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Thread: pKa

  1. #1
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    Cool pKa

    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
    prasannasagar

  2. #2
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    Smile

    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.

  3. #3
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    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.

  4. #4
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    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

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