Gel cap strength put to the test

The new machine from Stable Micro Systems measures the force required to split the outer shell of a capsule, comparing results from before the capsule has been filled with a capsule that has been filled for some time and then emptied. The comparative strength of the capsules will provide manufacturers with valuable information as to how the liquid or powder contents of their capsules can affect the mechanical strength of the capsule, and identify changes that may affect stability and long-term performance. When a capsule is tested using the company's Capsule Tensile Rig, the filling of the capsule is removed and the empty shell is mounted on an existing texture analyser (also supplied by Stable Micro Systems). Pressure is then applied until the capsule is split apart, with computerised software recording the force required to do so. The results of the test highlight three important parameters, according to the company: elastic stiffness, tensile force and elongation at break point. A reduction in elastic stiffness and tensile strength occurs when capsules become softer and begin to show a tendency to fail. The machine is available as an attachment to the company's existing textual analysis equipment which can be applied in several other industries, though the Capsule Tensile Rig has been designed as a precision fixture for the pharmaceutical industry. The product costs around £400 (€593) according to the company's business development director Jo Smewing, and has already been snapped up by one UK-based pharma firm, despite the official launch of the product not due for several weeks. The first public appearance of the product is likely to be at the British Pharmaceutical Conference in Manchester later this year, although it is likely to be available through the firm's website in the next few weeks. Stable Micro Systems is leading manufacturing of texture analysis equipment and serves many sectors including the food, adhesive and medical device industries. Around 25 per cent of the company's business comes from the pharmaceutical sector, and the firm provides a range of equipment for analyses of many parameters including tablet coating adhesion force, blister pack integrity and the assessment of tablet and gel strength.