Franz diffusion cells

In many cases, transdermal drug absorption is investigated using a Franz-diffusion cell. The concentrations both in the membrane and the acceptor compartment are assumed to be zero at the start of the experiment. At different time points, the cumulative drug amount per unit area in the receptor q(t) is determined and plotted versus time t (Figure 20.1). After some time, the flux... 

Figure 20.1 Plotting cumulative amount versus time in a Franz-diffusion cell experiment results in a curve approaching a straight line.

Franz diffusion cells apparatus (Crown Glass Company Inc., NJ), constant temperature water bath (Yamato Scientific Co. Ltd., Japan) and spectrophotometer (Shimadzu Siesakusho Ltd, Japan)... 

The in vitro diffusion studies for each sample were carried out by using the Franz diffusion cells with a diffusional area of about 1.76cm2. The acceptor compartment of the apparatus was filled with the buffer solution pH 6, USP [21], and maintained at 37 0.5°C via a circulating water system. The diffusion membrane (the cellulose membrane with a molecular weight cut-off point of 1000 or the hairless mouse skin) previously prepared was placed between die donor and the acceptor compartments of the assembly. An accurately weighed 4g of sample was then placed in the donor cell and the diffusion process was started. The solution in the acceptor compartment was continuously stirred with a small magnetic stirrer to maintain the sink conditions. Aliquots from the receptor cells were removed at 0.5,2,4, 8 and 24 h time intervals and replaced with equal... 

Franz diffusion cells (FDC) remain the workhorse of all permeation experiments in transdermal studies. FDCs use the permeation of a solute, assessed by high pressure liquid chromatography (HPLC) or radiation, to evaluate the effect of penetration... 

Figure 5 Plot of conductivity enhancement ratios (ERs) in INSIGHT at 24 hours versus permeability ERs in FDC for 12 enhancer formulations. A strong linear correlation indicates the validity of observations in INSIGHT when compared with those from traditional tools such as FDC. Abbreviations. INSIGHT, in vitro skin impedance guided high-throughput screening FDC, Franz diffusion cell.

VALIDATION OF IN VITRO SKIN IMPEDANCE GUIDED HIGH-THROUGHPUT SCREENING WITH FRANZ DIFFUSION CELLS... 

Different kinds of diffusion cell apparatus have been used in such in vitro experiments. Some of these are small volume diffusion cells as described by Grass and Sweetana [44], Using chambers [45] and Franz diffusion cells [46]. 

A modified Franz diffusion cell has been developed in our laboratory in order to simultaneously measure the amount of drug released by diffusion from a semisolid formulation and the amount of drug washed away by a fluid stream simulating the removal action exerted by... 

Bonferoni, M.C., et al. 1999. A modified Franz diffusion cell for simultaneous assessment of drug release and washability of mucoadhesive gels. Pharm Dev Technol 4 45. 

A variant of this simple apparams is that shown in Fig. 12.8 based on the Franz diffusion cell, which has been used to measure the release rate of tacrolimus from an ointment. ... 

Franz Diffusion Cells (FDC-6, Logans Instrument, Somerset, NJ). 

Before launching wound study, the ability of ATP-vesicles to penetrate the tissue was tested in skin penetration. The rat skin, which is known to have similar permeability characteristics as those of humans (19), was mounted in the FDC-6 Franz Diffusion Cells (26-28). ATP-vesicles or free ATP solution was placed in the donor dome and the receiving chamber was filled with neutral buffer. ATP, ADP, AMP and their metabolites were measured by HPLC using a modified technique described previously (29-31) in the two chambers at 2, 4, and 24 h and the contents were compared to obtain the permeability ratio. The result indicated that the ATP-vesicles dramatically increased nucleotide penetration through the skin (dermis and epidermis) by 10-20-fold (N=9, Fig. 5). 

In another study, Suedee et al. [45] used cellulose tris A -(3,5-dimethylphenyl carbamate) -(R3 or CDMPC) to study the permeation of racemic and R and S enantiomers of propranolol across human skin using Franz diffusion cell assembly. Enantioselectivity was observed in the permeation rates of the R and S pure enantiomers (Fig. 7) where the R S flux ratio was approximately 2. In contrast, the flux ratio from the racemate was only 1.2 (Fig. 8). However, the R S flux ratio approximated 1 in the controlled experiments in which CDMPC was absent, suggesting no inherent enantioselectivity in the permeation of propranolol across human skin (Fig. 9). Enantiomeric purity of the enantiomers was also confirmed, and no racemization was observed during the study. Solubility values of the enantiomers were equal but much higher than the racemate, and melting points of the enantiomers were accordingly lower than the racemate. The authors postulated that the observed differences in the permeation of... 

Another interesting application important to the pharmaceutical industry is the measurement of the absorption profile of drugs through the skin. This application is normally accomplished through the use of a Franz diffusion cell (FDC) with quantification by HPLC. IMS methods are more rapid than and compared well with HPLC results when the transdermal analyses of ibuprofen were made. Using IMS, the skin permeability coefficient was found to be 0.013 cm/h, which matched those determined using HPLC. 

Baert, B. Van Steelandt, S. De Spiegeleer, B., Ion mobility spectrometry as a high-throughput technique for in vitro transdermal Franz diffusion cell experiments, J. Pham. Biomed. Anal. 2011,55,472-478. 

The penetration of CysA in the skin and its percutaneous delivery were assessed in an in vitro model of porcine ear skin using a Franz diffusion cell. The quantity of CysA detected in SC and in the epidermis and dermis layers [E + D] was indicative of drug penetration into the skin, whereas the amount of drug in the receptor phase was indicative of its percutaneous dehvery. The in vitro skin penetration and percutaneous delivery of the cubic and hexagonal liquid crystalline phases compared to the control formulation (ohve oil) containing CysA are depicted in Fig. 12.16. 

The effect of these peptides on skin permeation efficiency was determined by diffusion experiments of Na-DFC through porcine skin using Franz diffusion cells. All systems were composed of Hn mesophases loaded with 1 wt% Na-DFC and 1 wt% of each CPP (the control was a system with Na-DFC and no CPP). These experiments indicated that all three peptides increased significantly the diffusion of Na-DFC through the skin. 

Skin penetration and gentamicin release from the antibiotic/polymer complexes was measured in vitro by Franz diffusion cell technique [26]. The gentamicin release was studied in 500 ml of phosphate-buffered saline (PBS, pH 7.4) at 37° C in a mild shaking environment (75-100 r.p.m.). Aliquots of 3 ml were assayed for graitamicin at the time points of 0, 0.25,0.5, 0, 75,1,2,3,4, 5,6,12 and 24 h. For assessment of the quantity of gentamicin sul te released, HPLC (High-performance liquid chromatogr hy) method has been used. 

Figure 5 Schematic diagram of Franz diffusion cell. (Reprinted from Ref. 108 with permission.)...

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