur exhibit 1.76-fold and 5.29-fold increase, respectively. Moreover, AC-ME is skin-compatible and does not damage skin structure. Finally, AC-ME can improve the therapeutic effect of Cur and exhibit superb anti-inflammatory effect in the rheumatoid arthritis (RA) model of mice. In a word, AC-ME would be a promising drug carrier for transdermal drug delivery.