| HS Code | 461070 |
| Product Name | PURASORB PDLG 5004 |
| Chemical Name | Poly(D,L-lactide-co-glycolide) |
| Abbreviation | PLGA |
| Monomer Ratio | 50:50 D,L-lactide:glycolide |
| Inherent Viscosity | 0.4 dL/g nominal |
| Appearance | White to off-white powder/granules |
| Glass Transition Temperature | 45–50 °C |
| Crystallinity | Amorphous |
| Solubility | Soluble in dichloromethane, chloroform, acetone, ethyl acetate, THF, and HFIP; insoluble in water |
| Biodegradability | Hydrolytically biodegradable to lactic acid and glycolic acid |
| Biocompatibility | Biocompatible |
| End Group | Ester-terminated |
| Storage Conditions | Store at -20 °C, desiccated, protected from moisture |
| Moisture Content | Typically <0.5% |
| Residual Monomers | Typically lactide and glycolide <0.5% |
As an accredited PURASORB PDLG 5004 Drug Delivery PLGA Copolymer factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | PURASORB PDLG 5004 Drug Delivery PLGA Copolymer supplied in 50 g sealed, labeled amber glass bottles with moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL: palletized, sealed drums of PURASORB PDLG 5004 Drug Delivery PLGA Copolymer, dry, secure, protected from heat and moisture. |
| Shipping | PURASORB PDLG 5004 is generally shipped as a non-hazardous, moisture-sensitive solid at ambient temperature in sealed, moisture-barrier packaging. Keep containers tightly closed. Avoid excessive heat, humidity, and light. No UN dangerous-goods classification. Follow the supplier’s SDS and storage instructions, often refrigerated. |
| Storage | Store PURASORB PDLG 5004 in a tightly sealed, moisture-proof container under inert gas (nitrogen or argon). Keep refrigerated at 2–8°C; for extended storage, use -20°C. Protect from light, heat, moisture, and oxidizing agents. Before opening, allow the container to equilibrate to room temperature to prevent condensation. Avoid repeated temperature cycling and humid air. Keep away from incompatible materials. Store upright. |
| Shelf Life | PURASORB PDLG 5004 has a 2-year shelf life from manufacture when stored at -20°C in unopened original packaging. |
The acid-terminated 50:50 poly(D,L-lactide-co-glycolide) with nominal inherent viscosity 0.4 dL/g in chloroform at 25 °C is used as the matrix polymer for emulsion-solvent evaporation production of depot microspheres delivering risperidone, leuprolide acetate, and naltrexone. In a typical batch record, the dispersed phase is composed of PURASORB PDLG 5004 dissolved in dichloromethane at 15–25% w/w, while the drug-to-polymer mass ratio is maintained between 1:5 and 1:20 for peptide APIs and between 1:10 and 1:30 for hydrophobic small molecules, resulting in calculated drug loadings of 5–15% w/w. The aqueous continuous phase contains poly(vinyl alcohol) at 1.0% w/v and is held at 2–8 °C. Emulsification is performed with a Silverson L5M-A rotor-stator mixer at 5,000–8,000 rpm for 2–5 min, followed by solvent extraction into 4–8 L of chilled water under marine-propeller agitation at 300–500 rpm for 3–4 h. The hardened microspheres are wet-sieved through 100 µm and 25 µm stainless-steel screens to isolate a Dv50 of 40–80 µm and freeze-dried at −40 °C and 0.1 mbar for 24–48 h. Residual dichloromethane is controlled to below the ICH Q3C Class 2 PDE of 6.0 mg/day, and batch release includes FDA 21 CFR 211 cGMP, USP 788 particulate matter, USP 71 sterility, USP 85 bacterial endotoxins, and ISO 10993-5:2009 cytotoxicity. Process failures observed on production-scale lines include burst release exceeding 30% in the first 24 h when residual solvent remains above 0.5% w/w or when the peptide salt forms crystalline domains at the polymer-water interface; therefore differential scanning calorimetry of the lyophilised cake is used to confirm the absence of drug melting endotherms above 100 °C before filling. The terminal dosage forms are single-dose vials containing lyophilised microsphere cake for reconstitution with sterile diluent, used for 1-month to 3-month depot injections.
