Tablet production process

When we have a headache, we open the medicine cabinet at home, take a tablet out of its blister pack, take it and wait for the magic to happen. What we don’t usually ask ourselves is how did that tablet become the solution to our ailments?

In all pharmaceutical forms, the dose of active ingredient is so small that manipulation is impossible. For this reason, excipients are added to increase the volume. Converting this mixture of active ingredient and excipients into tablets is a safe way of administering the correct dose in a way that is comfortable for the patient. Now, how do we get the tablet to compress? By compressing, right? It’s not that simple. The properties of each powdered solid are different and it is not easy to hold the particles together by simply applying pressure to them. And, in case it does compress, how do we ensure that it disintegrates at the right place and time to perform its therapeutic action correctly? To solve all these issues, other excipients come into play, whose functions are to bind, improve fluidity, lubricate, disintegrate, etc.

The first step in the manufacture of tablets is to mix the active ingredient with all the required excipients. And then what? In the best-scenario situation, although rare, it can be compressed directly. However, usually a previous process called granulation is required to ensure that the mixture is fluid enough to be handled and dosed and that, once compressed, it keeps its shape.

The granulation process, as its name suggests, consists of converting the powder into a granulate that has a uniform particle size and composition and is suitable for compression. This can be done by passing the mixture through rollers that exert pressure on the mixture and then break up the compacted mixture. This procedure is called dry granulation and is carried out with a compactor.  If, on the other hand, a liquid binder is used to form the granulate, this is called wet granulation. Wet granulation consists of a first step in which the binder is sprayed onto the powder mixture and stirred until the granulate is formed. This is followed by a drying phase prior to compression. A wet granulation line can have different configurations, the most common being an HSM mixer for granulating, followed by a fluid bed where drying takes place.

In the compression phase, the granulate fills the different stations of the tablet press and the tablets are generated by the action of the punches. The force with which the mixture is compacted is a critical parameter to ensure that the tablet disintegrates and releases its active ingredient at the right point.

Once the tablet is generated, a coating film can be applied. This phase can have an aesthetic purpose such as colouring, organoleptic such as hiding bad taste or therapeutic such as preventing the tablet from disintegrating in the acidic environment of the stomach, forcing the release of the active ingredient in the intestine. This procedure is carried out in a coating drum where the tablets are rotated while they are sprayed with the coating solution and dried with a stream of hot air.

Thus, only after having gone through the different stages of mixing, granulation, compression and coating, and thanks to the function of the excipients, the tablets can be blistered and cartoned to end up in our medicine cabinet at home and put an end to our headache.

If you are interested in learning more about tablet production and how we can help you, contact us: klinea@klinea.es