CHARACTERIZATION OF SOLID DISPERSION PIROXICAM WITH POLYETHYLENE GLYCOL

TF04

Vieira, MMS; Silva, AA; Freitas, LAP

Faculdade de Ciências Farmacêuticas de Ribeirão Preto - USP / Departamento: Ciências Farmacêuticas / Área de Concentração: Medicamentos e Cosméticos

Introduction: One of the most effective methods to improve the solubility of poorly water-soluble drugs is their incorporation into solid dispersions. Piroxicam, PX, is a non-steroidal anti-inflammatory drug and it is a poorly water-soluble drug, classified as class 2 in the Biopharmaceutical Classification System. PX association with hydrophilic materials to improve solubility has been extensively studied and a recent alternative is the hot melt technique, where drug is melted together with soluble carriers. Objective: The aim of this work was to evaluate solid dispersions and physical mixtures of PX and polyethylene glycol 4000 (PEG 4000) or polyethylene glycol 6000 (PEG 6000), and to evaluate the physical and chemical interactions and drug polymorphism. Methodology: Solid dispersion (SD) and physical mixtures (PM) containing piroxicam and PEG 4000 or 6000 where prepared at the ratios of 1:1, 1:4 and 4:1. SD where prepared by the melting method. A calorimeter DSC 50 Shimadzu was used to obtain thermograms at the temperature range of 0-300°C, at a heating rate of 10°C/min and under nitrogen atmosphere with flow rate of 50ml/min. The infrared spectra where obtained in a FT IR Nicolet Protege 460 the samples where prepared in KBr discs.  X-ray diffraction studies where taken in X-ray diffractometer D5005 Siemens, between 2 to 50°. Results: Infrared spectroscopy and X-ray diffraction analysis did not indicate interactions among PX and PEGs 4000 and 6000 in SD and PM, neither an evidence of drug polymorphism. The peaks size changed proportionally to the contents of drug and carrier in the solid dispersion, e.g., when drug ratio was higher (4:1), the curves showed a shape similar to the profile of pure drug. DSC thermograms showed a possible interaction among PX and PEGs 4000 and 6000 at the 1:1 ratio in SD and PM, because changes in melting points and fusion enthalpy occurred when compared to values for drug and carriers alone. Conclusion: The carriers PEGs 4000 and 6000 are useful to prepare solid dispersions containing PX, as demonstrated by the results in the analysis of the DSC, infrared spectroscopy and X-ray diffraction. No interactions occurred, neither an evidence of drug polymorphism. The possible interaction showed in the DSC 1:1 ratio was not confirmed by other analysis.