In subcutaneous solid implant extrusion, PURASORB PDLG 5004 is dry-blended with a micronised active pharmaceutical ingredient in a nitrogen-gloved isolator at residual moisture below 300 ppm as determined by coulometric Karl Fischer titration. Before extrusion, the polymer is vacuum-dried at 40 °C and <10 mbar for 12–24 h when relative humidity exceeds 60%; the 50:50 backbone has a nominal glass transition of 45–50 °C, but residual moisture above 500 ppm depresses the glass transition below 35 °C and induces autocatalytic hydrolysis. The blend is fed into a co-rotating twin-screw extruder with an L/D ratio of 40:1, barrel zone temperatures from 95 °C at the feed throat to 120 °C at the die, screw speed 50–100 rpm, and melt pressure 20–60 bar; the die diameter is typically 1.5–2.0 mm. Drug loadings for solid implants range from 10–30% w/w, and when melt viscosity drops below 0.5 kPa·s at the die, 5–10% w/w PEG 1500 is added as plasticiser only after a torque plateau is confirmed. Torque on the extruder main shaft is recorded continuously because acid-terminated 50:50 PLGA undergoes chain scission when barrel residence time exceeds 5 min; a torque deviation above 10% of the qualification window indicates polymer degradation and is a reject condition. The extrudate is air-cooled, pelletised, and then processed into implant rods of 2.0–2.5 mm diameter and 25–35 mm length. Release testing follows ISO 10993-1:2018, ISO 10993-6:2016, USP 905, USP 71, and USP 85. Residual ethylene oxide, if terminal sterilisation is used, is limited to 1 µg/g per ISO 10993-7:2008. The terminal product is a sterile single-use subcutaneous rod for sustained release of GnRH analogues or androgen-deprivation therapy agents.
For Atrigel-type injectable depot formulations, PDLG 5004 is dissolved in N-methyl-2-pyrrolidone or dimethyl sulfoxide at 30–45% w/w; below 25% w/w polymer loading the precipitated depot lacks mechanical cohesion upon contact with subcutaneous interstitial fluid, and the peptide or small-molecule payload releases with a burst exceeding 40% within 24 h. The organic solution is compounded in a jacketed glass reactor at 25–40 °C under dry nitrogen with overhead stirring at 50–150 rpm for 12–24 h until refractive index and dynamic viscosity stabilise. The API is added at 2–15% w/w as a separately sterilised solution or micronised suspension; after combining, the formulation is filtered through a 0.22 µm PTFE membrane when viscosity remains below 3,500 mPa·s at 25 °C and a shear rate of 10 s⁻¹. In vitro gelation is verified in phosphate-buffered saline at 37 °C with a gelation onset of 5–30 s; depot adhesion is assessed by immersion in 10 mL buffer for 24 h and measuring residual mass. Compliance for this solvent-containing product is anchored to ICH Q3C for residual N-methyl-2-pyrrolidone PDE 5.3 mg/day and dimethyl sulfoxide PDE 50 mg/day, USP 788, USP 71, and ISO 10993-11:2017 systemic toxicity. The terminal dosage form is a single-use pre-filled syringe containing a liquid depot solution that solidifies after injection.
