Development and validation of a capillary zone electrophoretic method for rapid and sensitive determination of galanthamine: Application in plant and pharmaceuticals.

Galanthamine is a second-generation cholinesterase inhibitor that has begun to be used in the treatment of Alzheimer's disease. In the presented research, a simple, accurate, precise and cost-effective capillary zone electrophoretic (CZE) method was used for the qualitative and quantitative estimation of Galanthamine from bulbs, leaves and fringes of Leucojum aestivum L. (summer snowflake) grown in Turkish habitats (Black Sea Region) and pharmaceutical dosage forms by capillary zone electrophoresis with direct UV detection form. Ultrasonic assisted extraction (UAE) and response surface methodology (RSM) were used to estimate optimum experimental conditions on the content extraction of Leucojum aestivum L. Metoprolol was used as a suitable internal standard. A linear relationship between the ratio and concentrations of Galanthamine in the range of 0.25µgmL-1-15.00µgmL-1was determined with a regression coefficient of 0.9996, for which the limit of detection (LOD) and limit of quantitation (LOQ) were 0.027 and 0.081µgmL-1, respectively. The high percentage recovery results showed that the matrix effect did not influence the developed method for analysis of pharmaceutical preparations. Validation parameters were carried out according to the guidelines of the International Conference for Harmonization (ICH). This method also allows for a number of cost- and time-saving benefits and can be readily employed for the analysis of plants and pharmaceutical formulations. The method can be used in industries for the determination of Galanthamine to analyze the quality of extraction and formulation without interference.

Analysis of amino acid neurotransmitters from rat and mouse spinal cords by liquid chromatography with fluorescence detection.

A RP-LC-FL detection method has been developed to identify and quantitate four amino acid neurotransmitters including glutamic acid, glycine, taurine and γ-aminobutyric acid in rat and mouse spinal cord tissue. 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde (CBQCA) was employed for the derivatization of these neurotransmitters prior to RP-LC-FL analysis. Different parameters which influenced separation and derivatization were optimized. Under optimum conditions, linearity was achieved within the concentration ranges of 0.50-50.00 µM for all analytes with correlation coefficients from 0.9912 to 0.9997. The LODs ranged from 0.03 µM to 0.06 µM. The proposed method has been successfully applied to the determination of amino acid neurotransmitters in biological samples such as rat and mouse spinal cord with satisfactory recoveries.

Determination of pK(a) values of some antihypertensive drugs by liquid chromatography and simultaneous assay of lercanidipine and enalapril in their binary mixtures.

In this study, pK(a) values were determined using the dependence of the retention factor on the pH of the mobile phase for three ionizable substances, namely, enalapril, lercanidipine and ramipril (IS). The effect of the mobile phase composition on the ionization constant was studied by measuring the pK(a) at different methanol-water mixtures, ranging between 50 and 65% (v/v), using LC-DAD method. Two simple, accurate, precise and fully validated analytical methods for the simultaneous determination of enalapril and lercanidipine in combined dosage forms have been developed. Separation was performed on an X-Terra RP-18 column (250 mm x 4.60mm ID x 5 microm) at 40 degrees C with the mobile phase of methanol-water 55:45 (v/v) adjusted to pH 2.7 with 15 mM orthophosphoric acid. Isocratic elution was performed in less than 12 min with a flow rate of 1.2 mL min(-1). Good sensitivity for the analytes was observed with DAD detection. The LC method allowed quantitation over the 0.50-20.00 microg mL(-1) range for enalapril and lercanidipine. The second method depends on first derivative of the ratio-spectra by measurements of the amplitudes at 219.7 nm for enalapril and 233.0 nm for lercanidipine. Calibration graphs were established for 1-20 microg mL(-1) for enalapril and 1-16 microg mL(-1) lercanidipine, using first derivative of the ratio spectrophotometric method. Both methods have been extensively validated. These methods allow a number of cost and time saving benefits. The described methods can be readily utilized for analysis of pharmaceutical formulations. The methods have been applied, without any interference from excipients, for the simultaneous determination of these compounds in tablets. There was no significant difference between the performance of the proposed methods regarding the mean values and standard deviations.

Spectrophotometric determination of acidity constants of some macrolides in acetonitrile-water binary mixtures.

The acidity constants of eight macrolides (erythromycin, roxithromycin, oleandomycin, azithromycin, josamycin, tylosin tartrate, tilmicosin and spiramycin) have been determined in acetonitrile-water binary mixtures (30%, 40% and 50% (v/v)) by spectrophotometric method. The pKa's available in literature determined by various methods are compiled in comparison with the value of this work. These results are expected to essentially facilitate the research on occurrence, fate and effects, analysis method development, and control of antibiotics in various treatment occurrences.