Patents by Inventor Subhasish Purkayastha

Subhasish Purkayastha has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9964552
    Abstract: A method is described for mass spectrometric analysis, detection and quantification of catecholamines. The methods can comprise reacting the catecholamines with a 4-aminoantipyrine reagent and detecting and/or quantifying the adduct produced by the reaction. The methods can also allow for multiplexing. Compounds formed by the reactions are also provided.
    Type: Grant
    Filed: October 22, 2014
    Date of Patent: May 8, 2018
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Subhakar Dey, Subhasish Purkayastha
  • Patent number: 9874575
    Abstract: A method is described for mass spectrometric analysis of a sample comprising phenolic OH, such as a steroid comprising a phenolic OH, using a quaternary amino oxy Cookson (QAOC) reagent. The QAOC reagent can improve ionization and fragmentation properties of phenolic OH samples, which can thereby improve quantitation and identification. The method can include derivatizing the phenolic OH sample with the QAOC reagent to create an adduct and analyzing the adduct using mass spectrometry. Derivatization of the sample can be a one-step reaction where the QAOC reagent comprises an aminooxy MS tag or can be a multi-step reaction, where the adduct is formed by the reaction of carbonyl substituted PTAD based reagent and the sample followed by combination with an aminooxy MS tag. The sample can also be enriched prior to reacting it with the reagent. The method can also allow for multiplexing.
    Type: Grant
    Filed: January 16, 2013
    Date of Patent: January 23, 2018
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Subhakar Dey, Subhasish Purkayastha
  • Publication number: 20170115258
    Abstract: Labeling reagents, sets of labeling reagents, and labeling techniques are provided for the relative quantitation, absolute quantitation, or both, of ketone or aldehyde compounds including, but not limited to, analytes comprising steroids or ketosteroids and includes testosterone. The analytes can be medical or pharmaceutical compounds in biological samples. Methods for labeling, analyzing, and quantifying ketone or aldehyde compounds are also disclosed as are methods that also use mass spectrometry.
    Type: Application
    Filed: October 31, 2016
    Publication date: April 27, 2017
    Inventors: Subhakar Dey, Sasi Pillai, Brian L. Williamson, Subhasish Purkayastha, Michal Weinstock
  • Publication number: 20170074871
    Abstract: Methods and apparatus for processing fluids on a macro- or micro-scale are described. In various aspects, a fluid may have a plurality of elongated (i.e., substantially rod-shaped) magnetic elements disposed therein within a fluid container. An illustrative fluid container is an actuator electrode or a processing vial of a microfluidic device, such as a digital microfluidic device. A magnet component may be configured to generate a magnetic force sufficient to influence the movement of the plurality of elongated magnetic elements within the fluid to be processed. For example, the magnetic force (or magnetic force gradient) may influence the plurality of elongated magnetic elements to rotate, spin, and/or move laterally side-to-side. The shape and movements of the plurality of elongated magnetic elements facilitate the rapid and efficient processing of the fluid, such as fluid mixing and/or fluid separation.
    Type: Application
    Filed: February 27, 2015
    Publication date: March 16, 2017
    Inventors: John L. Campbell, Thomas R. Covey, Chang Liu, Subhasish Purkayastha
  • Publication number: 20170052180
    Abstract: Systems and methods are provided for microbial identification using cleavable tags. Control information is sent to a mass spectrometer to select a peptide labeled with a first tag of a known microbe, fragment the labeled peptide of the known microbe, and monitor for an intensity of the first tag in an MRM method using a processor. An ion source provides a beam of ions from a sample that includes peptides labeled with the first tag. The first tag binds to a peptide of a known microbe and is cleaved from the peptide of the known microbe during mass spectrometry. The mass spectrometer receives the beam of ions and is adapted to perform the MRM method on the beam of ions. If the intensity of the first tag received from the mass spectrometer exceeds a threshold value, the known microbe is identified in the sample using the processor.
    Type: Application
    Filed: February 25, 2015
    Publication date: February 23, 2017
    Inventors: Subhasish Purkayastha, Subhakar Dey
  • Patent number: 9546393
    Abstract: A method for screening a drug for cytochrome P450 (CYP) induction is provided and can include incubating the drug with a microsome-containing biological sample and then quantitating at least one cytochrome P450 isoform. The isoforms can be selected from 2B6, 3A4, 1A2, and 3A5 isoforms. In some embodiments, the method uses liquid chromatography tandem mass spectrometry (LC-MSMS). A quantitated value can be compared to a threshold value and the drug can be determined to exhibit an acceptable CYP induction potential when the quantitated value does not exceed the threshold value. Isolated peptides are also provided.
    Type: Grant
    Filed: January 22, 2015
    Date of Patent: January 17, 2017
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Brian L. Williamson, Subhasish Purkayastha
  • Patent number: 9500622
    Abstract: Labeling reagents, sets of labeling reagents, and labeling techniques are provided for the relative quantitation, absolute quantitation, or both, of ketone or aldehyde compounds including, but not limited to, analytes comprising steroids or ketosteroids. The analytes can be medical or pharmaceutical compounds in biological samples. Methods for labeling, analyzing, and quantifying ketone or aldehyde compounds are also disclosed as are methods that also use mass spectrometry.
