| HS Code | 484079 |
| Product Name | PURASORB PL 49 Medical Device Poly(L-lactide) |
| Chemical Name | Poly(L-lactide) |
| Synonyms | PLLA, Poly(L-lactic acid), L-PLA |
| Cas Number | 26100-51-6 |
| Chemical Formula | (C3H4O2)n |
| Polymer Type | Homopolymer of L-lactide |
| Medical Grade | Medical Device Grade |
| Monomer | L-lactide |
| Inherent Viscosity | 4.9 dL/g nominal |
| Glass Transition Temperature | 55–60 °C |
| Melting Temperature | 175–180 °C |
| Density | 1.24 g/cm³ |
| Appearance | White to off-white granules or pellets |
| Form | Granules/pellets |
| Color | White to off-white |
| Residual Monomer | <0.5% |
| Water Content | <0.5% |
| Heavy Metals | <10 ppm |
| Tin Content | <50 ppm |
| Ash Content | <0.1% |
| Solubility | Soluble in chloroform, methylene chloride, and dioxane; insoluble in water and ethanol |
| Crystallinity | Semi-crystalline |
| Storage Conditions | Store in a cool, dry place protected from moisture and heat |
As an accredited PURASORB PL 49 Medical Device Poly(L-lactide) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | PURASORB PL 49 Medical Device Poly(L-lactide) is packaged in sealed aluminum foil bags, each containing 1 kg, with moisture protection. |
| Container Loading (20′ FCL) | PURASORB PL 49 Medical Device Poly(L-lactide) is loaded in clean, dry 20′ FCL containers, palletized, and secured for safe transport. |
| Shipping | PURASORB PL 49 Medical Device Poly(L-lactide) is shipped in sealed, moisture-barrier containers under ambient conditions. It is not classified as dangerous goods for transport and has no UN number. Protect from moisture, heat, and direct sunlight; store in a cool, dry, well-ventilated place. |
| Storage | Store PURASORB PL 49 in its original, tightly closed container in a cool, dry, well-ventilated area. Protect from moisture, heat, direct sunlight, and incompatible materials such as oxidizing agents. Recommended storage is 2–8°C unless the supplier specifies otherwise. Maintain stock rotation and follow the Safety Data Sheet and product label for handling and shelf-life requirements. |
| Shelf Life | Typically two years from manufacture when stored unopened under supplier-recommended cool, dry conditions, protected from moisture, light, and heat. |
A high-inherent-viscosity poly(L-lactide) such as PURASORB PL 49, with a nominal intrinsic viscosity of 4.9 dL/g measured in chloroform at 25 °C at 0.1 g/dL, enters resorbable orthopaedic interference screw production through a dedicated low-shear melt path because its molecular weight imposes a narrow gap between mould filling and thermo-mechanical chain scission. Raw material acceptance is performed against ASTM F1925-22, which sets specification limits for semi-crystalline poly(L-lactide) surgical implant resin, while device manufacturing operates under ISO 13485:2016 Clause 7.3 design and development controls and ISO 13781:2017 in vitro degradation testing for polylactide implants. The formulation for a monolithic interference screw is 100 wt% PURASORB PL 49 with no plasticizer; where osteoconductivity is specified, β-tricalcium phosphate is compounded at 10–30 wt%, because above 30 wt% the rise in zero-shear viscosity and melt elasticity prevents complete thread filling in tools with gate dimensions below 1.0 mm. Downstream production begins with vacuum drying to ≤100 ppm moisture at 80 °C for 4 h; injection moulding uses an 18–22:1 L/D general-purpose screw with a 2.0–2.5:1 compression ratio, barrel temperatures from 185 °C in the feed zone to 200–210 °C at the nozzle, a mould temperature of 100–120 °C, and a maximum barrel residence time of 15 min. On production-scale multicavity screw tools, barrel zone set points are sometimes reduced by 5–10 °C in the compression zone because screw recovery speeds above 120 rpm can add frictional heat and push melt stock above 230 °C, causing intrinsic viscosity loss greater than 0.5 dL/g over 20 min. Moulded parts are annealed at 110 °C for 2–4 h under nitrogen or vacuum to stabilise crystallinity and reduce post-mould shrinkage. The terminal products are ACL tibial interference screws, fracture fixation pins, and suture anchor bodies. The critical operational boundary is moisture: transfer or storage at relative humidity above 60% without pre-drying allows hydrolytic degradation in the feed throat, and amine-based additives or transesterification catalysts must be excluded because residual catalytic residues accelerate chain scission at processing temperature.
