1,2-propylene glycol solubility parameter

Table 1 list solvents and cosolvents used in parenteral products. Water for injection is the most common solvent but may be combined or substituted with a cosolvent to improve the solubility or stability of drugs.f The dielectric constant and solubility parameters are among the most common polarity indices used for solvent blending.f Ethanol and propylene glycol are used either alone or in combination with other... 

Eq. (28) thus obtained can be used to represent the solubility of poorly soluble drugs in aqueous mixed solvents if information about the properties of the binary solvent (composition, phase equilibria and molar volume), the nonideality parameters and the constant A is available. These parameters can be considered as adjustable, and determined by fitting the experimental solubilities in the binary solvent. We applied such a procedure to the solubilities of caffeine in water/AW-dimethylformamide (Herrador and Gonzalez, 1997) and water/1,4-dioxane (Adjei et al., 1980), of sulfamethizole in water/1,4-dioxane (Reillo et al., 1995) as well as of five solutes in water/ propylene glycol (Rubino and Obeng, 1991). It was shown that Eq. (28) provides accurate correlations of the experimental data. 

Physical Parameters. Guaifensin is obtained as minute rhombic prisms from ether, mp 78.5-79°C and bpjg 215°C. It has a slight bitter aromatic taste. 1 g dissolves in 20 ml water at 25°C much more soluble in hot water freely soluble in ethanol soluble in chloroform, glycerol, propylene glycol, DMF moderately soluble in benzene and almost insoluble in petroleum ether. 

Physical Parameters. It is normally obtained as a practically tasteless crystals obtained from methanol, mp 105-106°C. It is formd to be very sparingly soluble in hot water (0.05%), somewhat more (1 to 2%) in [95% (v/v)] ethanol and also soluble in glycerol and in propylene glycol. 

Solubility parameters Coalescing Agents Coupling Solvents, freeze thaw stabilisers. Propylene glycol benzyl alcohol glycol ethers ester alcohols ethylene glycol. 

Water is supplied in large excess in order to favour propylene glycol production. The reaction is catalysed by sulfuric acid and takes place at room temperature. In order to dilute the feed and to keep the propylene oxide soluble in water, methanol is also added. The reaction is carried out in a 5-litre stirred-jacketed glass reactor. Initial conditions described by Furusawa et al. (1969) have been applied an equivolumic feed mixture of propylene oxide and methanol is added to the reactor initially supplied by water and sulfuric acid, for a propylene oxide concentration of 2,15 mol/L. In agreement with previous works reported in literature, kinetic parameters of the reaction modelled by an Arrhenius law are summarised in table 1. 

Table 1. Solubility parameter of poly(propylene glycol). ...

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