Validated HPLC-RI Method for the Determination of Lactulose and its Process Related Impurities in Syrup

A simple, swift with good sensitivity and reproducibility, HPLC-RI method has been developed for the quantification of lactulose and related compounds (fructose, galactose, epilactose and lactose) in oral suspension formulation. The analysis was carried out by using mobile phase (water and acetonitrile 75:25) at the flow rate of 1.0 ml/min. on isocratic HPLC-RI system. After manipulating mobile phase composition and mobile phase flow rate a good separation of five components was achieved within 15 minutes of run time. This study is beneficial to determine the active ingredient as well as related compounds simultaneously, without using buffer in mobile phase which causes bad resolution and has limitation to analyze on other hyphenated techniques such as LC-MS.

A new stability indicating HPLC method for related substances in zolmitriptan

A sensitive, precise, specific, linear and stability indicating isocratic HPLC method was developed for the analysis of related substances in zolmitriptan. The potential known related substances are (S)-4-(4-aminobenzyl)-1,3-oxazolidin-2-one (impurity I) and (S)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one (impurity II). The method can be used for the detection and quantification of known and unknown impurities and degradants in the drug substance zolmitriptan during routine analysis and also for stability studies in view of its capability to separate degradation products.

HPLC method for simultaneous determination of impurities and degradation products in zonisamide

A gradient reversed phase HPLC method was developed and validated for the analysis of related substances in zonisamide (1,2-benzisoxazole-3-methanesulfonamide), using a Waters Symmetry C8 (150*3.9 mm) column with a flow rate of 1.0 ml/min and detection at 280 nm. The mobile phase component A consisted of a mixture of 0.02 M aqueous potassium dihydrogen phosphate-acetonitrile-methanol (75:10:15 v/v/v), pH adjusted to 4.0 with orthophosphoric acid. The mobile phase component B consisted of a mixture of 0.02 M aqueous potassium dihydrogen phosphate-acetonitrile-methanol (15:40:45 v/v/v), pH 2.0 with orthophosphoric acid. The limit of detection and limit of quantitation were in the range of 0.001-0.007% and 0.0035-0.25% respectively with respect to sample concentration of 2 mg/ml. The method was linear in the range of LOQ level to 200% of specified limits for II-VIII (< 0.10%, r²= 0.9958-0.9999). The method is sensitive, specific, linear, accurate, precise and stability-indicating for the detection and quantitation of precursors (viz., 4-hydroxycoumarin, 1,2-benzisoxazole-3-acetic acid, 1,2-benzisoxazole-3-bromoacetic acid, 1,2-benzisoxazole-3-methylbromide, sodium 1,2-benzisoxazole-3-methanesulfonate), process impurities (viz., 2-hydroxyacetophenone oxime and 3,3,3-tribromomethyl-1,2-benzisoxazole) and drug degradation products formed under stress conditions.

Development and validation of stability indicating method for the quantitative determination of venlafaxine hydrochloride in extended release formulation using high performance liquid chromatography

Objective:

Venlafaxine,hydrochloride is a structurally novel phenethyl bicyclic antidepressant, and is usually categorized as a serotonin–norepinephrine reuptake inhibitor (SNRI) but it has been referred to as a serotonin–norepinephrine–dopamine reuptake inhibitor. It inhibits the reuptake of dopamine. Venlafaxine HCL is widely prescribed in the form of sustained release formulations. In the current article we are reporting the development and validation of a fast and simple stability indicating, isocratic high performance liquid chromatographic (HPLC) method for the determination of venlafaxine hydrochloride in sustained release formulations.

Materials and Methods:

The quantitative determination of venlafaxine hydrochloride was performed on a Kromasil C18 analytical column (250 × 4.6 mm i.d., 5 μm particle size) with 0.01 M phosphate buffer (pH 4.5): methanol (40: 60) as a mobile phase, at a flow rate of 1.0 ml/min. For HPLC methods, UV detection was made at 225 nm.

Results:

During method validation, parameters such as precision, linearity, accuracy, stability, limit of quantification and detection and specificity were evaluated, which remained within acceptable limits.

Conclusions:

The method has been successfully applied for the quantification and dissolution profiling of Venlafaxine HCL in sustained release formulation. The method presents a simple and reliable solution for the routine quantitative analysis of Venlafaxine HCL.

Mass-spectrometry-based metabolomics: limitations and recommendations for future progress with particular focus on nutrition research

Mass spectrometry (MS) techniques, because of their sensitivity and selectivity, have become methods of choice to characterize the human metabolome and MS-based metabolomics is increasingly used to characterize the complex metabolic effects of nutrients or foods. However progress is still hampered by many unsolved problems and most notably the lack of well established and standardized methods or procedures, and the difficulties still met in the identification of the metabolites influenced by a given nutritional intervention. The purpose of this paper is to review the main obstacles limiting progress and to make recommendations to overcome them. Propositions are made to improve the mode of collection and preparation of biological samples, the coverage and quality of mass spectrometry analyses, the extraction and exploitation of the raw data, the identification of the metabolites and the biological interpretation of the results.