Objectives: To evaluate the barrier function of different skin layers in the process of percutaneous drug absorption. Methods: In vitro permeability via intact or stripped skin of 6 drugs (5-fluorouracil, theo-phyllin...Objectives: To evaluate the barrier function of different skin layers in the process of percutaneous drug absorption. Methods: In vitro permeability via intact or stripped skin of 6 drugs (5-fluorouracil, theo-phylline, hydroquinone, barbital, isosorbide dinitrate and ketoprofen) with a wide span of lipophilicity were investigated in the patch dosage forms. Results: Characteristic parabolic relations was observed between the permeability (Kp, cm/h) of the drugs with different lipophilicity and their LogPc via either intact or stripped skin. However, due to the absence of the stratum corneum, increased Kp ratio for the tested drugs was proportional to their solubility in water other than their LogKp. When isopropyl myristate was used as absorption promoter of the drugs, the parabolic relationship no longer existed. For the intact skin, increase of Kp ratio of the drugs was enhanced resulting from IPM as drug's LogPc decreased. On the other hand, in the case of stripped skin, this enhancement was positively related to the solubility of the drugs in IPM. Conclusion : These data and methods present a novel approach to describe percutaneous drug absorption via damaged or diseased skin.展开更多
文摘Objectives: To evaluate the barrier function of different skin layers in the process of percutaneous drug absorption. Methods: In vitro permeability via intact or stripped skin of 6 drugs (5-fluorouracil, theo-phylline, hydroquinone, barbital, isosorbide dinitrate and ketoprofen) with a wide span of lipophilicity were investigated in the patch dosage forms. Results: Characteristic parabolic relations was observed between the permeability (Kp, cm/h) of the drugs with different lipophilicity and their LogPc via either intact or stripped skin. However, due to the absence of the stratum corneum, increased Kp ratio for the tested drugs was proportional to their solubility in water other than their LogKp. When isopropyl myristate was used as absorption promoter of the drugs, the parabolic relationship no longer existed. For the intact skin, increase of Kp ratio of the drugs was enhanced resulting from IPM as drug's LogPc decreased. On the other hand, in the case of stripped skin, this enhancement was positively related to the solubility of the drugs in IPM. Conclusion : These data and methods present a novel approach to describe percutaneous drug absorption via damaged or diseased skin.
