Preparação e caracterização analítica de dispersões sólidas cristalinas de glibenclamida, obtidas através de secagem por aspersão.

Abstract

This study describes the preparation and characterization using several analytical techniques of crystalline solid dispersions of glibenclamide (GB) with sodium lauryl sulphate (SLS) or polyvinylpyrrolidone (PVP K30), exhibiting improved solubility in relation to the active pharmaceutical ingredient (API). The crystallinity of the drug in the solid dispersions with SLS prepared using spray-drying or evaporation under reduced pressure decreased by just 1.9% and 4.2% respectively in comparison with the API. The preparation of solid dispersions of GB with both SLS and PVP K30 by spray-drying using the surface-attached method resulted in improved dissolution of GB (9.0 ± 1.0% and 69.9 ± 9.3% at 60 min., respectively), in relation to the API (16.9 ± 6.2% at 60 min.). Thermal analysis data showed that no significant difference in the temperature of GB melting peak was observed in the solid dispersions with SLS and PVP K30 prepared by spray drying in relation to the temperature observed in the API or in the physical mixtures. This supports the idea that GB did not undergo amorphization in the solid dispersions. The infra-red spectroscopy data also corroborate the lack of GB amorphization since the amide NH-stretch band was present in the solid dispersions spectra and this band is reported to be absent in the spectrum of amorphous GB. Electron microscopy data revealed that solid dispersions prepared by rotary evaporation under reduced pressure are composed of particles with higher sphericity, uniformity and a more thorough dispersion of the hydrophilic carrier (SLS) than dispersions prepared by rotary evaporation under reduced pressure, which may explain the differences observed in the dissolution profile of the dispersions prepared by the two techniques. The solid dispersions of GB with PEG1500 and PEG6000 by spray drying also resulted in crystalline dispersions, but thermal analysis data support the idea of eutectic mixture between GB and carriers, which is corroborated by literature data. Taken together our results demonstrate that the solid dispersions of GB described in this study resulted in improved dissolution without evidence of significant amorphization.