Plastics in medical devices ppt

1. PLASTICS USED IN MEDICAL DEVICE APPLICATIONS 2.1 Material Requirements for Plastics used in Medical Devices

2. Requirements for plastics used inmedical devices

3. USP Class VI, ISO 10993 • USP Class testing is one of the most common methods of testing to determine bio-compatibility of materials. There are six classes, VI being the most rigorous. Class VI testing is aimed to certify that there are no harmful reactions or long-term bodily effects caused by chemicals that leach out of plastic materials. USP Class Testing standards are determined by the United States Pharmacopeia and National Formulary (USP-NF), the organization responsible for the quality and safety of medical devices and foods. Class testing is frequently conducted on plastic materials that come in contact with injectable drugs and other fluids found in various steps of the drug manufacturing process. Class VI testing extensively investigates the reaction in the body, skin, and living tissue to ensure safety. USP Class VI is a common standard for pharmaceutical tubing, fittings, single-use systems, and fabricated parts.

4. USP Class VI Testing Methods USP Class VI testing is conducted by producing an extract of the product with different extraction fluids, such as polyethylene glycol and vegetable oil, and injecting it in specimen (rabbits and mice) in vivo (alive), to observe the biological response to the extract. Testing is commonly done as: • Systemic Injection Test (Acute Systemic Toxicity):Test specimen are injected with the extract intravenously and observed for 72 hours. The specimen are monitored for any abnormal toxic reactivity. The scientist determines the test as pass/fail. • Intracutaneous Test:The purpose of this test is to check for any local skin reactions. Test Specimen are injected with the extract intracutaneously and observed for 72 hours. The reactions are scored and averaged. • Implantation Test:Specimen are implanted with the product material to observe the reaction of the live tissue in direct contact with the product over a span of at least 120 hours (5 days).

5. ISO 10993 • The ISO 10993 set entails a series of standards for evaluating the biocompatibility of medical devices to manage biological risk. • For the purpose of the ISO 10993 family of standards, biocompatibility is defined as the "ability of a medical device or material to perform with an appropriate host response in a specific application".

6. ISO 10993-1:2009 & FDA endpoints for consideration

7. Sterilization Methods

9. Chemical Resistance

10. Where can you find uses for polymers? • Everywhere! • There seems to be endless uses for polymers • Why? • Easier to produce • Biocompatibility • Often cheaper • Designed to mimic • Replacement to old practices • Designed to prevent additional surgery/trauma to patient

11. Polymeric Biomaterials are used in a Broad Range of Products

15. Contact Lenses And Intraocular Lenses • Poly(methyl Methacrylate)  Hard Contact Lenses • Water-soluble Polymer  Soft Contact Lenses • HydrogelsIntraocular lenses

16. SURGICAL SUTURES • Poly(glycolic acid), or condensation copolymers of glycolic acid with lactic acid. • A high tensile strength and is • compatible • The polymer degrades by hydrolysis to nontoxic glycolic acid.

17. Oxygen-Transport Membranes • Surgical work on the heart frequently requires the use of a heart lung machine to circulate and oxygenate the blood. • Poly(dimethylsiloxane) membranes are highly efficient gas transporters. • It is of interest that silicons rubber has approximately six times the oxygen permeability of fluorosilicones.

18. Artificial Kidney And Hemodialysis Materials • The function of a kidney is to remove low molecular weight waste products from the bloodstream. • Artificial kidneys have function by passage of the blood between the walls of a dialysis cell which is immersed in a circulating fluid. • Cellophane-Semipermeable dialysis membranes • The polymer is "heparinized" to prevent blood clotting-polycarbonate or cellulose acetate fibers.

19. Bones, Joints, And Teeth • Occasionally repaired with the use of polyurethanes, epoxy resins, and rapid curing vinyl resins. • Silicone rubber rods and closed cell sponges- replacement finger and wrist joints. • Elbow joints- vinyl polymers and nylon • Knee joints- cellophane and, more recently, silicone rubber • Poly(methyl methacrylate) is the principal polymer used both for acrylic teeth and for the base material

20. Heart Pump Designs

21. 2.2 Polymer Additives for Medical Device Applications Additives are used to enhance processability; improve toughness, strength, and dimensional stability; improve radiation, light, and thermal stability; provide color and improve aesthetics; improve flame retardance; make plastics conductive, biocompatible, and wear and scratch resistant; and improve long-term aging.

