Tablet press also referred to as tableting machine, pharmaceutical tablet press, tablet compressing machine, or tablet punching machine is a mechanical device that compresses powders into tablets of uniform size, shape, and weight containing approximately the same quantity of Active Pharmaceutical Ingredient (API) and excipients. Apart from its use in the pharmaceutical industries for manufacturing varieties of tablets, it can also be used to manufacture illicit drugs, cleaning products, and cosmetics.
All tablet press employs the same basic principle of compression. The basic unit of any tablet press is tooling consisting of two punches and a die called a station. The upper and lower punches come together in the die that contains the tablet formulation.
The development of tablet press has been a continuous process. In the past, we have hand-driven tablet press which has been modernized to electrical driven tablet press.
· Development of newer technology in tablet production e.g. development of direct compression technology.
· Development of stringent standard of cleanliness to comply with the Current Good Manufacturing Process (CGMP).
· The introduction of automation and continuous monitory of production processes.
· Increased rate of production resulting from increased demand, multiplication of disease conditions, and exponential increase in population.
Tablet press in current use can be classified into;
1. Single punch/single station/eccentric presses.
2. Multi-station/rotary presses.
There are numerous models of presses, manufactured by a number of companies, ranging in size, speed, and capacity.
Single punch tablet press, also known as eccentric press or single station press is the simplest machine for tablet manufacturing. This machine uses a single set of station tooling (a die and a pair of upper and lower punches).
The compaction force on the fill material is exerted by only the upper punch while the lower punch is static; such action equivalent to hammering motion and as a result, the single punch press is referred to as stamping process.
1. The single punch structure is rational and small.
2. Easy to operate and it operates at a high utilization ratio.
3. It can manufacture odd-shaped products with a diameter of up to 20 mm.
4. It is ideal for the development of tablets and small batch production.
5. Single punch tablet press utilizes a high amount of pressure to reduce weight variations between tablets while maintaining a low noise level at the same time.
Multi-station press is a mechanical device that unlike the single punch tablet press has several tooling stations which rotates to compress granules/powder mixture into tablets of uniform size, shape (depending on the punch design), and uniform weight. It was developed to increase the output of tablets.
In rotary press, the compaction force on the fill material is exerted by both the upper and lower punches leaving the powder granules to be compressed in the middle. This is known as accordion type of compression.
The capacity of a rotary tablet press is determined by the rotation speed of the turrent and the number of stations on the press.
· High productivity can be gained with a minimal amount of labor while saving money.
· Rotary press has an output of between 9000 – 234000 tab/hour thus saves time and meets up with the high demand of tablet dosage form.
· The powder-filled cavity can be automatically managed by a moving feeder.
· Rotary press decreases waste of valuable formulation in non-specific tablets.
· The machine allows independent control of both weight and hardness.
The two most important differences between a single punch tablet press and a rotary tablet press are
1. Single punch tablet presses utilize single-sided compression to make tablets, whereas rotary presses use double-sided compression, and
2. Single punch tablet press compression cycles do not have a dwell time, whereas rotary presses typically use a punch head flat which enables a dwell time as the punch passes under the compression roller.