[Endogenous metabolites as modulators of the transport of drugs by serum albumin]. / Endogennye metabolity kak moduliatory transporta lekarstvennykh veshchestv syvorotochnym al'buminom.

The ability of serum albumin to bind reversibly on its surface drugs and to transport them in the process of distribution and elimination has been well established. Some endogenous metabolites, particularly unesterified fatty acids, bile acids, L-tryptophan and bilirubin which are formed both under physiological conditions and in pathological states of the organism, e.g., in uremia can displace drugs from their areas of binding on albumin molecule. The detection of endogenous metabolites and the study of the mechanism through which they displace drugs from the specific areas on plasma proteins is the urgent task of pharmacology.

[Role of maternal and fetal plasma proteins in transplacental transport of drugs]. / Rol' belkov plazmy materi i ploda v transplatsentarnom perekhode lekarstvennykh veshchestv.

One of the factors influencing the rate of drug transport through the placenta is their binding by maternal and fetal plasma proteins. Concentrations of the components binding the drug on both sides of the placenta influence significantly its distribution in the fetomaternal pair. It is emphasized that in plasma of a fetus or newborn there is observed the free fraction increase for most drugs--beta-adrenoblockers, local anesthetics, narcotic analgesics, antiarrthythmic and antiepileptic agents. As for salicylates, diazepam and valproic acid, one can note their accumulation in the fetal blood during labour to which side effects often observed in newborns after treatment with these drugs may be related. Free fatty acids of plasma influence the binding of drugs by maternal and fetal plasma proteins. In the published clinical papers on the drug binding by proteins of plasma of the fetomaternal pairs the transport role, in addition to serum albumin and acid alpha 1-glycoproteid, of alpha 1-fetoprotein as well is not taken into consideration. The drug transport by this protein can account for the contradiction of views on the role of maternal and fetal plasma proteins in the transplacental transport of drugs.