John F. Bauer

Determination of temafloxacin, sarafloxacin, and difloxacin in bulk drug and dosage forms by high-performance liquid chromatography.

The fluoroquinolones, temafloxacin, sarafloxacin, and difloxacin, are determined in the bulk drug substances and in a variety of dosage forms using high-performance liquid chromatography (HPLC). The HPLC system used is also applicable for ciprofloxacin and norfloxacin. The procedure uses UV detection at 280 nm, which provides a linear response of the subject compounds to at least 20 µg/ml. Assay precision (RSD) values were ±1.2% or better for the bulk drugs and ranged from ±0.42 to ±2.3% for suspension, capsule, and tablet formulations. Drug recoveries were quantitative from the dosage forms tested. Sensitivity of the subject compounds is approximately 50 ng/ml (2.5 ng on column).

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. NIRS detected differences in the location or orientation of the water molecules within the crystal lattices.

Stability-indicating high-performance liquid chromatographic analysis of tin protoporphyrin and other free acid metalloporphyrins

In recent years, there has been increased interest in metalloporphyrins as therapeutic agents. The iron porphyrin, hemin (I), has been found to be useful in the treatment of acute porphyria’, while tin protoporphyrin (II) shows therapeutic activity against hyperbilirubinemia in infant?. Many metalloporphyrins are subject to degradation in aqueous solution due to solution pH or exposure to light. As a result, the need for a stability-indicating assay of metalloporphyrins has increased. Although there are a number of highperformance liquid chromatographic (HPLC) methods reported in the literature3-* for porphyrins and metalloporphyrin esters, a majority of these are not widely applicable to free acid metalloporphyrins. This work reports a stability-indicating HPLC analysis for tin protoporphyrin; however, the procedure may be applicable to a variety of free acid metalloporphyrins.