    Type: Grant
    Filed: May 20, 2013
    Date of Patent: November 22, 2016
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Subhakar Dey, Sasi Pillal, Brian L. Williamson, Subhasish Purkayastha, Michal Weinstock
  • Publication number: 20160305969
    Abstract: A method is described for mass spectrometric analysis, detection and quantification of catecholamines. The methods can comprise reacting the catecholamines with a 4-aminoantippyrine reagent and detecting and/or quantifying the adduct produced by the reaction. The methods can also allow for multiplexing. Compounds formed by the reactions are also provided.
    Type: Application
    Filed: October 22, 2014
    Publication date: October 20, 2016
    Applicant: DH TECHNOLOGIES DEVELOPMENT PTE. LTD.
    Inventors: Subhakar Dey, Subhasish Purkayastha
  • Patent number: 9257267
    Abstract: A composition, method, and kit for calibrating a mass spectrometer including a predetermined concentration of a calibrant having a mixture of amino acid polyethylene glycol compounds and a solvent for dissolving the calibrant. The calibrant can be used in either positive or negative ionization mode, and it can be used in calibrating an atmospheric pressure chemical ionization or an electrospray mass spectrometer. The calibrant can include a mixture to enable calibration across a broad range of masses.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: February 9, 2016
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Subhakar N. Dey, Marjorie S. Minkoff, Sasi K. Pillai, Subhasish Purkayastha, Brian L. Williamson
  • Publication number: 20160025741
    Abstract: Methods and systems for detecting allergens using mass spectrometry are provided herein. In some aspects, a sample can be screened for the presence or quantity of ovalbumin, lysozyme, casein (isoform S1 and S2), lactoglobulin, high and low glutens, wheat, rye, oats, barley, mustard, sesame, and various types of nuts including macadamia, pistachio, brazil, walnuts, peanuts and hazelnuts by detecting one or more peptides specific to the allergen of interest using selected MRM transitions.
    Type: Application
    Filed: September 2, 2012
    Publication date: January 28, 2016
    Applicant: DH Technologies Development Pte. Ltd.
    Inventors: Stephen J. Lock, Subhasish Purkayastha, Brian L. Williamson, Keling Dong
  • Patent number: 9188596
    Abstract: Quantification of vitamin D2, vitamin D3, and the monohydroxy and diihydroxy metabolites of vitamin D2 and vitamin D3, can comprise labeling analytes with mass spectrometry (MS) tagging reagents and performing LC-MSMS analysis of the labeled analytes. The labeled analytes can include a labeled standard and can have distinct retention times on a reversed phase column, as well as distinct masses. Under high energy collisions, reporter groups can be generated. The intensity or the peak area detected for each reporter group can be used for quantitation. In some embodiments, a one-step tagging reagent is used that is a dienophile-containing, labeled m Diels Alder reagent.
    Type: Grant
    Filed: December 12, 2013
    Date of Patent: November 17, 2015
    Assignee: DH Technologies Development Pte. Ltd
    Inventors: Subhakar Dey, Sasi Pillal, Brian L. Williamson, Subhasish Purkayastha
  • Publication number: 20150323554
    Abstract: A method, a labeling reagent, sets of labeling reagents, and labeling techniques are provided for the analysis of ketosterol biomarkers such as bile acid precursors from human plasma, serum or whole blood. This method is used for new born screening for Cerebrotendinous Xanthomatosis (CTX). Methods for labeling, analyzing, and quantifying ketosterol biomarkers are also disclosed as are methods that also use mass spectrometry.
    Type: Application
    Filed: May 17, 2013
    Publication date: November 12, 2015
    Applicant: DH Technologies Development Pte. Ltd
    Inventors: Andrea DeBarber, Subhasish Purkayastha, Robert D. Steiner, Michal Weinstock
  • Publication number: 20150140600
    Abstract: A method for screening a drug for cytochrome P450 (CYP) induction is provided and can include incubating the drug with a microsome-containing biological sample and then quantitating at least one cytochrome P450 isoform. The isoforms can be selected from 2B6, 3A4, 1A2, and 3A5 isoforms. In some embodiments, the method uses liquid chromatography tandem mass spectrometry (LC-MSMS). A quantitated value can be compared to a threshold value and the drug can be determined to exhibit an acceptable CYP induction potential when the quantitated value does not exceed the threshold value. Isolated peptides are also provided.
