Where it fits
The hydrophilic PVDF capsule serves feeds where lost potency is expensive: final sterile filtration of vaccines, biological reagents, sterile eye drops and antibiotics. Among sterilising-grade options, PVDF is usually chosen not for flux but to keep the active substance in the feed from being adsorbed onto the membrane.
Key characteristics
Hydrophilised PVDF is among the lowest protein-binding media available and has a low extractables background. Both matter as direct cost on high-value biologics: adsorbed active substance is never recovered, and anything that leaches out contaminates the feed it was meant to protect.
PVDF tolerates oxidising chemistries better than most hydrophilic media and holds its flux after peroxide or hypochlorite sanitisation, which suits lines on a regular chemical sanitisation cycle. A double-layer long-life option splits the area across two membranes in the same envelope — longer service at a slightly higher initial differential.
Choosing between options
Among sterilising-grade options, the division of labour runs like this:
| Product | Format | Rating range | Reason to pick it |
|---|---|---|---|
| Hydrophilic PVDF capsule (this) | Single-use, no housing needed | 0.1 – 0.65 µm | Lowest protein binding, oxidiser-tolerant sanitisation, double-layer long-life option |
| Highly asymmetric PES capsule | Single-use, no housing needed | 0.05 – 5 µm | Initial flux and dirt-holding first, with the widest choice of ratings |
| PVDF microporous pleated cartridge | Cartridge, needs a housing | 0.1 – 1.0 µm | A fixed high-volume line where cost per element comes first |
Operation & change-out
The hydrophilised membrane wets out with WFI or buffer alone, no alcohol needed. A PVDF support and shell can be specified for oxidising feeds, but that is an option to state at enquiry rather than the standard build. Cumulative autoclave cycles are limited by the polypropylene shell — keep to the datasheet figure.