Effects of nonionic surfactants on the physical stability of immunoglobulin G in aqueous solution during mechanical agitation.

The objective of this study was to evaluate the influence of nonionic surfactants in the presence of glycine and sodium chloride on the physical stability of immunoglobulin G (IgG) in aqueous solution. Among surfactants suitable for parenteral preparation, Polysorbate 80 (Tween 80) and Polyoxyl 35 Castor Oil (Cremophor EL) were selected. The physical stability of IgG in the absence and in the presence of excipients was investigated in aqueous solution during mechanical agitation (concentration of IgG 15%; pH 7.1; temperature 6 +/- 2 degrees C). Suitable concentrations of Tween 80 and Cremophor EL were experimentally determined by surface tension measurements at 6 +/- 2 degrees C. Glycine and sodium chloride were used in different concentrations. The influence of the excipients on the physical stability of IgG in solution has been examined by surface tension measurements, protein content assay (Kjeldahl and HPLC) and differential scanning calorimetry (DSC). Based on the results of the investigations, it was found that Tween 80 and Cremophor EL, used in experimentally determined critical micelle concentration (cmc), decreased the physical stability of IgG in solution. Tween 80 and Cremophor EL in the presence of glycine (1.5 g/l) could stabilize the IgG in solution during mechanical agitation. The comparison of the effects of Tween 80 and Cremophor EL on the physical stability of IgG, showed that Tween 80 had better stabilization effects on IgG in solution under the experimental conditions selected.

[UV-densitometry determination of pentazocine hydrochloride in tablets after low temperature extraction]. / UV-denzitometrijsko odredjevanje pentozocin hidrohlorida u tabletama nakon termomikro extrakcije.

TLC-UV densitometric method has been used for quantitative analysis of pentazocine hydrochloride in the pure form, as well as in tablets after thermomicro extraction and direct application on the thin layer plate. This procedure was based on the conversion of the investigated substance into the gaseous state, quantitative application on the silica gel GF254 plate and the elution was made with 100:0.15 (v/v) methanol-conc. ammonium hydroxide. Gas chromatography-mass spectometric identification was performed by NIST 90 mass spectra library. Densitometric determination of pentazocine hydrochloride was performed by HPTLC Scanner on 278 nm and the results were compared to the officinal BP 93 method. The method was precise (RSD % 0.69-3.88), accurate (recovery 96.04-101.65) and reproducible (SD 0.03-0.23). The linearity level (correlation coefficient r = 0.9911) was very satisfactory.

[Preparation and testing of buffers for fibrinogen]. / Izrada i ispitivanje pufera za fibrinogen.

Chloride-citrate-glucose solution was used in fibrinogen preparation for intravenous administration. Concentrated hydrochloric acid previously used for preparation of buffers for fibrinogen has been replaced by the diluted one enabling easier and more precise buffer pH regulation and faster fibrinogen dissolution. Procedure for spectrophotometric determination of the total citrate ion buffer system, sodium-citrate and citric acid was developed. Obtained results were within the prescribed limits but the ones obtained by officinal titration in non-aqueous medium were significantly decreased. Glucose was determined before sterilization by polymetric, and after sterilization by iodometric procedure. Chloride content was determined by coulometric titration and sodium content by flame photometry. Used analytic methods are simple and obtained results accurate and reproducible.

[Spectrodensitometric determination of lidocaine-chloride in antihemorrhoidal agents]. / Spektrodenzitometrijsko odredivanje lidokain-hlorida u nekim antihemoroidalijama.

Spectrodensitometric method was used in determination of lidocaine-chloride in some antihemorrhoidal agents after thermomicrodetection and its direct thin layer coating. This procedure is based on transference of the studied substance into the gaseous state, its quantitative transference on the basic layer of silicagel GF254, isolation in the benzene-methanol mixture and its identification. Determination was performed by spectrodensitometric determination of absorption. The results obtained are precise and reproducible and the procedure is suitable for determination of lidocaine-chloride in micrograms.