Estor offers highly specialized dialysis membranes produced by TORAY, a Japanese company and worldwide leader in nanotechnologies, chemistry, and advanced membrane development. TORAY is the only manufacturer who has succeeded in producing dialysis membranes of polymethylmethacrylate (PMMA) and their membranes are recognized worldwide for their outstanding biocompatibility, high removal performance of uremic toxins, a wide range of UFR, and unique adsorption characteristics for a variety of non-dialyzable uremic toxins.

 PMMA membranes are designed to provide high biocompatibility to patients and to add a third dimension to dialysis: adsorption. Whereas diffusion and convection remove small and medium-sized molecules, adsorption has the capacity to remove medium and high molecular weight molecules, including protein-bound uremic toxins (PBUT), responsible for many complications in the uremic patient.

 PMMA  FILTRYZER® hemodialysis membranes are unique membranes for the treatment of CKD patients requiring hemodialysis. PMMA membranes are recognized by nephrologists for their outstanding biocompatibility and proven ability to improve the patient’s quality of life.

PMMA membranes are known for their exceptional hemo- and biocompatibility and adsorption properties in addition to diffusion and convection filtration mechanisms. PMMA membranes allow the removal of non-dialyzable uremic toxins, improving the immune response in the CKD patient and providing a reduction in short and long-term comorbidities, a superior ability to maintain protein and muscle mass, a dramatic reduction of uremic pruritus and a reduction of cardiovascular disease risk. Clinical experiences have also demonstrated the efficacy of PMMA membranes in the removal sFLC for the treatment of myeloma kidney in patients requiring RRT. More recently, the PMMA membrane has proven its superiority in improving vaccination response to the anti-SARS-CoV-2 vaccine. Due to their excellent biocompatibility, the PMMA FILTRYZER series are the membranes of choice for performing the first hemodialysis treatments on incident patients and treating patients with low tolerability towards conventional membranes.

 The PMMA FILTRYZER series offer personalized dialysis, based on the individual needs of each patient.




The FILTRYZER B3-A series is the reference standard for biocompatibility and clinical tolerance.

The B3 is a low-flux membrane designed for conventional hemodialysis (HD). This membrane has a slightly anionic surface. Numerous studies have demonstrated the very low complement activation and a better removal of β2-microglobulin. The B3 is suggested for patients who need a mild hemodialysis, for example elderly patients or patients initiating hemodialysis.



FILTRYZER BG-U is one of the most recent series designed by TORAY. This series is the reference for biocompatibility and clinical tolerance. The BG-U membrane is slightly anionic and BG-U is characterized by an extraordinary uniform pore size and distribution guaranteeing high water permeability. This leads to an unprecedented adsorption capacity not only of small molecules, but also medium and high molecular weight molecules. Numerous studies have demonstrated the effectiveness of BG-U in reducing histamine-mediated uremic pruritus in CKD patients undergoing hemodialysis treatment.

Uremic pruritus

More than 50% of patients undergoing hemodialysis therapy are affected by uremic pruritus. This pathology has a negative impact on quality of life and is associated with an increased mortality risk (as shown in the DOPPS I and DOPSS II studies). The mechanisms behind uremic pruritus are not fully understood but appear to be a condition related to systemic inflammation caused by the release of histamine, rather than a cutaneous disease. Various studies have demonstrated that hemodialysis with the PMMA series BG-U reduces uremic pruritus and that this effect remains for 3-4 months after the patient has switched back to the previously used dialyzer.

Inflammatory mediators removal

The adsorption capacity, in addition to the mechanisms of diffusion and convection, allows medium to high molecular weight molecules removal not achievable by filtration, among which inflammation mediators IL-6, IL-8, TNF-alfa and HMGB-1

A-HDF (Adsorption HemodiaFiltration)

BG-U is the best PMMA series for working in HDF modality providing the unique A-HDF (Adsorption HemodiaFiltration). The combination of high convection and adsorption leads to a new generation of hemodialysis treatment.



FILTRYZER BK-F is characterized by a large pore size reaching 100 Å.

FILTRYZER BK-F is designed for the removal of medium and high molecular weight molecules. As the other PMMA series this membrane is a reference for biocompatibility and clinical tolerance and is characterized by a large pore size reaching 100 Å. The BK-F series offers a unique PMMA filter with ultra wide pores for the removal of medium to high molecular weight (HMW) molecules, as well as protein bound uremic toxins (PBUT) through the joint mechanisms of diffusion, convection and adsorption.


