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Nephrotoxicity and pharmacokinetics of gentamicin were studied on rats treated with the antibiotic for 30 days in doses of 6.25, 12.5 and 25 mg/kg administered daily. The pharmacokinetics of gentamicin and the time course of changes in the urea nitrogen levels of the blood serum were studied after the 1st, 5th, 8th and 30th injection. The analysis of the respective curves was used for calculation of the average integral values of the concentrations of the antibiotic (C) and urea nitrogen (E). After that the average integral values of these parameters ((CAVG and EAVG respectively) within the whole treatment couse with the use of every dose were calculated in the same way by using the curves of the dynamics of C and E changing. Comparison of the diagrams of E dependence on C for gentamicin and sisomycin showed that nephrotoxicity of sisomycin was 1.48 times higher than that of gentamicin.

The pharmacokinetics of ampicillin was studied in 30 children with diseases of the upper respiratory tracts. The data obtained with a single administration of anhydrous ampicillin in a dose of 25 mg/kg were estimated on one-compartment model. It was shown that the maximum antibiotic levels in the serum were attained in 1.52 hours and averaged to 4.56 micrograms/ml. The antibiotic half-life was 1.24 hours. The period of half-absorption of the antibiotic was 0.66 hours. Comparison of the experimental results with the literature data showed that the pharmacokinetic properties of anhydrous ampicillin and ampicillin trihydrate were close.

The pharmacokinetics of cephalexin monohydrate after its oral administration in a single dose was studied on rats and dogs. The analysis of the pharmacokinetic data obtained with the one-compartmental model showed that the rate of the antibiotic absorption in the rats was higher than that in the dogs. The periods of the cephalexin half-absorption and maximum concentration were 0.2 and 1.1 hour in the rats and 0.64 and 1.9 hours in the dogs respectively. The period of the antibiotic half-life was almost the same in both animal species. Selective localization of cephalexin in the kidney and liver tissues was noted. The antibiotic was mainly excreted by the kidneys (98.8 per cent for 24 hours).

The pharmacokinetics of sisomicin in the blood, infection foci and urine of patients with wound infections was studied comparatively. Higher blood levels of the antibiotic after intravenous injection as compared to those after intramuscular injection provided its more intensive penetration into the tissues of the wound edges and bottom. After intravenous injection the sisomicin concentration in the tissues was sufficient for inhibition of the strains of Staphylococcus, E. coli and Ps. aeruginosa detected in the patients, while after intramuscular injection the antibiotic levels were sufficient only for inhibition of the first two causative agents. Comparison of the data on the sisomicin pharmacokinetics in the blood and tissues of the wounds provided the characteristics of the level of the drug penetration into the focus of the infection ("therapeutic availability"). Since the levels of sisomicin in the blood and infection foci were highly variable in different individuals. It is recommended that the antibiotic be used under the control of its concentrations in patients. It was shown that the data on the sisomicin renal excretion might be used for the purposes of the pharmacokinetic control.

The pharmacokinetics and safety of the lincomycin ointment and gel were studied. It was shown that diffusion of lincomycin through the skin was satisfactory. Investigation of their general toxicity and organotropic properties revealed neither irritating effect nor changes in the internal organs associated with the toxic effect of the drugs. On the basis of the data on the stability of the lincomycin ointment and gel obtained on their storage the lincomycin ointment was recommended for industrial production.