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Biomedical subjects

S M Navashin

Publications and source records attributed to S M Navashin.

At least 37 records · Page 2Linked to original sources
PubMed1993

[A comparative study of liposome-incorporated beta-lactam antibiotics, fluoroquinolones and cephalosporin conjugates with fluoroquinolones].

Beta-lactam antibiotics (some penicillins and cephalosporins), a fluorquinolone (pefloxacin) and cephalosporin conjugates with fluorquinolones were liposome-encapsulated by the method of detergent dialysis. Under the experimental conditions the entrapment of the beta-lactams and pefloxacin to liposomes did not exceed 20 and 12.5 per cent of the initial quantity respectively. The liposome entrapment of the cephalosporin conjugates with fluorquinolones was much higher. The entrapment of the cefotaxime conjugate with ciprofloxacin amounted to 40 per cent and that of the cefamandol conjugate with pefloxacin amounted to 95 per cent of the initial quantity.

Anti-Bacterial Agents↗
PubMed1993

Use of gentamicin physiologically-based model for individual dosing.

A new approach to fixing initial doses of gentamicin (GM) for i.m. administration (that is most commonly used anyway) is discussed. This approach is based on a physiologically-based model allowing to reproduce individual patterns of GM concentration change in the patient's blood. This approach was used to reproduce the individual pattern of GM concentration change after the initial i.m. administration of 80 mg to 19 male patients (age-range 21 to 73 years, weight range 50-94 kg, creatinine concentration in the blood 0.4-1.6 mg/d). The GM concentration levels, obtained with the help of this model, were afterwards compared to the results of FPIA measurement of GM concentrations in the blood of the patients 0.5, 1, 2, 3, 5 and 7 h after administration. It proved that the average deviation of the predicted values from the actual was equal to 20 per cent for all the measuring time-points. For comparison we used individual patterns of GM distribution in blood calculated according to the one-compartment model from the same values of Vd, Cl and dose. In this case the error of pharmacokinetic prediction exceeded the 20 per cent and amounted to 43 per cent by 0.5 and 7 hours. Thus, the new approach with the physiologically-based model provides better accuracy for stable pharmacokinetic prediction for longer stretches of time upon administration, which is especially important for the correct establishment of dosing intervals.

Adult↗
PubMed1992

[Incorporation of an antineoplastic drug aclarubicin into liposomes in relation to the conditions of its encapsulation].

The results of liposome drug encapsulation of aclarubicin (aclacinomycin A), an antitumor antibiotic, are presented. The method of flow detergent dialysis was applied. Conditions providing maximum encapsulation of aclarubicin (the ratio of lipid components and the lipid/detergent ratio), as well as conditions providing stability of liposomal emulsion (the presence of antioxidants, stearic acid and cholesterol) were defined.

Aclarubicin↗
PubMed1992

[Obtaining liposomal preparations of various biologically active substances by the method of detergent flow analysis].

It was shown that detergent dialysis could be successfully used for liposomal encapsulation of substances belonging to different chemical groups with diverse therapeutic activity such as rifampicin, aclarubicin, amphotericin B, pefloxacin and insulin. Liposome encapsulation of substances poorly soluble or insoluble in aqueous media was likely the most promising. The optimal incorporation depended on both the composition of the lipids forming the liposomes and the properties of the compounds being encapsulated.

Anti-Bacterial Agents↗
PubMed1992

[Experience with using aclarubicin in the treatment of acute leukemia and blast crisis of chronic myeloid leukemia].

The clinical efficacy of aclarubicin, an anthracycline antibiotic, was studied in 48 patients with leukemia. The antibiotic was used in the following combinations with cytarabine: "7 + 7", "5 + 5" and "7 & 3". A complete remission was stated in 14 (42.4 per cent) out of 33 patients with acute nonlymphoid leukemia, 6 (43 per cent) out of the 14 patients having relapses. The combined therapy was effective in 4 out of 5 pre-resistant patients. The "7 + 3" scheme was the most beneficial. The most common adverse reactions were nausea and vomiting.

Aclarubicin↗
PubMed1991

[The antitumor activity of liposomal aclarubicin in vitro and in vivo].

Study on antitumor activity of free and liposomal anthracycline antibiotic aclarubicin in vitro and in vivo showed that liposomal aclarubicin was characterised by activity against ascitic Ehrlich carcinoma comparable to that of free aclarubicin when used in a dose of 25 mg/kg. Liposomal antibiotic had a more pronounced antimetastatic action and showed no toxicity (in a dose of 30 mg/kg). Liposomal aclarubicin had a higher activating capacity with respect to the macrophage tumoricidal properties.

Aclarubicin↗
PubMed1991

[Activity of glycolysis enzymes in cyclosporine-producing Tolypocladium sp].

Enzymes of various glycolysis stages, i.e. hexokinase, phosphofructokinase, pyruvate kinase and lactate dehydrogenase, were detected in cyclosporine-producing organisms belonging to Tolypocladium. The initial activity of the enzymes in the highly active strain was much higher than that in the starting low active strain. During the fermentation the activity of the glycolysis enzymes per 1 mg of mycelium protein in the both strains increased. This was accompanied by a decrease in respiration activity. Therefore, there was a direct correlation between cyclosporine biosynthesis and glycolytic activity of the mycelium in Tolypocladium sp.

Cyclosporine↗
PubMed1990

Quantitative analysis of antimicrobial effect kinetics in an in vitro dynamic model.

Variants of the available methods for estimating antimicrobial effect kinetics in an in vitro dynamic model were analyzed. Two integral parameters characterizing antimicrobial effect duration (TE) and intensity (IE) are suggested to define and analyze the concentration-effect relationships in these models, irrespective of the method of recording. TE is defined by the time from the moment of antibiotic administration to the movement when the bacterial count again reaches its initial level. IE is defined by the area between the microbial growth curves in the presence and absence of an antibiotic. TE and IE were used to quantify the antimicrobial effects of sisomicin on Pseudomonas aeruginosa 58, Escherichia coli 93, and Klebsiella pneumoniae 5056, simulating the pharmacokinetic profiles of the drugs observed following intramuscular administration in therapeutic doses, including the variability of aminoglycoside concentrations in human blood.

Anti-Bacterial Agents↗