Development and Evaluation of Praziquantel Solid Dispersions in Sodium Starch Glycolate

Fc Paula,Ac Lima,Mpd Gremião,Mv Chaud,Ln Pedreiro,Mmdc Vila,Mo Paganelli

doi:10.4314/tjpr.v12i2.5

Abstract

Purpose: To develop and characterize solid dispersions of praziquantel (PZQ) with sodium starch glycolate (SSG) for enhanced drug solubility.Methods: PZQ solid dispersion (SD) was prepared using co-precipitation method by solvent evaporation. The ratios of PZQ to SSG were 2:1, 1:1, 1:2, 1:3 (w/w). PZQ solubility was evaluated in purified water, and PZQ dissolution test was carried out in 0.1N HCl. Structural characterization of the dispersions was accomplished by x-ray diffraction (XRD) and infrared spe ctroscopy (FTIR) while the external morphology of the SDs, SSG and PZQ were studied by scanning electron microscopy (SEM). Mucoadhesion properties of the SD (1:3) and SSG, on mucin disks were examined using texture profile analysis.Results: The highest solubility was obtained with 1:3 solid dispersion, with PZQ solubility of 97.31 %, which is 3.65-fold greater than the solubility of pure PZQ and physical misture (PM, 1:3). XRD results indicate a reduction in PZQ crystallinity while infrared spectra showed that the functional groups of PZQ and SSG were preserved. SEM showed that the physical structure of PZQ was modified from crystalline to amorphous. The amount of PZQ in PM and SD (1:3) that dissolved in 60 min was 70 and 88 %, respectively, and these values increased to 76 and 96 %, respectively. The solid dispersion reduced the mucoadhesive property of the glycolate.Conclusion: Solid dispersion formulation using SSG is a good alternative approach for increasing the dissolution rate of PZQ.Keywords: Praziquantel, Drug bioavailability, Schistosomiasis, Solid dispersion, Co-precipitation, Sodium starch glycolate

Highlights

Poor bioavailability exerts strong limits to the performance of a drug by the necessity to administer a much higher dose than strictly required from a pharmacologic point of view
The infrared spectra of pure PZQ and solid dispersions (SD), physical mixtures (PM) were obtained by the KBr disk method recorded on a Fourier transform infrared (FTIR) spectrophotometer (Perkin Elmer, Spectrum One)
The results show that PZQ dissolution in SD was significantly greater than in PM

Summary

Introduction

Poor bioavailability exerts strong limits to the performance of a drug by the necessity to administer a much higher dose than strictly required from a pharmacologic point of view. For good oral bioavailability drug must be soluble in gastrointestinal fluids, i.e., aqueous soluble and possess permeability properties for good membrane diffusion in order to reach the bloodstream [1]. Oral bioavailability of poorly soluble and highly permeable drugs, whose absorption is controlled by dissolution rate, can be increased by formulation strategies aimed at increasing both solubility and dissolution rate. Among the several strategies available for improving drug bioavailability, solid dispersions (SD) have been used extensively [2,3,4,5,6]. The SD characteristics can be influenced by several factors such as preparation method, carrier type and drug:carrier ratio and pH modifiers [7, 8]

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