1. Longitudinal Sinkers : These sinkers make contact with the dosage forms along their long axis.
2. Lateral Sinkers : These either wrap around or contact the middle of capsule dosage forms, such as where the top and bottom halves of a capsule shell meet.
3. Screen Enclosures : These include two types: a wire cage that holds the capsule or a circular piece of wire screen placed on top of the capsule.
Internal Weights: These consist of two steel ball bearings, one inserted into each end of the capsule.
Sr. no |
Sinker type |
1 |
Sinker 5mm ID X 15.5mm OD |
2 |
Sinker 6mm ID X 18mm OD |
3 |
Sinker 8mm ID X 23mm OD |
4 |
Sinker 11mm ID X 23mm OD |
5 |
Cage type Sinker (Small/ Big) |
6 |
Spring type Sinker (Small/ Big) |
7 |
Helical coil Sinker |
8 |
Metformin Sinker |
9 |
Japanese Sinker |
10 |
3 Prong Sinker |
Selecting the appropriate sinker depends on the specific type of tablet or capsule being tested. Generally, consider the following guidelines :
Non-Contact : The sinker should ideally not touch the tablet to avoid affecting the dissolution rate.
Size Options : Sinkers are available in various sizes to fit most tablet and capsule dimensions.
Weight : Use the minimum amount of weight necessary to achieve the desired effect.
Coating : Coated sinkers are recommended if there is a risk of reaction between the steel and the tablet.
Basket-Type Sinkers : These can be effective, but ensure that the tablet’s outer coating does not block the mesh.
Wire Spirals : Should be as wide as possible to prevent clogging, which can affect the dissolution rate.
Japanese Sinkers : Adhere to strict dimensional standards specified by the Japanese Pharmacopeia (JP).