| Control point | Standard designation | Property / test method |
|---|---|---|
| Resin specification | ASTM F1925-22 | Inherent viscosity, residual lactide, heavy metals, tin catalyst residue |
| Absorbable orthopaedic plate/screw testing | ASTM F2502-17 | Mechanical test programme and dimensional requirements |
| In vitro degradation | ISO 13781:2017 | Molecular mass and mass-loss kinetics |
| Biocompatibility | ISO 10993-1:2018 | Risk-based biological evaluation plan |
Melt-spinning of PURASORB PL 49 into fibres for resorbable anchoring textiles is constrained by the same high molecular weight that later provides load-bearing capacity. The fibre-forming formulation is 100 wt% homopolymer; if a spin finish is required for filament handling, the add-on is held to 0.2–0.5 wt% from a biocompatible, silicone-free system to avoid altering the resorption profile. Compliance documentation combines ISO 10993-1:2018 for biological risk assessment, ASTM F1925-22 for resin lot specification, and ASTM D2256/D2256M-21 for single-strand tensile tenacity and elongation of melt-spun yarns. A single-screw extruder with 24:1 L/D, 3:1 compression ratio, and barrel zones from 190 °C to 225 °C feeds a melt pump and spin pack containing 10–40 capillaries; spinneret melt temperature is maintained at 220–230 °C, and quench air at 15–20 °C is controlled across the filament bundle. Winding speeds are matched to first-stage draw ratios of 4:1–6:1 at 60–80 °C, followed by a relaxation stage at 1.05:1–1.10:1 and 110 °C to balance orientation and crystallinity. Draw ratios above 8:1 under these conditions produce fibrillation and reduce elongation at break below the point acceptable for braided structures, so industrial lines reject spin cakes exhibiting whiteness or filament splitting before braiding. The terminal product types are braided suture anchor limbs, resorbable ligament fixation tapes, and warp-knitted textiles for soft-tissue reinforcement. Moisture control again governs process stability: undried pellets generate voided filaments and spatter at the die, while trace degradation can reduce braid tenacity below specification after gamma sterilisation.
Compression moulding of PURASORB PL 49 into resorbable craniofacial plates and orbital floor sheets uses the homopolymer at 100 wt% without plasticiser or filler because thin-section impact resistance declines when inorganic fillers exceed 10 wt% in parts below 0.6 mm, as measured by notched impact testing under ASTM D256. The dried resin, maintained at ≤100 ppm moisture, is pressed at 180–190 °C under 5–10 MPa platen pressure, cooled under pressure to 80 °C, and then annealed at 100–110 °C for 2–4 h to increase crystallinity to 40–50% by differential scanning calorimetry. Compliance records cite ASTM F2502-17 for absorbable plates and screws and ISO 10993-5:2009 for cytotoxicity. Plates are CNC-machined or laser-trimmed after annealing; terminal products include maxillofacial bone plates, orbital floor sheets, and resorbable mesh panels. Platen temperature control must remain within ±5 °C to avoid sticking below the window and premature degradation above it.
