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Weiser J.R.,Cornell University | Zawaneh P.N.,Cornell University | Zawaneh P.N.,Millennium: The Takeda Oncology Company | Putnam D.,Cornell University
Biomacromolecules | Year: 2011

The synthesis of new polymeric biomaterials using biocompatible building blocks is important for the advancement of the biomedical field. We report the synthesis of statistically random poly(carbonate-ester)s derived from lactic acid and dihydroxyacetone by ring-opening polymerization. The monomer mole feed ratio and initiator concentration were adjusted to create various copolymer ratios and molecular weights. A dimethoxy acetal protecting group was used to stabilize the dihydroxyacetone and was removed using elemental iodine and acetone at reflux to produce the final poly(lactide-co-dihydroxyacetone) copolymers. The characteristics of the copolymers in their protected and deprotected forms were characterized by 1H NMR, 13C NMR, GPC, TGA, and DSC. Hydrolytic degradation of the deprotected copolymers was tracked over an 8-week time frame. The results show that faster degradation occurred with increased carbonate content in the copolymer backbone. The degradation pattern of the copolymers was visualized using SEM and revealed a trend toward surface erosion as the primary mode of degradation. © 2011 American Chemical Society. Source

Huang S.-C.,Millennium: The Takeda Oncology Company | Korlipara V.L.,St. Johns University
Expert Opinion on Therapeutic Patents | Year: 2010

Importance of the field: Substance P is involved in mediating a number of biological effects such as emesis, pain, inflammation, bronchoconstriction, antitumor activity, and regulation of gastrointestinal and CNS function by binding to the neurokinin-1 (NK1) receptor. Antagonists of this receptor have the potential to be useful in the treatment of various disease conditions. Areas covered in this review: More than 300 patents have been filed by nearly 20 companies and 2 academic institutions in the past 2 decades. This review provides an overview of the patenting activity in the NK1 antagonist field over the last 20 years. What the reader will gain: Chemically diverse non-peptide NK1 receptor antagonists have been identified since the discovery of CP-96,345 by Pfizer in 1991. Representative examples of patented ligands and their biological activities are presented in a company-wise approach. Take home message: The NK1 receptor research has led to the clinical introduction of aprepitant in 2003 and its water soluble injectable form, fosaprepitant dimeglumine, in 2009 by Merck for the prevention of postoperative nausea and vomiting and for inhibiting chemotherapy-induced nausea and vomiting. In addition, maropitant citrate received approval in 2007 for veterinary use. © Informa UK Ltd. Source

Kothari K.,University of Minnesota | Kothari K.,Millennium: The Takeda Oncology Company | Ragoonanan V.,University of Minnesota | Ragoonanan V.,DuPont Company | Suryanarayanan R.,University of Minnesota
Molecular Pharmaceutics | Year: 2015

We investigated the influence of drug-polymer hydrogen bonding interactions on molecular mobility and the physical stability in solid dispersions of nifedipine with each of the polymers polyvinylpyrrolidone (PVP), hydroxypropylmethyl cellulose (HPMCAS), and poly(acrylic acid) (PAA). The drug-polymer interactions were monitored by FT-IR spectroscopy, the molecular mobility was characterized using broadband dielectric spectroscopy, and the crystallization kinetics was evaluated by powder X-ray diffractometry. The strength of drug-polymer hydrogen bonding, the structural relaxation time, and the crystallization kinetics were rank ordered as PVP > HPMCAS > PAA. At a fixed polymer concentration, the fraction of the drug bonded to the polymer was the highest with PVP. Addition of 20% w/w polymer resulted in ∼65-fold increase in the relaxation time in the PVP dispersion and only ∼5-fold increase in HPMCAS dispersion. In the PAA dispersions, there was no evidence of drug-polymer interactions and the polymer addition did not influence the relaxation time. Thus, the strongest drug-polymer hydrogen bonding interactions in PVP solid dispersions translated to the longest structural relaxation times and the highest resistance to drug crystallization. © 2014 American Chemical Society. Source

Blair D.,Chestnut Hill College | Blair D.,Millennium: The Takeda Oncology Company | Dufort F.J.,Chestnut Hill College | Chiles T.C.,Chestnut Hill College
Biochemical Journal | Year: 2012

Signals derived from the BCR (B-cell antigen receptor) control survival, development and antigenic responses. One mechanism by which BCR signals may mediate these responses is by regulating cell metabolism. Indeed, the bioenergetic demands of naïve B-cells increase following BCR engagement and are characterized by a metabolic switch to aerobic glycolysis; however, the signalling pathways involved in this metabolic reprogramming are poorly defined. The PKC (protein kinase C) family plays an integral role in B-cell survival and antigenic responses. Using pharmacological inhibition and mice deficient in PKCβ, we demonstrate an essential role of PKCβ in BCR-induced glycolysis in B-cells. In contrast, mice deficient in PKCδ exhibit glycolytic rates comparable with those of wild-type B-cells following BCR cross-linking. The induction of several glycolytic genes following BCR engagement is impaired in PKCβ-deficient B-cells. Moreover, blocking glycolysis results in decreased survival of B-cells despite BCR engagement. The results establish a definitive role for PKCβ in themetabolic switch to glycolysis following BCR engagement of naïve B-cells. © The Authors Journal compilation © 2012 Biochemical Society. Source

Hu M.,Millennium: The Takeda Oncology Company | Zhou T.,Sanofi S.A.
Journal of Biopharmaceutical Statistics | Year: 2011

Intravascular ultrasound (IVUS) is a clinical imaging procedure used to assess drug effects on the progression of coronary atherosclerosis in clinical trials. It is an invasive medical procedure of measuring coronary artery atheroma (plaque) volume, and leads to high missing rates (often over 30%). This paper uses an IVUS Phase II clinical trial data to explore the missing mechanism of IVUS endpoint, the percent atheroma volume (PAV). We proposed a moving-window method to examine the relationship between continuous covariates such as lipid endpoint and the probability of missing IVUS values, which provides a general approach for missing mechanism exploration. The moving-window method is more intuitive and provides a fuller picture about the relationship. In the example, some covariates such as lipid measures also have high missing rates after 12 months because of compliance issues probably caused by fatigue of blood drawing. We found that if the method of last observation carried forward (LOCF) is used to impute the lipid endpoints, it leads to biologically unexplainable results. Using the multiple imputation approach for the missing covariates results in a more reasonable conclusion about the IVUS missing mechanism. Age, race, and baseline PAV are identified as key potential contributors to the probability of missing IVUS endpoint. This finding can be used to reduce missing values in future IVUS trials by setting up appropriate inclusion and exclusion criteria at the trial design stages. Copyright © Taylor & Francis Group, LLC. Source

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