Otto H. York Department of Chemical, Biological and Pharmaceutical Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA.
Math Biosci. 2011 Jan;229(1):16-21. doi: 10.1016/j.mbs.2010.10.004. Epub 2010 Oct 30.
A method was proposed to evaluate the effect of desquamation on the time to reach steady-state drug delivery rate and concentration in the skin layers. Evaluation of the effective time constant, in terms of key physicochemical properties of the system, does not require solving the fundamental equations. Laplace transforms and the residue theorem were applied to monitor the evolution of the medicament in the skin layers and subsequent uptake into the systemic circulation. The equilibrium flux and the effective time constant declined with increasing stratum corneum turnover velocity and were not affected by the speed at which cells in the viable epidermis moved toward the surface of the skin. Ninety eight percent of the equilibrium penetration rate was reached after four time constants. This dynamic metric helped measure the extent to which high lipophilicity or molecular weight delayed percutaneous drug absorption.
提出了一种评估角质层剥落对达到稳定药物传递速率和皮肤各层药物浓度时间的影响的方法。从系统的关键物理化学性质方面评估有效时间常数，无需求解基本方程。拉普拉斯变换和留数定理被应用于监测药物在皮肤各层中的演变以及随后进入体循环的情况。平衡通量和有效时间常数随角质层周转率的增加而降低，且不受表皮活细胞向皮肤表面移动速度的影响。经过四个时间常数后，达到 98%的平衡渗透速率。这种动态指标有助于衡量高亲脂性或分子量如何延迟经皮药物吸收。