| Residual solvent | ICH Q3C category | Permitted daily exposure | Relevant scenario |
|---|---|---|---|
| Dichloromethane | Class 2 | 6.0 mg/day | Microsphere and implant extraction |
| Chloroform | Class 2 | 0.6 mg/day | Microsphere solvent substitution |
| N-Methyl-2-pyrrolidone | Class 2 | 5.3 mg/day | In situ forming depot vehicle |
| Ethyl acetate | Class 3 | 50 mg/day | Periodontal and ophthalmic microspheres |
| Acetone | Class 3 | 50 mg/day | Nanoparticle nanoprecipitation |
| Dimethyl sulfoxide | Class 3 | 50 mg/day | In situ forming depot co-solvent |
When the finished dosage form must undergo 0.22 µm terminal filtration, PDLG 5004 is processed by nanoprecipitation from acetone or acetonitrile at a polymer concentration of 5–15 mg/mL; the drug-to-polymer ratio is held between 1:10 and 1:20, yielding nanoparticle drug loading of 5–10% w/w. The organic phase and an aqueous phase containing 0.5–1.0% w/v Poloxamer 188 are pumped into a microfluidic reactor with 100 µm channel depth at organic:aqueous flow-rate ratios of 1:2 to 1:5 and total flow rates of 5–10 mL/min. The resulting dispersion has a Z-average of 100–200 nm, polydispersity index below 0.15, and zeta potential of −20 to −30 mV. Purification is performed by tangential flow filtration using a 100 kDa regenerated cellulose cassette to remove acetone below the ICH Q3C Class 3 PDE of 50 mg/day; the retentate is then mixed with trehalose at 5% w/v and lyophilised at a shelf temperature of −35 °C for primary drying and 20 °C for secondary drying. Compliance includes ISO 10993-4:2017 hemocompatibility, USP 788, USP 85, and USP 71. The terminal product is a sterile lyophilised powder for reconstitution as intravenous oncology nanoparticles.
Ophthalmic sustained-release microspheres based on PDLG 5004 are produced by aseptic emulsion-solvent extraction using ethyl acetate or dichloromethane as the dispersed solvent, polymer concentration 10–20% w/v, and drug loading of 10–20% w/w for dexamethasone or anti-vascular endothelial growth factor agents. The organic phase is filtered through a 0.22 µm PVDF membrane before emulsification into a continuous phase of 1% w/v poly(vinyl alcohol) at 2–8 °C under high-shear mixing at 6,000–10,000 rpm. Particle size is controlled by wet-sieving through 20 µm and 53 µm sieves to obtain a Dv50 of 10–20 µm and a Dv99 below 50 µm, because larger particles can obstruct retinal blood flow. Terminal sterilisation by gamma irradiation is avoided because the acid-terminated 50:50 PLGA backbone undergoes chain scission at 25 kGy, producing viscosity loss above 30%; therefore aseptic manufacturing is selected. Published data for PDLG 5004-specific intravitreal microsphere formulations remain limited, so the process ranges are drawn from peer-reviewed 50:50 PLGA systems with equivalent inherent viscosity. Batch release follows USP 789, USP 71, USP 85, ISO 10993-5:2009, and ICH Q3C residual ethyl acetate PDE 50 mg/day. The terminal product is a single-dose glass vial containing lyophilised microspheres for intravitreal injection after reconstitution.
Periodontal pocket geometry imposes a Dv99 ceiling of 60 µm and a Dv50 of 20–40 µm for PDLG 5004 microspheres loaded with minocycline hydrochloride or doxycycline hyclate; larger particles are expelled by sulcular fluid flow, while particles below 10 µm are phagocytosed too rapidly to maintain therapeutic concentration. The polymer is dissolved in ethyl acetate at 10–20% w/v, and the tetracycline antibiotic is added at 15–30% w/w relative to polymer, equivalent to a drug-to-polymer ratio of 1:3 to 1:6. The emulsion is formed with a continuous phase of 1% w/v poly(vinyl alcohol) at room temperature, extracted under reduced pressure at 150–200 mbar for 2–4 h, and dried by lyophilisation. Ethylene oxide sterilisation is used instead of gamma irradiation because the acid-terminal PLGA degrades under 25 kGy; residual ethylene oxide is controlled below 1 µg/g according to ISO 10993-7:2008. Release testing includes USP 71, USP 85, and ISO 10993-10:2010 for sensitisation. The terminal dosage form is a unit-dose cartridge containing sterile microsphere powder for subgingival administration.