Injectable poly(L-lactic acid) microspheres are produced from PURASORB PL 49 by solvent evaporation from a dichloromethane-in-water emulsion rather than by melt dispersion, because the high intrinsic viscosity preserves particle identity during terminal gamma sterilisation and later in vivo resorption. A representative finished-vial formulation contains 150 mg PLLA microparticles per vial, with mannitol or sodium carboxymethylcellulose as a lyoprotectant at a polymer-to-excipient ratio of 1:0.8 to 1:1.5; the particle-size distribution is controlled to 20–75 μm because the lower limit avoids macrophage phagocytosis and the upper limit prevents needle obstruction through 26 G or 30 G needles. Compliance is established under ISO 10993-1:2018, with aseptic filling supported by ISO 14644-1:2015 Class 7 cleanroom conditions and terminal sterilisation validated under ISO 11137-1:2006 at 25–35 kGy; bacterial endotoxin release is tested according to USP <85> or the regional pharmacopoeial equivalent. Downstream production employs high-shear rotor-stator homogenisation at 5,000–15,000 rpm to create the primary emulsion, vacuum extraction of dichloromethane to below the ICH Q3C limit of 600 ppm for Class 2 residual solvent, and lyophilisation to cake moisture below 1 wt%. Terminal product type is a sterile injectable suspension for soft-tissue volume restoration. The principal process boundary is solvent removal, because dichloromethane retention must be validated below compendial limits, and the PLLA microparticle surface must remain free of residual poly(vinyl alcohol) above the specification limit for the intended clinical use.
PURASORB PL 49 is converted into bioresorbable vascular scaffold tubes through a sequence of extrusion, draw-down, laser machining, and crimping, with radial strength retention intended to exceed 6 months in the coronary environment by preserving the 4.9 dL/g intrinsic viscosity through tube formation. The scaffold body composition is 100 wt% homopolymer; a drug-polymer coating, when required, is applied at 1–3 wt% of the scaffold mass using a separate poly(D,L-lactide) carrier, but the coating is outside the raw material specification for PURASORB PL 49. Compliance is governed by ISO 25539-2:2020 for vascular stents, with material specification documented under ASTM F1925-22 and biological evaluation under ISO 10993-1:2018; hemocompatibility endpoints are selected according to ISO 10993-4:2017. Downstream processing begins with vacuum drying to ≤100 ppm moisture, followed by single-screw extrusion at 190–210 °C into a tube with outside diameter 1.0–1.5 mm, draw-down to a wall thickness of 0.3–0.5 mm, and annealing at 110 °C to raise crystallinity to 35–45% without causing excessive brittleness in strut bending. Femtosecond laser cutting creates strut thicknesses of 100–150 μm; the heat-affected zone must be held below 10 μm to avoid local amorphous orientation loss and crack formation during subsequent crimping onto a delivery balloon. Bench tests under ISO 25539-2:2020 radial loading and fatigue protocols track radial strength retention, recoil, and late recoil, with each lot qualified by molecular mass distribution analysis to ensure degradation kinetics meet vessel support requirements. Terminal products are bioresorbable vascular scaffolds for coronary and peripheral vessel applications. The main processing boundary is heat accumulation during laser cutting and crimping: excessive local heating reduces strut toughness, while insufficient crystallinity after annealing leaves the scaffold susceptible to recoil below the labelled diameter.
Competitive PURASORB PL 49 Medical Device Poly(L-lactide) prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8618136850665 or mail to admin@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8618136850665
Email: admin@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
PURASORB PL 49 Medical Device Poly(L-lactide) is a semicrystalline resorbable polyester supplied by Corbion Biomaterials as white granules. The grade designation corresponds to an inherent viscosity midpoint of 4.9 dL/g, measured by capillary viscometry in chloroform at 25 °C and a polymer concentration of 0.1 g/dL. Certificates of analysis typically list residual lactide at or below 0.5 % w/w, with catalyst residue reported to medical-device lot-release limits. Because the material is derived from L-lactide and retains high optical purity, it develops crystallinity after annealing and is intended for implant components in which hydrolytic strength retention must be maintained for a longer period than lower-viscosity poly(L-lactide) grades or amorphous poly(DL-lactide) copolymers. The resin falls within the scope of ASTM F1925-17, and finished devices are commonly evaluated under ISO 10993-1:2018 biological risk assessment.
