Understanding the way in which drug is released from drug carrying hydrogel based ophthalmic lenses aids in the development of efficient ophthalmic drug delivery. Various solute–polymer interactions affect solute diffusion within hydrogels as well as hydrogel–bulk partitioning. Additionally, surface modifications or coatings may add to resistance of mass transfer across the hydrogel interface. It is necessary to consider both interfacial resistances as well as the appropriate driving force when characterizing interface flux. Such a driving force is induced by a difference in concentration which deviates from equilibrium conditions. We present a Galerkin finite element approach for solute transport in hydrogels which accounts for diffusion within the gel, storage effects due to polymer–solute interaction, as well as partitioning and mass transfer resistance effects at the interface. The approach is formulated using a rotational symmetric model to account for realistic geometry. We show that although the resulting global system is not symmetric in the case of partitioning, it is similar to a symmetric negative semidefinite system. Thus, it has non-positive real eigenvalues and is coercive, ensuring the validity of the finite element formulation as well as the numerical stability of the implicit backward Euler time integration method employed. Two models demonstrating this approach are presented and verified with release experimental data. The first is the release of moxifloxacin from intraocular lenses (IOLs) plasma grafted with different polyacrylates. The second accounts for both loading as well as the release of diclofenac from disc shaped IOL material loaded for varied time periods and temperature.

了解从基于水凝胶的载药眼镜片中释放药物的方式有助于开发有效的眼药传递。各种溶质-聚合物相互作用会影响溶质在水凝胶中的扩散以及水凝胶-体的分配。另外，表面改性或涂层可增加跨水凝胶界面的传质阻力。在表征界面通量时，必须同时考虑界面电阻和适当的驱动力。这种驱动力是由偏离平衡条件的浓度差异引起的。我们提出了一种Galerkin有限元方法来分析水凝胶中的溶质，它解释了凝胶中的扩散，由于聚合物-溶质相互作用而产生的存储效应，以及在界面处的分配和传质阻力效应。该方法是使用旋转对称模型制定的，以解决实际几何问题。我们表明，尽管在分区的情况下所得的全局系统不是对称的，但它与对称的负半定系统相似。因此，它具有非正实数本征值并具有强制性，从而确保了有限元公式的有效性以及所采用的隐式向后欧拉时间积分方法的数值稳定性。展示了两种证明这种方法的模型，并用发布的实验数据进行了验证。首先是莫西沙星从嫁接到不同聚丙烯酸酯的人工晶状体（IOL）中释放出来。