Hi Praven,

Increasing the volume of the dissolution medium is expected to increase the release rate of the active ingredient from HPMC matrix because of the following :

1. Increase the hydration rate of the HPMC

2. Better sink condition.

Let me know if you are looking for a more specific answer for a certain case you are facing.

Thank you.

Hi!

The use of a 2L dissolution apparatus versus a 1L apparatus can significantly impact the drug release profile of HPMC-based extended-release (ER) tablets due to changes in hydrodynamic conditions and sink capacity. HPMC (hydroxypropyl methylcellulose) matrices rely on gel layer formation for controlled drug diffusion and erosion. In a 2L medium, the increased volume enhances the sink conditions, reducing drug saturation near the tablet surface and potentially increasing the drug release rate, especially for poorly soluble drugs. Additionally, the fluid dynamics in a 2L vessel may alter shear stress and boundary layer thickness around the tablet, influencing gel formation and erosion kinetics. The larger volume can also dilute any acids or salts released from the formulation, affecting the local microenvironmental pH and ionic strength, further modulating polymer swelling and drug solubility. Therefore, dissolution results in a 2L vessel may not be directly comparable to those in 1L, and method transfer or scale-up requires revalidation of the dissolution profile for regulatory and biopharmaceutical equivalence.