Ph partition hypothesis pdf
DEVIATIONS FROM pHPARTITION THEORY The pHpartition theory provides a basic frame work for understanding drug absorption. but it is an over simplification of a more complex process. the inflection point of the pHabsorption curve should occur at a pH equal to the pka of the drug.pH Partition hypothesis: pH Partition hypothesis The theory states that for drug compounds of molecular weight greater than 100, which are primarily transported across the biomembrane by passive diffusion, the process of absorption is governed by The dissolution constant The lipid solubility of the unionized drug The pH at the absorption site Most of the drugs are weak electrolytes their degree of ionization ph partition hypothesis pdf
The pHpartition hypothesis is frequently applied to estimate membrane permeation at a particular pH, assuming that only the neutral form of an acid or a base can
In general, the octonal pH 7. 4 buffer partition coefficient value in the range of 1 to 2 of a drug is sufficient for passive absorption across lipoidal membranes. Parenterally administered drugs are secreted directly into the gastric juice. The concentration ratio (concentration of drug in gastric juice divided by concentration in plasma) depends on the dissociation constant of the drug. THE GASTRIC SECRETION OF DRUGS: A pH PARTITION HYPOTHESIS. Parkhurst A. Shore, PDF; Abstract. Parenterally ph partition hypothesis pdf pH Range In GIT The pH range in GIT from 18 that of the stomach is from 13 and of the intestine (from duodenum to colon) 58, then certain generalization regarding ionization and absorption of drugs can be made, as predicted from pH partition hypothesis.
Under subclinical dose (Fig. 4d), for pH 6. 5, the pH Partition Hypothesis is predicted to hold, but below that pH, the hypothesis is inverted. In the alkaline pH region, the ABL has only minimal impact, since the lipid membrane is rate limiting then. ph partition hypothesis pdf [PPT pH Partition Theory. Contents of the powerpoint on pH Partition Theory include: pHPARTITION THEORY DRUG pKa AND GASTROINTESTINAL pH LIPOPHILICITY AND DRUG ABSORPTION DEVIATIONS FROM THE pH PARTITION THEORY A UNIFYING HYPOTHESIS CONCLUSION REFERENCES. DRUG ABSORPTION: downloadDownload PDF here[buttonRating: 4.88 / Views: 555