Template Synthesis, Spectral, Thermal and Glucose Sensing of Pr3+ Complexes of Metformin Schiff-Bases.

Schiff-bases of metformin with each of salicylaldehyde (HL1); 2,3-dihydroxybenzaldehyde (H2L2); 2,4-dihydroxybenzaldehyde (H2L3); 2,5-dihydroxybenzaldehyde (H2L4); 3,4-dihydroxybenzaldehyde (H2L5) and 2-hydroxynaphthaldehyde (HL6) and their complexes with Pr(III) were synthesized by template reaction. The complexes were characterized through elemental analysis, conductivity and magnetic moment measurements, IR, UV-Vis., fluorescence, GC-MS and XRD spectroscopy. The complexes exhibit a series of characteristic emission bands for Pr3+ ion in the 481-472 and 590-580 nm range with a 318-332 nm excitation source. The complexes have eight coordinated structure with the formulae [PrL1-4,6(NO3)2(H2O)3].nH2O where n = 1, 1½, 3, 4, 4 and [PrL5(NO3)(H2O)5].2H2O. The suggested stereochemistry was confirmed using TGA, DTG and DTA analysis and a mechanism for thermal decomposition was proposed. Coates-Redfern equation was used to calculate kinetic and thermodynamic parameters of the main decomposition step. The utility of the complexes towards the detection of glucose at physiologically relevant pH in phosphate buffer using UV-Vis and fluorescence spectroscopy as well as viscosity measurements are tried where the association constants were calculated. Graphical Abstract ᅟ.

LC for analysis of two sustained-release mixtures containing cough cold suppressant drugs.

A liquid chromatographic method was applied for the analysis of two sustained-release mixtures containing dextromethorphane hydrobromide, carbinoxamine maleate with either phenylephrine hydrochloride in pharmaceutical capsules (Mix 1) or phenyl-propanolamine, methylparaben, and propylparaben, which bonds as a drug base to ion exchange resin in pharmaceutical syrup (Mix 2). The method was used for their simultaneous determination using a CN column with a mobile phase consisting of acetonitrile-12 mM ammonium acetate in the ratio of 60:40 (v/v, pH 6.0) for Mix 1 and 45:55 (v/v, pH 6.0) for Mix 2.

High-performance liquid chromatographic determination of flavoxate hydrochloride and its hydrolysis product.

Liquid chromatographic method was presented for the determination of flavoxate hydrochloride (FX) and its hydrolysis product. The method was based on high-performance liquid chromatographic (HPLC) separation of FX from its hydrolysis product on CN column using a mobile phase consisting of acetonitrile-12 mM ammonium acetate (45:55, vol/vol, pH 4.0) with UV detection at 220 nm and flow rate of 1.5 mL min(-1). The proposed HPLC method for the determination of FX was utilized to investigate the kinetics of acidic hydrolytic process at different temperatures and to calculate its activation energy. In addition, the proposed HPLC method was used for pH-rate profile study of hydrolysis of FX in Britton-Robinson buffer solutions. The 3-methylflavone-8-carboxylic acid ethyl ester, as impurity of flavoxate hydrochloride, can be separated by the proposed HPLC method.

HPLC method for the simultaneous determination of atenolol and chlorthalidone in human breast milk.

A high-performance liquid chromatographic method was optimized and validated for the determination of atenolol and chlorthalidone (CT) in human breast milk. The milk samples were extracted and purified using ACN and phosphoric acid for precipitation of proteins followed by removal of ACN and milk fats by extraction with methylene chloride. The samples were applied, after an extraction procedure, to a cyanide column using a mobile phase consisting of ACN/water (35:65 v/v) and buffered at pH 4.0 with flow rate of 1.0 mL/min. Quantitation was achieved with UV detection at 225 nm using guaifenesin as the internal standard. The effectiveness of protein precipitation and clean up procedure were investigated. The method was validated over the range of 0.3-20 microg/mL for atenolol and 0.25-5 microg/mL for CT.

High performance liquid chromatographic determination of 3-methylflavone-8-carboxylic acid, the main active metabolite of flavoxate hydrochloride in human urine.

High performance liquid chromatographic (HPLC) method was presented for the determination of 3-methylflavone-8-carboxylic acid as the main active metabolite of flavoxate hydrochloride (FX) in human urine. The proposed method was based on using CN column with mobile phase consisting of acetonitrile-12 mM ammonium acetate (40:60, v/v) and adjusted to apparent pH 4.0 with flow rate of 1.5 ml min(-1). Quantitation was achieved with UV detection at 220 nm. The proposed method was utilized to the determination of dissolution rate for tablets containing flavoxate hydrochloride. The urinary excretion pattern has been calculated using the proposed method.