The Technical Vault
By SOSCleanroom
DURAN PURE 891081306
GL 25
Transparent PFA
PTFE-Coated Silicone
32 x 22 mm
Autoclavable
200°C Max.
CoA Supported
5 Caps/Pack
Technical Overview: GL 25 PFA Premium Closure
DURAN® PURE 891081306 is a transparent GL 25 screw cap with a PFA (perfluoroalkoxy) body and an installed PTFE-coated silicone liner. It is a pharmaceutical-oriented closure component in the DWK Life Sciences DURAN PURE range, intended for compatible GL 25 bottles and qualified filling, storage, or laboratory workflows.
The manufacturer specifies 32 mm cap outside diameter, 22 mm cap height, 5 caps per pack, autoclavable: yes, and 200°C maximum temperature. These are specifications for the cap product. They are not dimensions or capacity specifications for the bottle to which it is fitted.
Unlike the protective dust cover supplied with standard DURAN PURE glass bottles, this is a functional screw-cap assembly with its own liner. However, a functional cap designation is not a certified universal leakproof, pressure-rated, vapor-tight, or sterile-barrier claim. The complete container-closure system requires validation for the actual use.
Exact-SKU takeaway: 891081306 = GL 25, transparent PFA cap, PTFE-coated silicone liner, 32 x 22 mm, autoclavable, 200°C manufacturer maximum, 5 caps per pack. This is a cap-only purchase; DURAN PURE bottles are separately sold. Standard supply is non-sterile.
Exact Manufacturer Specifications
| Specification | DWK value / status |
|---|
| Manufacturer | DWK Life Sciences |
| Brand | DURAN PURE |
| Catalog number | 891081306 |
| Product type | Premium screw cap with sealing liner |
| Thread finish | GL 25 |
| Cap polymer | PFA (perfluoroalkoxy) |
| Cap color | Transparent |
| Sealing material | PTFE-coated silicone |
| Liner included | Yes; part of complete cap assembly |
| Cap outside diameter | 32 mm |
| Cap height | 22 mm |
| Order quantity | 5 caps per pack |
| Manufacturer brochure packing | 5 caps per PE bag |
| Bottles included | No |
| Autoclavable | Yes |
| Maximum temperature | 200°C, exact-cap specification |
| Delivered sterile | No; standard PURE products are non-sterile |
| Cleanroom manufactured | Yes; exact product overview says Class 8, PURE general FAQ says ISO Class 7 |
| Inspection | Visual and dimensional inspection |
| Lot presentation | Single-lot delivery |
| Quality certificate | Certificate of Analysis (CoA) |
| Traceability | 100% manufacturing-process traceability |
| Change control | Managed changes and customer notification |
| Extractables | Manufacturer report available on request |
| Material test reference | USP <88> Class VI, per DWK |
| FDA regulatory reference | Type III Packaging Material DMF #28044 for PURE caps |
| China regulatory reference | CDE/NMPA B20220000817 for PURE caps |
| Matching bottle example | 25 mL amber GL 25 DURAN PURE 818061406; bottle sold separately |
| Matching bottle example | 25 mL clear GL 25 DURAN PURE 818011401; bottle sold separately |
| Separate replacement seal | 292481456, GL 25 PTFE-coated silicone, 10/pack |
| Related GL 45 cap | 891088679, 51 x 26 mm, 5/pack, not interchangeable |
| Specific capping torque | Not published in exact SKU overview |
| Maximum autoclave cycles | Not published in exact SKU overview |
| Certified leakproof / vapor-tight rating | Not established for complete bottle-and-cap system |
| Certified pressure / vacuum rating | Not established |
| Specific cap shelf life | Not confirmed; bottle dating must not be transferred to cap |
| Shipping weight and carton dimensions | Not verified |
Critical scope: GL 25 is the thread size, not a 25 mL cap volume. The 32 mm diameter is the cap outside diameter; the 22 mm height is the cap height. Do not transfer the bottle's glass properties, amber light attenuation, or five-year bottle shelf-life designation to this closure.
PFA vs. PTFE-Coated Silicone: How the Components Differ
The cap body is made from PFA, a fluoropolymer distinct from the liner. The sealing liner consists of silicone elastomer with a PTFE coating. These three names refer to different material roles in one closure, rather than a single blended plastic.
| Component | Material | Technical role |
|---|
| Cap body | PFA | Provides the threaded closure structure |
| Seal core | Silicone elastomer | Provides compressibility when correctly installed |
| Seal surface | PTFE coating | Creates a chemically durable facing under appropriate conditions |
PTFE-coated silicone is not the same as a solid PTFE disc. A coating does not establish zero extractables, zero permeation, universal solvent compatibility, or guaranteed isolation of every underlying material under all use conditions. Evaluate solvent type, concentration, contact time, temperature, compression, and seal condition.
