cholecalciferol and retinol-palmitate

Cholecalciferol (D

Topics: Cholecalciferol; Diterpenes; Lipids; Micelles; Retinyl Esters; Surface Tension; Taurocholic Acid; Vitamin A

HPLC stationary phases of monolithic and fused core type can be used to achieve fast chromatographic separation as an alternative to UPLC. In this study, monolithic and fused core stationary phases are compared for fast separation of four fat-soluble vitamins. Three new methods on the first and second generation monolithic silica RP-18e columns and a fused core pentafluoro-phenyl propyl column were developed. Application of three fused core columns offered comparable separations of retinyl palmitate, DL-α-tocopheryl acetate, cholecalciferol and menadione in terms of elution speed and separation efficiency. Separation was achieved in approx. 5 min with good resolution (Rs > 5) and precision (RSD ≤ 0.6 %). Monolithic columns showed, however, a higher number of theoretical plates, better precision and lower column backpressure than the fused core column. The three developed methods were successfully applied to separate and quantitate fat-soluble vitamins in commercial products.

Topics: alpha-Tocopherol; Cholecalciferol; Chromatography, High Pressure Liquid; Diterpenes; Retinyl Esters; Silicon Dioxide; Vitamin A; Vitamin K 3; Vitamins

Microemulsion electrokinetic chromatography (MEEKC) was carried out in a pH 2.5 phosphate buffer to effectively suppress the electroosmotic flow (EOF). With 66.6% (w/w) 25 mM phosphate buffer pH 2.5, 20.0% (w/w) 2-propanol, 6.6% (w/w) 1-butanol, 6.0% (w/w) sodium lauryl sulphate (SDS), and 0.8% (w/w) n-octane as the separation medium, the fat-soluble vitamins A palmitate, E acetate, and D3 were baseline separated within 11 min. With strongly suppressed EOF, the polarity of the separation voltage was reversed (positive electrode at the outlet); the n-octane micro droplets surrounded by negatively charged SDS molecules migrated towards the detector. The aqueous part of the microemulsion was modified with 20% (w/w) 2-propanol to improve partition between the n-octane phase and the surrounding aqueous medium. The fat-soluble vitamins were separated in order of decreasing hydrophobicity with a high migration time stability (repeatable within 0.1% RSD). Excellent accuracy and precision were obtained when the system was applied for the determination of vitamin E acetate in commercial vitamin tablets; quantitative data corresponded to 97.0% of label claim, intra-day results varied within 1.72% RSD (n=6), and inter-day results varied within 3.22% RSD (n=5).

Topics: alpha-Tocopherol; Buffers; Cholecalciferol; Chromatography, Micellar Electrokinetic Capillary; Diterpenes; Emulsions; Oils; Reference Standards; Retinyl Esters; Solubility; Tocopherols; Vitamin A; Vitamin E; Vitamins

A reversed-phase high performance liquid chromatographic method is described for the simultaneous determination of vitamins D3, E and K1 and retinyl palmitate in plasma. Narrow-bore columns are recommended because this alternative provides a good separation efficiency, plus greater economy and sensitivity. Detection limits for individual vitamins range from 0.42 to 2.8 ng. All vitamins were separated in less than 9 min. Recovery studies showed good results for all solutes (88.8-100.3%) and the intra-day coefficients of variations ranged from 1.0 to 4.5%. This method permits the simple determination of fat-soluble vitamins using 1 ml of cattle heparinized plasma.

Topics: Animals; Anticarcinogenic Agents; Cattle; Cholecalciferol; Chromatography, Liquid; Diterpenes; Indicators and Reagents; Retinyl Esters; Spectrophotometry, Ultraviolet; Vitamin A; Vitamin E; Vitamin K 1; Vitamins

A rapid and precise method for the determination of fat-soluble vitamins from a water-based multivitamin mixture was developed utilizing solid-phase extraction and reversed-phase high-performance liquid chromatography (HPLC). Cholecalciferol, alpha-tocopherol acetate, and retinol palmitate were extracted in a single stage from the matrix using Bond Elut C18 columns. The vitamins were then chromatographed on a Hypersil 5-microns C18 column, using a water:methanol gradient, and quantified simultaneously using individual UV absorption maxima. The recovery of added analytes varied from 92.6 to 100.6%. The assay coefficient of variation was 1.7-2.7%. The sample preparation method and HPLC assay described here are practical for pharmaceutical quality control purposes.

Topics: Cholecalciferol; Chromatography, High Pressure Liquid; Diterpenes; Dosage Forms; Retinyl Esters; Spectrophotometry, Ultraviolet; Vitamin A; Vitamin E; Vitamins