ABSTRACT
The objective of the current study was to develop and validate a sensitive and specific LC-MS compatible stability indicating reversed phase liquid chromatographic method for the quantitative determination of Gabapentin and its related substances using Corona charged aerosol detection (CAD). The chromatographic conditions were optimized using a Kinetix Biphenyl column with gradient elution using a mobile phase composed of pH 4.2 ammonium acetate, acetonitrile, and methanol. Forced degradation was observed in basic and peroxide conditions and the major degradants were identified by LC-MS/MS analysis. The developed RP-HPLC CAD method was validated according to ICH guidelines. The LOD and LOQ values for Gabapentin and all its related impurities ranged from 0.075µg/mL to 0.18µg/mL and 0.25µg/mL to 0.60µg/mL, respectively. The recovery for all impurities ranged from 91.0 to 105.6%w/w. Solutions were stable for 7days at room temperature. The validated method produced acceptable precision, linearity, accuracy, robustness and ruggedness.
Subject(s)
Amines/analysis , Chromatography, High Pressure Liquid/methods , Chromatography, Reverse-Phase/methods , Cyclohexanecarboxylic Acids/analysis , gamma-Aminobutyric Acid/analysis , Gabapentin , Spectrometry, Mass, Electrospray IonizationABSTRACT
MS-275, a histone deacetylase inhibitor (HDACi), is undergoing clinical trials for treatment of various cancers. Pentoxifylline, a nonselective phosphodiesterase (PDE) inhibitor, has been shown to increase the effectiveness of antitumor chemotherapy. In the present study, the potential anti-cancer activity of MS-275 in combination with pentoxifylline in panel of cell lines and human breast cancer xenograft model were examined. A Panel of cancer cell lines were treated with MS-275 and pentoxifylline to determine their impact on cellular proliferation, cell cycle regulation, apoptosis, anti-angiogenesis. The in vivo activities of MS-275 and pentoxifylline were assessed in a Matrigel plug angiogenesis model and human breast cancer (MDA-MB-231) xenograft model. Combination of MS-275 with pentoxifylline showed enhanced anti-proliferative activity in a panel of cancer cell lines (HCT 116, MCF-7, PC3 and MDA-MB-231). Apoptotic studies performed using, Hoechst staining and cell cycle analysis reveal that this combination at the lower concentrations induces apoptosis downstream of the HDAC inhibition and PDE regulation. Further, combination showed enhanced antiangiogenic activity in Matrigel tube formation assay using HUVECs and in Matrigel plug assay in vivo. A significant inhibition (P<0.001) of tumor growth was observed in mice bearing MDA-MB-231 breast cancer xenograft treated with the combination of MS-275 (5mg/kg p.o.) and pentoxifylline (60 mg/kg i.p.) than treatments alone, without much signs of toxicity. Taken together, our study demonstrated enhanced anticancer activity of MS-275 and pentoxifylline combination both in vitro and in vivo with reduced toxicity. However, further studies are required to understand the mechanism for this combination effect.
Subject(s)
Angiogenesis Inhibitors/pharmacology , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Benzamides/pharmacology , Breast Neoplasms/drug therapy , Histone Deacetylase Inhibitors/pharmacology , Pentoxifylline/pharmacology , Phosphodiesterase Inhibitors/pharmacology , Pyridines/pharmacology , Animals , Apoptosis/drug effects , Breast Neoplasms/blood supply , Breast Neoplasms/enzymology , Breast Neoplasms/pathology , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Synergism , Female , HCT116 Cells , Human Umbilical Vein Endothelial Cells/drug effects , Human Umbilical Vein Endothelial Cells/enzymology , Humans , MCF-7 Cells , Mice, SCID , Neovascularization, Pathologic , Tumor Burden/drug effects , Xenograft Model Antitumor AssaysABSTRACT
A simple, sensitive, and rapid HPLC-MS/MS method was developed and validated for quantitative estimation of memantine in human plasma. Chromatography was performed on Zorbax SB-C(18) (4.6 × 75 mm, 3.5 µm) column. Memantine (ME) and internal standard Memantine-d6(MED6) were extracted by using liquid-liquid extraction and analyzed by LC-ESI-MS/MS using multiple-reaction monitoring (MRM) mode. The assay exhibited a linear dynamic range of 50.00-50000.00 pg/ml for ME in human plasma. This method demonstrated an intra- and interday precision within the range of 2.1-3.7 and 1.4-7.8%, respectively. Further intra- and interday accuracy was within the range of 95.6-99.8 and 95.7-99.1% correspondingly. The mean recovery of ME and MED6 was 86.07 ± 6.87 and 80.31 ± 5.70%, respectively. The described method was successfully employed in bioequivalence study of ME in Indian male healthy human volunteers under fasting conditions.