23. Things to Consider WhenUsing Additives • How the various additives affect the chemical resistance, sterilization resistance, extractables and leachables, biocompatibility, and toxicity of the final product. • The additives should also be nonmigratory and continue to provide the functional performance over the shelf life of the device. • All components of the formulation must be resistant to the chemicals, solvents, reagents, and disinfectants that the part, component, or device encounters.

24. Plasticizers • Plasticizers are added to plastics to make them flexible, pliable, and processable. There are two types of plasticizers: • (1) the primary plasticizer and • (2) the secondary plasticizer or extender. • The primary plasticizer improves the elongation and softness of the plastic. The secondary plasticizer or extender enhances the compatibility and plasticizing effect of the primary plasticizer. The most commonly plasticized material is polyvinyl chloride (PVC). A large number of plasticizers have been used with PVC, • The most common family being the phthalates, especially, di(2-ethylhexyl) phthalate (DEHP)

26. Wear-Resistant and Lubricious Additives Wear-resistant additives lower the coefficient of friction (COF) of a material— especially at its surface—thus reducing the rate of wear or removal of material. The two most commonly used additives are fluoropolymers and silicones. when both fluoropolymers and silicones are blended with most other polymers, the fluoropolymers and silicones will bloom to the surface (due to their lower surface energies) and produce a wear-resistant, lubricious surface. Molybdenum disulfide, graphite, and aramid fibers have also been used for wear resistance. The lubricious surface prevents the adhesion of fluids or material to the device or component during medical procedures. For this reason, several tubing and minimally invasive devices like catheters also incorporate fluoropolymers into the formulation, producing lubricious parts.

27. Pigments Pigments, colorants, and special effect additives provide aesthetics, color, identification, and branding of medical devices. Pigments must be able to withstand processing temperatures and sterilization conditions and still maintain their original color specification in both transparent and opaque parts. Pigments used in plastics are either inorganic or organic. Organic pigments are the most commonly used additives for plastics. They are based on various chromophoric families like azo pigments, pthalocyanine pigments, anthraquinone chromophores, and various other chrompophores.

28. Laser Marking Information like dates, lot and batch numbers, bar codes, logos, and product identification can be permanently etched onto plastic parts by using a fine laser [either the carbon dioxide (CO2) type or the Nd:YAG type] on the part. Many plastics are not inherently laser markable and need specific types of additives to be incorporated in low loadings (0.53%) into the resin. Figure: Laser marking on a keyboard (light on dark).

29. Radiopaque Additives Devices like catheters, guide tubes, surgical tools, dental products, stents, and balloons that are used inside the body, in many cases, need to be opaque to fluoroscopy or X-rays so that the surgeons are able to see the device as it is guided through or placed in the body. Most plastics are transparent to X-rays and require additives that are radiopaque. The most common radiopaque additives used are barium sulfate, bismuth subcarbonate, bismuth trioxide, bismuth oxychloride, tantalum, and tungsten. These additives render the plastic visible under X-rays.

30. Antimicrobials Antimicrobial additives prevent the growth of infection and fever-causing microorganisms such as bacteria, mold, fungi, and algae in and on a plastic part To prevent and inhibit such growth, several antimicrobial additives have been developed for use in various types of plastics and applications Antimicrobial additives can either be organic or inorganic compounds. • Triclosan; • Zinc pyrithione • Silver. Silver is not toxic, flammable, or corrosive. The slow release of silver ions makes it an effective additive for the long-term inhibition and destruction of microorganisms. Applications of silver antimicrobials include urinary catheters, where the additive prevents biofilm formation, and in endoscopes and stents.

