Leo A J
BioByte Corporation, 201 W. Fourth Street, Suite 204, Claremont, California 91711, USA.
J Pharm Sci. 2000 Dec;89(12):1567-78. doi: 10.1002/1520-6017(200012)89:12<1567::aid-jps7>3.0.co;2-7.
A parameter that measures hydrogen-bond donor (HBD) strength of solutes is useful in modeling many biological interactions. The solvents octanol and chloroform, have about equal HBD strength and thus will accommodate the hydrogen-bond acceptor (HBA) groups in solutes about equally well. Because the solvent octanol has a strong acceptor oxygen, solutes with HBD groups will favor it over chloroform on that basis. With its eight alkane carbons, octanol also favors solutes with a significant amount of alkane character, a property referred to in this paper as 'excess alkane affinity' (XAA). On the other hand, it is easier to form a cavity in the solvent chloroform, so larger solutes tend to favor that solvent. After allowing for XAA and molecular volume, the difference between log P(oct) and log P(clf) is a measure of the effective sum of HBD. This value is given the symbol epsilonalpha and appears to be on the same scale as Abraham's summation operatoralpha(2)(H).
一种用于测量溶质氢键供体（HBD）强度的参数，在模拟许多生物相互作用中很有用。溶剂辛醇和氯仿具有大致相同的HBD强度，因此对溶质中氢键受体（HBA）基团的容纳能力也大致相同。由于溶剂辛醇有一个强接受性的氧原子，基于这一点，带有HBD基团的溶质会比氯仿更倾向于辛醇。辛醇有八个烷烃碳，它也有利于具有大量烷烃特性的溶质，本文将这种特性称为“过剩烷烃亲和力”（XAA）。另一方面，在溶剂氯仿中更容易形成空穴，所以较大的溶质往往更倾向于这种溶剂。在考虑XAA和分子体积之后，log P（oct）和log P（clf）之间的差值是HBD有效总和的一种度量。这个值用符号εα表示，并且似乎与亚伯拉罕求和算子α(2)(H)处于相同的尺度。
