Objectives: The purpose of the study was to determine the omega-3/omega-6 ratio in swine brain homogenate by HPLC with UV detection and to discuss the values obtained by comparison to the human species. Materials and methods: Determinations were performed by HPLC method using as mobile phase an isocratic mixture (A:B – 5:95) of mobile phase A = 25% acetonitrile in water and B = acetonitrile with a flow-rate of 1.2 mL/min and UV detection at 205nm. Chromatographic column: Phenomenex C8 150×4.6 mm 5μm. 50 g swine brain was hydrolyzed with 100 mL 0.5N HCl, the organic phase was extracted in 50 mL hexane, concentrated by evaporation and resumed in 200 μL acetonitrile. Results: Polyunsaturated fatty acids were separated as follows arachidonic acid (AA) – Rt = 2.69 min, docosahexaenoic acid (DHA) – Rt = 3.12 min and eicosapentaenoic acid (EPA) – Rt = 3.97 min. The following omega-3/omega-6 ratios were calculated (DHA + EPA)/AA = 0.572 ± 0.451, EPA/AA = 0.027 ± 0.015 and DHA/AA = 0.689 ± 0.612. Conclusions: The values obtained for these ratios should be balanced, but in reality they are in favor of the ratio denominator. Considering the physiological and nutritional similarities and that an accurate diagnosis of neurodegenerative disease is set in post-mortem, swine brain homogenate could serve as an animal model for human nervous tissue.
Objectives: A simple, quick and low cost HPLC-UV method for assay of meloxicam in plasma and pharmaceutical dosage forms was developed.
Methods: Separation and assay of meloxicam, using a simple reverse phase HPLC-UV method was achieved using an Agilent Zorbax SB C18 column, with methanol and 1% aqueous solution of glacial acetic acid as mobile phase. Elution was performed with composition gradient, meloxicam being detected at 355 nm with a 5 minutes analysis time. The method was tested on human plasma and pharmaceutical dosage forms.
Results: The retention time of the meloxicam was 3,7 minutes. Regression analysis showed good linearity, with correlation coefficient R= 0,9997; linear regression equation: y = 206,1x –77,5 over the 20-2000 ng/ml concentration range. Limit of detection was determined to be 5 ng/ml and limit of quantification was set at 15 ng/ml. The recovery of the analyte in human plasma was low: 30,50%, however it was reproducible, with a coefficient of variation of 4,83%. The analysis of the tablets resulted in a 85,82% of meloxicam compared to the declared concentration.
Conclusions: The method proposed is quick, simple and adequate for detecting the meloxicam in human plasma. Although the recovery rate was low, it was reproducible, which leads to the fact, that improving extraction procedure can optimize the method.