White Paper: Validation of Solid Phase Cytometry for Rapid Sterility Testing

Home » Guide » White Paper: Validation of a Solid Phase Cytometry Method as a Rapid Alternative Method to USP <71> for Confirmation of Drug Product Sterility

Improving Sterility Testing Through Rapid Microbiological Methods

Sterility testing remains one of the most time-critical and risk-sensitive steps in the release of sterile and compounded drug products. Traditional culture-based methods under USP <71> are well established but require extended incubation periods, which can be challenging for products with short shelf lives.

This previously published white paper, authored by Anthony T. Grilli, MS, explores the validation of solid phase cytometry as a rapid alternative method for sterility testing, using Scan RDI technology to detect viable microorganisms more quickly while maintaining scientific and regulatory rigour. The paper outlines laboratory qualification and validation work carried out by Cormica Focus Laboratories and discusses how rapid microbiological methods can support timely, confident sterility confirmation.

Why This Research Matters:

Adoption of rapid microbiological methods within pharmaceutical sterility testing has historically required careful justification to demonstrate equivalence to compendial approaches. Robust validation, clear understanding of detection principles, and alignment with regulatory expectations remain critical for successful implementation.

The scientific principles discussed in this paper continue to inform how manufacturers and compounders evaluate sterility testing strategies today. As product lifecycles shorten and pressure to reduce time to release increases, understanding alternative approaches alongside traditional USP <71> testing is increasingly valuable.

Cormica’s Expertise in Sterility and Rapid Microbiology Testing

Cormica supports pharmaceutical, medical device, and combination product manufacturers with accredited sterility testing, rapid microbiological methods, and broader microbiology services across its global laboratory network in the US, UK, and EU.

Our global laboratory network provides manufacturers with high-quality, GMP– and ISO 17025-aligned testing to accelerate product development, regulatory submissions, and ongoing compliance.

Authors:

Walter Zwisler, MS

Tony holds an MSc in Microbiology from Rutgers University and has over 30 years of experience in industrial microbiology. He is General Manager of Cormica Focus Laboratories and an active member of PDA, ASTM, and CETA.

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With accredited laboratories in the UK, EU and US, we support pharmaceutical, medical device and combination product manufacturers worldwide. Local support combined with global quality, delivered by teams who understand your regulatory requirements.

Our Clients’ Experiences

The exceptional team at Cormica have been amazing at supporting our needs in both terms of testing, sterility predominantly, and advice in completing our projects. Their knowledge and focus on doing what is correct for the customer is second to none and the range of testing services they provide is exceptional....

After speaking with them at a trade show it became immediately evident that they were the ‘go-to’ group for the services we required. Their professionalism, clarity and honesty made them an easy choice to work with and working with them has most definitely optimised our business opportunities.

We collaborate with Cormica on several pharma projects, they have consistently demonstrated a high level of expertise, professionalism, and attention to detail in all aspects of CMC-related work, including formulation development, analytical method validation, and routine testing for stability studies...

We're very pleased with the testing conducted for us. Their team demonstrated exceptional professionalism and efficiency, and the results were delivered exactly as promised. They made the entire process seamless. We will definitely be returning for any future testing projects.

Cormica was able to carry out specialised testing for odour control and gas permeability services that no other labs we contacted were able to offer. The team was knowledgeable, professional, and easy to work with throughout the process. Their support made the experience smooth and efficient.

Working with the Cormica was a real pleasure. We had a very urgent matter for an extensive study with a critical schedule. Cormica's handling of this challenge was outstanding!

We’ve been impressed with Cormica’s sterility testing services. The team are very responsive and adaptable, with great turnaround times and consistent communication throughout our projects.

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