Polyethylene glycol , dissolution

Water-miscible, nonvolatile liquids such as low molecular weight polyethylene glycol (PEG-400 and PEG-600) have come into use because of their ability to mix with water readily and accelerate dissolution of dissolved or suspended drugs. 

Scanning electron microscopic examination before and after dissolution and in vivo implantation show no significant changes in surface topography for the implants prepared as they are clinically used, that is, without additives. However, distinct changes in surface characteristics and the appearance of pores are evident with the inclusion of water-soluble additives such as polyethylene glycol 400. 

Chiou, W.I. and Riegelman, S. (1971). Increased dissolution rates of water insoluble cardiac glycosides and steroids via solid dispersions in polyethylene glycol 6000. J. Pharm. Sci., 60(10), 1569-1571. 

WY Lo, SL Law. Dissolution behavior of griseofulvin solid dispersions using polyethylene glycol, talc, and their combination as dispersion carriers. Drug Dev Ind Pharm 1996 22 231-236. 

Fernandez M, Margarit MV, Rodriguez IC, Cerezo A. Dissolution kinetics of piroxicam in solid dispersions with polyethylene glycol-4000. Int J Pharm 1993 98 29-35. 

All but the polyurethane are characterized by methylene backbones with ligands that are sufficiently polar to make them water soluble. Thus, upon dissolution in water, the polarity of the water molecule associates with the polarity of the acrylic or acrylamide groups to form a shell. We discussed hydrophilic polyurethanes that are typically cross-linked and are not (but could be) considered effective thickeners. Nevertheless they too have hydration shells developed due to the influence of the polyethylene glycol backbone. The extent of that shell is determined by the hydro-philicity of the ligand the acrylic > acrylamide > alcohol > polyurethane. The volume... 

The combination of solid-state ATR-IR and solid-state NMR data supported the conclusion that the presence of crystalline material was responsible for changes in the dissolution profiles of the different lots. The results appear consistent with historical examples of changes in API physical form of solid, high molecular weight, polyethylene glycol dispersion formulations of amorphous indomethacin and griseofulvin (92-95). 

Doshi, D.H. Ravis, W.R. Betageri, G.V. Carbamezepine and polyethylene glycol solid dispersions preparation, in vitro dissolution, and characterization. Drug Dev. Ind. Pharm. 1997, 23 (12), 1167-1176. 

Polyethylene glycols can also be used to enhance the aqueous solubility or dissolution characteristics of poorly soluble compounds by making solid dispersions with an appropriate polyethylene glycol. Animal studies have also been performed using polyethylene glycols as solvents for steroids in osmotic pumps. 

Vervaet C, Remon JP. Bioavailability of hydrochlorothiazide from pellets, made by extrusion/spheronization, containing polyethylene glycol 400 as a dissolution enhancer. Pharm Res 1997 14 1644-6. 

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