Abstract
This specification covers amorphous poly(lactide) and poly(lactide-co-glycolide) resins used in the manufacture of surgical implants. Materials covered by this specification are virgin poly(lactide) and poly(lactide-co-glycolide) resins that can be fully solvated at room temperature by methylene chloride (dichloromethane) or chloroform (trichloromethane). The poly(d,l-lactide) homopolymers are amorphous and shall be composed of meso-lactide or equimolar (racemic) combinations of d-lactide and l-lactide. The poly(d,l-lactide-co-glycolide) copolymers are amorphous and shall be composed of a combination of glycolide and either meso-lactide or a racemic combination of d-lactide and l-lactide. The resins shall be manufactured in pellet, granular, powder, flake, or other form and shall conform to the chemical and physical property requirements specified. Tests for chemical identification (by infrared, proton nuclear magnetic resonance, and carbon-13 nuclear magnetic resonance spectroscopy), specific rotation, molar mass, and residual monomer, residual solvent, and heavy metal content shall be performed and shall conform to the requirements specified. Additional tests for residual catalyst and residual water content may be performed as well.
Scope
1.1 This specification covers virgin poly(lactide) and poly(lactide-co-glycolide) resins able to be fully solvated at 30°C by either methylene chloride (dichloromethane) or chloroform (trichloromethane). The poly(d,l-lactide) homopolymers covered by this specification are considered to be amorphous (that is, void of crystallinity) and are polymerized either from meso-lactide or from equimolar (racemic) combinations of d-lactide and l-lactide. The poly(d,l-lactide-co-glycolide) copolymers covered by this specification are also considered to be amorphous and are co-polymerized from a combination of glycolide and either meso-lactide or racemic quantities of d-lactide and l-lactide, and typically possess nominal mole fractions that equal or exceed 50 % lactide.
1.2 Since poly(glycolide) is commonly abbreviated as PGA for poly(glycolic acid) and poly(lactide) is commonly abbreviated as PLA for poly(lactic acid), these polymers are commonly referred to as PGA, PLA, and PLA:PGA resins for the hydrolytic byproducts to which they respectively degrade. PLA is a term that carries no enantiomeric specificity and therefore also encompasses the isotactic d-PLA and l-PLA moieties, each of which carries potential for crystallization. Therefore, specific reference to d,l-PLA is essential to appropriately differentiate the amorphous atactic/syndiotactic d,l-lactide based polymers and copolymers covered by this specification.
1.3 This specification is not applicable to lactide based polymers or copolymers that possess isotactic polymeric segments sufficient in size to deliver potential for lactide based crystallization. This specification is not applicable to lactide-co-glycolide copolymers that possess glycolide segments sufficient in size to deliver potential for glycolide based crystallization, thereby requiring fluorinated solvents for complete dissolution under room temperature conditions. This specification is specifically not applicable to lactide-co-glycolide copolymers with glycolide mole fractions greater than or equal to 70 % (65.3 % in mass fraction). This specification is not applicable to block copolymers or to polymers or copolymers synthesized from combinations of d-lactide and l-lactide that differ by more than 1.5 total mole percent (1.5 % of total moles).
1.4 This specification addresses material characteristics of both poly(lactide) and poly(lactide-co-glycolide) resins intended for use in surgical implants and does not apply to packaged and sterilized finished implants fabricated from these materials.
1.5 As with any material, some characteristics may be altered by processing techniques (such as molding, extrusion, machining, assembly, sterilization, etc.) required for the production of a specific part or device. Therefore, properties of fabricated forms of this resin should be evaluated independently using appropriate test methods to assure safety and efficacy.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
