Evaluation of bases for topical preparations by microdialysis

微透析用于测定水杨酸、吲哚美辛外用和透皮制剂中碱的作用，以及曲尼司特透皮给药吸收促进剂的作用。所检测的软膏基质为溶剂型、聚脂型、白凡士林型、亲水性聚脂型吸收软膏、亲水性软膏。采用市售吲哚美辛凝胶和乳膏制备。结果表明：(1)透析液中水杨酸的回收率为4.8%。(2)溶碱处理下，水杨酸向完整皮肤的转移明显少于无角质层的皮肤。完整皮肤组织中水杨酸的最大浓度为68 μ M，去除鳞状层后，水杨酸的浓度增加了50倍。(3)水杨酸对水杨酸的转移效果较好，完整皮肤组织中水杨酸的最大浓度为622 μ m .白凡士林也有类似的结果。(4)亲水性聚乳酸软膏和吸收性聚乳酸软膏的效果与聚乳酸相似。(5)在疏水碱和吸收软膏中，皮肤组织浓度曲线下面积与血浆浓度曲线下面积的治疗比大于时间。这些结果表明，疏水碱和吸收软膏是有用的基础药物的局部作用。(6)吲哚美辛的回收率为5.2%。吲哚美辛从亲水性软膏和吸收性软膏向皮肤组织转移良好，在皮肤组织中的最大浓度为30-65 μ m .在吲哚美辛的商业制剂中也得到了类似的结果。(7) 20%油酸和10%丙二醇的混合物对曲尼司特的吸收促进效果最好。(8)最后，人们认识到微透析是评估局部透皮给药制剂功能的有用技术。

Microdialysis has been used to determine effects of bases for topicaland transdermal preparations of salicylic acid , indomethacin and effects of absorption enhancer for transdermal delivery of tranilast. The ointment bases examined were solbase, poloid, white petrolatum, hydrophilic poloid absorptive ointment, hydrophilic ointment. Also, gel and cream preparation of indomethacin on market were used. Results obtained in this study were as folows :(1) Recovery % of salicylic acid in the dialysate was 4.8%. (2) In case of solbase, transfer of salicylic acid to intact skin was remarkably less than the skin without stratum corneum. maximum concentration of salicylic acid in intact skin tissue was 68mu M and the value increased by5Ot imes by removal of stratum comeum. (3)In case of poloid, transfer of salicylic acid was fairly good and maximaum concentration in intact skin tissue was 622mu M.White petrolaum showed similar results. (4) Hydrophilic poloid and absorptive ointment showed similar results to poloid. (5)Theratio of area under the curve of concentration in skin tissue vs. time to area under the curve of concentration in plasma was greater in hydrophobic base and absorptive ointment. These results suggest that hydrophobic base and absorptive ointment are useful as a base for drugs of topical action. (6)Recovery % of indomethacin in the daillysate was 5.2%. Transfer of indomethacin to skin tissue from hydrophilic ointment and absorptive ointment was good and maximum concentration in skin tissue was 30-65mu M.Similar results was obtained in commercial preparations of indomethacin. (7)A mixture of oleic acid 20% and propyleneglycol 10% was most effectve as a absorption enhancer for tranilast. (8)Finally, it is recognized that microdialysis is a useful technique for evaluation of function of topical transdermal delivery preparations.