pKa

[sagarprasanna]

for a formulator
how does a Pka valuve matters
what kind of conclusions can be made on a drug having particular pKa with respect to selecting dissolution media
so dear members
if any one of u explain with examples like drug having pKa 2.3 or some drugs have 2 or 3 pKa values. In such cases what will be the your contribution to make me clear about the importance of pKa for a formulator
with regards

[prasanna]

Dear
Pka value indicates the environment where ur Drug will get unionised and the absorption will me maxium and by getting that u can choose the medium, where the release of the drug will be maxium.

[mini]

as we know that only unionized form of drug is absorbed passively through the intestinal membrane. But at the same time for a drug to get released its dissolution or rather ionization is also equally important. Therefore there must be a balance between the fraction of drug in ionized and unionized form. pKa of a drug tells the pH where ur drug will get ionized. this pH value ranges from pKa+1 to pKa-1. there an extensive ionization is not desirable. sometimes A drug moleclue may have more than 1 pKa value this is due to presence of two or ionic groups on the same molecule which may vary with degree of their basicity. Eg. Of such a drug is meslamine which is having three pKa values.

[ATP]

Ibuprofen pKa is 5.2 and the dissolution media used is pH 7.2 that makes pKa+2 which is the value were all the drug is completely ionized and can get dissolved.
Regards