identical pH [Dissolution / BCS / IVIVC]

posted by Helmut Homepage – Vienna, Austria, 2019-09-10 12:58 (1540 d 20:57 ago) – Posting: # 20571
Views: 5,896

Hi amer,

❝ I have constructed IVIVC using in vivo data and dissolution data done at pH 1.2. if i have a new dissolution data (say done at pH 2), how can i predict the in vivo concentrations based on the new dissolution…

[image]Dissolution at \(\small{pH\;2}\) is rather unusual. Recall the definition: \(\small{pH=-\log_{10}[\text{H}^{+}]}\), where \(\small{[\text{H}^{+}]}\) is the activity of the \(\small{[\text{H}^{+}]}\) ion. Hence, at \(\small{pH\;2}\) you have \(\small{10^{0.8}\approx6.31\times}\) lower activity of \(\small{[\text{H}^{+}]}\) than at \(\small{pH\;1.2}\). Whether this is relevant, depends on the \(\small{pk_\text{a}}\) of the drug. However, it might lead to wrong conclusions.

Valid predictions based on IVIVC require dissolution at identical pH values. Repeat the exercise at \(\small{pH\;1.2}\).

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