The high molecular weight associated with the 4.9 dL/g midpoint increases melt viscosity relative to PL 38 and PL 32 grades, and the difference is most visible during injection molding of small, thin-wall fixation devices. Higher viscosity raises screw recovery torque and pressure drop across hot-runner drops, so processors using reciprocating-screw injection machines with 18 mm to 25 mm screw diameters typically reduce screw speed to 40–80 rpm and maintain a melt cushion of 3–5 mm to avoid venting instability. Published shear-viscosity master curves for this exact grade are limited, but comparative molding trials on 30:1 L/D twin-screw compounders show that PL 49 requires lower feed rates and higher barrel torque than PL 38 when extruded through strand dies. The design implication is that narrow flow channels, sharp transitions in runner geometry, and insufficient gate freeze-off can cause jetting, burn marks, or lactide reformation if melt residence time exceeds the thermal stability window. Tooling for PL 49 therefore uses larger sprue bushings, polished runner surfaces, and gate land lengths of 0.8–1.2 mm on cold-runner systems.
Pre-drying is the limiting operational boundary for PL 49 because residual moisture accelerates hydrolytic chain scission at melt temperatures above the melting point. The polymer should be dried in a vacuum oven at 80 °C for 8–12 h or in a desiccant dryer with a dew point of −40 °C until moisture content falls below 250 ppm. Karl Fischer titration is used to verify moisture content before process start. If the resin is exposed to ambient air at relative humidity above 60 % for more than 30 min, re-drying is required. Melt temperatures for the grade are commonly held between 190 °C and 210 °C, with a practical upper limit of 220 °C; excursions above 230 °C promote lactide reformation and molecular weight loss. Residence time in the barrel should not exceed 8 min at 210 °C. Processing under nitrogen blanket or vacuum venting at −0.08 MPa on the second half of a twin-screw profile limits oxidative discoloration.
Hydrolytic degradation of PL 49 proceeds by bulk erosion in aqueous media, with molecular weight decline preceding mass loss and strength loss following the same sequence. The high inherent viscosity delays the point at which molecular weight falls below the threshold for load-bearing function, making the grade appropriate for screws and plates that require multi-month strength retention. In phosphate-buffered saline at 37 °C, high-molecular-weight poly(L-lactide) may retain more than half of its initial bending strength beyond 12 weeks; however, published data for this specific configuration is limited because the degradation profile depends on part crystallinity, residual monomer, implant surface area, and sterilization dose. Annealing at 110–130 °C increases crystalline content and reduces the initial water uptake rate, but may introduce internal stress if cooling is non-uniform. Device designs using PL 49 should account for the transition from semicrystalline polymer to fragmented debris as degradation proceeds, and in vitro degradation studies should follow ASTM F1635-16 methods when establishing strength-loss curves.
| Grade | Inherent viscosity midpoint (dL/g) | Processing route | Relative strength retention |
|---|---|---|---|
| PL 32 | 3.2 | Injection molding | Shorter |
| PL 38 | 3.8 | Injection molding | Intermediate |
| PL 49 | 4.9 | Injection molding, extrusion, compression molding | Extended |
| PL 65 | 6.5 | Compression molding, machining | Longest |
On injection lines, PL 49 demonstrates pronounced shear thinning but remains sensitive to shear heating because high molecular weight chains generate viscous dissipation. Barrel profiles are set with a reverse temperature gradient from 180 °C in the feed zone to 200–210 °C at the nozzle, and mold temperature is selected according to the targeted crystalline state: 20–30 °C for amorphous pre-forms and 90–110 °C for crystallized implants requiring dimensional stability during later sterilisation. Back pressure is restricted to 2–5 MPa to limit screw-induced heating. Hot-runner systems require externally heated manifolds and valve gates with sufficient bore diameter; internal runner diameters below 2.5 mm can generate pressure drops exceeding 100 MPa at high injection speeds and should be avoided unless simulation is available. When short shots occur, raising melt temperature is preferred over increasing injection velocity because the latter amplifies shear heating and can degrade the polymer at the gate entrance.
