Sumit Majumdar

Publications (10) View all

• Article: Rapid deamidation of recombinant protective antigen when adsorbed on aluminum hydroxide gel correlates with reduced potency of vaccine.

  Ajit Joseph M D'Souza, Kevin D Mar, Joanne Huang, Sumit Majumdar, Brandi M Ford, Beverly Dyas, Robert G Ulrich, Vincent J Sullivan
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  ABSTRACT: Deamidation of the recombinant protective antigen (rPA) correlates with decreased effectiveness of the vaccine in protecting against infection by Bacillus anthracis. We present data demonstrating dramatic deamidation of amino acid positions 713 and 719 of rPA adsorbed onto aluminum hydroxide gel, an adjuvant, relative to rPA stored in solution without adjuvant. Although deamidation did not impact total levels of rPA-specific antibodies in a mouse model, it did correlate with a decrease in toxin-neutralizing antibodies. On the basis of these data, we hypothesize that interactions of rPA with aluminum hydroxide gel are destabilizing and are the direct cause of reduced vaccine efficacy. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci.
  Journal of Pharmaceutical Sciences 12/2012; · 3.06 Impact Factor
• Article: Methotrexate (MTX)-cIBR conjugate for targeting MTX to leukocytes: conjugate stability and in vivo efficacy in suppressing rheumatoid arthritis.

  Sumit Majumdar, Meagan E Anderson, Christine R Xu, Tatyana V Yakovleva, Leo C Gu, Thomas R Malefyt, Teruna J Siahaan
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  ABSTRACT: Methotrexate (MTX) has been used to treat rheumatoid arthritis at low doses and leukemia at high doses; however, this drug can produce severe side effects. Our hypothesis is that MTX side effects can be attenuated by directing the drug to the target cells (i.e., leukocytes) using (cyclo(1,12)PenPRGGSVLVTGC) peptide (cIBR). To test this hypothesis, MTX was conjugated to the N-terminus of cIBR peptide to give MTX-cIBR conjugate. MTX-cIBR (5.0 mg/kg) suppressed joint arthritis in adjuvant arthritis rats and prevented periarticular inflammation and bone resorption of the limb joints. In vitro, the toxicity of MTX-cIBR peptide against Molt-3 T cells was inhibited by anti-lymphocyte function-associated antigen-1 (LFA-1) antibody and cIBR peptide in a concentration-dependent manner, suggesting that the uptake of MTX-cIBR was partially mediated by LFA-1. Chemical stability studies indicated that MTX-cIBR was most stable at pH 6.0. The MTX portion of MTX-cIBR was unstable under acidic conditions, whereas the cIBR portion was unstable under basic conditions. In biological media, MTX-cIBR had short half lives in rat plasma (44 min) and homogenized rat heart tissue (38 min). This low plasma stability may contribute to the low in vivo efficacy of MTX-cIBR; therefore, there is a need to design a more stable conjugate to improve the in vivo efficacy.
  Journal of Pharmaceutical Sciences 04/2012; 101(9):3275-91. · 3.06 Impact Factor
• Article: Evaluation of the effect of syringe surfaces on protein formulations.

