Difference Between Viable and Nonviable Particles

The main difference between viable and nonviable particles is that viable particles are the particles with at least one microorganism, affecting the sterility of a product whereas nonviable particles are the particles without microorganisms but, act as a transporting agent for viable particles.

Viable and nonviable particles are the two types of particulate matter for which the cleanroom environments are monitored during quality control and quality assurance in the pharmaceutical industry. This aspires to deliver high quality and safe products to the consumer.

Key Areas Covered

1. What are Viable Particles
     – Definition, Monitoring, Effect
2. What are Nonviable Particles
     – Definition, Monitoring, Effect
3. What are the Similarities Between Viable and Nonviable Particles
     – Outline of Common Features
4. What is the Difference Between Viable and Nonviable Particles
     – Comparison of Key Difference

Key Terms

  Air Sampler, Microorganisms, Nonviable Particles, Settled Plates, Sterility, Viable Particles

What are Viable Particles

Viable particles refer to particles that contain one or more living organisms. It may affect the sterility of the pharmaceutical product. As they can germinate, viable particles can be monitored by capturing, colonizing, and counting them. The two methods involved in monitoring viable particles are settled plates and air sampler.

1. Settled plates – It measures the microorganisms that settle on a particular surface area over a given period of time from the air. After the collection, the plates can be incubated to facilitate the growth of the microorganisms. By counting the number of colonies formed over the surface area, the density of microorganisms within the cleanroom environment can be calculated.
2. Air sampler – It collects microorganisms in the air by impaction and delivers them onto a plate. The microorganism count is given by the number of colony-forming units per cubic meter (cfu/m³).
   

   Figure 1: Bacterial Sedimentation from Air

What are Nonviable Particles

Nonviable particles refer to particles that do not contain living organisms. But, they may act as carriers of microorganisms. The size of nonviable particles can be 0.5-5.0 microns. The maximum permitted number of nonviable particles per m3 as described in the EU GMP guidelines is shown in the below table.

Maximum Permitted Number of Nonviable Particles per m3

The monitoring of nonviable particles is done with particle counters, which are unable to distinguish between viable and nonviable particles. However, they are more technically advanced than the air sampler.

Figure 2: Cleanroom

Similarities Between Viable and Nonviable Particles

• Viable and nonviable particles are the two types of particulate matter found in the cleanroom environment.
• Both have to be measured to assure the quality of the pharmaceutical product.
• The measurement of total particle count is defined in ISO 14644.

Difference Between Viable and Nonviable Particles

Definition

Viable Particles: Particles that contain one or more living organisms

Nonviable Particles: Particles that do not contain living organisms

Living organisms

Viable Particles: Consist of living organisms

Nonviable Particles: No living organisms

Size

Viable Particles: 0.2-30 microns

Nonviable Particles: 0.5-5.0 microns

Monitoring

Viable Particles: By settled plates or air sampler

Nonviable Particles: Using a particle counter

Significance

Viable Particles: Able to germinate

Nonviable Particles: Act as a transporting agent for the viable particles

Examples

Viable Particles: Fungi, bacteria, virus, spores

Nonviable Particles: Dust, mist, fogs, fumes, and tiny wastes

Conclusion

Viable particles are microorganisms while nonviable particles are small organic particles in the air. Viable particles affect the sterility of the product. Nonviable particles serve as carriers of viable particles. Different laboratory methods are involved in measuring both viable and nonviable particles. The main difference between viable and nonviable particles is the type, monitoring method, and the effect.

Reference:

1. Kelly, Jason. “Pharmaceutical Industry Cleanroom Monitoring: Viable and Non-Viable Particle Detection.” Controlled Environments Magazine, 15 June 2016, Available Here

Image Courtesy:

1. “Air sample room. Method of sedimentation. after 20 hours” By Evgeniya Zholnerchik – Own work (CC BY 4.0) via Commons Wikimedia   
2. “Cleanroom outside” By Stan Zurek – Own work (CC BY-SA 3.0) via Commons Wikimedia