Characteristics of Methotrexate transport by normal and leukemic human leukocytes were measured in vitro. At high external drug levels (3:20 MM) drug uptake by all cell types was temperature-insensitive, nonsaturable, and nonconcentrative. The steady-state cell/medium drug distribution ratio was about 0.03. During clinical treatment with Methotrexate, plasma drug levels generally reach 0.2 MM. ...

An incomplete understanding of the transport forces and local tissue structures that modulate drug distribution has hampered local pharmacotherapies in many organ systems. These issues are especially relevant to arteries, where stent-based delivery allows fine control of locally directed drug release. Local delivery produces tremendous drug concentration gradients and although these are in part...

Diffusion coefficients of drug compounds are crucial parameters used for modeling transport processes. Interestingly, diffusion of a solute can be generated not only by its own concentration gradient but also by concentration gradients of other solutes. This phenomenon is known as multicomponent diffusion. A multicomponent diffusion study on drug-surfactant-water ternary mixtures is reported he...

Psyllium has a mucilaginous property that makes it a good candidate to be utilized as an excipient in the preparation of controlled release systems. Various formulations were prepared using theophylline as a model drug and investigated with a view to achieve an ideal slow drug release profile. The addition of hydroxypropyl methylcellulose (HPMC) to psyllium significantly reduced the burst relea...

There is increasing evidence that pregnancy alters the function of drug-metabolizing enzymes and drug transporters in a gestationalstage and tissue-specific manner. In vivo probe studies have shown that the activity of several hepatic cytochrome P450 enzymes, such as CYP2D6 and CYP3A4, is increased during pregnancy, whereas the activity of others, such as CYP1A2, is decreased. The activity of s...