The process making “Pharmaceutical Solid Dose Tablets” for the purpose of therapeutic use in the prevention, treatment or cure of disease can be a daunting task. It requires experts in the fields of pharmacological development, rotary tablet press operations, manufacture engineering, quality control and tooling. Each member is an integral part of producing safe, pure and marketable tablets.

The drug development process is complicated. In this article, we will cover only the basics of manufacturing these tablets that start out in a research & development Independent Lab, CDMO, or Brand Name Manufacture. 

The Pharmaceutical Formulation

The process begins with a pharmaceutical formulation containing an API, Excipient and Fillers to aid in the flow and stabilization of the product to be compressed/ tableted. This formula may go through a process of wet or dry granulation, or may be simply blended into a product for direct compression. Whether using a hydraulic lab press or high output rotary press, the process remains virtually the same but does increase in difficulty with the speed and volume of material being compressed. Quite simply, the number of tablets needed for Clinical Trials will be far less than that of commercialization. With increased needs, so goes the necessity to produce larger amounts of product which will require more presses running at higher speeds to maintain production levels.

The Compression Process

1. The Product will flow from the hopper above the compression table into a feed frame which aids in the filling of the die. Wilson Tool manufactures these dies to the TSM standard to ensure adequate fill.
2. The lower punch, in the fill position, will then move across a weight cam pushing the lower punch up, so that excess powder can be scrapped off, thus achieving the desired tablet weight.
3. The lower punch will return to down position at the same time as the upper punch is entering the die for pre-compression. This can be a real area of concern in the process due to clearance. The clearance is the gap between the outside of the punch and inside wall of the die. Too much clearance could cause powder to blow past the punch causing yield loss, friability issues, lamination problems, and underweight tablets. Wilson Tool Engineers look at more than just one source to calculate clearance, they pull 20 years of experience looking at the bulk density of products along with multiple sources to achieve a desirable clearance.
4. After pre-compression comes main compression. This is where the product is compressed past the point of material elasticity and the final shape and sized is determined. In this main compression, you may run into issues of capping, picking, or sticking, especially with the need for Logos and Bisects in the pharmaceutical industry. Working with your Wilson Tool Sales Engineer on the front end of tablet design and tool maintenance can identify these issues before they start.
5. The last part of the process is ejection of the completed tablet. During this part of the process, the tablet is warm and expands slightly. You may now see some of the acute issues we discussed earlier – sometimes these yield loss issues may develop later as they tablet sits and cools. Reviewing product post production and cool down is a good time to evaluate the process for improvements if needed.

The tablets are now ready for coating and packaging. It is very important throughout the manufacturing of each batch to inspect both warm and cold tablets, checking dissolution, friability, flashing and most importantly weight.

For more information on compression tools from Wilson Tool, please contact our Tooling Technicians or visit wilsontool.com/tablet. 

Credits
Fundamentals of Tablet Compression Armin H. Gerhardt 2010
TSM 7^th addition 2006
Michael Tousey -Techceuticals Tablet Pro 2016
Compression Method, By Pharma Approach 2019

March 20, 2020