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Chemical erosion mechanism of glass surface and main factors affecting the formation of glass contai



In this article, we will talk about the chemical erosion mechanism of glass surface and the main factors affecting the formation of glass containers. If you want to know more about the medical glass bottles, welcome to contact us through the way at the end of the article, AVT dedicated service for you!

The erosion of glass by water begins with the exchange of hydrogen ions in water and alkali metal ions in glass, and the infiltration of water molecules into the glass. The silicic acid in the glass reacts with the exchanged alkali metal ions to form silicates. In addition, water molecules can also react directly with the silicon-oxygen framework.

The reaction product Si(OH)4 is a polar molecule, which can polarize the surrounding water molecules and Orient them around itself, forming a highly dispersed system called silicic acid gel, which is mostly attached to the glass surface and forms a film except for a part of it dissolved in aqueous solution.

In alkaline solution, OH- concentrates on the glass surface and adsorbs various cations in the glass. At the same time, OH- ions can also directly destroy the silicon oxygen framework, so that the Si-O bond fracture, finally become silicate ions, or with the cation adsorbed on the glass surface to form silicate, and gradually dissolved in lye. When the dissolution limit is exceeded, particles invisible to the naked eye are formed. Alkali erosion of the glass does not create a protective silicone film, so the erosion will continue.

According to the above chemical reaction mechanism, it is not difficult to judge that the glass packaging material with low alkali metal ion content and low alkaline dissolution has a lower possibility of delamination and glass chip formation. For pharmaceutical preparations with alkaline pH value or whose components may interact with alkaline metal ions, glass packaging materials with low alkaline dissolution should be selected in order to avoid chemical erosion on the inner surface of the container and threaten the quality of the drug.

The above reactions and situations * occur between the glass and the medium, in the case of drugs, the situation is more complicated.

The main factors affecting the formation of glass containers
Influencing factors include chemical composition of glass containers, production process, treatment after molding, drug preparation (such as composition, ionic strength, complexing agent, pH value), and sterilization method, etc.

(1) chemical composition of glass
The main composition of glass is silicon dioxide, and its chemical composition is not constant, and fluctuations are allowed within a certain range. The chemical composition of glass produced by different manufacturers is also slightly different. Type ⅰ borosilicate glass contains 70% ~ 80% silicon, 7% ~ 13% boron trioxide, and a small amount of sodium oxide, potassium oxide and alumina. It has strong water resistance and heat shock resistance. Type ⅲ soda-calcium glass contains 60% ~ 75% silicon, 12% ~ 18% sodium oxide and potassium oxide, 5% ~ 12% calcium oxide, magnesium oxide and alumina, with higher content of alkali metal elements and weak water resistance.

(2) the processing mode after molding
Ordinary sodium calcium silicate glass in the annealing process, but also the glass surface for neutral treatment. Heating the glass can precipitate sodium oxide on the inner surface of the container. After contact with the solution for a period of time, sodium ions migrate into the solution and produce OH-, which increases the pH value of the non-buffer solution.

(3) Chemical composition in solution
Some chemical components in the solution, such as citric acid, glutaric acid, ethylenediamine tetraacetic acid (EDTA), phosphate and so on, can accelerate the formation of the detachment. PH is another key factor, as alkaline solutions (pH>8.5) can cause the inner surface of the glass to dissolve, increasing the risk of silicon-rich areas forming delamination.

(4) Terminal sterilization
The chemical stability of glass changes dramatically with increasing temperature and pressure. When the temperature is below 100℃, the glass extraction rate increases by 50%-250% for every 10℃ increase in temperature. Above 100℃ (as in autoclave sterilizing pans), erosion is always intense. When the pressure is increased to 2.94 ~ 9.80MPa, the glass with better chemical properties can also be severely damaged in a short time; At the same time, a large amount of silicon oxide is transferred into the solution.

In summary, if the drug preparation contains EDTA, phosphate or solution is alkaline, or terminal sterilization is needed, in order to reduce the risk of desiccation and ensure the quality of the preparation, the pharmaceutical glass packaging material with high borosilicate content, low alkali metal content and alkaline/low alkaline dissolution resistance should be selected.

Iwata nitrate-IRAS long term low alkali treatment tube bottle

In order to prevent the surface of borosilicate glass tube from leaching alkaline substances, Iwada Nitrate Industry co., Ltd. developed a unique low alkaline treatment method - IRAS treatment.

This technology is produced through the integrated pipeline of tube bottle forming engineering, which can inhibit alkaline dissolution from the inside of tube bottle. It conforms to the standards of Japanese pharmacopoeia (JP), European Pharmacopoeia (EP) and United States Pharmacopoeia (USP).

In USP660, 60℃ * 75% influence factor test and other comparative tests, IRAS long-term low alkali treatment tube bottle showed superior low alkaline effect. In the long term, the alkaline dissolution amount of IRAS long term low alkali treatment tube bottle meets the requirements of JP, EP and USP.

In addition, IRAS long-term low alkali treatment tube bottles also have no residue after cleaning; Prevent droplet splashing and hanging on the wall during freeze-drying; No effect of disassembly caused by solvent; Integrated assembly line production, high cost efficiency advantage.

According to the individual needs of different products, IRAS products can also be supplemented with other functional processes, including low adhesion process, transparent shading process, cleaning, sterilization, aseptic packaging process, etc., to tailor the bottle products to meet the needs of pharmaceutical manufacturers.

Iwata Glass Industry Co., Ltd. was founded in 1918, focusing on the production of medical glass containers, using unique state-of-the-art technology in the field of medical products continue to develop research, fully meet the needs of customers. Its major partners include Takeda Pharmaceutical Industries, Astellas Pharmaceutical, Otsuka Pharmaceutical, Tanabe Mitsubishi Pharmaceutical, NIPRO, API Corporation, Sawai Pharmaceutical, Towa Pharmaceutical, Takeda TEVA Pharmaceutical, Nippon Meditech, etc. Welcome to call our 400 number: 400-62626-623 or visit our official website: avt-avt.com, AVT dedicated service for you!