PermeGear, Inc. manufactures Franz Cells, Side-Bi-Side cells, and related equipment for studying membrane transport and drug diffusion through biological and synthetic membranes. Applications include experimentation in the areas of drug discovery, drug transport, drug screening, controlled release, formulation optimization, dermatology, skin toxicology, oral absorption, buccal absorption, percutaneous absorption, equilibrium dialysis, and protein binding.
When deciding which type of diffusion cell system you need, or before running an experiment with your new diffusion cell or system, it is important to not only be familiar with the equipment but have a well-planned experimental protocol with clear objectives. What do you want to know about a particular compound or membrane? Does it matter which type of membrane you use? What membranes are available that will fit your needs? How will you interpret and present the results? There are many parameters to consider, and working out the details beforehand will reduce the number of failed attempts and produce consistency between experiments that is crucial when comparing results.
Diffusion is, by definition, the random movement of molecules through a domain driven by a concentration gradient, from high concentration to low concentration. In vitro diffusion is generally passive diffusion of a permeant from a vehicle in the donor chamber, through an artificial or biological membrane into a receptor fluid in a receptor chamber, disregarding delivery systems such as iontophoresis and microneedles. The permeant is the molecular species moving through or into the tissue/membrane. Permeation is the movement of the permeant through the membrane that encompasses first partitioning the membrane and then diffusion through the membrane. Penetration can occur into the membrane without necessarily diffusing, or passing through, the membrane.
Flux is the amount of permeant crossing a membrane per unit area into the circulating system per unit time, and for in vitro permeation this “system” is the receptor chamber, expressed in units of mass/ area/time. Similarly, accumulation is the amount of permeant crossing a membrane within a certain time, expressed in units of mass/area. Diffusivity is a property of the permeant and is a measure of how easily it penetrates a specific membrane expressed in units of area/time. The permeability coefficient (Kp) describes the rate of permeant penetration per unit concentration expressed in distance/time.
Medium size class has orifice diameters up to 25mm.
Largest class has orifice diameters between 15mm and 60mm.
In all classes of Side-Bi-Side Cells the volumes are dependent on orifice diameter and other factors.
In-Line Cells locate the membrane of interest in the horizontal plane and have donor chambers open to the air although occluded donor chambers are available.
Made from the plastic Kel-F (3M product) or Neoflon (Daikin product).
Most researchers will find the products they require within our standard diffusion cell offerings. Occasionally an experiment requires non-standard features. At PermeGear, we understand the varying technical needs of researchers and are almost always able to customize our cells to your specifications.