ANALYSIS POLYVINYLPYRROLIDONE IN DOSAGE FORMS

Abstract

This article deals with the selection of the mobile and stationary phase for identifying polyvinylpyrrolidone formulations drug compounds by TLC.

Full Text

Chromatography is a physical and chemical method to divide blends where the divided components are distributed between two phases: one of these phases is fixed, and another constantly moves in certain direction. To identify substances using the method of thin-layer chromatography (TLC) we carried out the analysis with simultaneous chromatography of an equal quantity of the substance under analysis and standard sample on the same chromatogram. If the substances are identical, corresponding to them chromatographic zones have the similar form, adsorbtion or coloration intensity, and equal values of Rf (relation of a distance from the start line before the spot center to distance from the start line to a front of a moving phase) [1, 2]. Polyvinylpyrrolidone (PVP) is a primary product of polymerization of N-vinylpyrrolidone. It belongs to high-molecular linear polymers with linear structure molecules about 100 µm long, which in low concentrations are able to reduce hydrolytic resistance. After administration into a blood fl PVP positively infl the system geodynamics and microcirculation. PVP is similar to albumin by its physiological properties, and is able to replace it [3]. Pharmaceutical practice uses soluble as well as insoluble PVP brands (figure 1). PVP is a part of a big number of contemporary dosage forms, including lyophilized drugs. In this connection, the working out of its identification method is a timely problem. TLC analysis is rather easy method to identify substances. It is listed in Russian and foreign pharmacopoeias. Materials and methods: Polyvinylpyrrolidone (BASF, Germany), LHS-1208, lyophilisate for preparation of injections solutions 9 mg, Ormustin, lyophilisate for preparation of injection solutions 125 mg (Blokhin Russian Cancer Research Center of the Ministry of Health of Russia), different organic solvents: water ammonium 25%, ASC: acetone, AD.: benzole, AD, n-hexane, CP, methanol, CP; propanol-2, ASC; chloroform, CP; ethylacetate, CP; ethanol, ASC (Himmed, Russia); n-butanol, ASC (Ekos-1, Russia); glacial acetic acid (GAA), CP (Mosreaktiv, Russia); ethanol 95% (Bryntsalov-A Fereyn, Russia); crystalline iodine, ASC (Himmed, Russia); Sorbfil PTSH-AF-A chromatographic plates, 10×15 cm (Russia); Silica gel 60 F 254, 10×10 cm with glass base (Merck, Germany); glass chamber with lid for TLC analysis. Methods of TLC analysis: Moving phase was prepared in separate bin by blending of the chosen solvents and poured into the chamber, spreading filtered paper with eluent over the walls. The chamber was closed with a lit and put for 25-30 minutes for chamber saturation with eluent vapors. 5 μl of the samples of ormustin lyophilisates and LHS-1208 under study and water solution of tracking standard was placed on the start line of chromatographic plate. After air-drying, the plate with probes on it was put into chromatographic chamber with eluent, then it was closed with a lid and chromatographed using ascending technique. Once the eluent front reached the finish line (development length 12 cm for Sorbfil plate and 7 cm for Silica gel 60 F), the plate was put out from the chamber and dried out in a warm air til complete elimination of eluent smell. To reveal PVP the plate was put into the chamber saturated with iodine vapors for 1 minute until the appearance of bright yellow spots. The spots appeared in the samples were identified considering the tracking standard spot and they were characterized by the Rf retention value. 1. Tracking standard preparation: accurately weighed quantity of PVP excipient - 300 mg, are dissolved in 5 ml of water for injections (60 mg/ml concentration); 2. LHS-1208 preparation: a flask with lyophilized dosage form LHS-1208 is dissolved in 10 ml of water for injections (60 mg/ml PVP concentration); 3. Preparation of ormustin solution: flask with lyophilized dosage form of ormustin is dissolved in 5 ml of water for injections (60 mg/ml PVP concentration); 4. Preparation of iodine chamber: crucible with 1.0 g of iodine crystals was installed on the bottom of the exsiccator for 15 minute for iodine distillation. Results and discussion: During the experiment on two plates (Sorbfil and Silica gel 60 F) we assorted moving phase for chromatographic experiment using different solvent systems. PVP Rf values in different solvent systems are shown in the table 1. As we can see from the table 1, PVP at Silica gel 60 F plate at 22 systems does not have any chromatographic movement. Probably it is linked with a high adsorption capability of the substance under study. Sorbfil plates application at 30 different systems showed that only in two cases PVP moved from the start line: propanol-2: 25% ammonia (3:2) and ethanol-2: 25% ammonia (3:2). Revelation limits in these systems were almost the same and amounted to 0.3 µg/ml. These systems are those chosen for PVPidentification in composition of lyophilized dosage forms of ormustin and LHS-1208. Conclusions To determine PVP in lyophilisates we assorted moving and stable phases by the results of the study conducted. The data of the research can be used as an express method for the identification of the substance under study in different dosage forms.