Physicochemical Characterization of Phenobarbital Polymorphs and Their Pharmaceutical Properties

Spectral Methods for the Characterization of Polymorphs and Solvates

“…43 This situation is particularly evident in the IR spectrum of 9,10-anthraquinone-2-carboxylic acid, where the hydroxyl stretching mode of the crystalline methanolic solvate is particularly well-resolved from the remainder of the proton stretching vibrations. 44 Infrared spectroscopy has been used to obtain additional information on the methanol solvate of urapidil, 45 the N,N′-dimethylformamide and dioxane solvates of furosemide, 46 the dioxane solvate of phenobarbital, 47 and the dimethyl sulfoxide and 1-methyl-2-pyrrolidone solvates of 3-amino-1-(m-trifluoromethylphenyl)-6-methyl-1H-pyridazin-4-one. 48 Although both IR absorption and Raman scattering yield information on the energies of the same vibrational bands, the different selection rules governing the band intensities for each type of spectroscopy can yield useful information.…”

Preparation of drug polymorphs (a review)

“…sulfathiazole [23], tolbutamide, barbital [24] Sublimation drying based on solvent sublimiation (in vacuo at reduced temperature) from a preliminarily frozen drug solution phenobarbital [13] Crystallization on a surface based on crystallization from a saturated solution or melt in drops placed on various surfaces and films sulfathiazole [25], indomethacin [26] Dehydration and desolvation methods Dehydration based on dehydration of drug crystal-hydrates by melting and subsequent crystallization from the melt [27], cimetidine [28] Desolvation based on desolvation of drug solvates by melting and subsequent crystallization from the melt [27,29] saturation is insufficient for secondary nucleation. At high degrees of supersaturation, homogeneous nucleation that leads to formation of a phase of low crystallinity dominates.…”

“…The limiting step at moderate degrees of supersaturation is diffusion, which enhances formation of irregularly shaped particles (needles, dendrites). In this instance, the particle size varies over a relatively narrow range because the degree of super- [10], barbital [11], prednisolone acetate [12], phenobarbital [13], glycine [14] Non-equilibrium crystallization methods Non-equilibrium crystallization from the melt based on relatively fast crystallization from the melt paracetamol [15] Polythermal crystallization based on rapid reduction of drug solubility in solution by cooling of the resulting preliminary hot saturated drug solution codeine [16], chloramphenicol palmitate [17], diflunisal [18] Solvent exchange based on rapid isothermal reduction of drug solubility in solution by adding a solvent that reduces the solubility of the drug in the resulting solution sulfamethoxydiazine, diflunisal [18], histidine [19], sulfathiazole [20] Spray drying based on creating the required degree of drug supersaturation in a solution dispersed in a gas-heat-transfer stream due to solvent evaporation streptocide [21], phenobarbital [22] Spraying from supercritical solvents based on creating the required degree of drug supersaturation in a supercritical solution upon dispersion due to solvent evaporation (CO 2 is usually used)…”

Polymorphism: an evaluation of the potential risk to the quality of drug products from the Farmácia Popular Rede Própria

“…The order of the dissolution rate among the forms is F > B > E > C > A > D, and the order of the hardness among the tablets containing them is D > A > C > E > B = F (Otsuka et al, 1994).…”