Heparan sulfate (HS) and chondroitin sulfate/dermatan sulfate (CS/DS) glycosaminoglycans (GAGs) participate in many important biological processes. Quantitative disaccharide analysis of HS and CS/DS is essential for the characterization of GAGs and enables modeling of the GAG domain structure. Methods involving enzymatic digestion and chemical depolymerization have been developed to determine the type and location of sulfation/acetylation modifications as well as uronic acid epimerization. Enzymatic digestion generates disaccharides with Δ-4,5-unsaturation at the non-reducing end. Chemical depolymerization with nitrous acid retains the uronic acid epimerization. This work shows the use of hydrophilic interaction liquid chromatography (HILIC)-MS for quantification of both enzyme-derived and nitrous acid depolymerization products for structural analysis of HS and CS/DS. This method enables biomedical researchers to determine complete disaccharide profiles on GAG samples using a single LC-MS platform.

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Estimation of related substancesby usinghigh-performance liquid chromatographic method was developed and validated for the determination of Tigecycline in the present work. Reversedphase chromatography was performed on Waters 2489 UV 2695 pump, Waters 2998 PDA 2695 pump Software Empower 2 photodiode array detector using Zorbax Eclipse plus C18 (100 mm × 4.6 mm, 1.8 µm particle size) column with eluent-A: pH 6.50 buffer: acetonitrile: DMSO (90:5:5 %v/ v/v) and eluent-B: pH 6.50 buffer: acetonitrile: DMSO (71:24:5 %v/v/v) as mobile phase at a flow rate of 1.0 mL/min. with UV detection at 270 nm.Linearity was observed in the concentration range of Tigecycline LOQ-1.13% (R2 = 1.000), the concentration range of di-MA-TIG impurity 0.04-0.23% (R2 = 1.000), the concentration range of CMI 0.05-0.23% (R2 = 0.999). The limit of quantitation (LOQ) and limit of detection (LOD) were found to be di-MA-TIG impurity 0.0001 and 0.0004mg/ mL, CMI impurity 0.0001and 0.0004µg/mL, Tigecycline 0.0001and 0.0005mg/mL respectively. The method was validated as per ICH guidelines. The %RSD precision was found to be less than 1.0 %. The percentage recovery was in good agreement with the labeled amount in the pharmaceutical formulations and the method is simple, specific, precise and accurate for the determination of Tigecycline in pharmaceutical formulations.

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