Novel spectrophotometric method for determination of cinacalcet hydrochloride in its tablets via derivatization with 1,2-naphthoquinone-4-sulphonate

This study represents the first report on the development of a novel spectrophotometric method for determination of cinacalcet hydrochloride (CIN) in its tablet dosage forms. Studies were carried out to investigate the reaction between CIN and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 8.5), an orange red-colored product exhibiting maximum absorption peak (λmax) at 490 nm was produced. The stoichiometry and kinetic of the reaction were investigated and the reaction mechanism was postulated. This color-developing reaction was employed in the development of a simple and rapid visible-spectrophotometric method for determination of CIN in its tablets. Under the optimized reaction conditions, Beer's law correlating the absorbance with CIN concentration was obeyed in the range of 3 - 100 μg/ml with good correlation coefficient (0.9993). The molar absorptivity (ε) was 4.2 × 105 l/mol/cm. The limits of detection and quantification were 1.9 and 5.7 μg/ml, respectively. The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in the tablets. The proposed method was applied successfully for the determination of CIN in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.80 - 102.23 ± 1.27 - 1.62%. The results were compared favorably with those of a reference pre-validated method. The method is practical and valuable in terms of its routine application in quality control laboratories

Wet deposition of major ions and trace elements in the eastern Mediterranean basin

Elemental and ionic composition of the eastern Mediterranean precipitation was determined on the Mediterranean coast of Turkey between January 1992 and January 1994. Measured concentrations were comparable with the concentrations reported from other rural stations. Concentrations of elements and ions show strong short-term and well-defined long-term variations. Short-term variations are due to transport from different source areas whereas longterm (seasonal) variations are governed by the seasonal changes in the wet removal of particles during their transport from source areas to the eastern Mediterranean region. The most important characteristic of the precipitation in the eastern Mediterranean region is the extensive neutralization of acidity by the airborne CaCO3 particles from soil. Wet deposition fluxes of elements and ions are smaller than the fluxes reported from other rural stations owing to small annual rainfall in the region. Except for soil-related elements, wet deposition fluxes of all elements are significantly higher in the winter season. Annual wet deposition fluxes are highly episodic, with only 10-20 of the samples accounting more than 50% of annual fluxes for most of the measured elements and ions