Robust quality control starts with quality technologies

The latest developments in machine vision can bring quality inspections to the next level, supporting accurate, high-speed and fully automated robotic operations. When a leading pharmaceutical manufacturer wanted to upgrade its tabletting quality assurance machines, Optimal Industrial Automation developed a cutting-edge application that will futureproof the company’s testing activities for years to come.

Oral solid dosage (OSD) forms, such as tablets and capsules, are the dominant drug delivery system. To ensure product quality and patient safety, these medicines need to be thoroughly tested during production and in their final delivery form before they are released into the marketplace.

Final quality checks are typically performed on a number of systematically picked samples within a batch. If these meet the necessary quality targets, the entire set of OSD forms is considered suitable for distribution. Conversely, if the samples are off spec, the batch is discarded. When manufacturing is a continuous process, then frequent evaluations of OSD form samples can detect trends and prevent products from moving outside of specification and being rejected. The detection of quality trends can prompt manual or automatic changes in key processing conditions, not only ensuring product quality compliance but also improving productivity and efficiency.

Automating quality checks

The latest advances in industrial automation can help pharmaceutical manufacturers improve quality control and assurance activities, enabling the automated, high-speed, high-precision inspection of raw materials in process product and final product forms. More precisely, according to recent estimates, digital technologies can increase the productivity of pharmaceutical companies by 50 to 200%, especially when applied to quality testing, where faster testing processes can reduce lead times for quality control labs by 60 to 70%.

In particular, a robotised system can be a game-changer in the characterisation of tablets and capsules, as it can be used to perform the many highly repetitive tasks that inspections involve, such as sample collection, preparation and analysis. Such a solution was able to greatly advance tablet inspection and overall manufacturing efficiency for a leading pharmaceutical producer.

As a forward-looking business, the company had been an early adopter of continuous manufacturing and at-line automated tablet testing machines, with a number of units populating its shop floor. These received tablets from the press and used an automated feeder to deliver tablets to the testing section and correctly position them for accurate analytical analysis. With the well-established inspection machine being discontinued by the original vendor, the OSD form manufacturer was interested in leveraging a more advanced setup. In particular, the company was keen to improve inspection speed, tablet positioning accuracy and overall machine reliability to ultimately advance performance and productivity.

To develop a suitable system, the company contacted its long-standing automation and process control partner, the Optimal Group, formed by Optimal Industrial Automation and Optimal Industrial Technologies. The organisation has been supporting the digitalisation of businesses and the application of Process Analytical Technology (PAT) in the pharmaceutical industry with state-of-the-art solutions for decades. In particular, Optimal Industrial Automation’s engineers and system integrators have extensive expertise in machine vision and robotics, which they could apply to help the manufacturer meet their requirements and futureproof their operations.

An eye for product quality

The industrial automation specialist suggested and developed an innovative cybernetic setup for tablet inspection. This consists of a system that receives OSD forms from the tablet press unit and determines the position of each in a reception tray by means of a 2D camera. This vision system provides the XY coordinates that are used by a six-axis robot to pick each individual tablet in turn and place them onto a high-precision weigh platform. After the mass has been measured, the robot picks up the tablet, rotates it to the correct orientation and places it with high precision into an analytical instrument. The correct positioning of the tablet is critical for accurate and repeatable measurements.

The analytical instrument selection can be tailored to a client’s particular requirements. It is often more convenient to use the same type of instrument in the at-line system and in the laboratory so that all of the pre-existing models can be used, saving considerable time and validation effort. In this specific case, Optimal used a Bruker multipurpose analyser.

Through a PAT knowledge management platform, synTQ, and the customer’s productspecific multivariate analysis (MVA) prediction model, a prediction of content uniformity is made. Then, in combination with the weight, that is used to determine the assay, synTQ is used to bi-directionally interface to the instrument in a GMP-compliant way, to run the client’s preferred MVA software, and to store all data in a compliant way. The synTQ platform is, therefore, critical in meeting the PAT requirement as well as providing flexibility in instrument and MVA type selection.

Following this quality inspection, the robotised arm places the tablets into a tray for storage. The tested tablets are placed in uniquely identified and easy-to-handle pockets within stackable trays to support traceability. The testing unit incorporates multiple trays to support uninterrupted, autonomous operations for many hours, meaning that once a tray is full, the system picks another one and starts to fill it. By using this technology, it is possible to analyse at least one tablet per minute, which is much faster than the previous technology.

The entire machine, including the robot and vision system, is controlled by a PLC, which communicates with synTQ and SCADA software. The SCADA software monitors all operations, visualises key data, allows operators to interact with the unit, and provides KPIs and status information. The tablet inspection machine can operate in two modes: stand-alone operation, where all recipe data is supplied from the local SCADA, or it can be integrated with the control system of the manufacturing plant, either batch or continuous. In this second configuration, the recipe data would be fed from the manufacturing plant’s SCADA or a distributed control system. This configurable design provides the OSD manufacturer with a very flexible setup.

Adding value

The resulting unit, with its additional capabilities, improves the overall performance of quality inspections both in terms of inspection speed and tablet positional accuracy. It reduces operator intervention to a minimum and provides an easier method for manual post-analysis tablet selection (if required). The machine offers an integrated or stand-alone operation and, due to the speed of operation, allows a continuous process to make timely operational changes to ensure consistent product quality.

Benedict Yelf, Machine Vision and Automation Engineer at Optimal, commented: “This automated testing system for OSD is a game-changer because of its uniqueness and the growing market demand for such a solution. While the backbone is standardised, we can customise key components, such as the analytical instrument within the cell, to address specific requirements.” www.optimal-ltd.co.uk