Polymer Industries have served pharmaceutical industry with various polymer product compositions to meet critical requirements of pharma and biotech industries. Silicone resin formulations very easily meets FDA and USP requirements with ultra low extractable and leachable properties. Due to its inherent properties such as biocompatibility and inertness to cells/human tissues, silicone rubber is most widely used polymer in pharmaceutical and biotech industries.
Every product puts a demand on the material used, but none so more than the medical industry. In terms of meeting both the regulatory requirement & performance, the answer is thermosetting Liquid Silicone Rubber (LSR).

Overview of Silicone Rubber Chemistry
Silicone Rubber is chemically known as PDMS (Polydimethylsiloxane). It contains Si-O Backbone Structure in polymeric chain, which is responsible for its superior performance as mentioned below:

• Flexibility at lower temperature up to - 80°C 
• High heat resistance up to 250°C. 
• Greater weather and oxidative resistance

Key properties of Product made of Silicone Resin

Silicone Resin is a translucent polymer, widely preferred for pharma industry because of below reasons:

• Nonreactive and Inert to Biological Tissues/ Cells
• Excellent Biocompatibility
• Smooth Surfaces tend to prevent contamination of Fluid on its surface
• Easy to clean and sterilize by any standard sterilization process
• Free from Toxic ingredients
• Free of Phthalate and Bisphenol content
• Low level of Extractable compare to any other polymers
• Excellent flexibility to facilitate dynamic applications (Peristaltic Pump)
• Translucent compare to other rubbers to visualize flow of material
  

Types of Available Silicone Rubber
Based on chemistry of cure mechanism, there are two types of silicone rubber available as stated below.
Peroxide Cured Silicone Rubber:
While processing of silicone resin, a catalyst is added to strengthen its physical properties. When peroxide catalyst is used for processing, it is called as peroxide cured silicone rubber. Most common Catalyst is DCP (Dicumyl Peroxide).
The peroxide curing process leaves behind by-products in the form of volatile organic acids. To remove by-products, peroxide grade silicone products are treated in tray drier (hot air circulating oven) at 200°C for 3 to 4 hours.
This treatment is called post curing process, which eliminates the by-products by converting it into gaseous form. But still, ineffective post curing process may lead to leaching of by-products in food contact and medical applications.

Platinum Cured Silicone Rubber:
Platinum complex based catalyst is added in silicone resin while it is being processed. Chemically it is known as addition reaction. This reaction does not generate any kind of by-products in platinum curing system of silicones. Prevention of by-product generation makes it safe to use in critical application of food, pharma and biotech industries.

Advantages:

• Superior Transparency to see visibility of Fluid Flow Transfer
• Free of By-products and Odor
• Smooth surface Resists stickiness of transfer fluid. It prevents Contamination and Bacterial Growth
• Better Physical properties like Tensile Strength, Tear Resistance
• By-product free Silicone Resin contains Low level of Extractable and Leachable enhances its usage of Critical product transfer in Pharma and Biotech Industry
• Maintains physical characteristics in storage condition of long period enhance its Shelf life. Doesn’t turn yellowish during prolonged storage period

Above listed characteristics make platinum cured silicones the center of attraction among R&D specialist of pharmaceutical and biopharmaceutical industry. Awareness among polymer industries has been improved to provide silicone solutions to their clients.
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About the author: The author is holds a bachelors degree in Rubber Technology and works at Ami Polymer Pvt. Ltd. He can be contacted via phone: +91 8691013936 or email: tech@amipolymer.com