Top 5 tips for better stability monitoring

Published: 30-Jul-2020

Based on our experience providing stability storage this article provides our top 5 tips for better stability monitoring

A good stability program is required for the registration and commercialisation of any pharmaceutical or regulated consumer product. This is also essential in determining the shelf life of any product and an integral aspect of the product development process. It also gives both regulators and consumers confidence that the product will perform ‘as expected’ from the date of manufacture through to the end of the product’s shelf life.

Stability studies must be conducted to ICH guidelines and many companies will also have their own SOPs in addition to these guidelines. As such stability programmes and techniques for monitoring samples in storage can vary widely across companies.

Before any samples can be placed within a stability chamber, a validated monitoring system for temperature and humidity must be in place. Monitoring provides continual feedback on the performance of the room and conditions samples are being exposed to within.

Here are our top 5 tips for better stability monitoring

1. Location of monitoring probes

Each chamber is a temperature and humidity controlled enclosure which can be defined as:

“Any device which provides a space in which temperature and/or humidity is controlled. Temperature controlled enclosures are designed to maintain a specific temperature and humidity within their working volume and must not expose their contents to conditions beyond their tolerance limits. It is essential to verify that the enclosure is capable of meeting these tolerances. This is achieved by performing a temperature and humidity mapping of the working volume.” NSAI Guide to Mapping Enclosures, 2012

Most controlled enclosures will have two monitoring probes, continually feeding results back to a Central Monitoring System, from two set locations within the enclosure. Based on experience we suggest having:

  • One probe by the front door to monitor the impact of the door opening and closing
  • The second probe positioned at the back of the chamber

As heat rises, humidity falls and due to gravity both the ceiling and floor need to be monitored to account for variations in temperature and humidity. To account for this, place one high and one low probe at the front and back of your chamber.

This above method will encompass the hot/cold spots within the chamber. Usually there will not be any variation in the middle of the chamber, and you will gain a good picture from those two probe locations. A good mapping process will also confirm that all areas are the same.

2. Responding to incidents

Having a back-up plan to avoid issues that can affect sample storage and data integrity is important. What happens with your out of hours notifications? What happens if there is a fridge alarm when you are off site? Is this alarm acknowledged straight away or ignored until you return?

When a chamber is out of tolerance, investigations must be performed to identify the cause of the issue, determine the impact on stored samples and minimise downtime.

To manage any incidents, we recommend:

  • Building a clear process around reacting to any incidents including responsibilities and key contacts
  • Creating a small set list of people who will be sent a notification by text and email to manage any issues

Remote access is another feature which can prove extremely useful around monitoring. If a chamber provides an alarm or alert to the user, being able to access the CMS system remotely, can speed up reaction times.

If your site is not in operation 24/7, there must always be a responsible person ‘on-call’ to react to any alerts. Alarm nominees should be trained in the actions which they may take in the event of an alarm situation. These possible actions along with the use of the alarms and set points should be described in your procedure.

3. Repetitive alarms

Do you have a chamber that produces a regular alarm that is never reviewed?

In addition to monitoring samples, one of the goals of stability monitoring is to predict serious issues, such as system failures, before they occur to manage the cost and frequency of preventive maintenance. The alert limits should be set to allow preventive actions to be completed prior to an excursion occurring.

A clear alert management process with key contacts and responsibilities will ensure any repetitive alerts are fixed. This can also help avoid significant maintenance costs or data integrity issues further down the line.

4. Alarm time delays

All fridges have a defrost cycle which in normal circumstances will trigger an alarm every time there is a cycle change.

Implementing an alarm time delay on fridge cycles will mean that a defrost cycle will not trigger an alarm, but anything longer than the delay will trigger an alert.

This is a useful way to manage normal fluctuating conditions without causing an alarm.

5. Shelving and spacing of products

To ensure ease of air flow and prevent cold spots we use perforated shelving. Through spacing products, storing all your samples on shelving and not on the ground you will avoid blocking any air vents or ducts.

Keeping 180 degrees clear access around any vents or ducts will also ensure a steady air flow and consistent temperature and humidity conditions.

Your procedures should ensure that:

  • Your product is not stored directly on the floor
  • The storage area is not loaded in such a way as to prevent or restrict air flow and so reduce the temperature and humidity capability of the unit
  • The capacity of the storage area is sufficient for the purpose

To discuss how we can help you with your stability storage contact the team today.

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