    Type: Application
    Filed: January 22, 2015
    Publication date: May 21, 2015
    Inventors: Brian L. Williamson, Subhasish Purkayastha
  • Patent number: 8975404
    Abstract: Provided herein are labeling reagents for analyte determination in a sample, and methods of manufacturing the labeling reagents. By way of non-limiting example, analytes may include one or more of peptides, proteins, nucleic acid molecules, carbohydrates, lipids, steroids and/or small molecules. Also provided are labeled analytes themselves after one or more labeling reagents binds to an analyte. Analytes may be labeled for determination of the analyte by mass analysis, such as by mass spectrometry. Further provided are compounds that may be used in making the labeling reagents and labeled analytes, such as reporter group compounds. Also provided are kits that include at least one labeling reagent, and may further include or more other reagents, containers, enzymes, buffers, a labeled analyte (e.g., as a standard) and/or instructions. Further examples are also possible.
    Type: Grant
    Filed: January 22, 2007
    Date of Patent: March 10, 2015
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Sasi K. Pillai, Subhakar Dey, Subhasish Purkayastha, Darryl J. C. Pappin
  • Publication number: 20150051111
    Abstract: A method is described for mass spectrometric analysis of a sample comprising phenolic OH, such as a steroid comprising a phenolic OH, using a quaternary amino oxy Cookson (QAOC) reagent. The QAOC reagent can improve ionization and fragmentation properties of phenolic OH samples, which can thereby improve quantitation and identification. The method can include derivatizing the phenolic OH sample with the QAOC reagent to create an adduct and analyzing the adduct using mass spectrometry. Derivatization of the sample can be a one-step reaction where the QAOC reagent comprises an aminooxy MS tag or can be a multi-step reaction, where the adduct is formed by the reaction of carbonyl substituted PTAD based reagent and the sample followed by combination with an aminooxy MS tag. The sample can also be enriched prior to reacting it with the reagent. The method can also allow for multiplexing.
    Type: Application
    Filed: January 16, 2013
    Publication date: February 19, 2015
    Inventors: Subhakar Dey, Subhasish Purkayastha
  • Publication number: 20150045256
    Abstract: A method for screening a drug for cytochrome P450 (CYP) induction is provided and can include incubating the drug with a microsome-containing biological sample and then quantitating at least one cytochrome P450 isoform. The isoforms can be selected from 2B6, 3A4, 1A2, and 3A5 isoforms. In some embodiments, the method uses liquid chromatography tandem mass spectrometry (LC-MSMS). A quantitated value can be compared to a threshold value and the drug can be determined to exhibit an acceptable CYP induction potential when the quantitated value does not exceed the threshold value. Isolated peptides are also provided.
    Type: Application
    Filed: August 21, 2014
    Publication date: February 12, 2015
    Inventors: Brian L. Williamson, Subhasish Purkayastha
  • Patent number: 8940545
    Abstract: A method for screening a drug for cytochrome P450 (CYP) induction is provided and can include incubating the drug with a microsome-containing biological sample and then quantitating at least one cytochrome P450 isoform. The isoforms can be selected from 2B6, 3A4, 1A2, and 3A5 isoforms. In some embodiments, the method uses liquid chromatography tandem mass spectrometry (LC-MSMS). A quantitated value can be compared to a threshold value and the drug can be determined to exhibit an acceptable CYP induction potential when the quantitated value does not exceed the threshold value. Isolated peptides are also provided.
    Type: Grant
    Filed: October 14, 2010
    Date of Patent: January 27, 2015
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Brian L. Williamson, Subhasish Purkayastha
  • Publication number: 20140349885
    Abstract: A method, a labeling reagent, sets of labeling reagents, and labeling techniques are provided for the relative quantitation, absolute quantitation, or both, of ketone or aldehyde compounds including, but not limited to, analytes comprising steroids or ketosteroids. The analytes can be medical or pharmaceutical compounds in biological matrices. Methods for labeling, analyzing, and quantifying ketone or aldehyde compounds are also disclosed as are methods that also use mass spectrometry.
    Type: Application
    Filed: December 6, 2012
    Publication date: November 27, 2014
    Inventors: Subhakar Dey, Subhasish Purkayastha
  • Patent number: 8853133
    Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination and/or quantification by mass spectrometry using compounds comprising a reporter moiety and a non-encoded detectable label. The compounds can be used in sets for the analysis of mixtures of labeled analytes.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: October 7, 2014
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: Subhasish Purkayastha, Subhakar Dey
  • Publication number: 20140127825
    Abstract: Quantification of vitamin D2, vitamin D3, and the monohydroxy and diihydroxy metabolites of vitamin D2 and vitamin D3, can comprise labeling analytes with mass spectrometry (MS) tagging reagents and performing LC-MSMS analysis of the labeled analytes. The labeled analytes can include a labeled standard and can have distinct retention times on a reversed phase column, as well as distinct masses. Under high energy collisions, reporter groups can be generated. The intensity or the peak area detected for each reporter group can be used for quantitation. In some embodiments, a one-step tagging reagent is used that is a dienophile-containing, labeled m Diels Alder reagent.
    Type: Application
    Filed: December 12, 2013
    Publication date: May 8, 2014
    Applicant: DH TECHNOLOGIES DEVELOPMENT PTE. LTD.
    Inventors: Subhakar Dey, Sasi Pillal, Brian L. Williamson, Subhasish Purkayastha