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In search of reliable genetic markers of protracted and complicated pneumonia, the authors studied blood groups, haptoglobin phenotype, sulfadimisine acetylation. These markers proved essential for predicting pneumonia course and prognosis.

Genetic determination of pharmacokinetics of sulfalen, a new antibacterial drug, has been studied in 28 twin pairs of Moscow Russian population. In order to determine the degree of heritability of such pharmacokinetic parameters of sulfalen as t 1/2 (half-life); Vd and delta (apparent and specific volumes of distribution) and Co (apparent initial concentration) Holtsinger H-statistics values have been calculated, which are 0.891, 0.866, 0.766 and 0.797 respectively. Possible causes of discrepancies between these values and the coefficients of genetic determination G, calculated by decomposition of general phenotypical dispercion of the parameters via the main equation of quantitative traits of genetics are given (0.913, 0.762, 0.828, 0.856 in that order). The data obtained make it possible to assume that genetic determination t 1/2 of sulfalen is carried out within the system of monogenous interaction (HD = 0.91, HA = 0), that of Vd and Co--within the system of additive-polygenous interaction, while linear and non-linear effects contribute to delta determination (HD = 0.232, HA = 0.596).

Combined use of benzylpenicillin or ampicillin with sulfalen or sulfadimethoxine resulted in a decreased binding of the antibiotics to the blood serum proteins and slower elimination of penicillins from the experimental rabbits. It is quite possible that the decreased levels of the antibiotic binding to the proteins caused their slower elimination rates, which was realized by increasing the volume of the drug distribution mainly at the expense of the peripheral compartment and decreased excretion with the urine.

Combined use of sulfalen and sulfadimethoxine with benzylpenicillin and ampicillin resulted in increased binding of sulfalen to serum proteins of man. Acetylsalicylic acid promoted a decrease in the sulfanilamide binding to the serum proteins. The observed changes in the sulfanilamide binding to proteins of human blood serum were due to increased or decreased affinity of the drugs to the protein molecules.

Comparative study of sulfamonomethoxin pharmacokinetics in the man given the drug per os or parenterally in the form of methylglucaminate showed that the latter favours higher blood concentrations of the drug 12 hours following injection. Sulfamonomethoxinmeglumin is absorbed more rapidly and has a greater bioavailability. The drug is mainly excreted with urine, more than a half being excreted in an acetylated form. It is recommended that the initial and maintenance doses be not less than 1000 and 500 mg for both dosage forms respectively. The interval between sulfanilamide administrations should not exceed 24 hours.

The use of sulfalen and sulfadimethoxine in combination with acetylsalicylic acid resulted in the decreased binding of the sulfanilamides by serum proteins, most pronounced with respect to sulfadimethoxine. The decreased binding of the drugs by serum proteins in rabbits was accompanied by decreased elimination of sulfalen and increased excretion of sulfadimethoxine from the host. The different effect of acetylsalicylic acid on the kinetics of sulfalen and sulfadimethoxine in the rabbits was partially due to the unequivalent effect of the decreased binding of the sulfanilamides by the serum proteins on their combined use.

Half-life of sulfalen, a new antibacterial drug, with the biotransformation, performed by means of microsomal acetyltransferase, has been studied in 53 individuals of Moscow Russian population. The absence of sex dimorphism for the trait studied is demonstrated. Distribution of individuals according to values of the pharmacokinetic parameter mentioned within the population is bimodal with the correlation of phenotypic frequencies of "rapid" and "slow" inactivators--72 and 28%. Possible causes of discrepancies between the observed sulfalen inactivator frequencies and similar data on isoniazid are discussed.