Azithromycin.

Azithromycin is an azalide, a subclass of macrolide antibiotics. It is derived from erythromycin, with a methyl-substituted nitrogen atom incorporated into the lactone ring, thus making the lactone ring 15-membered. It prevents bacteria from growing by interfering with their protein synthesis. It binds to the 50S subunit of the bacterial ribosome and thus inhibits translation of mRNA. Azithromycin is used to treat or prevent certain bacterial infections, most often those causing middle ear infections, strep throat, pneumonia, typhoid, bronchitis, and sinusitis. In recent years, it has been used primarily to prevent bacterial infections in infants and those with weaker immune systems. It is also effective against certain sexually transmitted infections, such as nongonococcal urethritis, chlamydia, and cervicitis. Recent studies have indicated it also to be effective against late-onset asthma, but these findings are controversial and not widely accepted. The present study gives a comprehensive profile of azithromycin, including detailed physico-chemical properties, nomenclature, formulae, methods of preparation, and methods of analysis (including compendial, electrochemical, spectroscopic, and chromatographic methods of analysis). Developed validated stability-indicating (HPLC and biodiffusion assay methods under accelerated acidic, alkaline, and oxidative conditions, in addition to effect of different types of light, temperature, and pH. Detailed clinical applications also presented (mechanism of action, ADME profile, clinical uses and doses, side effects, and drug interactions). Each of the above stages includes appropriate figures and tables. More than 80 references were given as a proof of the above-mentioned studies.

Imatinib mesylate.

Imatinib (INN), marketed by Novartis as Gleevec (United States) or Glivec (Europe/Australia/Latin America), received Food & Drug Administration (FDA) approval in May 2001 and is a tyrosine kinase inhibitor used in the treatment of multiple cancers, most notably Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia. Like all tyrosine kinase inhibitors, imatinib works by preventing a tyrosine kinase enzyme. Because the BCR-Abl tyrosine kinase enzyme exists only in cancer cells and not in healthy cells, imatinib works as a form of targeted therapy-only cancer cells are killed through the drug's action. In this regard, imatinib was one of the first cancer therapies to show the potential for such targeted action and is often cited as a paradigm for research in cancer therapeutics. This study presents a comprehensive profile of imatinib, including detailed nomenclature, formulae, physico-chemical properties, methods of preparation, and methods of analysis (including compendial, electrochemical, spectroscopic, and chromatographic methods of analysis). Spectroscopic and spectrometric analyses include UV/vis spectroscopy, vibrational spectroscopy, nuclear magnetic resonance spectrometry ((1)H and (13)C NMR), and mass spectrometry. Chromatographic methods of analyses include electrophoresis, thin layer chromatography, and high-performance liquid chromatography. Preliminary stability investigations for imatinib have established the main degradation pathways, for example, oxidation to N-oxide under oxidative stress conditions. Stability was also carried out for the formulation by exposing to different temperatures 0°C, ambient temperature, and 40°C. No remarkable change was found in the drug content of formulation. This indicates that the drug was stable at the above optimized formulation. Stability studies under acidic and alkaline conditions have established the following main degradation products: α-(4-Methyl-1-piperazinyl)-3'-{[4-(3-pyridyl)-2-pyrimidinyl] amino}-p-tolu-p-toluid-ide methanesulfonate and 4-(4-methylpiperazin-1-ylmethyl)-benzoic acid. The main degradation products under oxidation conditions, that is, 4-[(4-methyl-4-oxido-piperazin-1-yl)-methyl]-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-enzamide, 4-[(4-methyl-1-oxido-piperazin-1-yl)-methyl]-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-benzamide, and 4-[(4-methyl-1,4-dioxido-piperazin-1-yl)-methyl]-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-enzamide. Clinical application studies for pharmacodynamics, pharmacokinetics, mechanism of action, and clinical uses of the drug were also presented. Each of the above stages includes appropriate figures and tables. More than 50 references were given as proof of the above-mentioned studies.

Gemifloxacin.

A comprehensive profile on Gemifloxacin, a novel fluoroquinolone synthetic broad-spectrum antibacterial agent for oral administration, particularly indicated for treatment of community-acquired respiratory tract infections, such as pneumonia and acute bacterial exacerbations of chronic bronchitis, is prepared. This profile contains the following sections: introduction, general physicochemical informations, X-ray powder diffraction patterns, methods of preparations, methods of analysis and stability, spectroscopic methods of investigations, and identifications including ultraviolet/visible spectroscopy, infrared (vibrational) spectroscopy, proton and carbon-13 nuclear magnetic resonance spectrometry, and mass spectrometry. Section 7 includes compendial BP identification methods, thin-layer chromatography, gas chromatography, high performance liquid chromatography. The pharmacological applications section includes uses, mode of action, pharmacokinetics, and toxicity investigations.

Validated liquid chromatographic-fluorescence method for the quantitation of gemifloxacin in human plasma.

A highly selective, sensitive and rapid high performance liquid chromatographic method has been developed and validated to quantify gemifloxacin in human plasma. The gemifloxacin and internal standard (ciprofloxacin) were extracted by ultrafiltration technique followed by injection into chromatographic system. Chromatographic separation was achieved on a reversed phase C(18) column with a mobile phase of acetonitrile:0.1% trifluoroacetic acid (20:80, v/v) using isocratic elution (at flow rate 1 mL min(-1)). The analytes were detected at 269 and 393 nm for excitation and emission, respectively. The assay exhibited a linear range of 25-5000 ng mL(-1) for gemifloxacin in human plasma. The lower limit of detection was 10 ng mL(-1). The method was statistically validated for linearity, accuracy, precision and selectivity following FDA guidelines. The intra- and inter-assay coefficients of variation did not exceed 7.6% deviation of the nominal concentration. The recovery of gemifloxacin from plasma was greater than 97.0%. Stability of gemifloxacin in plasma was excellent with no evidence of degradation during sample processing (auto-sampler) and at least 3 months storage in a freezer at -70 °C. This validation method is applied for clinical study of the gemifloxacin in human volunteers.