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Biomedical subjects

H Y Ando

Publications and source records attributed to H Y Ando.

22 records · Page 2Linked to original sources
PubMed1978

Kinetics of drug transport and concurrent metabolism in human cell cultures I: theory.

A method for evaluating the passive permeability and single-step metabolism of drugs in suspension cultures of mammalian cells was formulated assuming linear kinetics. It was assumed that the metabolizing enzymes are driven by endogenous substrates present in steady-state quantities. The presence of the drug in radiolabeled tracer quantities was assumed to cause only a small perturbation from the endogenous steady-state operating point. The time course solutions for the drug and its metabolite are given in terms of macroscopic constants, and their physical interpretations are given in terms of metabolic and transport parameters.

Biological Transport↗
PubMed1977

Skin as an active metabolizing barrier I: Theoretical analysis of topical bioavailability.

A model and explicit equations were developed to be used in the experimental design and data evaluation of situations where simultaneous metabolism and transport of drugs occur in the skin. By treating the skin as a two-ply laminate composed of the stratum corneum and the viable epidermis, which contains most of the catabolic enzymes that might render a drug inactive by metabolism, equations were developed permitting the in vitro assessment of factors that may affect topical bioavailability in vivo. Two situations were investigated. In the first, the drug was placed on the dermis side of the diffusion cell and did not penerate the stratum corneum. In the second, the drug, placed on the epidermis side, penetrated the stratum corneum and then passed through the metabolizing epidermis. Expressions for determining the metabolic rate constant from experimental data along with concentration profiles and flux expressions are given both for the drug and its metabolite.

Administration, Topical↗