<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sander, John R. G.</style></author><author><style face="normal" font="default" size="100%">Bucar, Dejan-Kresimir</style></author><author><style face="normal" font="default" size="100%">Henry, Rodger F.</style></author><author><style face="normal" font="default" size="100%">Baltrusaitis, Jonas</style></author><author><style face="normal" font="default" size="100%">Zhang, Geoff G. Z.</style></author><author><style face="normal" font="default" size="100%">MacGillivray, Leonard R.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A red zwitterionic co-crystal of acetaminophen and 2,4-pyridinedicarboxylic acid.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Pharmaceutical Sciences</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">zwitterion cocrystal acetaminophen pyridinedicarboxylate crystn crystal engineering solid state</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010///</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">Wiley-Liss, Inc.</style></publisher><volume><style face="normal" font="default" size="100%">99</style></volume><pages><style face="normal" font="default" size="100%">3676 - 3683</style></pages><isbn><style face="normal" font="default" size="100%">0022-3549</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We report on a co-crystal of acetaminophen (APAP) and 2,4-pyridinedicarboxylic acid (PDA).  The co-crystal was discovered by screening using the soln.-mediated phase transformation (SMPT) technique.  Despite the bulk solids of each component being white in color, the new co-crystal phase exhibited a red color.  The new phase was analyzed using single-crystal X-ray diffraction and identified as (APAP)·(PDA)·(1).  Structural anal. revealed PDA to exist in a hitherto unreported zwitterionic form in the co-crystal.  A structural anal. of pure PDA revealed the presence of the zwitterion form in (PDA)·(H2O) (2), as well.  The components of 1 self-assemble as a three-dimensional (3D) hydrogen-bonded network with a pronounced 2D structure.  The origin of the red color was investigated using d. functional theory calcns., which demonstrate a decreasing π-π* sepn. involving the components of the solid. © 2010 Wiley-Liss, Inc. and the American Pharmacists Assocn. J Pharm Sci 99:3676-3683, 2010. [on SciFinder(R)]</style></abstract><issue><style face="normal" font="default" size="100%">9</style></issue><notes><style face="normal" font="default" size="100%">CAPLUS AN 2010:933031(Journal)</style></notes></record></records></xml>