Determination of heptaminol in pharmaceutical preparations by high-performance liquid chromatography

Orthophthaldehyde as a fluorescent probe for the feasible and sensitive assay of heptaminol: application to dosage forms and real human plasma

The antihypotensive drug heptaminol was determined using a spectrofluorimetric method and ortho-phthaladehyde as a fluorescence probe. The drug was mixed with the reagent in the presence of 2-mercaptoethanol and the reaction was carried out in slightly alkaline aqueous solution containing 0.1 M sodium hydroxide. The resulting product exhibited high fluorescence activity that was measured at 451 nm after excitation at 334 nm. The linearity range of the method was 5-100 ng ml^-1 with a lower detection limit of 1.8 ng ml^-1 . The procedure was evaluated according to the International Council of Harmonization guidelines. The proposed method was applied to analyze the drug in pharmaceutical tablets and oral drops. In addition, the present study represents the first spectrofluorimetric method for the determination of the cited drug in real human plasma. The method provided high recovery percentages without any interference from coexisting pharmaceutical excipients or the components of human plasma.

Fluorescamine-based fluorophore for spectrofluorimetric determination of heptaminol in human plasma; application to spiked human plasma

An innovative approach to determine heptaminol spectrofluorimetrically was developed, determining the optimum conditions needed, then validated for determination of heptaminol in its pure form, its tablets and in spiked human plasma. The presented method is based on the reaction between fluorescamine reagent with the primary amine group found in heptaminol, using a borate buffer at pH 9.0 that yields a highly fluorescent product, fluorescence was measured at 471 nm after excitation at 393 nm. The linearity of the constructed calibration curve was (75-850 ng/ml) with LOD and LOQ values 23.85 and 72.29 ng/ml respectively. The method was validated following the International Council for Harmonisation (ICH) guidelines indicating good accuracy and precision. Finally, the presented approach was adapted for in vitro study of heptaminol in spiked human plasma with a mean percentage recovery 100.52 ± 1.19% as well as in its tablets with a mean percentage recovery 99.47 ± 1.25%.

Liquid chromatographic assay of heptaminol in serum and its oral pharmacokinetics in the dog

In order to investigate the pharmacokinetics of heptaminol in dogs, a high-performance liquid chromatographic assay of the drug was devised and it was evaluated in a general purpose validation design through analysis of variance. Heptaminol and its internal standard n-propylamine were salted out from plasma together with acetonitrile, the previously proposed "solvent demixing " extraction procedure. Both amines were derivatised in acetonitrile with the o-phthaldialdehyde, 2-mercaptoethanol procedure of Roth. The adducts were quantitated by reversed-phase high-performance liquid chromatography on Radial-Pak cartridges with ultraviolet detection. Peak height ratios were linearly related to concentrations up to 250 mumol l-1 with a 2% coefficient of variation. Sensitivity was 3.5 mumol l-1 (signal-to-noise ratio of 5). Means of the usual pharmacokinetic parameters in four dogs were: elimination half-life 3.75 h, apparent distribution volume 2.18 l kg-1 and total clearance 0.402 l kg-1 h-1, similar to the results obtained in humans by other authors using radiolabelled heptaminol .

Determination of heptaminol in human plasma and urine by high-performance liquid chromatography

Heptaminol was measured in plasma and urine following pre-column derivatisation with o-phthalaldehyde and reversed-phase high-performance liquid chromatography employing fluorescence detection. The limits of detection were sufficient for pharmacokinetic studies of the drug after clinically-used doses. Plasma concentrations of heptaminol reached peak levels (2.19 micrograms/ml) at 0.75 h after single oral doses (0.47 g of heptaminol) and declined with a half-life of 2.1 h (+/- 0.5 S.D.). Heptaminol was well absorbed and excreted rapidly, mainly unchanged in urine, 82% dose (+/- 10 S.D.).