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PURASORB PDLG 5004 is an acid-terminated poly(DL-lactide-co-glycolide) copolymer supplied as a white to off-white granular solid for parenteral drug delivery formulation. The model designation encodes three release-critical variables: the PDLG backbone, a nominal 50:50 molar ratio of DL-lactide to glycolide, and a midpoint inherent viscosity of 0.4 dL/g measured in chloroform at 25 °C and 0.1 g/dL using a method aligned with ISO 1628-1. The carboxylic acid terminus provides a reactive chain end and increases water uptake relative to ester-capped equivalents of the same molar mass. The amorphous copolymer is soluble in dichloromethane, chloroform, acetone, ethyl acetate, and tetrahydrofuran, but is not water-soluble; this solubility profile governs solvent selection during microsphere and implant manufacturing. For sustained-release parenteral dosage forms, the grade is processed into microspheres, monolithic implants, or in situ forming depots, with the final release profile depending on drug loading, particle size, matrix porosity, and post-processing residual solvent and monomer levels.
The 50:50 molar composition places PDLG 5004 in the fastest-degrading standard PLGA class because the glycolide-rich sequences increase ester bond density and reduce crystallinity; the polymer is fully amorphous, unlike poly(L-lactide) homopolymers and some 85:15 PLGA grades. Differential scanning calorimetry per ISO 11357-2 using a 10 °C/min heating ramp under nitrogen typically reports a glass transition temperature of 44–48 °C; no melting endotherm is present. The glass transition has practical consequences for lyophilization and drying operations, because product temperatures above this range can cause particle coalescence or implant deformation during secondary drying.
Analytical release testing for the raw material includes ¹H NMR in deuterated chloroform for comonomer ratio, gel permeation chromatography per ISO 16014-1 for weight-average molar mass, and gas chromatography for residual lactide and glycolide. Because the polymer is acid-terminated, the carboxylic acid content is higher than that of ester-terminated PDLG 5004A at the same inherent viscosity; the terminal acid groups participate in bulk autocatalysis and can also interact electrostatically with basic drug substances during microsphere hardening.
| Parameter | Typical value or range | Analytical method |
|---|---|---|
| DL-lactide:glycolide molar ratio | 50:50 (nominal) | ¹H NMR, deuterated chloroform |
| Inherent viscosity | 0.38–0.42 dL/g | ISO 1628-1; chloroform, 25 °C, 0.1 g/dL |
| End group | Carboxylic acid | Supplier specification |
| Glass transition temperature | 44–48 °C | ISO 11357-2; 10 °C/min, nitrogen |
| Weight-average molar mass | 30,000–50,000 g/mol | ISO 16014-1 GPC, polystyrene calibration |
| Residual lactide and glycolide | ≤0.5% total | GC-FID, external standard |
| Residual solvent | ≤0.1% | Headspace GC |
| Appearance | White to off-white granules | Visual inspection |
For solvent-extraction microsphere processes, PDLG 5004 is dissolved at 5–20 wt% in dichloromethane or at 5–15 wt% in ethyl acetate; the organic phase is emulsified into a continuous aqueous phase containing 0.5–2.0 wt% poly(vinyl alcohol) using a rotor-stator homogenizer. Tip speed rather than rotor speed controls droplet breakup: a 3–6 m/s tip speed range typically yields a D10–D90 particle-size window suitable for injectable suspension when the homogenization time is 60–300 s. Particle size is measured by laser diffraction per ISO 13320, with a target D50 of 30–70 µm for intramuscular or subcutaneous administration through 19–21 G needles. Solvent removal is conducted by stirring under vacuum at 30–40 °C for 4–24 h; residual dichloromethane is then quantified by headspace GC according to Ph. Eur. 2.2.28. Residual solvent limits follow ICH Q3C, with dichloromethane controlled as a Class 2 solvent; for parenteral products, the applied limit is typically tighter than the general Option 1 limit of 600 ppm and must be justified by toxicological data. Batch-to-batch viscosity variation within the 0.38–0.42 dL/g window can produce measurable shifts in droplet breakup and release; therefore, emulsification speed should be re-qualified when changing polymer lot.
