- Bisphosphonate prodrugs: Synthesis and in vitro evaluation of novel clodronic acid dianhydrides as bioreversible prodrugs of clodronate
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P,P'-Diacetyl, P,P'-dibutyroyl, P,P'-dipivaloyl, and P,P'-dibenzoyl (dichloromethylene)bisphosphonic acid dianhydride disodium salts (2a-d) were synthesized and evaluated as novel bioreversible prodrugs of clodronate. The anhydrides were prepared by reacting anhydrous tetrasodium clodronate with a large excess of the corresponding acid anhydride. The dianhydrides 2a-d alone were more lipophilic than the parent clodronate, as determined by drug partitioning between 1-octanol and phosphate buffer at pH 7.4. They also were stable toward chemical hydrolysis in aqueous solutions (pH 7.4 and 2.0). The half-lives for chemical degradation in a buffer solution at 37 °C varied from 0.7 to 286 h and from 15 to 790 h at pH 2.0 and 7.4, respectively. The dianhydrides 2a,b,d underwent complete enzymatic hydrolysis to clodronate in 80% serum at 37 °C after 1 min, although 2c had a half-life of 3.3 h. The aqueous solubility of clodronate decreased considerably in the presence of Ca2+ ions. This is most probably due to formation of poorly water-soluble chelates, which may also hinder the oral absorption of clodronate. However, Ca2+ ions did not have an effect on the aqueous solubility of clodronic acid dianhydrides, and therefore, these prodrugs may improve oral absorption of the parent drug. In conclusion, these novel dianhydride derivatives may be potentially useful prodrugs of clodronate which, due to their lipophilicity and lack of Ca2+ chelating, increase its bioavailability after oral administration.
- Ahlmark, Marko,Veps?l?inen, Jouko,Taipale, Hannu,Niemi, Riku,J?rvinen, Tomi
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- Bisphosphonate-Generated ATP-Analogs Inhibit Cell Signaling Pathways
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Bisphosphonates are a major class of drugs used to treat osteoporosis, Paget's disease, and cancer. They have been proposed to act by inhibiting one or more targets including protein prenylation, the epidermal growth factor receptor, or the adenine nucleotide translocase. Inhibition of the latter is due to formation in cells of analogs of ATP: the isopentenyl ester of ATP (ApppI) or an AppXp-type analog of ATP, such as AMP-clodronate (AppCCl2p). We screened both ApppI as well as AppCCl2p against a panel of 369 kinases finding potent inhibition of some tyrosine kinases by AppCCl2p, attributable to formation of a strong hydrogen bond between tyrosine and the terminal phosphonate. We then synthesized bisphosphonate preprodrugs that are converted in cells to other ATP-analogs, finding low nM kinase inhibitors that inhibited cell signaling pathways. These results help clarify our understanding of the mechanisms of action of bisphosphonates, potentially opening up new routes to the development of bone resorption, anticancer, and anti-inflammatory drug leads.
- Malwal, Satish R.,O'Dowd, Bing,Feng, Xinxin,Turhanen, Petri,Shin, Christopher,Yao, Jiaqi,Kim, Boo Kyung,Baig, Noman,Zhou, Tianhui,Bansal, Sandhya,Khade, Rahul L.,Zhang, Yong,Oldfield, Eric
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supporting information
p. 7568 - 7578
(2018/05/31)
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- Transition state in DNA polymerase β Catalysis: Rate-Limiting chemistry altered by base-pair configuration
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Kinetics studies of dNTP analogues having pyrophosphate-mimicking β,β-pCXYp leaving groups with variable X and Y substitution reveal striking differences in the chemical transition-state energy for DNA polymerase β that depend on all aspects of base-pairing configurations, including whether the incoming dNTP is a purine or pyrimidine and if base-pairings are right (T*A and G*C) or wrong (T*G and G*T). Br?nsted plots of the catalytic rate constant (log(kpol)) versus pKa4 for the leaving group exhibit linear free energy relationships (LFERs) with negative slopes ranging from -0.6 to -2.0, consistent with chemical rate-determining transition-states in which the active-site adjusts to charge-stabilization demand during chemistry depending on base-pair configuration. The Br?nsted slopes as well as the intercepts differ dramatically and provide the first direct evidence that dNTP base recognition by the enzyme-primer-template complex triggers a conformational change in the catalytic region of the active-site that significantly modifies the rate-determining chemical step.
- Oertell, Keriann,Chamberlain, Brian T.,Wu, Yue,Ferri, Elena,Kashemirov, Boris A.,Beard, William A.,Wilson, Samuel H.,McKenna, Charles E.,Goodman, Myron F.
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p. 1842 - 1848
(2014/04/17)
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- 2-MeS-β,γ-CCl2-ATP is a potent agent for reducing intraocular pressure
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Extracellular nucleotides can modify the production or drainage of the aqueous humor via activation of P2 receptors and therefore affect the intraocular pressure (IOP). We have synthesized slowly hydrolyzable nucleoside di- and triphosphate analogues, 1, and 8-14. Analogues 8-14 were completely resistant to hydrolysis by alkaline phosphatase over 30 min at 37 °C. In human blood serum, analogues 8-14 exhibited high stability, e.g., analogues 9 and 10-14 were only 15% and 0% degraded after 24 h, respectively. Moreover, analogues 8-14 were highly stable at pH 1.4 (t1/2 1 h-30 days). Analogues 8-14 were agonists of the P2Y1 receptor (EC50 0.57-9.54 μM). Ocular administration of most analogues into rabbits reduced IOP, e.g., analogue 9 reduced IOP by 32% (EC50 95.5 nM). Analogue 9 was more effective at reducing IOP than several common glaucoma drugs and represents a promising alternative to timolol maleate, which cannot be used for the treatment of patients suffering from asthma or cardiac problems.
- Eliahu, Shay,Martín-Gil, Alba,Perez De Lara, María Jesús,Pintor, Jesús,Camden, Jean,Weisman, Gary A.,Lecka, Joanna,Sévigny, Jean,Fischer, Bilha
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experimental part
p. 3305 - 3319
(2010/09/06)
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- Tablet with improved bioavailability containing dichloromethylenediphosphonic acid as the active substance
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The invention concerns tablets with improved bioavailability of the active substance dichloromethylenediphosphonic acid or of a physiologically tolerated salt thereof and with a content of microcrystalline cellulose as a pharmaceutical auxiliary substance, pharmaceutical packs containing these tablets, the use of the active substance dichloromethylenediphosphonic acid together with microcrystalline cellulose for the production of a tablet with improved bioavailability and the process for producing the tablet.
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- Oral compositions
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Oral compositions providing antitartar and antigingivitis benefits containing an antitartar agent and a stannous salt.
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- Oral composition for calculus retardation
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Oral compositions, such as toothpaste, mouthwash, and the like, containing certain polyphosphonic acids and their salts which retard dental calculus formation without damaging tooth structure.
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