Vanka Uma Maheswara Sarma

LC-ESI-MS/MS determination of paclitaxel on dried blood spots.

A simple and rapid high-performance liquid chromatography-tandem mass spectrometric assay for determination of paclitaxel on rat dried blood spots was developed and validated. The extracted sample was chromatographed without further treatment using a reverse-phase Oyster ODS3, 4.6 × 50 mm, 3 µm column with mass spectrometry detection. The mobile phase comprised of acetonitrile-water, 60:40 v/v, with a flow rate of 0.4 mL/min was used. The calibration was linear over the range 0.2-20 ng/mL. The limits of detection and quantification were 0.08 and 0.2 ng/mL, respectively. The intra- and inter-day precision (CV%) and accuracy (relative error %) were less than 10 and 12%, respectively.

Comparison of conventional and supported liquid extraction methods for the determination of sitagliptin and simvastatin in rat plasma by LC–ESI–MS/MS

Three extraction methods were compared for their efficiency to analyze sitagliptin and simvastatin in rat plasma by LC–MS/MS, including (1) liquid–liquid extraction (LLE), (2) solid phase extraction (SPE) and (3) supported liquid extraction (SLE). Comparison of recoveries of analytes with different extraction methods revealed that SLE was the best extraction method. The detection was facilitated with ion trap-mass spectrometer by multiple reactions monitoring (MRM) in a positive ion mode with ESI. The transitions monitored were m/z 441.1→325.2 for simvastatin, 408.2→235.1 for sitagliptin and 278.1→260.1 for the IS. The lower limit of quantification (LLOQ) was 0.2 ng/mL for sitagliptin and 0.1 ng/mL for simvastatin. The effective SLE offers enhanced chromatographic selectivity, thus facilitating the potential utility of the method for routine analysis of biological samples along with pharmacokinetic studies.

HPTLC METHOD FOR DETERMINATION OF DARUNAVIR IN RAT PLASMA AND ITS APPLICATION IN PHARMACOKINETIC STUDIES

A new, rapid, and sensitive high-performance thin-layer chromatography coupled with electrospray ionization mass spectrometry (HPTLC-ESI/MS) has been developed and validated for the quantification of darunavir in rat plasma and its application in pharmacokinetic studies. Detection and quantification were performed without using an internal standard. Protein precipitation method was followed for extracting darunavir from plasma. A saturated mixture of toluene: acetone: methanol (6:2:2 v/v) was used as mobile phase. Densitometric quantification was performed at λ = 262 nm by reflectance scanning. The method was linear over a concentration range of 5–150 ng/µL. The intra-day and inter-day precisions, expressed as RSD, were in the range of 2.15–2.77 (n = 3) and 2.13–2.47 (n = 3) respectively. The LOD was 1.24 ng/µL and LOQ was 3.85 ng/µL. The method proved to be accurate with a recovery between 94.77–98.44 and it was selective for the active principle tested. Additionally, selectivity of the method was confirmed by mass spectrometry. The mass spectra showed darunavir ion at m/z 569.80 [M +Na]+ being acquired directly from the rat plasma sample bands spiked with darunavir by an elution-based interface. The method was applied for the determination of plasma levels as well as pharmacokinetic study of darunavir administered orally to rats. Supplemental materials are available for this article. Go to the publishers online edition of Journal of Liquid Chromatography & Related Technologies to view the free supplemental file.

