Using Moisture Analysis to Improve Drug Storage

In order to protect active ingredients from external factors such as light, heat, or air, a rubber stopper is frequently utilized to plug the container. The pharmaceutical industry has relied on this solution for a number of years, but what happens if the seal itself starts to interact with the material it is being used to protect?

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

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

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

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

The user must complete specialized training which must be performed properly in order to gather repeatable and accurate results with the titrator, especially where medical devices are concerned; if there is anything at all wrong with the product it is deemed worthless. A dedicated piece of equipment is required for the best chance of avoiding this.

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

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

The results are comparable with those obtained using Karl Fischer, but without the specialized training. Another benefit is the less hazardous and easier maintenance routine. There is a reduction in cleaning and no requirement to replace chemical reagents or glassware.

Whether it is in a controlled lab environment or the less constant conditions of the factory floor, Computrac moisture analyzers have been created to work consistently regardless of placement.

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

Four stoppers were cut into eight pieces of relatively equal size to analyze the moisture content of rubber stoppers by using a KF coulometric titrator with an oven attachment. The cut pieces were mixed and five pieces were selected at random for testing. To carry out moisture analysis with the Computrac® Vapor Pro®, a single, intact stopper was selected and placed in a vial.

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

The average result when utilizing the Vapor Pro was inside the margin of error of the KF in every test run, whilst taking a shorter time on average.

When employed by a well-trained user, Karl Fischer titration is known to be both precise and accurate, but the Computrac® system has shown that equally precise and accurate results can be achieved but without a long training process. Additionally, the Vapor Pro series will obtain these results in a shorter time and with smaller standard deviation in comparison to the KF technique.

About AMETEK Arizona Instrument

Initially known as the Quintel Corporation, Arizona Instrument LLC was founded in 1981 by a group of engineers breaking away from The Motorola Corporation who were dedicated to the idea of providing precision moisture analysis instruments that were accurate, reliable, and easy to use.

The first instrument released was the MA Moisture Analyzer, but the company quickly expanded its Computrac® moisture analysis line and became an accepted leader in moisture analysis, setting a standard that has been adopted by many Fortune 500 companies. Today the Computrac® line is comprised of three technologies: rapid loss-on-drying, high temperature loss-on-ignition, and moisture specific analysis using polymer capacitance sensor, GREEN alternative to Karl Fischer.

In 1986, Arizona Instrument acquired Jerome Instrument Corporation the manufacturers of the Jerome® toxic gas analyzers. At the time of purchase the corporation had an established reputation for accuracy and durability, which complemented and added depth to the Arizona Instrument’s offerings; and these traditions continue today. The Jerome® line is comprised of instruments used for detecting low-level mercury and hydrogen sulfide gases. Both portable detection and fixed position monitoring solutions are available, using gold film sensor and atomic fluorescence spectroscopy technologies as the method of detection.

Through the years Arizona Instrument has pursued and maintained a total quality management system, being certified initially as ISO 9001:1994 then ISO 9001:2000 and most recently ISO 9001:2008. Though the company is located in Chandler, Arizona, its distributors and service centers located around the world provide consistent, dependable service to its many customers worldwide.

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Last updated: Sep 29, 2020 at 7:59 AM


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