title: Solubility, dissolution rate and phase transition studies of ranitidine hydrochloride tautomeric forms.
abstract: Understanding the polymorphic behavior of pharmaceutical solids during the crystallization process and further in post-processing units is crucial to meet medical and legal requirements. In this study, an analytical technique was developed for determining the composition of two solid forms of ranitidine hydrochloride using two peaks of Fourier transform infrared (FTIR) spectra without the need to grind the samples. Solubility studies of ranitidine hydrochloride showed that Form 2 has a higher solubility than Form 1. Solution-mediated transformation is very slow and occurs from Form 2 to Form 1 and not the reverse. No solid-solid transformation was observed due to grinding or compressing the pure samples of either forms and of a 50/50 wt.% mixture. Grinding was found to be a proper technique for increasing the bulk solid density of the ranitidine hydrochloride without the risk of solid-solid transformation. Dissolution rate found to be equally fast for both forms. The solubility data were modeled using the group contribution parameters and UNIversal QUAsi-Chemical (UNIQUAC) theory. There was a good agreement between the experimental solubility data of ranitidine hydrochloride and the results of UNIQUAC equation.
authors.affiliation: Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ont., N6A 5B9, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Mirmehrabi
authors.forename: S
authors.initials: S
authors.lastname: Rohani
authors.forename: K S K
authors.initials: KS
authors.lastname: Murthy
authors.forename: B
authors.initials: B
authors.lastname: Radatus
mesh_terms: D000897:Anti-Ulcer Agents / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004339:Drug Compounding; D006851:Hydrochloric Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D011899:Ranitidine / Q000737:chemistry*; D012984:Software; D012995:Solubility; D012996:Solutions; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014465:Ultrasonics
chemical_list: D000897:Anti-Ulcer Agents; D012996:Solutions; D012997:Solvents; D011899:Ranitidine; D006851:Hydrochloric Acid