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This background material explains the theory behind the log P and log D calculation: Introduction. Symbols used. Definition of logP and logD. Example. Partition and distribution coefficients. Relation between macro and micro partition coefficients. LogP calculation methods. Examples for logP and logD calculations.
6 sty 2024 · LogD = LogP − log (1 + 10 (pH − pKa) δ i) where δ i = {1, − 1} for acids and bases, respectively. The astute reader will notice that only a single pKa is provided here which is the global pKa. In Figure 4 I show how the LogD varies with pH for two acidic and two basic drugs.
log D is the logarithm of the distribution coefficient. Definition of log P and log D. The partition coefficient is the ratio of the concentration of the compound in octanol to its concentration in water.
12 sty 2019 · Of particular interest is the log D at pH = 7.4 (the physiological pH of blood serum). Applications like Marvin allow the user to calculate the logD but also display the pH distribution profile, as shown below for Warfarin.
30 gru 2017 · Sterilization. Sterility Assurance Level (SAL) and Log Reduction (D Value) in Sterilization. Log reduction & its calculation, sterility assurance level (SAL) & its requirement of 12 log reduction for sterilization and calculation of sterilization time. Ankur Choudhary Dec 30, 2017 Print Online Courses Question Forum 3 comments.
In order to accurately measure and report lipophilicity, the scientist must take great care in measurement of logP at a pH where the compound exists in its neutral form (>pH 12 in the case of 5-Methoxy-2-(1-piperidin-4-ylpropyl)pyridine), and/or report logD at a specific pH.
Here is a LogD cheat sheet created from their work, summarizing how much affinity is expected from a change based on lipophilicity considerations alone. For a methyl group for example, the median LogD change is about 0.3, indicating that you'd expect about a 2-fold increase in lipophilic potency due to the methyl group's contribution to LogD.
