O/W型水杨酸微乳的制备与质量评价OA

The O/W microemulsions containing salicylic acid were prepared and evaluated.Isopropyl myristate was used as the oil phase and a mixture of Tween 80 and polyethylene glycol 400(1:1)was used as the mixed surfactants.The microemulsion formulation was optimized by solubility analysis,pseudo-ternary phase diagram construction,and central composite design-response surface methodology.The results showed that,the optimized formulation,consisting of 5%oil phase and 42.7%surfactant mixture,achieved a maximum drug-loading capacity of 48.303 mg/g.The microemulsion thus prepared was a transparent,clear O/W liquid with particle size of(7.66±0.31)nm and polydispersity index of 0.11±0.04,demonstrating excellent thermal and freeze-thaw stabilities.In vitro release experiments showed that the microemulsion exhibited sustained release of salicylic acid in different media,with cumulative release rates approaching 82%to 96%over 48 hours,which was significantly higher than those of free salicylic acid.In addition,in vitro tyrosinase inhibition assays indicated that the microemulsion enhanced the bioavailability of salicylic acid,achieving inhibition rate of over 95%when the salicylic acid content was 0.5%or more.In conclusion,the optimized microemulsion formulation had superior drug-loading capacity,stability,and sustained-release characteristics,effectively improving the therapeutic efficacy of salicylic acid.This microemulsion system was proposed as a potential drug delivery carrier,which might offer new technical support for the clinical application of salicylic acid.