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S Djokić

Publications and source records attributed to S Djokić.

10 recordsLinked to original sources
PubMed1995

10,11,12,13-Tetrahydro derivatives of tylosin. II. Synthesis, antibacterial activity and tissue of 4'-deoxy-10,11,12,13-tetrahydrodesmycosin.

4'-Deoxy-10,11,12,13-tetrahydrodesmycosin was prepared in six-step reactions. Antibacterial screening shows retained antibacterial spectrum of tylosin with some improvement against tylosin-sensitive Staphylococci and Haemophilus influenze. However, the pharmacokinetic data demonstrated rapid distribution from blood in tissues and prolonged maintenance in all tissues, especially in the lungs, in comparison with tylosin.

Animals↗
PubMed1994

Structure-activity relationship among polyhydro derivatives of tylosin.

Tetra-, hexa- and octahydro derivatives of tylosin were prepared by the reduction of the conjugated double bond and carbonyl groups. Hydrogenation of the diene did not change the in vitro antimicrobial activity of compounds, while reduction of carbonyls causes small or complete loss of activity.

Magnetic Resonance Spectroscopy↗
PubMed1992

Disk diffusion sensitivity testing and antibacterial activity of azithromycin.

Azithromycin (CAS 83905-01-5) disks with the selected loading (10, 15, 20 micrograms) were used for determination of the most suitable azithromycin disk concentration. Estimation was carried out by means of the regression line related to the zone size inhibition. Testing was performed on a variety of freshly isolated gram-positive, gram-negative and anaerobic bacteria derived from various specimens collected from patients. Using the disk diffusion method with 10 micrograms of azithromycin per disk in total 431 gram-positive, 875 gram-negative bacterial strains and 59 anaerobic bacteria were analysed. It was concluded that azithromycin disk containing 10 micrograms is sufficient for determination of bacterial sensitivity.

Anti-Bacterial Agents↗
PubMed1988

Comparative studies on the effects of erythromycin A and azithromycin upon extracellular release of lysosomal enzymes in inflammatory processes.

In the present studies the in vivo and in vitro effects of erythromycin A and azithromycin, a new type of macrolide (Fig. 2.), were investigated upon extracellular release of lysosomal enzymes, beta-glucuronidase (beta-Gluc) and beta-N-acetylglucosaminidase (beta-Glm) by using two experimental model systems: in vivo-adjuvant-induced arthritis in rats and in vitro- human polymorphonuclear leucocytes (PMNL) exposed to bovine serum albumin/anti-bovine serum albumin (BSA/anti-BSA), immune complex. Administrations of erythromycin A or azithromycin at doses of 5, 10 and 15 mg/kg into rats one day prior and 2, 4, 6, 8 and 10 days after a single subplantar injection of Freund's complete adjuvant significantly (p less than 0.01) inhibited extracellular release of lysosomal enzymes tested in the synovial fluid of injected left hind paw. These effects were dose-dependent. Further, erythromycin A and azithromycin at concentrations of 10(-7) M, 10(-6) M and 10(-5) M significantly (p less than 0.01) reduced excocytosis of both lysosomal enzymes, beta-Gluc and beta-Glm from human PMNL initiated by BSA/anti-BSA in a dose-related fashion. However, azithromycin was by far more effective (p less than 0.01) in decreasing extracellular release of beta-Gluc and beta-Glm either in the in vivo or in vitro experiments in comparison with erythromycin A. Appropriate control experiments excluded the possibilities that erythromycin A or azithromycin interfered with activities of lysosomal enzymes or with test reagents. Also, in no instances was there enhanced release of a cytoplasmic enzyme LDH.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1987

Erythromycin series. XII. Antibacterial in vitro evaluation of 10-dihydro-10-deoxo-11-azaerythromycin A: synthesis and structure-activity relationship of its acyl derivatives.

Antibacterial in vitro evaluation of 10-dihydro-10-deoxo-11-azaerythromycin A (5), the new 15-membered semi-synthetic macrolide antibiotic with nitrogen as additional atom in the aglycone ring of erythromycin A (1), was reported. Although amine (5) and its 13,14-cyclic carbonate (14) were less active than 1 against erythromycin-sensitive Staphylococcus aureus strains they showed advantageous properties against Gram-negative test organisms and clinical isolates. Also, a large number of acyl derivatives of 5 were synthesized and evaluated. N-11 monoacyl compounds exhibited 2 to 50 times lower in vitro antibacterial efficacy than the parent amine (5).

Anti-Bacterial Agents↗
PubMed1978

Erythromycin VI: kinetics of acid-catalyzed hydrolysis of erythromycin oxime and erythromycylamine.

Kinetic data were obtained, by qualitative and quantitative analysis, of the hydrolytic degradation of erythromycin oxime and erythromycylamine separated by TLC. The pseudo-first-order rate constants were determined at three temperatures (17,26, and 36 degrees), and the temperature dependency of the reaction was studied. The activation energy for the hydrolysis and methanolysis of the compounds was calculated. The factors contributing to the differences in the reaction rate are discussed.

Amines↗
PubMed1977

Erythromycin series. V. Quantitative analysis of cladinose and methylcladinoside by densitometry of thin-layer chromatograms.

A direct, quantitative, thin-layer chromatographic method is described for the determination of sugar cladinose and methylcladinoside in the presence of other acid-degradation products of the antibiotics erythromycin oxime and erythromycyl-amine. Cladinose and methylcladinoside are separated from compounds which cause interference on pre-coated silica gel F254 plates, and are measured directly on the thin-layer plate using a densitometer. Standard graphs obtained for cladinose and methylcladinoside show a linear relation between the square root of the peak area and the logarithm of the amount of substance present in the spot, as well as between the square of the area and the logarithm of the amount. This method is very successful in stability studies on the antibiotics erythromycin oxime and erythromycylamine in an acid medium. The technique seems to be particularly useful in instances in which the usual analytical methods either cannot be applied or can be applied only with difficulty.

Chromatography, Thin Layer↗