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Selection Of Stainless Steel Materials Used In Pharmaceutical Machinery

May 07, 2019

Selection of stainless Steel Materials used in Pharmaceutical Machinery


Material requirements for pharmaceutical equipment in pharmaceutical processes

While people are concerned that pharmaceutical equipment materials should be "easy to clean or sterilize, corrosion resistant, without chemical changes with drugs or adsorption of drugs", not to forget another principle of material selection, this is the effective control of insoluble particles.

There are some particles in medicine, such as dust, metal or other particles. The existence of particles directly affects the quality of drugs and endangers peopleundefineds lives. A large number of clinical data show that if the drug is contaminated by dust particles of 7-2 μ m, especially intravenous administration, it can lead to pyrogen reaction, pulmonary arteritis, microthrombus or foreign body granuloma and so on, which can lead to death. Therefore, for the first time in 1985, the Pharmacopoeia of our country limited the insoluble particles of infusion, stipulating that the number of particles greater than or equal to 10 μ m per milliliter should not exceed 50 and that of particles greater than or equal to 25 μ m should not exceed 5.

At the same time, it is clearly pointed out in the literature that the pollution of aseptic and insoluble particles is the two main characteristics of the aseptic drug, which is different from the aseptic drug, and is also one of the most important items in the production process and control. Pollution control of insoluble particles is one of the most difficult indicators to control in the production of sterile raw materials. The insoluble particles of each sterile product must be within a certain range, that is, the insoluble particles greater than 10 μ m and less than 25 μ m should be controlled under 300 / g. The insoluble particles greater than 25 μ m were controlled below 30 / g.

There are four sources of insoluble particles listed in the production process, namely utility systems, operating systems, process material systems, and equipment or appliance systems. The key to the control of insoluble particles in equipment or appliance system is closely related to the selection of materials. When some materials make high-speed contact on the surface of materials, a certain amount of metal particles can be produced based on the low hardness of the surface of the materials. Such as 316L stainless steel surface hardness is relatively soft, the high-speed movement of the material and the relatively soft material surface contact must produce metal particles. In order to ensure the quantity of insoluble particulate pollution, it is necessary to strictly control the related links, especially the selection of materials.

Discussion on selection of commonly used stainless Steel Materials in Pharmaceutical equipment

Among the metallic materials, austenitic stainless steel is the most widely used material for pharmaceutical equipment products. The common products are 316L (00Cr17Ni14Mo2), 316 (0Cr17Ni12Mo2), 304L (00Cr19Ni11), 304 (0Cr19Ni9) and 1Cr18Ni9Ti (commonly known as 18x8). Their common characteristics are corrosion resistance and good heat resistance. The common character of these austenitic stainless steels is corrosion resistance, but its "corrosion resistance" is relative, which means that these austenitic stainless steels have high chemical stability under certain external conditions and certain corrosion media. However, when this type of austenitic stainless steel is used in some medium, there will be intergranular corrosion, pitting corrosion and so on, especially in the medium containing Cl-. The solution is usually ultra-low carbon or low carbon (i.e. 316L or 304L). However, ultra-low carbon is not the fundamental solution to such corrosion, but also related to other factors.

Three problems of ultra-low carbon austenitic stainless steel which need to be pointed out are as follows: (1) even ultra-low carbon austenitic stainless steel will be corroded when the content of Cl- in the medium exceeds a certain value; (2) when the content of Cl- in the medium is small, the ultra-low carbon austenitic stainless steel will be corroded due to the improper processing and treatment. (3) because of the reduction of C content, the composite mechanical index of ultra-low carbon austenitic stainless steel is relatively low, especially the surface hardness is low, which makes it easy to produce insoluble particles in high-speed and material operation. Therefore, people should note that 316L is not corrosion-free stainless steel, nor is it a material without metallic particles, let alone that 316L must conform to GMP.