31. The American Type Culture Collection (ATCC) provides standards of various test organisms for the above tests.

32. Conductive Fillers Electrically conductive additives prevent the material, component, or part of a device from accumulating electrostatic discharge (ESD). These additives quickly dissipate the static or electrical charge from a part’s surface. If the charge is not dissipated immediately, it will accumulate over time, leading to a sudden release of electricity. This sudden discharge can cause the malfunction of the device, damage sensitive components, cause explosions or fires, and send unwanted static electricity through the body. A secondary effect of static electricity is the accumulation and adherence of dust particles to the surface. This can affect the cleanliness and effectiveness of the device. Materials fall into the following categories: • Insulator • Antistatic • Static dissipative • Electromagnetic interference (EMI) shielding • Conductive—Material’s ability to conduct electricity.

33. Nanoadditives Major trends in medical devices are implants, miniaturization, weight reduction, increasedfunctionality, and electronics. Examples of such devices are micropumps, implantable defibrillators, pacemakers, implantable biosensors and drug delivery systems. Some of the advantages of using nanoadditives are the following: • Improved mechanical properties and dimensional stability, reduced shrinkage • Weight reduction • Decreased permeability to gases • Improved thermal stability and heat distortion temperature • Increased flame retardance and reduced smoke emissions • Improved chemical resistance • Tailored surface modification and functionality • Improved electrical conductivity • Optical clarity compared to conventional filled polymers • Robust processing window • Improved colorability

34. Nanoadditives

35. Nanoadditives Synthesis Approach

36. Nanoclays, Nanosilicates,and Nanotalcs Clays are naturally occurring minerals belonging to the family of inorganic aluminosilicates. Clays exist in several different forms • Montmorillonite (MMT) • POSS (Polyhedral oligomeric sesquisiloxanes)

37. Nanoadditives Dispersion ways

38. Nanoadditives Comaptibilization

39. Carbon Nanotubes

40. Carbon Nanotubes Carbon nanotubes were discovered by Sumio Iijima of NEC Corp. in 1991. They can be formed by various techniques like • laser ablation, • plasma arcing, and • chemical vapor deposition. Carbon nanotubes can come as single-walled carbon nanotubes (SWNTs), with diameters of 12 nm, or multiwalled nanotubes (MWNTs) with diameters of 812 nm, Carbon nanotubes are conductive and possess high strength and flexibility. Low loadings of carbon nanotubes make the composite stronger, stiffer, and electrically conductive when blended into polymers

41. Nanosilver Nanosilver (550 nm in particle size) when incorporated into an ion exchange or zeolite matrix can be blended into several polymer matrices like polyolefins, PVC, polycarbonates, nylons, polyesters, polyurethanes, silicones, and thermosets to provide permanent antimicrobial protection to the part Applications of silver antimicrobials include surgical gloves, surgical masks, surgical instruments, tubing for fluid management, catheters, endotracheal tubes, urinary catheters, infusion systems, endoscopes, arterial and cardiovascular stents, medical apparel, and wound dressings.

42. Stabilizers Additives that are used to enhance the properties of medical devices during processing are stabilizers. • Thermal stabilizersCalcium or Zinc-based stabilizers usually contain calcium stearate and small quantities of zinc soaps like zinc octoate. • Antioxidants Several amines, phenolics, phosphites, thioesters etc. are employed as antioxidants for plastics. • Radiation sterilization improvers • tint-based stabilizers • Inorganic fillers increase radiation resistance of polymer • UV Absorbers: Typical examples are benzophenones and benzotriazoles. These are low cost, effective stabilizers that function by the absorption of UV light.

43. References • Plastics in Medical Devices Properties, Requirements, and Applications 3rd Edition by Vinny R. Sastri - November 24, 2021. • An Overview of the Plastic Material Selection Process for Medical Devices | February 2013. • An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling, Journal of Hazardous Materials 344 (2018) 179–199. • Biomedical Polymers: Presented by Mr. D.A.Pawade, Guided by DR N.H. ALOORKAR, SATARA COLLEGE OF PHARMACY,SATARA