Medical device manufacturers using PL 49 must demonstrate that lot-to-lot resin variation does not change finished device safety or performance. The supplier’s quality system is aligned with ISO 13485:2016, and the product is manufactured under conditions suitable for medical-device components under ASTM F1925-17 or ISO 13781:2017. The certificate of analysis lists inherent viscosity, residual lactide, residual solvent, moisture, heavy metals, and stannous catalyst content where required. For device master files, a grade change from lower-molecular-weight PL 38 to PL 49 requires design verification because creep, degradation time, and sterilisation response are not linear with inherent viscosity. Conversely, substitution of PL 49 by amorphous poly(DL-lactide) copolymers is not acceptable in load-bearing designs because the amorphous polymer loses strength significantly faster and lacks the semicrystalline phase that contributes to dimensional stability.
| Requirement | Designation | Role |
|---|---|---|
| Biological evaluation planning | ISO 10993-1:2018 | Device biocompatibility endpoints |
| Quality management | ISO 13485:2016 | Supplier and device QMS |
| Polymer resin specification | ASTM F1925-17 | Semi-crystalline poly(L-lactide) requirements |
| Absorbable implant degradation testing | ASTM F1635-16 | In vitro degradation test method |
| Radiation sterilization validation | ISO 11137-1:2006 | Dose setting and dose audit |
| Ethylene oxide residue | ISO 10993-7:2008 | Residual ethylene oxide limits |
On production-scale twin-screw compounding lines, PL 49 exhibits higher melt pressure than lower-IV grades at identical throughput, and strand pelletizing is recommended with water-bath temperature below 10 °C to prevent strand tack. Batch-to-batch variation in inherent viscosity of ±0.2 dL/g does not require process revalidation when the manufacturer’s documented tolerance includes that range, but it can shift pack-holding pressure and part weight by 1–2 % in closed-loop injection molding. Process transfer studies should therefore record melt pressure, cushion, and screw recovery time for each lot. Vacuum drying trays should not be loaded above 2 cm granule depth because uneven heat transfer leaves residual moisture in the centre of the bed. If moisture remains, the first indication is a fall in melt pressure as molecular weight drops during plastication.
PL 49 is used in injection-molded suture anchors, interference screws, and craniofacial plates because the polymer supports load-bearing designs with longer strength retention than PL 32 or PL 38. Suture anchors made from PL 49 require thread-tip sharpness and eyelet geometry adjustments because the high-molecular-weight melt solidifies with greater orientation and can form residual stress at sharp corners. Bone screws typically use a mold temperature of 100–115 °C to develop crystalline domains that resist creep during insertion torque. Craniomaxillofacial plates use compression molding or machining from annealed sheet; sheets are annealed at 120 °C for 4 h to stabilise shrinkage before machining. Published flexural strength values for PL 49 are product-specific, but high-IV poly(L-lactide) test specimens are commonly reported in the range of 100–130 MPa under ISO 178:2019 three-point bending. The difference from lower-IV grades is not only in initial strength but in the time-dependent loss of strength under wet in vivo conditions.
Terminal sterilization procedures for PL 49 must be selected with the polymer’s hydrolysis sensitivity in mind. Gamma irradiation at typical doses of 25 kGy can reduce molecular weight and may accelerate subsequent strength loss; therefore dose setting should be performed under ISO 11137 with degradation studies on the finished device. Ethylene oxide cycles are less chain-scission-inducing but leave residual gas that must meet ISO 10993-7. Steam autoclave is incompatible with the grade because the combination of moisture and heat causes rapid hydrolytic degradation. The polymer should not be compounded with amine-based additives that promote transesterification or with metal carboxylates that alter resorption kinetics. Storage conditions are recommended at −20 °C to 8 °C in sealed foil bags under inert gas; after opening, the resin should be re-dried before processing.
