What Is Tablet Compression?
The process where powders or granules are filled into the die cavity and then pressure is applied to convert these powders or granules into solid unit mass is known as tablet compression process.
Working Principle Of Compression Machine?
Basic principle of a tablet compression machine working is based on the application of pressure.
What Are Types Of Compression Machines?
There are following 2 main types of the tablet compression machines
- Single punch Compression Machine
- Rotary Compression Machine
Difference Between Single Punch And Rotatory Compression Machine?
Single punch compression machine has only one pair of upper and lower punch and only one die.
Rotary compression machine also known as multi station compression machine has multiple pairs of upper and lower punches with multiple dies as well.
Types of Rotary Compression Machine?
Rotary tablet compression machines are of two types.
- Single feed
- Double Feed
Difference Between Single Feed And Double Feed?
Single feed compression machines have only one feeding system (hopper and feeder) and compress one tablet per rpm by each punch.
Double feed compression machines have two feeding systems (hopper and feeder) and compress two tablets per round by each punch.
What Are The Components Of Compression Machines?
Following are the main components of the tablet compression machines.
- Hopper
- Feeder
- Turret
- Punches
- Dies
- Cams
- Pressure Roller
- HMI
- Lubrication System
Types Of The Feeding System?
For compression machines there are two types of feeding system
- Gravity Feeding
- Force feeding
Force feeders are installed in high speed compression machines.
What Is The Hopper?
It is the component of a tablet compression machine where powder or granules are filled to feed die cavities.
Difference Between Upper And Lower Punch?
The stem of the lower punch is longer than the upper punch as its long stem is helpful for tablet ejection from the die cavity.
Stages Of Tablet Compression?
There are four stages of tablet compression
- Feeding
- Filling
- Compaction
- Ejection
What Is Tablet Compression Cycle?
The tablet compression is a continuous cyclic process which is completed in above mentioned 4 stages and is known as tablet compression cycle.
Types Of Pressure Rollers?
There are two types of compression machine pressure rollers
- Main Pressure Rollers
- Pre Compression Rollers
Function of Main & Pre Compression Rollers?
Main compression rollers are used to apply the main pressure to compress the tablets at required hardness.
Pre compression rollers are used to remove entrapped air in powder or granules to prevent capping.
What Is Dwell Time and Its Importance?
The duration of time for which the punch head remains under the main compression pressure roller is known as dwell time.
Dwell time helps to overcome tablet capping and lamination defects.
Types Of Compression Tooling?
Following types of compression machine tooling are available
- B type tooling
- D type tooling
- BB tooling
- DB tooling
What Is The Difference Between B Type and D Type tooling?
B type tooling is used to compress tablets which have less diameter and require less pressure.
D type tooling is used to compress tablets with large diameter and high pressure.
What Are Common Tablet Compression Defects?
Following are the main tablet compression defects
- Sticking
- Picking
- Capping
- Lamination
- Weight Variation
- Hardness Problem
- Flow Problem
- Friability Issues
MOC Of Hopper,Punches and Dies?
- Material of construction of the hopper is 316L.
- The material of construction of the punches is OHNS Oil Hardened Non Shrinkable Steel.
- MOC of dies is HCHC High carbon high chromium steel grade.
Why Are Metal Detectors and Tablet Dedusters Used?
Metal detector is used to detect any type of the metal compressed in the tablets and tablet deduster is used to remove dust of fine powders from the tablet surface.
Inprocess Tests For Tablet Compression?
Following inprocess tests are performed for tablet compression.
- Physical Observation
- Thickness
- Weight Variation
- Tablet Hardness
- Friability Testing
- Disintegration Test
Why Do We Use Dust Cups?
Duct cups are used for upper punches to collect any oil or debris and protect the tablets from oily or black spots.
What Is AWC?
AWC is an automatic weight control system which is installed in advance high speed compression machines to automatically control the weight of tablets within specified range.
AWC working is based on compression force.
How is the Load Cell Calibrated?
We use dummy punches and dies to calibrate the load cells of tablet compression machines.
Dummy punches and dies are installed at specific positions of the machine and an external encoder is attached to the encoder of the machine.
When pressure is applied the value of pressure on PLC and external encoder must be the same for calibration.
Which Lubricants Are Used For Compression Machines?
Food grade lubricants are used for compression machine.The food grade lubricants must be certified by ISO 21469.
When to Perform Inprocess Checks?
For tablet compression inprocess checks are performed during following conditions
- At the start of compression process
- After major breakdown
- When compression machine remains stop for long duration (shift change)
Weight Variation Limits For Tablets?
Weight variation limits for tablet compression as per BP,IP and USP are as,
| BP/IP | USP | %Deviation |
| 80mg or less | 130 mg or less | ±10% |
| Above than 80 mg or less than 250 mg | 130 mg to 324 mg | ±7.5% |
| 250mg or more | More than 324 mg | ±5% |
Friability Limit For Tablets?
The friability acceptance criteria for uncoated tablets is not more than 1%.
What is Tablet Friability?
Percentage weight loss is known as tablet friability.
Disintegration Time For Tablets?
- Disintegration time for uncoated tablets is NMT 15 minutes and for coated tablets is NMT 30 minutes.
- Disintegration time of sugar coated tablets is NMT 60 minutes.
- Disintegration time for dispersible tablets is NMT 3 minutes and for effervescent tablets is NMT 5 minutes.
- Enteric coated tablets should remain stable in acidic media for 2 hours and should disintegrate in basic media within 60 minutes.
- Disintegration time for rapidly disintegrating tablets or Oro dispersible tablets is NMT 30 second.