[Effect of different grades of agar-agar on the nature of the test microbe growth inhibition zones in controlling antibiotic activity by means of agar diffusion]. / Vliianie razlichnykh sortov agar-agara na kharakter zon zaderzhki rosta test-mikrobov pro kontrole aktivnosti antibiotikov metodom diffuzii v agar.

The effect of various agar grades on the size and margin character of the inhibition growth zones in assay of antibiotic activity by the agar diffusion method was studied. It was shown that not all the agar grades could be used in antibiotic activity assay. Depending on the agar type the size of the inhibition growth zones produced by the same antibiotic concentration significantly varied. The variations in the size of the inhibition growth zones depended on the agar ability to bind antibiotics and were mainly defined by the agar purity. The agars with low content of nitrogen admixtures bound the antibiotics to a low extent. The commerical grades of the agars of the South-Sea and Korsakov Plants, the experimental grade of the TINRO agar with additional purification, as well as the agars imported from Argentina and France proved to be most useful for determination of the antibiotic activity by the agar diffusion method.

[Quantitative determination of the gentamicin and dimethyl sulfoxide in the "Gentaplast" film-forming aerosol preparation]. / Kolichestvennoe opredelenie gentamitsina i dimetilsul'foksida v plenkoobrazuiushchem aérozol'nom preparate "Gentaplast".

A method for quantitative determination of gentamicin and dimethylsulfoxide (DMSO) in "Gentaplast", a film-forming aerozol preparation was developed. Gentamicin was determined microbiologically after extraction. DMSO was determined by titration with the use of the Redox method. The results of determination of gentamicin and DMSO in "Gentaplast" were statistically treated.

[Microbiological study of gentamiycin]. / Mikrobiologicheskoe izuchenie gentamitsina

Gentamycin prepared at the All-Union Research Institute of Antibiotics did not differ by its antibacterial spectrum and the activity level from gentamycin samples from other countries. By its activity against clinical strains of Ps. aeruginosa gentamycin was somewhat inferior than polymyxin but much more superior than carbenicillin. An agar-diffusion method using Bac. pumilus NTCC 8241 as the test microbe was developed for determination of gentamycin activity. The gentamycin sulfate complex and the components of gentamycin had the same activity levels, antibacterial spectrum and diffusion capacity.

[Gentamicin stability and a method for its quantititive determination]. / Ustoichivost' gentamitsina i metod ego kolichestvennogo opredeleniia

Stability of gentamycin in solutions at various pH levels was studied. It was shown that in acid media inactivation proceeded according to the equation of the 1st order reaction. Dependence of the inactivation rate constant on the temperature corresponded to Arrenium equation. A polarimetric procedure for determination of gentamycin providing the assay of the antibiotic levels at various purification stages biginning from the eluates after the ion-exchange columns is described. The results obtained with the above procedure were shown to correlate satisfactorily with those of the microbiological analysis.

[Determination of neomycin in the film-forming aerosol preparation "Neotizol'"]. / Opredelenie neomitsina v plenkoobrazuiushchem aérozol'nom preparate "Neotizol'"

A colorimetric method for guantitative determination of neomycin in the aerozol preparation "Neotizol" was developed. The determination was performed after neomycin isolation from the film-forming composition with the carboxylic ion exchange resins IRC-50 and KB-2 containing 2.5-3 per cent of divinylbenzol. The results of the colorimetric determination were compared with the data of the microbiological assay. The results of neomycin determination in the aerozol preparation "Neotizol" were treated statistically.