Identification, preparation, and characterization of several polymorphs and solvates of terazosin hydrochloride.

The phenomenon of polymorphism is prevalent in pharmaceuticals, yet it is unusual to identify more than three or four forms for any particular drug. Terazosin hydrochloride has been found to exist at room temperature in four solvent-free forms that can be isolated directly, one solvent-free form that can be prepared by desolvation of a methanolate, a methanol solvate, and a dihydrate. This study presents characterization and methods for preparation of each of these forms.

Ritonavir: an extraordinary example of conformational polymorphism.

Purpose: In the summer of 1998, Norvir semi-solid capsules supplies were threatened as a result of a new much less soluble crystal form of ritonavir. This report provides characterization of the two polymorphs and the structures and hydrogen bonding network for each form.

Methods: Ritonavir polymorphism was investigated using solid state spectroscopy and microscopy techniques including solid state NMR, Near Infrared Spectroscopy, powder X-ray Diffraction and Single crystal X-ray.

Non-invasive determination of ethanol, propylene glycol and water in a multi-component pharmaceutical oral liquid by direct measurement through amber plastic bottles using Fourier transform near-infrared spectroscopy.

Fourier transform near-infrared (FT-NIR) spectroscopy was used to quantify rapidly the ethanol (34-49% v/v), propylene glycol (20-35% v/v) and water (11-20% m/m) contents within a multi-component pharmaceutical oral liquid by measurement directly through the amber plastic bottle packaging. Spectra were collected in the range 7302-12,000 cm-1 and calibration models set-up using partial least-squares regression (PLSR) and multiple linear regression. Reference values for the three components were measured using capillary gas chromatography (ethanol and propylene glycol) and Karl Fischer (water) assay procedures.

The use of near-infrared spectroscopy to monitor the mobility of water within the sarafloxacin crystal lattice.

Near-infrared spectroscopy (NIRS) is proposed as a technique to study the mobility of water within the sarafloxacin crystal lattice. An investigation of two samples of sarafloxacin revealed that NIRS can distinguish between acceptable and unacceptable batches for formulation purposes. X-ray powder diffraction (XRPD), mid-infrared (mid-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) could not detect any differences between the two samples.

Role of an isomorphic desolvate in dissolution failures of an erythromycin tablet formulation.

The investigation of dissolution failures for erythromycin dihydrate tablet formulation over a 12-month period using a near-infrared spectroscopy technique revealed the role of a desolvated dihydrate in the retardation of dissolution. Near infrared spectroscopy (NIR) indicated a dehydrated dihydrate of erythromycin is produced during formulation and gradually binds with Mg(OH)2. The binding delays the process of dissolution.