Simultaneous determination of bioactive compounds in Piper nigrum L. and a species comparison study using HPLC-PDA

Piper nigrum L. is a traditional medicine widely used in India for illnesses such as constipation, diarrhoea, earache, gangrene, heart disease, hernia, hoarseness, indigestion, insect bites, insomnia, joint pain, liver problems, lung disease, oral abscesses, sunburn, tooth decay and toothaches. In this study, six bioactive compounds, namely piperine (1), pellitorine (2), guineensine (3), pipnoohine (4), trichostachine (5) and piperonal (6) were quantified in different extracts of P. nigrum L. and compared with those of P. longum L. and P. chaba Hunter. To evaluate the quality of P. nigrum, a simple, accurate and precise HPLC-PDA method was developed for the simultaneous determination of the above-mentioned six compounds. The separation was achieved by Phenomenex Luna RP C18 column (150 × 4.6 mm, 5 µm, Phenomenex Inc, CA, USA) with a binary gradient solvent system of water–acetonitrile, at a flow rate of 1.0 mL min−1 and detected at 210, 232, 262 and 343 nm. All six calibration curves showed good linearity (R 2 > 0.9966). The method was reproducible with intra- and inter-day variations of less than 2% and 5%, respectively. The results demonstrated that this method is simple, reliable and suitable for the quality control of these plants.

Estimation of Costunolide and Dehydrocostus Lactone in Saussurea lappa and its Polyherbal Formulations followed by their Stability Studies Using HPLC-DAD

BACKGROUND Saussurea lappa is one of the popular Ayurvedic herb; costunolide and dehydrocostus lactones are well-known sesquiterpene lactones contained in many plants used as popular herbs, such as S. lappa, and have been considered as potential candidates for the treatment of various types of tumor. OBJECTIVE The present study was used for the quantification of costunolide and dehydrocostus lactone in S. lappa and its polyherbal formulations, stability studies of markers and characterization of their degradants. MATERIALS AND METHODS HPLC analysis was performed on Waters NOVAPAK HR C18 column (300 mm × 3.9 mm i.d., 6 μm) using isocratic elution with acetonitrile and water (60:40% v/v). RESULTS The calibration curves of both analytes showed good linearity within the established range 5-100 μg/ml. The limits of detection (LOD) and quantification (LOQ) were 1.5 and 4.6 μg/ml for costunolide and 1.3 and 4.0 μg/ml for dehydrocostus lactone, respectively. Good results were achieved with respect to repeatability (%RSD < 2.0) and recovery (99.3-101.8%). CONCLUSION The method was found to be precise, accurate, specific, and was successfully used for analyzing costunolide and dehydrocostus lactone in S. lappa and its polyherbal formulations. The developed method was found to be suitable for stability studies of markers and characterization of their degradation products.

Validated High-Performance Thin-Layer Chromatographic Method for the Determination of Dibenzyl Cyclooctadiene Lignans from Schisandra grandiflora

A simple, accurate, and rapid high-performance thin-layer chromatographic (HPTLC) method has been established and validated for the simultaneous quantification of the four biologically active dibenzyl cyclooctadiene lignans, i.e., schisandrin (1), gomisin B (2), deoxyschisandrin (3), and gomisin N (4) from the hexane extract of Schisandra grandiflora (Wall.) Hook. f. & Thoms. Separation was performed on silica gel 60 F254 plates using a saturated mixture of toluene—ethyl acetate—methanol (6:1:1 v/v) as the mobile phase. Quantitation was performed using densitometric absorption—reflection mode at 225 nm. The method was validated for its selectivity, linearity, precision, and accuracy. HPTLC was hyphenated with a mass spectrometer as an additional tool for the confirmation of the markers using an interface. The developed method is simple and convenient which can be applied for the regular quality analysis of the raw plant material used in Chinese traditional herbal formulations.

