Have you ever reached out for a capsule and wondered how those pellets or granules got inside the drug as you looked at the transparent pill or shook it about as if it were a mini maraca? Moreover, why are there pills that contain such pellets or granules and others do not? The pharmaceutical industry finds that in comparison to single-unit dosage forms, pills with multiparticulates tend to provide a more even and predictable distribution in the gastro-intestinal tract. This type of oral drug delivery system requires a very exacting process known as spheronization.
There are actually a few other techniques that also produce pellets available for drug-loaded granules. However, spheronization’s technology is recognised as one of the more cost-efficient techniques. It is a fast and simple process that, while widely used by the pharmaceutical industry, is also applied in processing agrochemicals, detergent additives, and even food.
The process mainly involves four steps to produce spheronized products. These include wet mixing, extrusion, spheronization, and drying and/or coating. The wet mixing results in a wet mass that is extruded to create rod-shaped particles in uniform or constant diameter. This makes the extrusion step a very crucial one as it determines the size of the sphere. In order to obtain, for instance, a 1 mm diameter, the manufacturer would need to use a 1 mm screen for the extruder. Once the pelletization results in the ideal diameter, the manufacturer uses the spheronizer, which is expected to yield the required level of sphericity.
The design of the equipment is essentially simple but certain machines will have a few additions. The difference in design is meant to deliver a range of applications and produce varying levels of batch sizes. For instance, some spheronizers can perform continuous production of 50 kilograms per hour while other spheronizers can only do batch sizes of 1 to 150 grams. In addition to production rate requirements, pharmaceutical manufacturers need to consider other factors for their spheronizers like disc speed and load, disc groove geometry, retention time, and many others.
Pellets or granules achieved through the use of extruders for spheronization offers a wide range of advantages over other techniques. From offering a fast and cost-efficient method to producing particles of uniform size, the very exacting process has allowed the pharmaceutical industry to create medicine that can be safely and efficiently delivered in the body, reducing the risk of local irritation in the gastro-intestinal tract. So the next time you grab an ibuprofen or any other capsule, thank your lucky stars for extruders and spheronizers.
Caleva Process Solutions Ltd. is a British-based designer as well as manufacturer of Extruders and Spheronizers for the pharmaceutical industry.