Patients undergoing hemodialysis therapy are affected by immunodeficiency, which makes them susceptible to infections, malign tumors and a reduced response to Hepatitis B vaccination. Initially recognized for the treatment of oxidative stress, new clinical evidence has shown that the BK-F series is capable of lowering serum levels of sCD40, HMW glycoprotein responsible for the reduced response to HBV vaccination.

Cardiovascular risk

Chronic hemodialysis patients have a higher cardiovascular mortality and morbidity compared to the general population. The BK-F series has been shown to improve anemia, to reduce the levels homocysteine and medium- and high molecular weight molecules. The RISCAVID study demonstrated an increased cardiovascular risk in patient with serum levels of sCD40L > 7,6 ng/mL. The activation of the CD40/CD40L pathway plays a key role in endothelial cell (EC) dysfunction and in vascular calcification through osteoblastic differentiation of vascular smooth muscle cells (VSMC). Cantaluppi et al. have shown that the PMMA membrane reduces the serum levels of sCD40L to below the dangerous level of 7,6 ng/mL.

Multiple myeloma

Renal failure is major cause of morbidity and mortality in patients with multiple myeloma. Approximately 10% of patients diagnosed with multiple myeloma require dialysis for acute renal failure caused by the accumulation of both κ (25 kD) and λ (50 kD) monoclonal free light chains (FLC). As the techniques of plasma-apheresis are ineffective in reducing FLC, they must be removed by increased hemodialysis with adsorptive PMMA dialyzers. The BK-F series has been shown to be particularly efficient in adsorbing sFLC.

Enhanced Adsorption Dialysis (EAD®) System

We have developed the Enhanced Adsorption Dialysis (EAD) System for performing sequential dialysis treatments for maximal sFLC adsorption performance in patients affected by multiple myeloma and AKI requiring hemodialysis treatment. Considering sFLC, The adsorption with PMMA membrane has its maximum effectiveness in the first few hours of the dialysis treatment, while it is less effective in the second part of the dialysis when the membrane becomes saturated. The EAD System, through the use of a specific bloodline set and a second dialyzer, BK-F, doubles the adsorptive capacity. The result is a significant increase in FLC removal, working with standard bicarbonate dialysis modality, avoiding albumin loss and thus resulting in an economic and repeatable treatment.

The first experiences with the EAD technique demonstrate its effectiveness in removing free light chains (FLC). In fact, while dialysis using only one PMMA BK-F filter results in 15% removal (pre-treatment values 2096±179 mg/l and post-treatment values 1776 ± 225 mg/l), the EAD technique results in 53.1% removal (pre-treatment values 2105±505 mg/l post-treatment values 986 ±168 mg/l). There were no differences in the length of the dialysis sessions or in the use of anticoagulant compared to a standard hemodialysis with a single PMMA filter.


NEW FILTRYZER NF-H and NF-U are the most recent PMMA membranes by TORAY.

With these membranes TORAY has succeeded in further improving the hemocompatibility and antithrombogenicity characterizing PMMA membranes.

NEW FILTRYZER NF has the same outstanding adsorption capacity that distinguishes the PMMA membrane, allowing the adsorption of high molecular weight molecules (HMW and PBUT) that cannot be removed by standard diffusion/convection mechanisms.

Pre- and post-transplant patients

Due to its excellent hemocompatibility and antithrombogenicity, NEW FILTRYZER NF is the dialyzer of choice for pre- and post-transplant patients.

By not activating the complement system and by reducing endothelial cell and platelet activation, the PMMA NF series can be the ideal dialysis membrane for patients on transplant waitlist and patients who have received organ transplant and are experiencing Delayed Graft Function (DGF).

DGF is a form of acute renal failure occuring in 20– 50% of the kidney transplants from deceased donors and is associated with an increased risk of acute rejection and a worse long-term graft survival.

Ischaemia-reperfusion injury is characterized by a massive activation of the innate immunity, with the priming of the complement and the coagulation cascade within the graft, resulting in the recruitment of inflammatory cells and coagulation and complement activation leading to delayed graft function (DGF).

As described in literature, NF-H has been used in BHD modality, while NF-U has been used also in HDF modality, with optimal result in terms of efficacy and safety (albumin loss).