  Sumit Majumdar, Brandi M Ford, Kevin D Mar, Vince J Sullivan, Robert G Ulrich, Ajit Joseph M D'souza
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  ABSTRACT: Packaging of drugs in prefillable syringes offers considerable advantages over conventional vials. Almost all major biotech molecules are available on the market today in prefilled syringes, and are safe and efficacious. Newer high-concentration liquid formulations, especially fusion proteins, however, can suffer from instability in prefilled syringes due to syringe components like silicone oil. To assess the effect of siliconized and modified syringe surfaces on protein formulations, the stability of the recombinant protective antigen (rPA) for anthrax, abatacept, a fusion protein formulation with known silicone oil sensitivity, and an antistaphylococcal enterotoxin B (anti-SEB) monoclonal antibody (mAb) was assessed in siliconized, uncoated, and BD-42-coated (a proprietary coating developed by BD Technologies) prefilled syringes under different conditions. Both the soluble protein content and the number of subvisible particles were followed over time. When filled in siliconized syringes, all three protein solutions showed increased number of subvisible particles relative to uncoated or BD-42-coated syringes; the abatacept formulation with known silicone sensitivity also developed visible particles. Although rPA and anti-SEB mAb formulations mainly showed individual droplets, presumably of silicone, the abatacept formulation also showed droplets entangled in a fibrous structure. Uncoated glass and BD-42-coated syringes considerably reduced the formation of both visible and subvisible particles after immediate contact and after agitation. The anti-SEB mAb also adhered as a thin layer to the siliconized surface after agitation, irrespective of storage temperature. The development of visible particles could not be correlated with the loss of soluble protein fraction at protein concentrations above 4 mg/mL. It appears that protein formulations interact differently with different surfaces. The BD-42 coating appears to be a promising solution for packaging silicone-sensitive proteins in prefillable syringes and needs to be investigated further. It is demonstrated that BD-42 provides an inert surface with adequate lubrication while limiting the formation of visible and subvisible particles. It is hypothesized that these particles are formed due to the release of silicone droplets in the solution and result in the formation of silicone-induced visible aggregates.
  Journal of Pharmaceutical Sciences 02/2011; 100(7):2563-73. · 3.06 Impact Factor
• Article: Peptide-mediated targeted drug delivery.

  Sumit Majumdar, Teruna J Siahaan
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  ABSTRACT: Targeted drug delivery to specific group of cells offers an attractive strategy to minimize the undesirable side effects and achieve the therapeutic effect with a lower dose. Both linear and cyclic peptides have been explored as trafficking moiety due to ease of synthesis, structural simplicity, and low probability of undesirable immunogenicity. Peptides derived from sequence of cell surface proteins, such as intercellular adhesion molecule-1 (ICAM-1), LHRH, Bombesin, and LFA-1, have shown potent binding affinity to the target cell surface receptors. Moreover, peptides derived from ICAM-1 receptor can be internalized by the leukemic T-cells along with the conjugated moiety offering the promise to selectively treat cancers and autoimmune diseases. Systematic analyses have revealed that physicochemical properties of the drug-peptide conjugates and their mechanism of receptor-mediated cellular internalization are important controlling factors for developing a successful targeting system. This review is focused on understanding the factors involved in the development of an effective drug-peptide conjugate with an emphasis on the chemistry and biology of the conjugates. Reported results on several promising drug-peptide conjugates have been critically evaluated. The approaches and results presented here will serve as a guide to systematically approach targeted delivery of cytotoxic drug molecules using peptides for treatment of several diseases.
  Medicinal Research Reviews 09/2010; 32(3):637-58. · 10.70 Impact Factor
• Article: ICAM-1 peptide inhibitors of T-cell adhesion bind to the allosteric site of LFA-1. An NMR characterization.

  Tahl Zimmerman, Julen Oyarzabal, Eider San Sebastián, Sumit Majumdar, Bimo A Tejo, Teruna J Siahaan, Francisco J Blanco
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  ABSTRACT: We have used nuclear magnetic resonance to characterize the binding site of two intercellular adhesion molecule-1 derived cyclic peptides, cIBC and cIBR, to the I-domain of leukocyte function-associated antigen-1. These peptides inhibit the leukocyte function-associated antigen-1/intercellular adhesion molecule-1 interaction known to play a key role in autoimmune diseases and cancer metastasis. Perturbation of the chemical shifts and intensities of the nuclear magnetic resonance signals corresponding to a number of residues of the I-domain of leukocyte function-associated antigen-1 show that both peptides bind to the I-domain allosteric site, the binding site of I-domain allosteric inhibitors such as lovastatin, and therefore the peptides probably also act as allosteric inhibitors of leukocyte function-associated antigen-1. Molecular models of the interaction of these two cyclic peptides with leukocyte function-associated antigen-1 I-domain show that the binding mode of the three molecules are analogous: the hydrophobic residues of the peptides remain buried and occupy the same positions as the apolar groups of lovastatin, while the peptides regions containing the most polar residues are flexible and primarily exposed to the solvent. These results suggest an allosteric mechanism for the inhibitory effect on T-cell adhesion displayed by both peptides, which exhibit potential as therapeutic agents.
  Chemical Biology &amp Drug Design 11/2007; 70(4):347-53. · 2.28 Impact Factor