Material qualification: The manufacturer identifies these materials and offers an extractables report, but a given pharmaceutical formulation may still require an extractables/leachables assessment and assembled container-closure integrity testing.
Why This Is Not an Ordinary Polypropylene GL 25 Cap
The DURAN PURE premium design combines a transparent PFA fluoropolymer cap body with a PTFE-coated silicone sealing liner and manufacturer pharmaceutical documentation. A conventional PP GL 25 screw cap may share the nominal thread size but not the same material set, cleaning program, extractables information, temperature specification, or regulatory support.
Substitution should consider the formulation, bottle fit, cleaning and sterilization method, actual cap material and gasket, lot traceability requirements, and the approved quality procedure. The GL 25 thread alone is not proof of equivalent closure behavior.
Manufacturer Cleanroom Classification: Source Discrepancy
DWK's exact GL 25 cap product overview describes manufacture in a Class 8 cleanroom. A separate current DURAN PURE product-family FAQ describes cap manufacture and packaging in an ISO Class 7 cleanroom environment. These statements conflict if intended to describe the same production step and controlled area.
Both sources support the more general statement that DURAN PURE caps are cleanroom-manufactured, but they do not establish one unambiguous cleanroom class for every operation or current lot. The distinction may reflect different processes, facilities, or a document revision; the reviewed information does not determine the cause.
Procurement action: If the customer's specification mandates ISO Class 7 or ISO Class 8 production, request a current, product-specific DWK cleanroom/manufacturing declaration for 891081306. Neither claim means this cap is supplied sterile or certified for direct aseptic filling.
Sterility, Autoclaving, and Maximum Temperature
The exact DWK cap page specifies autoclavable: yes and maximum temperature 200°C. DWK's general PURE technical FAQ describes moist-heat autoclaving around 121°C for 15-20 minutes for suitable PURE bottles and caps. This general example is not a guaranteed validated sterilization process for all laboratories or filled systems.
Because the gasket contains silicone, the listed 200°C maximum must be evaluated for the complete lined cap. The laboratory should not infer permission for indefinite operation at 200°C, pressurized sealed heating, an unlimited number of sterilization cycles, or process conditions above the manufacturer's listed maximum.
| Question | Manufacturer-based interpretation |
|---|
| Autoclavable? | Yes, exact cap listing |
| Maximum temperature? | 200°C, exact cap listing |
| Supplied sterile? | No, standard PURE product family is non-sterile |
| Example steam cycle? | General DWK FAQ discusses 121°C for 15-20 min; process validation required |
| Certified repeated-cycle life? | Not established for exact SKU |
| Pressure-rated sealed heating? | Not established |
| Dry heat above 200°C? | Do not assume; silicone-lined cap maximum is 200°C |
| Configured bottle-and-cap integrity? | Requires application-specific validation |
USP Class VI, Extractables, and Regulatory Documentation
DWK identifies the cap materials as USP <88> Class VI pharmaceutical-grade materials. This supports material biocompatibility-related qualification as described by the manufacturer. It does not establish that the finished assembly is sterile, approved for injection-contact use, or suitable for every drug product.
The manufacturer lists FDA Type III Packaging Material DMF #28044 and China CDE/NMPA B20220000817 for the DURAN PURE cap family. These are separate from bottle-family filings such as FDA DMF #28042. Any need to reference a filed DMF in a pharmaceutical submission should be addressed through the appropriate regulatory process and documentation request.
- CoA: DWK supplies manufacturer lot documentation for its PURE caps.
- Extractables report: Available from the manufacturer; it is not the same as formulation-specific leachables qualification.
- Visual and dimensional inspection: Manufacturer quality checks support consistency; do not confuse with a claim that every cap is individually inspected for every dimension.
- Traceability: 100% manufacturing-step traceability and single-lot delivery.
- Change management: Manufacturer documentation and customer notification of changes.
Regulatory boundary: The existence of a DMF does not represent FDA approval of a particular cap-and-bottle combination, a finished pharmaceutical product, a validated seal, or a universal extractables/leachables clearance.
