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Stress degradation studies and development of validated stability indicating densitometric method for estimation of alpha lipoic acid in bulk and capsule dosage form

Srivastava Shruti, Dhaneshwar Suneela, Kawathekar Neha

Acta Chromatographica

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2023

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Vol. 35, no. 2

180--186

EN

A precise, sensitive, specific and accurate stability indicating densitometric method was developed and validated for alpha-lipoic acid (ALA) in bulk and capsule dosage form. The study employed pre-coated silica gel 60F254 TLC plates as stationary phase and toluene: chloroform: methanol: formic acid (5:3:1:0.05; v/v/v/v) as mobile phase. The developed method furnished compact spots of alpha-lipoic acid (Rf 0.28 ± 0.05) after derivatization, offered good linearity in range 80–400 ng/spot with correlation coefficient of 0.998. The values for detection and quantitation were found 18.022 and 54.612 ng/spot respectively. ALA was subjected to stress degradation studies and total 13 degradation products were resolved. Thus, the proposed method offered good results according to ICH guidelines, and can be used for identification, routine quantitative determination as well as for monitoring the stability of ALA in bulk and in capsules.

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Stability-indicating liquid chromatographic method for analysis of pitavastatin calcium in tablet dosage forms

Panchal H. J, Suhagia B. N

Acta Chromatographica

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2011

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Vol. 23, no. 1

81--94

EN

A simple, specific, sensitive, precise, accurate, and robust stability-indicating reversed-phase liquid chromatographic (LC) method has been established for analysis of pitavastatin calcium in tablet dosage forms. LC separation was achieved on a 250 mm × 4.6 mm i.d., 5-μm particle, C18 column with acetonitrile-water-triethylamine 80:19.8:0.2 (υ/υ), adjusted to pH 3.5 ± 0.05 with orthophosphoric acid as isocratic mobile phase at a flow rate of 1.5 mL min-1. Detection, with a photodiode-array detector, was at 238 nm, the wavelength of maximum absorbance in a spectrum obtained from its solution in methanol. The retention time was approximately 5.70 min. The method was validated for linearity, accuracy, precision, limits of detection and quantification, and robustness. Quantification was performed over the concentration range 0.1–2.5 μg mL-1. Mean recovery was 100.26 ± 0.75%. The limit of detection (LOD) was 0.0055 µg mL-1. The method was successfully used for analysis of pitavastatin calcium in tablets and for stability studies, because the method separates pitavastatin calcium from its degradation products and from excipients.

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Copolymers of L-lactide and trimethylene carbonate evaluation of surface properties and degradation in aqueous medium

Pamuła E., Gaugain E., Dessart A., Dobrzyński P.

Inżynieria Biomateriałów

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2005

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R. 8, nr 47-53

25--27

EN

Two poly(L-lactide-co-trimethylene carbanates)s having the carbonate content of 15% and 50%, respectively were prepared by ring-opening copolymerization with the use of zirconium acetylacatonate as an initiator. The copolymers were characterized by NMR,GPC, DSC and AFM. Wettability and surface energy of the copolymers were also evaluated. The copolymers were submitted to degradation in phosphate buffered saline at 37 Celcius degrees for 10 weeks. It was shown that degradation mechanism and kinetics depend on chemical structure of the copolymers.