Bioequivalence and Bioavailability Forum

Hi Outlaw Torn,

❝ ❝ […] dissolution testing is possible but technically demanding.

❝ If you can elaborate, it would be great. If not, that's okay too.

Dissolution is not my cup of tea. Only a few examples dealing with suspensions, e.g., this one:

A suspension sample equivalent to a typical dose (5 mL) was taken on a weight basis using a suitable syringe–cannula system, and quantitatively transferred to the dissolution vessel midway between the surface of the dissolution medium and the top of the rotating blade. To calculate the exact weight of suspension added to the vessel, syringe and cannula were weighed at three stages: empty, filled with the suspension, and after the sample was expelled into the dissolution vessel.

But in Dissolution Technologies we find:

Questions and Answers February 2017
Q How is the sample prepared, and how it is it added to the dissolution equipment for dissolution testing of a dry syrup for oral suspension?
A […] If a product, powder or granule, when reconstituted as directed in the instructions to the patient, results in a solution, no dissolution test is required.

(my emphasis)

❝ I'm still trying to wrap my head around whether there is the need to do dissolution testing in syrups.

❝ Also, Appendix III seems to imply that only solid dosage forms are eligible for BCS-based biowaivers. Is that your understanding?

After reading it again, yes. This leaves us with nobody’s [msg]answer[/msg] about solutions:

• No critical excipients ⇒ in vivo study may (!) be waived (note the elastic clause).
  
• Critical excipients ⇒ in vivo study, unless the differences in the amounts of these excipients can be adequately justified by reference to other data.

No idea what “other data” are. When it comes to similarity of excipients see the GL’s Appendix III, Section IV.2.