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.

The present paper describes the reverse phase-high performance liquid chromatographic method and was validated as per ICH guidelines for the determination of related substances in Cabazitaxel. RP-Liquid chromatography technique was performed with pH 3.0 phosphate buffer and acetonitrile as mobile phase at a flow rate of 0.8 mL/min. on Waters 2489 UV 2695 pump, Waters 2998 PDA 2695 pump Software Empower 2 photodiode array detector using Zorbax SB C18 column with UV detection at 220 nm. Linearity was observed in the concentration range of Cabazitaxel LOQ-0.10% (R 2 = 0.9998), the concentration range of CBZM01 impurity 0.03-0.225% (R 2 = 0.9997), the concentration range of CBZM02 impurity 0.03-0.225% (R 2 = 0.9997), the concentration range of CBZN09 impurity 0.03-0.225% (R 2 = 0.9998). Limit of detection (%) and the limit of quantitation (ng/mL) were found to be CBZM01 impurity 0.002% and 73ng/mL, CBZM02 impurity 0.002 % and 71ng/mL, CBZN09 impurity 0.002 % and 6ng/mL and Cabazitaxel 0.002 % and 0.008 % respectively. The percent recovery was in good agreement with the labeled amount in the dosage forms and hence, the method is specific, simple, reproducible and accurate for the determination of Cabazitaxel.

The separation of the tryptic peptides of the human hemoglobin A 0-chain by reversed phase high performance liquid chromatography under different elution conditions on several microparticulate alkylsilica supports is described. Similar methods have been used to separate the tryptic peptides of $-chain hemoglobin variants including HbC, HbE, and Hb(Kempsey) .Selectivity differences which can be achieved under the different chromatographic conditions have been exploited to permit the assignment of all the anticipated peptide fragments derived from the tryptic digestion of these O-chain Hb-variants.

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