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The Phoenix™ Dry Heat Diffusion Cells deliver improved ease of use, high durability, and greater versatility compared to conventional hand-blown vertical diffusion cells. Phoenix cells operate using dry heat, eliminating the need for water jacketing.
This allows construction from heavy-duty borosilicate glass with tight dimensional tolerances. The large-diameter opening in the sampling arm enables extract-and-replace sampling with standard pipette tips (~300 μL). This simplifies the sampling process while reducing training and operating costs.
Features of the Dry Heat Diffusion Cells
Powerful Mixing
Special grooves machined into the tops and sides of the mixer inserts creates strong circulation and nearly instant homogenization of cell contents. This design prevents localized regions of higher API concentration beneath the membrane, reducing test variability. This ensures the accuracy and consistency needed for permeability testing.
Test Preparation
Phoenix cells are quick to set up. Dosage forms are applied through an easily accessible opening in the cell cap, with no clamps required. Bubbles can be easily detected and removed by simply lifting the cell and tipping it to one side. This streamlined setup simplifies permeability testing and makes the process more efficient.
Chemical Compatibility
The Phoenix press-on cell cap is made from polyether ether ketone (PEEK) and sealed with Viton™ O‑rings (fluor elastomer). The threaded cell cap is made from polytetrafluoroethylene (PTFE) and can be sealed with either Viton or Kalrez™ (perfluoro elastomer) O-rings. This offers higher compatibility with aggressive solvents such as THF and DMSO.
Diffusion Cell Design
The most important feature of any laboratory testing instrument is its ability to deliver results that are both accurate and precise. Accuracy ensures that results reflect the true value, while precision ensures consistency across repeated tests. Variability, the enemy of precision, arises from inconsistencies in the test instrument, the procedure, or the materials being tested.
With these factors in mind, the Phoenix dry heat diffusion cell is designed to minimize instrument variability and reduce potential procedural inconsistencies (operator error). Drawing on 30 years of experience with manual and automated diffusion cell systems, the Phoenix cell is more durable and easier to operate. The system delivers significantly better test results.
Constructed from precision-bore tubing similar to that used in barrel syringes, each borosilicate glass cell is dimensionally consistent. The generous 9 mm internal diameter of the sampling arm promotes rapid homogenization of receptor media. It allows the use of standard pipette tips to reduce costs. Standard 16 mm evaporation caps fit onto the flanged end of the sampling arm.
- Phoenix cells are durable, portable, quick to assemble, and easy to clean
- Three interchangeable cell cap kits are designed to work with each cell
- Slotted evaporation caps prevent media loss while allowing manual pipette sampling or automated probe sampling
- Convenient fill mark indicates when receptor media has reached the level of the membrane
Receptor Media Volume Adjustment
Phoenix diffusion cells let analysts adjust the receptor media volume simply by changing the mixer insert. For example, using the short mixer-insert (13 mm height) maximizes the available volume for a particular cell size.
The tall mixer insert (30 mm height) reduces the volume while still enabling sampling from the center of the cell’s main body, as specified in USP <1724> Semisolid Drug Products—Performance Tests.
This flexibility is especially useful for permeability testing, providing precise control over test conditions.
