Capsule Sinkers

Capsule Weights &Sinkers

When the density of the dosage form is less than the density of the dissolution media, floating may

occur. USP 711 states: "

A small, loose piece of non-reactive material such as not more than a few turns of wire helix may be attached to dosage units that would otherwise float. Other validated sinkerdevices may be used."

The choice of sinker or capsule weight depends on the type and size of the dosage form. The sinker should not occlude the surface of the dosage form more than necessary because of the risk of affecting the dissolution rate. Sinkers are available coated or uncoated. PTFE (Teflon) coated sinkers work well with magnetic retrievers whilst uncoated type 316 stainless steel sinkers are more durable. Care should be taken to ensure that direct contact of stainless steel with the dosage form does not cause interference with the active ingredient