Simultaneous Determination of Six Marker Compounds in Piper nigrum L. and Species Comparison Study Using High-Performance Thin-Layer Chromatography-Mass Spectrometry

The isolation and characterization of bioactive compounds from medicinal plants is usually a significant challenge in phytochemical analysis because of the natural chemical complexity of plant extracts. However, there exists a need for analytical tools which can quantitatively separate and characterize the components from these biosources with greater chromatographic selectivity and lesser analytical run times that facilitate the evaluation with enhanced separation profiles. Hyphenation of thin-layer chromatography (TLC/HPTLC) with mass spectrometry (MS) is an alternative for screening herbal extracts because of its rapid analysis and ability to aid structural characterization with powerful analytical capacity. The aim of the present study was to develop a sophisticated analytical method which utilizes HPTLC-MS coupling for the chromatographic profiling and evaluation of the therapeutically important genus Piper (Piperaceae). In this study, six marker compounds, namely, trichostachine, piperine, 4,5-dihydropiperlonguminine, guineensine, pellitorine, and sesamin were analyzed and quantified in extracts of Piper nigrum L. and compared with those of Piper longum L. and Piper chaba Hunter. All the samples tested showed similar phytochemical profiles, but the contents of the active ingredients varied. Additionally, HPTLC-MS further allowed confirming the identification of the constituents in the analyzed samples with greater chromatographic selectivity where HPTLC facilitated a selective chromatographic resolution, while MS offered an efficient characterization of the target compounds in one analytical run. The study finds a potential utility in adopting HPTLC-MS as a rapid and high throughput method for the efficient quantification and identification of marker compounds from medicinal plants.

UPLC–MS/MS quantitative analysis and structural fragmentation study of five Parmotrema lichens from the Eastern Ghats

Graphical abstract Figure. No caption available. HighlightsDesign of a method to analyze lichen extracts through UPLC MS (HR MS/MS and MRM).Dozens of lichen compounds newly identified from five closely shaped Parmotrema species.MS Fragmentation patterns analyzed for 5 classes of compounds.Good anti‐glycation activities for three lichen extracts collected in Eastern Ghats. ABSTRACT Comparative phytochemical analysis of five lichen species [Parmotrema tinctorum (Delise ex Nyl.) Hale, P. andinum (Mull. Arg.) Hale, P. praesorediosum (Nyl.) Hale, P. grayanum (Hue) Hale, P. austrosinense (Zahlbr.) Hale] of Parmotrema genus were performed using two complementary UPLC–MS systems. The first system consists of high resolution UPLC‐QToF‐MS/MS spectrometer and the second system consisted of UPLC–MS/MS in Multiple Reaction Monitoring (MRM) mode for quantitative analysis of major constituents in the selected lichen species. The individual compounds (47 compounds) were identified using Q‐ToF‐MS/MS, via comparison of the exact molecular masses from their MS/MS spectra, the comparison of literature data and retention times to those of standard compounds which were isolated from crude extract of abundant lichen, P. tinctorum. The analysis also allowed us to identify unknown peaks/compounds, which were further characterized by their mass fragmentation studies. The quantitative MRM analysis was useful to have a better discrimination of species according to their chemical profile. Moreover, the determination of antioxidant activities (ABTS+ inhibition) and Advance Glycation Endproducts (AGEs) inhibition carried out for the crude extracts revealed a potential antiglycaemic activity to be confirmed for P. austrosinense.

INHIBITORY EFFECTS OF DERRIS INDICA DERIVED CONSTITUENTS AGAINST ADVANCED GLYCATION END PRODUCTS AND THEIR SIMULTANEOUS DETERMINATION BY HPLC

Antiglycating potentials of Derris indica L., derived constituents were evaluated against advanced glycation end product formation using in vitro bioassays and compared with those of commonly used standards. The structures of 12 constituents of Derris indica were characterized by spectroscopic analyses (NMR and Mass). Further, these constituents were simultaneously determined using high performance liquid chromatography (HPLC) using a Waters XTerra RP18 column (250 × 4.6 mm, 5 µ) with a gradient elution system comprising of acetonitrile, water and 0.1% (v/v) acetic acid, flow rate 0.8 mL/min and column temperature 25°C, respectively. The limits of detection (LODs) were below 0.10 µg/mL, whereas the limits of quantification (LOQs) were below 0.30 µg/mL. It is concluded that the method has merits such as high sensitivity, specificity, and simplicity versus those of the other methods reported in the literature.