Sieves or screeners are an essential part of every pharmaceutical production process, particularly as product quality and integrity are so important. The use of sieves safeguards against customer compensation or litigation, as it eliminates all oversized contamination. It therefore ensures that ingredients and finished products are quality assured during production and before use or despatch.
Where are sieves used?
Most pharmaceutical processes are hazard analysis and critical control point (HACCP) controlled. This means that an analysis of the process is carried out in terms of where hazards can occur. Critical control points are identified and some form of prevention is put in place. Sieves will help considerably at any point at which there is a risk of contamination entering the process.
These critical control points are found in many different areas of the production process. On the primary side, a good example is where raw ingredients are de-bagged because of the potential for parts of the bag to be accidentally introduced into the process. On the secondary side, many pharmaceutical companies consider the finished powder packaging area critical and place a sieve here to prevent contamination and therefore customer complaints.
Features and benefits of check screening sieves
Sieves used for check screening are designed to be extremely simple to operate and maintain, with the emphasis on making them easy to strip down and clean effectively. Their compact design means that they can be placed in small or restricted height areas of the production process – possibly where a sieve was not originally deemed necessary but is now essential.
All contact parts of the sieve are manufactured from stainless steel and can be polished to very low surface roughness (Ra) values in order to ensure good flow properties and easy cleaning. These components are simple to remove and wash in an autoclave or other cleaning vessel, thus removing any chance of cross-contamination between different batches of material.
Improvements in containment
Employers have been using occupational exposure limits (OELs) for many years to safeguard their employees’ health. They are used to assess the adequacy of the control measures and indicate if a problem ever occurs. This has forced manufacturers of process equipment to design machines that contain dust and fumes much more effectively so that these OELs can be met. In the case of sieving equipment, this is especially important as the very action of a vibrating sieve causes dust to be generated.
Traditionally, sieves have used either over-centre toggle clamps or circular band clamps to secure the component parts together. These are not ideal mechanisms for ensuring dust-tight operation, as they rely on operators to tighten them correctly to ensure an adequate seal. The Russell Compact Airlock Sieve™ addresses this clamping issue by utilising a validatable pneumatic clamping system, giving large improvements in product containment and operator health and safety.
The GMP design of the sieve is based on clean lines, which makes sanitation and performance greater. Clean down times are reduced as the sieve is simple to disassemble in seconds without the need for tools. Crevice-free, smooth surfaces make the product contact parts easy to clean and fully washable.
The unit is clamped together with an airlock system. This pneumatic lock gives an even and high clamping force across all sealing faces, and therefore guards against powder leakage more effectively than traditional band clamps or over-centre toggle clamps. To assist with FDA process approval, this pneumatic clamping system can be validated, as it provides a repeatable and measurable seal.
It is obvious that sieves or screeners continue to have a large part to play in the safe production of pharmaceutical products. However, it is important that companies using this equipment choose carefully, making sure that they comply with the new ATEX legislation and safeguard the health and safety of their operators.