The acid terminus of PDLG 5004 accelerates hydration of the polymer matrix, which is advantageous for degradation but increases burst release when the drug is poorly encapsulated or the matrix is highly porous. In O/W and W/O/W emulsification, burst release is primarily controlled by surface-associated drug and open porosity at the particle surface. High loading above 20 wt% of a hydrophobic small molecule reduces polymer viscosity during solvent evaporation and can produce a skinning effect; when the evaporation rate exceeds the polymer vitrification rate, a hollow-core or porous-shell morphology results. Process adjustments include reducing the organic-phase polymer concentration to 10–15 wt%, adding a hardening step with cold water at 2–8 °C, and lengthening solvent extraction to 4–6 h under controlled overhead agitation at 200–500 rpm. For peptides, primary emulsion viscosity and osmotic gradients in W/O/W systems create additional instability; the inner aqueous phase is typically buffered at pH 4–7 and the outer phase is saturated with the organic solvent for 0.5–2 h before extraction to reduce coalescence.
Release testing under USP <711> Apparatus 4 has been used to compare PLGA 50:50 grades; release intervals for PDLG 5004-based microspheres containing hydrophobic actives are generally reported between 30 and 90 days, while highly water-soluble peptides may release over 14–30 days from the same matrix. These intervals are not intrinsic properties but depend on particle size, drug loading, and residual solvent. Published data for this specific grade under a single standardized formulation are limited; therefore, formulation-specific in vitro–in vivo correlation is required.
For monolithic implant manufacturing by hot-melt extrusion, PDLG 5004 is processed on a co-rotating twin-screw extruder with an L/D ratio of 30:1 to 40:1 and a screw diameter of 9–16 mm for pilot batches or 18–27 mm for production. Barrel temperatures are set between 130 °C and 160 °C; the die is held 5–10 °C below the melt section to control strand swelling. The polymer must be vacuum-dried at 40–45 °C for 12–24 h to a moisture content below 0.1%; moisture content is verified by Karl Fischer titration per ISO 15512. Inadequate drying produces torque excursions, melt fracture, and surface defects on the implant; production lines have also observed feed-block sticking when the feed throat is not kept dry. Melt pressure and screw speed are controlled at 20–80 bar and 50–150 rpm in pilot configurations. Injection molding of implant rods requires clamp force settings typical of small medical molds, 10–50 tonnes, and a mold temperature below the glass transition to prevent deformation.
Terminal sterilization of PDLG 5004 implants by gamma irradiation according to ISO 11137 produces dose-dependent chain scission; the resulting inherent viscosity reduction must be measured before release. A dose of 25 kGy can reduce the inherent viscosity by a measurable amount, with the magnitude depending on packaging atmosphere, temperature, and absorbed dose rate. Because the polymer is amorphous and has a glass transition below 50 °C, dry-heat sterilization is not compatible; steam sterilization causes rapid ester hydrolysis and loss of molecular weight. Electron beam processing can reduce residence time and oxidative side reactions, but requires dose mapping to confirm a minimum sterilizing dose across the product load. Ethylene oxide residues are controlled by ISO 10993-7, and the process is not preferred for biodegradable polyesters if alternative methods are feasible. Sterile filtration of PDLG 5004 solutions is limited by viscosity; above 5 wt% in dichloromethane, the solution viscosity usually exceeds practical filtration thresholds through 0.22 µm membranes, forcing aseptic processing or terminal sterilization of the solid or finished implant.
Irradiation temperatures above -20 °C may promote chain scission and free-radical recombination; dry ice or liquid nitrogen-cooled irradiation is sometimes used to preserve molecular weight. After irradiation, the product should be characterized for molar mass by GPC, glass transition by DSC, and residual monomer by GC-FID. For terminally sterilized microspheres, changes in particle morphology after irradiation should be assessed using scanning electron microscopy and laser diffraction; aggregation that increases particle size beyond the injectable range may cause failure under USP <790>.
