I received my Master’s degree in chemical engineering from SU, USA. I worked as a writer and researcher for Fortune 500 company clients.
With an increasing number of patients and diseases, the need for medicines is growing more than ever. This has created pressure on the pharmaceutical industries to produce high-quality medicines. Tablets are a form of medicine that is solid and is given as oral dosage. A good tablet is free from any sort of defects (pharmaguideline, 2017). However, there are cases when tablets are products with defects. Common issues faced in the production processes of tablets include Weight variation, hardness, friability, picking, laminating, mottling, sticking, capping, chipping, and double press or impression. These tablet defects can happen because of various reasons. This review highlights various issues related to the production process of tablets.
Common issues faced in the production processes of tablets are weight variation, hardness, friability, picking, laminating, mottling, sticking, capping, chipping, and double press or impression (Jonathan Gaik, 2018). Among these mentioned defects laminating/capping, hardness, and picking/sticking are the three most commonly encountered issues faced in the production process of making tablets. Generally, these defects stem from various issues in the production process with unit upstream, tablet press, compression failure, and prevention of proper ejection of the product if it is too wet or too dry. Other issues include poor quality of raw materials, formation of too many fines in the milling process, defects in the formulation process. bad compressibility and flow of the powder (Rajani et al., 2018).
The capping phenomenon occurs when there is a fracture at the top of the tablet. The top layer gets separated and detached from the solid tablet body. This issue generally arises when air is trapped in the tablet powder material during the compression stage. Capping can also stem from the issue of failure of compression of the formulation because of accumulation of powder fines (Jonathan Gaik, 2018).
In the compression process of the tablets, generally, the air is expelled from the powder granules and each of the particles sticks together. The press machine is designed in such as manner that it allows the air to dissipate during the compression process. Sometimes, the tablet powder consists of very fine dry granules. When air is released during the compression press process these dry fine granules get pushed in the outward direction of the air being released. These dry fine particles get accumulated near the tablet band and the tablet cup and themselves don't stick. Consequently, the dry fine particles cause hindrance in the compression of granule particles resulting in the fracture of the tablets. When the fracture defect occurs on the top part of the tablet it is called capping. However, when a fracture defect occurs on the lower portion of the tablets the phenomenon is called lamination. The process of lamination is discussed in the next section (Jonathan Gaik, 2018),
Capping can be fixed by co-operating with certain guidelines in the production process. These guidelines or procedures to be followed are discussed in the next sections (Jonathan Gaik, 2018).
The term lamination is used when a split occurs anywhere in the tablet other than the top layer. Usually, lamination defect is similar to capping and caused by the same issues. Nevertheless, it is essential to diagnose the issue of lamination properly. Often, lamination occurs due to over-compression of the tablets. As greater compression can cause the granules to flatten out and thus prevent them from binding together. The lamination may also occur when fine or light particles do not combine, as the particles fail to compress well (Jonathan Gaik, 2018).
Sticking and Picking
The defect of sticking happens when the formulation granules stick to the face of the press punch. Quite differently, picking defect occurs when the mixture granules stick on the design embossing of the punch tip such as in logos or lettering. Both picking and sticking result in the production of defective tablets. In quality control of the tablets, generally, a visual inspection is carried out to identify picking and sticking. However, this method of visual inspection is very time-consuming and tends to decrease the overall production yield of the tablet. Unfortunately, sometimes many manufacturers have no option but to carry out visual detection as a quality control measure. When the batch of the product reaches the compression stage, the skilled operator should efficiently adjust the press to comply with the product's characteristic designs. The quality of the product is majorly affected by the tablet's press setup, operation, tooling, and maintenance. There may be cases when the granules are not completely dried, in other words, they may be hard and dry on the outside but wet and moist inside. This scenario in turn seriously affects the tablet's quality. The undried particles can break open during compression and stick to the punch press surfaces causing sticking. In such cases, it is essential to keep checking the process of drying the granules (Rajani et al., 2018; Chattoraj et al., 2018).
Another issue arising in the tablet production process is the variation in the hardness of the tablets. A soft tablet tends to cause a range of issues not only in the pressing process but also in the consistency of the product. A soft tablet can lead to product recall due to the poor film coating process and packaging of the product (Rajani et al., 2018).
A research paper by Gordon, Marc. (2008), presented a study on tablet friability of two differently sized tablets that comprised the same formulation. The study revealed that granules containing lower moisture contents required higher compression and ejection forces to manufacture a tablet at a given hardness. However, it did not influence the friability of the tablets. Increased tablet hardness and decreased tablet thickness majorly decreased the tablet friability of the larger tablet among the two. On the other hand, friability wasn't affected by increasing granulating fluid quantity or by increasing the granulation particle size. Although it improved compatibility. The experiment conducted in the study revealed that doubling the amount of magnesium stearate in the granulation in one of the tablets decreased the ability to obtain a maximum tablet hardness, and for the other tablet strength increased friability.
To sum it up, early identification of issues during formulation, milling, and processing before the tablet compression stage, helps to eradicate the mentioned defects. Or in other words identification of issues before it enters for tablet press. Even if issues become visible at the tablet press stage, skilled technicians should be able to fix them with minimal process downtime.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Nikita Nandakumar Thattamprambil