Overcoming the Problems of Tablet and Capsule Transfer
It is commonly acknowledged that extreme care must be taken when attempting to transport tablets and capsules from one process to another by whatever means used. The fragile nature or these products means damage can easily occur during the transport stage thus potentially wasting valuable finished goods.
Tablet and capsule handling systems must be carefully designed to avoid damage or breakages
Popular methods used for the transfer of these products are vacuum, gravity, and air all of which are standard practice within the pharmaceutical and associated industries. Hanningfield can offer much experience in this area but several points must be taken into consideration to achieve efficient material handling without damage to the finished product.
Design
Special attention has to be taken regarding design and construction materials to avoid damage to the finished product. Using specially developed design techniques it is possible to adapt standard Hanningfield process equipment to suit this highly specialised yet popular application.
For example, removable silicone liners can be supplied to fit inside vacuum transfer hoppers to avoid contact between the tablet and any metal surfaces. Specially designed air flow control valves can also be fitted to ensure when vacuum conveying of tablets, they can only move in one direction during vertical transfer cycles.
Methods
Vacuum Transfer is a well established process that can be adapted to efficiently convey coated and uncoated tablets very successfully. Internal surfaces must be specially designed to ensure the tablets do not come into contact with sharp edges or corners during transfer (‘step-less conveying’). Other precautions are taken to ensure tablets will only move in one direction during transfer by use of a specially design uni-directional flow valve. The Hanningfield uni-vac system offers a number of enhanced capabilities that combine to provide safe effective tablet transfer without compromising the finished product.
Gravity is the simplest and most common transfer technique for the efficient transfer of tablets and capsules. This process is however limited to a vertical or near vertical flow path only, whereas vacuum and air powered systems can transport across horizontal distances as well as vertically upwards. To control tablet transfer, Hanningfield can supply a special flexible vane butterfly valve to minimise risk of damage when opening and closing the valve.
Air (positive pressure) is used by Hanningfield for the efficient transfer of both empty and filled hard shell capsules. Capsules are less likely to suffer from damage than tablets during conveying but internal conveying pipes must be smooth bore without ledges and sharp corners as with vacuum conveying. The positive pressure system provides a high flow, low pressure air cushion that gently moves the capsules through the convey pipe-work. Static is a common problem with capsule transfer so any system design for this application must provide an anti-static design.
Summary
In addition to good and efficient design, experience is also necessary to ensure all aspects of product protection are taken care of. This is where Hanningfield can provide the necessary input at the system concept stage to ensure a successful project conclusion using our highly skilled team of experienced engineers to guide the customer every step of the way.
