Worldwide, the pharmaceutical industry invests vast amounts of resources in developing, improving and producing tablets. The requirements of the industry are widely known: high production rates, a dry and stable product with an acceptable shelf-life, easily modified release and performance characteristics, accurate dosage and compression tooling that enables the manufacture of tablets with unique shapes and embossing identification on both sides. Industry investment also offers advantages for the patient; tablets are portable, easy to administer, have small bulk and any unpleasant tastes or appearances can be masked.

Consider for a moment what we as an industry are trying to achieve. We are trying to blend together a range of active ingredients and excipients, all of which have differing particle size, shape and characteristics, and are usually in a powdered form. This mixture is then transformed into a compacted product using a high-speed mechanical tablet press. During the compression process, many factors govern the quality of the tablet and the ease or difficulty with which the tablets are produced. The tablet press should, of course, be well maintained and correct set-up procedures should be followed. It goes without saying that the tablet compression tooling should be in pristine condition.

Figure 1: Combination sink unit and drainer.

Figure 2: Micro-fine polishing machine.

Maintenance High quality tablet compression tooling is expensive, even though they are consumable items. With all this potential damage to punches and dies during tablet production transportation and storage, an acceptable method of cleaning, repairing, validating and storing tooling is required by anyone who manufactures tablets. Additionally, inspection authorities are looking more closely at conditions under which punches and dies are cleaned, validated, stored and issued.

Figure 3: The Approve system to check, validate and measure tooling.

Theory into practice One company, AstraZeneca (Macclesfield, UK), has for many years taken exceptional care of its tablet compression tooling by employing the latest ideas and procedures for punch and die cleaning, polishing and secure storage. However, the company has recently completely refurbished its existing facilities and updated its procedures to ensure that it stays at the forefront of technology and current good manufacturing practices.

Figure 4: Cabinets and drawers for tooling storage.

Punches and dies are removed from the tablet compression machine, placed securely into specially designed baskets and are transported from the tablet production area to the tool storage area. The baskets of punches and dies are loaded into an ultrasonic cleaner that has been fitted into a purpose-designed stainless steel combination sink unit and drainer (Figure 1).

The ultrasonic cleaner has a digital display and touch panel controls for easy operation. When the tooling has been thoroughly cleaned, it is manually rinsed in the adjoining sink unit and then immediately dried in the drain area. Any necessary repairs are done by trained operators, using standard industry accepted equipment and procedures. After cleaning, the tools are polished automatically (Figure 2).