High performance liquid chromatographic determination of N-butyryl glucosamine in rat plasma

PURPOSE: A high performance liquid chromatography (HPLC) method for determination in plasma of N-butyryl glucosamine (GLBU), a highly water-soluble compound with no chromophore was developed. METHOD: To 100 muL of plasma containing GLBU was added fucose as internal standard. GLBU and fucose were derivatized using 1-phenyl-3-methyl-5-pyrazolone in the presence of sodium hydroxide at 70 degrees C for 30 min. The solution was neutralized with hydrochloric acid and the excess derivatizing reagent was extracted with chloroform. The aqueous layer was injected into an isocratic HPLC system consisting of an autoinjector, a single pump and a UV detector set at 245 nm. Two different 25 cm reversed phase columns were used, a 4 and a 10 microm C(18) columns. The mobile phase was a mixture of phosphate buffer (pH 7) and acetonitrile (80:20), which was run through a pump at a flow rate of 1.0 mL/min at ambient temperature. RESULTS: Derivatized fucose and GLBU appeared 24 and 28 min, and at 34 and 37 min using 4 and 10 microm columns, respectively. The assay was linear over the range of 0.2-200 microg/mL with a limit of quantification of 0.2 and 1 microg/mL for the 4 and 10 microm columns, respectively. The method was applied to the determination of GLBU in rat plasma after oral administration of 233 mg/kg of GLBU. CONCLUSION: The present assay is precise, and accurate with sufficient sensitivity for pharmacokinetic studies following therapeutically relevant doses.     

Automated determination of lysine by colorimetric method with ninhydrin

Summary A Technicon AutoAnalyzer has been adapted to analyse lysine of fermentation broths from lysine-producer mutants, with a photometric method with ninhydrin. Linearity and accuracy have been tested, with errors lower than 5.5%. The great advantadge is its speed, analysing one sample every 5 minutes, automatically.     

The determination of glucosamine and galactosamine in some glycoproteins by radioisotope dilution

1. The principle of radioisotope dilution was applied on a semi-micro scale to the determination of glucosamine and galactosamine in some glycoproteins, such as immunoglobulins, a urinary glycoprotein and blood-group-specific substances. 2. The glycoprotein was hydrolysed in the presence of [1-(14)C]glucosamine or [1-(14)C]galactosamine or both. The amino sugars were made to react with naphthyl isothiocyanate and the products formed were isolated by the method of Scott (1962). The specific radioactivities determined from liquid-scintillation counting and the extinction at 240mmu or 222mmu were used to calculate the content of amino sugars in the protein analysed. 3. Where the values could be compared with those found by other workers, differences were in general not very great. The advantages of the method are that high concentrations of acid can be employed and undesirable side reactions, which may occur with the free sugars, do not affect the results. A potential source of error of the method is discussed.     

Spectrophotometric estimation of cobalt with ninhydrin

A violet coloured complex was developed when cobalt metal reacts with ninhydrin at pH 8.2, using sodium acetate buffer solution. Absorbance of the complex was measured at 395 nm. Various factors, such as volume of the ligand used, solution pH, stability of the complex with time and interference of other metals, which effect the complex formation have been studied in detail. Present developed method can be used for the spectrophotometric estimation of cobalt with ninhydrin complex. The method is simple, selective and cheap for the determination of cobalt in very less time.     

Utility of ninhydrin reagent for spectrofluorimetric determination of heptaminol in human plasma

For the determination of heptaminol (HEP) in its authentic and dosage form as well as in human plasma, a new simple, sensitive and cheap fluorimetric method of analysis was developed and validated. The presented method is based on the reaction between aliphatic primary amino moiety present in HEP with ninhydrin and phenylacetaldehyde using Torell and Stenhagen buffer at pH 8.2 that yields a highly fluorescent derivative which after excitation at 390 nm showed a fluorescence emission at 464 nm. The effects of various experimental factors on both the development and stability of the fluorescent product was evaluated and optimized. In the concentration range (0.5–6.0 μg/ml), the constructed calibration curve was linear with a good correlation coefficient (0.9997) and the calculated limit of detection (LOD) and limit of quantitation (LOQ) were 0.14 and 0.43 respectively. The presented method was successfully applied for determination of Corasore® tablets and validated according to ICH guidelines.