On the Electrolytic detection technology of the mo

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Electrolytic testing technology for the moisture permeability of drug packaging materials (Part I)

Abstract: the moisture permeability testing of packaging materials is of great significance for the quality assurance of drugs. This paper introduces the testing principle of electrolytic moisture analyzer and its application in the detection of drug packaging materials in combination with the latest drug packaging materials standards

key words: electrolysis, moisture permeability, drug packaging materials, drugs, humidity

water is the medium of chemical reaction. After moisture absorption, drugs can cause caking (such as sodium bicarbonate), deliquescence (such as calcium chloride, chloral hydrate), dilution (such as glycerol, lactic acid), mildew (such as glucose, pepsin), hydrolysis (such as penicillin), oxidation (such as vitamin C) and other changes, As a result, it is difficult for some drugs to prepare or control the accurate dose, and even reduce the efficacy of some drugs or produce irritation and toxicity. Therefore, the requirements for water vapor permeability of drug packaging are very high. The water vapor permeability of packaging materials can directly affect the stability of the quality of packaged drugs, which is an important performance index of packaging materials

1 standard testing requirements

in order to effectively strengthen the quality control of drug packaging products, facilitate the packaging production enterprises to produce products that meet the requirements of drug packaging and facilitate the use of drug production enterprises, the State Food and drug administration has launched a series of new standards on drug packaging materials. Electrolytic analysis, as a test method to detect the moisture permeability of films and sheets, appears in some new standards. Before that, there was only weighing method in Chinese standards to detect the moisture permeability of films and sheets, while there were weighing method, infrared method, electrolytic analysis method and other methods in ISO standards

ybb (bopp/vmcpp biaxially oriented polypropylene/vacuum aluminized cast polypropylene) and YBB (pt/al/pe cellophane/aluminum/polyethylene) clearly require that the test be carried out according to the second method (electrolytic analysis) of the water vapor transmission method (YBB). The first method in YBB - cup type the first batch of copper alloy functional new material samples produced by Guoliang copper in June this year were officially offline (i.e. weighing method). Generally, this method is applicable to films and sheets with water vapor transmission of not less than 2g/(m224h). Electrolytic analysis method is more applicable to the determination of water vapor transmission of pharmaceutical films, sheets and pharmaceutical aluminum foil with small moisture transmission data. Therefore, although some standards only require the moisture permeability test of materials according to YBB and do not specify the specific test method, because the water vapor transmission of these inspection materials is very small, the test still needs to be carried out according to the description in the standard according to the electrolytic analysis method

2 introduction to electrolytic analysis

ISO is a widely used and comprehensive test standard for moisture permeability of electrolytic analysis. The gas transmission cell is designed in such a way that, with the test specified inserted, it is divided into a dry chamber and a controlled humidity chamber The dry side of the specimen is swept by a flow of dry carrier gas, and water vapour permeating through the specimen from the controlled-humidity chamber is carried by the carrier gas into an electrolytic cell. This cell contains two spiral wire e, including pendulum, coated with a thin layer of phosphorous pendant, mounted on the inside wall of a glass capillary The carrier gas is passed through the capability when the movement it holds is quantitative. Many paper-making enterprises have losses, which are absorbed by the phosphorus persistent and decomposed electrically into hydrogen and oxygen by the application of a d.c. voltage of about 70V to the electronics The mass of the moisture which permeates through the specimen and is decomposed per unit time is calculated from the electrolytic current required. (the gas permeation chamber is designed in this way. When the test sample is inserted, it will be divided into a dry chamber and a humidity controllable experimental machine. Of course, it does not lag behind the wet chamber. The dry side of the sample is purged by the dry carrier gas flow, and the water vapor will be carried into an electrolytic chamber by the carrier gas flow after penetrating through the sample from the wet chamber. This chamber contains two spiral electrodes, and a thin layer of pentoxide is covered inside the glass capillary Phosphorus. The carrier gas flows through the capillary, where the moisture in the carrier gas flow will be quantitatively absorbed by phosphorus pentoxide. By applying a DC voltage of 70V to the two electrodes, the absorbed moisture can be electrolyzed into hydrogen and oxygen. The mass of water vapor that penetrates through the sample and is electrolyzed in unit time will be calculated from the resulting current.) The test principle of electrolytic analysis method is shown in Figure 1

(to be continued)

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