The acid-terminated PDLG 5004 differs from PDLG 5002 primarily in chain length and initial viscosity. PDLG 5002 has a midpoint inherent viscosity of 0.2 dL/g, lower weight-average molar mass, and more chain ends per unit mass; this accelerates water uptake and bulk degradation, shortens the release interval, and reduces mechanical strength in monolithic implants. PDLG 5004A is the ester-terminated counterpart at the same 0.4 dL/g viscosity class. Capping the terminal carboxylic acid removes one acidic end group per chain and lowers the initial hydrophilicity and autocatalytic rate; PDLG 5004A is therefore selected when lower initial water uptake, reduced ionic interaction with basic drugs, or longer lag time is required. Compared with a 75:25 PLGA grade such as PDLG 7504, the 50:50 composition degrades faster and releases encapsulated drug faster at equivalent inherent viscosity; 75:25 grades generally extend release duration by approximately 1.5–2× in comparable microsphere formulations.
| Grade | DL-lactide:glycolide ratio | Midpoint inherent viscosity (dL/g) | End group | Primary effect |
|---|---|---|---|---|
| PURASORB PDLG 5004 | 50:50 | 0.4 | Carboxylic acid | Medium chain length, acid-catalyzed bulk erosion |
| PURASORB PDLG 5002 | 50:50 | 0.2 | Carboxylic acid | Lower viscosity, faster degradation, shorter release |
| PURASORB PDLG 5004A | 50:50 | 0.4 | Ester-capped | Lower initial hydrophilicity, slower early degradation |
| PURASORB PDLG 7504 | 75:25 | 0.4 | Carboxylic acid | Longer degradation-controlled release |
Compared with poly(L-lactide) homopolymers, PDLG 5004 is amorphous and degrades in months rather than years because methyl substitution is absent in glycolide sequences and the racemic DL-lactide prevents crystallization. Compared with polycaprolactone, the glass transition is higher but degradation is much faster. These differences are used in combination products where a two-stage release is required: a 50:50 PLGA such as PDLG 5004 provides the first release phase, while a 75:25 PLGA or poly(L-lactide-co-glycolide) provides the second phase.
In situ forming depot systems are prepared by dissolving PDLG 5004 in a bioacceptable solvent such as N-methyl-2-pyrrolidone at 20–40 wt%. Upon injection into an aqueous environment, solvent exchange and polymer precipitation form a depot. The 0.4 dL/g viscosity grade balances injectability through 21–23 G needles with sufficient depot integrity; lower-IV PDLG 5002 produces depots that are less cohesive and may fragment, while higher-IV grades raise viscosity and injection force. Burst release is strongly dependent on solvent miscibility, polymer concentration, and injection depth. The acid terminus accelerates water infiltration but can also improve drug-polymer compatibility for weak bases through ionic interaction. In situ depots are not terminally sterilized easily by moist heat; sterile filtration of the organic solution may be possible at polymer concentrations below 10 wt% depending on solvent type and membrane compatibility.
Storage conditions specified in the supplier certificate of analysis require sealed aluminum-polyethylene laminated packaging with desiccant at 2–8 °C. The polymer should be equilibrated to room temperature before opening to avoid condensation; once opened, it should be used or re-sealed under dry nitrogen. Under these conditions, the manufacturer assigns a shelf life based on retest intervals and the package label provides the exact expiry. Regulatory support for parenteral applications typically includes a Type IV drug master file and biocompatibility data generated under ISO 10993-1 and USP <88>; finished-product manufacturers remain responsible for sterility USP <71>, bacterial endotoxin USP <85>, particulate matter USP <790>, and residual solvent compliance. The polyester backbone is incompatible with strong bases, nucleophilic amines, and long exposure to aqueous solutions at neutral to alkaline pH; these conditions accelerate ester hydrolysis and reduce molecular weight during processing or storage. For aqueous formulations, the polymer should be stored dry and not premixed with water until immediately before use.
