Glass bottle is most common traditional packaging form for pharmaceuticals, which has many advantages including high barrier property and corrosion resistance. However, glass bottles are fragile, which would be a trouble for transportation. Plastic bottle, has the advantages mentioned for glass bottle and is not easy to break during transportation, which is widely used in medical industry. Common plastic medical packages include HDPE bottles, PET bottles and laminated plastic bottles containing barrier layer, etc. One disadvantage of those plastic bottles is high cost. Flexible plastic bags are low in cost and suitable for transportation. With the development of adhesives and lamination processing techniques, flexible plastic bags are widely used in medical packaging industry.
Moisture barrier property is one of those factors that decide the applicability of flexible packaging films in medical packaging. To be specific, if the moisture barrier property of packaging material is poor, solid medicine may cake, concentration of liquid may be reduced, compositions may be changed and the efficacy may be compromised.
This article provides a study on the moisture barrier property test method of flexible medical packaging films.
The moisture barrier property of packaging material is expressed by its water vapor transmission rate. Main test methods of water vapor transmission rate of plastic film and sheeting include cup method (gravimetric method), electrolytic sensor method, infrared sensor method and humidity sensor method. This article describes infrared sensor method and test procedures. The testing instrument used is Labthink’s C390 Water Vapor Transmission Rate Test System.
The infrared sensor method mainly involves two processes i.e. permeation of water molecules and quantitative determination by infrared sensor. In testing process, a constant humidity difference is generated between the two sides of the specimen by controlling the humidity inside and outside of the test dish. Due to the humidity difference, the water vapor will permeate through the specimen from high humidity side to low humidity side. The nitrogen in low humidity side will carry the water vapor to the infrared sensor. Then the water vapor transmission rate will be calculated automatically after the test is finished.
The tests shall be performed according to the following procedures.
Cut three pieces of specimens from the aluminum coated film for medical packaging.
Apply vacuum grease on the surface of the three test cells and then mount the three pieces of specimens on the test cells and make sure the specimen is mounted to the test cell tightly and no air bubbles between the specimen and test cell.
Set test temperature, test humidity, specimen name, specimen thickness, test mode and other parameters. Then click Start Test to start the test. Turn on the gas supply and adjust the flow rate until the humidity inside the instrument reaches specified value.
Testing will be performed automatically. Test results will be displayed automatically after completion of tests.
The barrier property of packaging materials may influence the quantity of water vapor that enters the medical package, which is significant to the efficacy of medicine during its shelf life. This article provides infrared sensor method of water vapor transmission rate of aluminum coated film for medical packaging with Labthink’s C390 Water Vapor Transmission Rate Test System. This testing instrument is easy to operate and provides simplified test operation and accurate test results, which can measure the water transmission rate of the test specimens precisely.
Labthink Instruments Co., Ltd is one high-tech enterprise that specializes in research & development of packaging testing instruments and providing packaging testing services. The testing instruments cover various test items including oxygen barrier property, seal integrity, heat seal strength, lamination strength and removal force of bottle caps, etc. For more details about the testing instruments and testing services, please visit en.labthink.com.