EFFECT OF COUNTERIONS ON THE INTERACTIONS IN SOLID DISPERSIONS BETWEEN POLYETHYLENE-GLYCOL, GRISEOFULVIN AND ALKALI DODECYL SULFATES

Citation
M. Alden et al., EFFECT OF COUNTERIONS ON THE INTERACTIONS IN SOLID DISPERSIONS BETWEEN POLYETHYLENE-GLYCOL, GRISEOFULVIN AND ALKALI DODECYL SULFATES, International journal of pharmaceutics, 110(3), 1994, pp. 267-276
Citations number
9
Categorie Soggetti
Pharmacology & Pharmacy
ISSN journal
03785173
Volume
110
Issue
3
Year of publication
1994
Pages
267 - 276
Database
ISI
SICI code
0378-5173(1994)110:3<267:EOCOTI>2.0.ZU;2-E
Abstract
Solid dispersions of polyethylene glycol (PEG) 3000 and 10% w/w griseo fulvin with or without different surfactants incorporated were prepare d by the melting method. The anionic surfactants lithium dodecyl sulph ate (LiDS), sodium dodecyl sulphate (SDS) and potassium dodecyl sulpha te (KDS) were added in equivalent amounts, similar to 2% w/w. Phase an alysis was performed by X-ray powder diffraction and investigation of short-range structure by C-13-CP/MAS solid-state NMR. In all samples w ith surfactant added, solid solutions (PEG/MDS)(1-x) griseofulvin(x) w ere formed. The properties of the solid solutions with Na+ and K+ ions were almost identical. The addition of LiDS created a structure of th e solid solution that was more crystalline than that structure of the sodium- and potassium-containing compounds. The ion with the highest c harge-to-radius ratio, Li+, formed chemical bonds that were different from those of the other ions. This was indicated by a changed influenc e on the hydrophilic parts of the griseofulvin molecules in the lithiu m compound. The melting behaviour of the solid solutions, investigated by DSC, showed a second transformation in the melt at 186-196 degrees C, indicating a two-phase region in the liquid phase. For the lithium -containing compounds the transformation appeared at lower temperature than for the sodium- and potassium-containing compounds.