Matching DURAN PURE GL 25 Bottles
DURAN PURE 891081306 is designed for appropriately matched GL 25 bottles. The manufacturer PURE line includes both 25 mL amber and 25 mL clear Type I borosilicate glass bottle configurations with this thread size.
| SKU | Component | Key distinction |
|---|
| 891081306 | GL 25 PFA/PTFE-silicone cap | 5 caps/pack; this product |
| 818061406 | 25 mL amber DURAN PURE bottle | GL 25; 10 bottles/case; dust cover, not functional cap |
| 818011401 | 25 mL clear DURAN PURE bottle | GL 25; 10 bottles/case; dust cover, not functional cap |
| 292481456 | GL 25 replacement PTFE-coated silicone seal | 10 seals/pack; separately sold |
| 891088679 | GL 45 PFA/PTFE-silicone premium cap | 51 x 26 mm, 5/pack; not interchangeable with GL 25 |
Quantity example: One case of 10 DURAN PURE GL 25 glass bottles would require two packs of five 891081306 caps if one matching cap is desired per bottle. This is a purchasing calculation, not a statement that those bottles or extra seals are included in this cap pack.
GL 25 vs. GL 45 vs. GLS 80: Avoiding Substitutions
GL 25, GL 45, and GLS 80 are distinct threaded neck systems. This product is only GL 25. A larger-looking cap or one sold under the same DURAN PURE brand is not necessarily interchangeable.
| Thread | Example DURAN PURE closure | Interchangeability |
|---|
| GL 25 | 891081306 PFA premium cap | This listing; use matching GL 25 bottles |
| GL 45 | 891088679 PFA premium cap | Different size; not GL 25 |
| GLS 80 | 891169109 GLS 80 screw cap | Wide-mouth size; not GL 25 |
A proper thread match is necessary, but complete seal integrity and compatibility also depend on glass neck geometry, gasket condition, closing method, sample chemistry, and process validation.
GL 25 Replacement Seal: 292481456
DWK's DURAN PURE technical brochure identifies 292481456 as the separately sold PTFE-coated silicone replacement seal for GL 25 premium caps, supplied 10 seals per pack. The manufacturer seal family describes a platinum-cured silicone material under the PTFE coating.
The replacement-seal SKU is a distinct product for appropriate maintenance or replacement under an approved procedure. A new 891081306 cap already includes its liner. Do not add the 292481456 quantity to the cap's five-per-pack count.
Before reusing caps or replacing liners, verify that the approved method permits reuse, that the replacement is correct, and that the cap has not become chemically, mechanically, or thermally compromised.
Chemical Compatibility and Seal Performance
PFA, PTFE, and silicone have different chemical and mechanical properties. The cap should be evaluated as an integrated assembly rather than selecting by one component alone. Relevant factors include organic solvent composition, acidic or alkaline conditions, temperature, contact duration, vapor exposure, liquid contact with the liner, and repeated processing.
- Aqueous solutions: Consider additives, buffer pH, concentration, and required cleanliness.
- Organic solvents: Review PFA and PTFE facing as well as silicone seal behavior under the complete mixture.
- Volatile substances: Assess vapor migration, sealing pressure, headspace, and container-closure integrity.
- Trace-sensitive analysis: Evaluate potential background and extractables/leachables as required by the method.
- Thermal processing: Consider silicone-lined cap limits, seal compression, and approved sterilization conditions.
- Long-term storage: Verify method-defined storage duration, material interaction, and seal integrity.
- Transport: Do not treat an ordinary GL 25 screw cap as a certified dangerous-goods or pressure-shipping closure without qualification.
Do not claim: Universal leakproof or hermetic sealing, zero vapor loss, universal acid/base resistance, quantified tightness, or a specific chemical-compatibility certificate that has not been supplied for the actual assembly.
Receiving, Installation, and QC Checklist
- Confirm SKU: DURAN PURE 891081306.
- Verify quantity: Five transparent GL 25 caps with PTFE-coated silicone liners.
- Inspect packaging: Check manufacturer lot identification and condition.
- Inspect components: Check cap threads, body, and seated liner for visible damage or contamination.
- Retrieve documentation: Match CoA to the received cap lot.
- Check bottle fit: Confirm the container has the correct GL 25 finish and compatible sealing face.
- Verify chemistry: Review the sample formulation and all component materials.
- Apply approved closure procedure: Use specified capping torque or test procedure if required by your SOP; no exact numerical torque is published in the reviewed SKU listing.
- Confirm sterilization requirements: Standard supply is non-sterile despite cleanroom manufacture.
- Test containment: Apply laboratory leak or integrity testing where the application requires it.
- Retain traceability: Record relevant cap lot, bottle lot, and qualification records.
Important Limitations and Unsupported Claims
- This is a cap, not a bottle: No DURAN PURE glass bottle included.
- GL 25 only: Not interchangeable with GL 45 or GLS 80.
- Cap material is PFA: Do not call it polypropylene or polyethylene.
- Liner is PTFE-coated silicone: Not a solid PTFE disc and not linerless.
