Improving Drug Storage and Efficacy with Moisture Analysis

To protect active ingredients from external factors such as heat, light, or air, a rubber stopper is often used to plug the container. This is a solution the pharmaceutical has relied on for many years, but what happens if the seal itself starts to interact with the material its working to protect

Keeping Pharmaceutical Ingredients Within a Controlled Moisture Content Range is Essential for Long Term Storage and Drug Efficacy

The problem stems from rubber being inherently hygroscopic and vulnerable to moisture absorption, both of which may alter the moisture level of the contents of the container. In an effort to prevent this, rubber stoppers are subject to strict quality assurance monitoring processes by the companies that use them.

Moisture Analysis of Rubber Stoppers has Traditionally been Performed Using Karl Fischer (KF) Titration

This process does manage accurate and precise result, but it can take a long time and is difficult for untrained personnel. With the upkeep of the Karl Fisher machine itself possibly seeming unnecessary when new glassware and chemical reagents are available at the click of a mouse.

In order to obtain accurate and repeatable results using the titrator the user must undergo specialized training which must be performed properly, especially where medical devices are concerned; if there is anything at all wrong with the product it becomes worthless. To stand the best chance of avoiding this you need a dedicated piece of equipment.

Computrac® Offers a User Friendly, Chemical Free Alternative to Karl Fischer

Ametek has a such an instrument in the form of the new Vapor Pro® XL (VPXL), part of their Computrac® Vapor Pro® series of instruments. The VPXL uses a moisture specific relative humidity (RH) sensor to determine the moisture level of a sample more quickly than the KF titrator and without the use of chemical reagent.

The results are comparable with those gained through Karl Fischer, but without the specialized training. Another advantage is the easier and less hazardous maintenance routine, as there is less cleaning and no having to replace glassware or chemical reagents.

Whether in a controlled lab environment or the less constant conditions of the factory floor, Computrac moisture analyzers have been built to perform consistently regardless of location.

The Data Presented below Demonstrate Five Stopper Samples of Varying Moisture Content, Size and Composition

In order to analyze the moisture content of rubber stoppers using a KF coulometric titrator with an oven attachment, four stoppers were cut into eight pieces of relatively equal size. The cut pieces were then mixed and five pieces were randomly selected for testing. To perform moisture analysis with the Computrac® Vapor Pro®, a single, intact stopper was chosen and placed in a vial.

The Computrac® Vapor Pro® Series Correlates Well with Karl Fischer

In every test run, the average result using the Vapor Pro was within the margin of error of the KF, whilst taking a shorter average time.

In the hands of well-trained user, Karl Fischer titration is known to be both accurate and precise, but the Computrac® system has demonstrated that equally accurate and precise results and be achieved but with without a lengthy training process. As well as this, the Vapor Pro series will achieve these results in a shorter time and with smaller standard deviation in comparison to the KF method.

Arizona Instrument

This information has been sourced, reviewed and adapted from materials provided by AMETEK Brookfield Arizona


For more information on this source, please visit AMETEK Brookfield Arizona



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