Determination of iodine-containing admixtures in semisynthetic penicillins

Dependence of the values defining the content of iodine sorbing admixtures in semisynthetic penicillins on pH, reaction time and drug aliquots was studied. On the basis of this study a general approach to development of procedures for determining iodine sorbing admixtures in semisynthetic penicillins was suggested. Procedures for determination of iodine sorbing admixtures in carbenicillin, carfecillin, ampicillin, oxacillin, azlocillin and ampiox were developed.     

The determination of lipopolysaccharide admixtures in protein preparations

A new method for the determination of lipopolysaccharide (LPS) admixtures in protein solutions has been developed. The method includes the periodate oxidation of LPS, biotinylation with biotin hydraside, immobilization on a nitrocellulose membrane and the development of biotinylated LPS in the streptavidin--alkaline phosphatase system. Proteins are previously removed from the solution by treatment with hot phenol. Development with the use of 5-bromoinodyl phosphate and nitrotetrazolium blue makes it possible to detect about 30 pg of LPS immobilized on the nitrocellulose membrane.     

Removal of biologically active admixtures from immunoglobulin preparations

Inclusion of an additional treatment of the products obtained at centrifugation stages b1 and b13 with activated bentonite and aluminium hydroxide into the alcohol method for the production of immunoglobulin from placental and abortion blood permits obtaining preparations with lowered content of proteolytic enzymes and thermostable acid phosphatase, free from chorionic gonadotropin and blood pigment. The treatment of the final preparation with DEAE cellulose removes blood group antigens from immunoglobulins. The preparations obtained by this method have been shown to meet the requirements for immunoglobulins imposed by technological specifications.     

Spectral control of metal admixtures in tetracycline]

Analysis of circular dichroism spectra made it possible to offer a method for estimation of tetracycline solutions contamination with metal ions. By its sensitivity the method is much superior to the spectrophotometric one used at present for determination of the antibiotic purity. In the latter method formation of complexes with metals is traced by batochromic displacement of the absorption spectra. The new method is rapid, relatively selective and requires comparatively small quantities of the substance for the analysis, which provides its use under both laboratory and manufacture conditions. The method is based on identification of the circular dichroism spectra of tetracycline complexes with metals in the long wavelength region. The presence of the circular dichroism concervative bands with strictly defined extremums in the spectra of tetracycline low acid solutions contaminated by multiply charged metal ions allowed vs. the circular dichroism spectra of pure tetracycline sample to conclude that the solution contained admixtures and to suggest their nature. It was shown that the charge, ion radius and tetracycline:metal relation were the factors defining the mark and location of the dichroism band extremums. At lambda(extr)-410-415 nm the tetracycline complexes with light metal ions such as Mg2+, Al3+ and Ca2+ were detected by the circular dichroism negative band in the spectra, while the complexes with heavy metal ions such as Sc3+, Sr3+, Cu3+, Cd3+, Ba2+, Y3+ and the cerium subgroup lanthanides were detected by the circular dichroism positive band. The tetracycline complexes with the lanthanides of the second half of the yttrium subgroup (Ho(3+)-Lu3+) were characterized by the presence of the circular dichroism minimum at lambda(min)-425 nm. When the tetracycline concentration was above 1.5 x 10(-3) M, multiligand complexes with circular dichroism negative extremum at lambda(min)-400 nm formed.     

Absorption spectrum of admixtures coloring butyl acetate extract

Colour of butyl acetate extract (BAE) at the clarification stage in chemical purification of benzylpenicillin is one of the important qualitative parameters necessary for the process control. BAE is benzylpenicillin-enriched butyl acetate with colouring pigments and admixtures of unknown nature. The routine laboratory photocolorimetric method provides only periodical control. It is labour-consuming and does not enable determination of the process end. The specific characteristics of the butyl acetate extracts and their components in UV and visible spectra were studied and the absorption region of the admixtures (350-500 nm) colouring the extract with a maximum at 390 +/- 10 nm was determined. A photometric method, a definite wave length and analyzer Luch-II are recommended for optimal control of the clarification process. The apparatus was tested under laboratory conditions.     

Purification of antibiotic solutions of finely dispersed admixtures]

A possibility of complete separation of fine disperse admixtures from antibiotic fermentation broth filtrates by filtration with the use of special additives was shown. The purity of the filtrates and filtration rate depended on the procedure of addition, amount and average size of the particles of the filtration material.     

Determination of bacterial endotoxin admixtures in inactivated influenza vaccines

The materials substantiating the possibility of using the method for the determination of the lethal effect of endotoxin on dactinomycin-treated mice are presented. This determination is made with a view to detecting the admixtures of endotoxins in whole-virion and subvirion inactivated influenza vaccines at different stages of their manufacture, as well as in the final product. The proposed test is highly sensitive, rather simple in its practical realization and can be used for evaluating the degree of the purification of influenza vaccines from endotoxins.     

Methods of determining admixtures in commercial preparations of tetracycline]

The results and conditions of separation and quantitative determination of the admixtures of epi- and anhydro-derivatives of tetracycline in its market products were compared and analyzed using the following chromatographic methods: chromatography in a thin layer of a sorbent in 2 modifications, circular paper chromatography, chromatography on a column of gel Sephadex G-25. The comparison of the results of the study provided recommendation of the column chromatography with gel Sephadex G-25 for separate or summation quantitative determination of 4-epitetracycline. The method of chromatography in a thin layer of a sorbent may be successfully used for semiquantitative determination of the admixture levels in tetracycline market drugs.     

Elimination of admixtures from antibiotic sediments during their treatment with solvents

A model for determination of the admixture concentration in the secondary mother solution was developed. The concentration was determined depending on the solvent volume used for repulping the precipitate and on the impurity level of the initial antibiotic paste. When the values of X1 and X2 are known it is possible to estimate the amount of the admixtures remaining in the paste layer after separation of the secondary mother solution with regard to the volume of the latter in the precipitate pores. Optimization of paste repulping should be considered in combination with displacement washing and the apparatus used for separation of the phases, as well as the requirements for the purity level of the finished product.     

Thermal stability of glucose oxidase and its admixtures with synthetic polymers

The thermal stability of glucose oxidase in solution was studied as a function of time and temperature between 37–60°C. As expected, the rate of thermal inactivation increased with temperature and at 60°C more than 80% of the enzyme's activity was lost after 0.5 hr incubation. Similar stability measurements on enzyme solutions containing water soluble synthetic polymers showed that several of the polymers significantly enhanced the thermal stability of glucose oxidase. Copolymers of vinyl acetate with either vinyl pyrrolidone or vinyl alcohol were found to be particularly effective. The molecular weight of the added polymers was found to be unimportant in the stabilization process but both polymer concentration and compositions were shown to be critical parameters.