- Five caps per pack: Not five complete bottle-and-cap kits.
- Manufactured in cleanroom: DWK's Class 8 versus ISO Class 7 statements require clarification for class-specific claims.
- Not delivered sterile: Cleanroom manufacture does not establish aseptic-ready status.
- Autoclavable does not mean approved for every cycle: Validate processing.
- 200°C is a maximum: Not a continuous service guarantee or permission for higher processing temperatures.
- USP <88> Class VI applies to materials: Does not establish finished-drug approval.
- DMF #28044 is for PURE caps: Do not replace it with the bottle DMF #28042.
- Not universally chemically compatible: Qualify the actual formulation and all materials.
- No certified leakproof or vapor-tight result: Not established for the assembled container.
- No verified pressure/vacuum rating: Do not infer one.
- No manufacturer-confirmed cap shelf life: The PURE bottle's five-year dating is not necessarily applicable.
- Extractables report available: It is not automatically a lot-specific leachables validation.
Technical FAQs
1. What is DURAN PURE 891081306?
A transparent PFA GL 25 screw cap with PTFE-coated silicone liner, five caps per pack.
2. What are the cap dimensions?
32 mm outside diameter and 22 mm height, per DWK.
3. Is the cap PFA, PTFE, or silicone?
The cap body is PFA; the included sealing liner is PTFE-coated silicone.
4. Is the liner already included?
Yes. The premium screw cap is a lined closure; no extra replacement liner is included beyond the installed liner.
5. Does this SKU include glass bottles?
No. The purchase unit contains five caps only; bottles are separately sold.
6. What bottle neck fits this cap?
GL 25; confirm the selected bottle-and-cap fit before production use.
7. What is the matching 25 mL amber bottle?
DURAN PURE 818061406, an amber Type I borosilicate GL 25 bottle sold separately.
8. What is the matching 25 mL clear bottle?
DURAN PURE 818011401, a clear Type I borosilicate GL 25 bottle sold separately.
9. Can I use this cap on a GL 45 bottle?
No. A GL 45 bottle requires a suitable GL 45 closure, such as DURAN PURE 891088679.
10. Can it be used on a GLS 80 bottle?
No. GLS 80 is a different, much larger thread configuration.
11. Is the cap autoclavable?
Yes, DWK explicitly lists this SKU as autoclavable. Validate the actual cycle and installed assembly.
12. What is the maximum temperature?
200°C, according to the exact-cap specification. This is not a guaranteed continuous-use or filled-system rating.
13. Is the cap sterile when delivered?
No. DURAN PURE standard supply is non-sterile even though the cap is cleanroom-manufactured.
14. Is it produced in ISO Class 7 or Class 8?
DWK sources differ: the exact product overview says Class 8, while the broader PURE FAQ says ISO Class 7. Request current exact-SKU confirmation if a class is mandatory.
15. What does the PTFE-coated silicone seal do?
It combines a PTFE facing with a compliant silicone elastomer for appropriate sealing applications; actual integrity requires testing.
16. Is the liner a solid PTFE disc?
No. DWK specifies PTFE-coated silicone, not an all-PTFE gasket.
17. Is it guaranteed leakproof or vapor-tight?
No certified finished-system leakage or vapor-tight rating was established from the reviewed SKU listing.
18. Is a Certificate of Analysis available?
Yes. DWK lists CoAs and single-lot traceability for DURAN PURE screw caps.
19. Is an extractables report available?
Yes, according to DWK. This is distinct from a formulation-specific leachables assessment.
20. What does USP Class VI mean here?
DWK states the materials meet USP <88> Class VI; it does not certify approval of any finished drug product.
21. What FDA DMF applies to this cap family?
DWK lists Type III Packaging Material DMF #28044 for PURE caps, separately from bottle DMF #28042.
22. What China regulatory number is listed?
CDE/NMPA B20220000817 for DURAN PURE caps.
23. Is a replacement silicone/PTFE seal sold separately?
Yes. DURAN PURE 292481456 is the GL 25 PTFE-coated silicone seal, 10 per pack.
24. Does this cap have the same five-year expiry as PURE bottles?
A specific five-year cap shelf life was not confirmed. Use the documentation for the delivered cap lot.
25. How many caps come in a pack?
Five transparent GL 25 caps with their PTFE-coated silicone liners.
Manufacturer Technical Resources
These are technical manufacturer references and certificate resources, not DWK product-detail or shopping links. The general references do not replace the lot-specific CoA or application qualification.
For pricing, GL 25 bottle matching, replacement liners, or cap CoA assistance: Contact SOSCleanroom at Sales@SOSsupply.com or (214) 340-8574.
Last updated: October 28, 2026
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