Filter tests membrane characterization

The apparams equipped with Sunflower CeRam Inside (23-8-1178), characterized in Table 30.10, was used in pilot plant tests. The plant consisted of feed tank (1) equipped with cooler (2) membrane module housing (3) pretreatment filters (4) pressrue pump TONKAFLO (5) circulating pump Grandfos (6) non-return valve (7) two needle valves and four ball valves (Figure 30.14). 

The sieve effect is based on the difference between the particle size and the pore size of the filter. A typical NF membrane lies in the range of 150-500 Da (weight in grams of mole of the molecule i.e., the molecular weight of the smallest molecule that can be 90% restricted by the top layer of the manbrane). NF membranes are characterized by the retention of charged and neutral particles tested by experimental filtration tests with preselected molecules (see Table 2.2). 

From a methodological point of view, tite PAMPA-BBB system is quite simple. The lipids, dissolved in dodecane, are soaked with a filter mounted in a two-compartment chamber. The drug is added to the donor compartment (which can be either the upper or lower chamber), and its passage through the artificial membrane is measured in the acceptor compartment (Fig. 14.17). A standard compound with well-characterized permeability proper-hes (e.g., verapamil) is tested in parallel. Compounds that readily cross the blood-brain barrier have an in vitro permeability (P,) > 2.7 10" cm s in the PAMPA assay. On the opposite, drugs with low blood-brain barrier permeation have a < 0.710 cm s". Beside... 

Ceramic membranes can be characterized in terms of pore size, pore size distribution, interfacial area, tortuosity, etc. Various tests are carried out to obtain information on the above such as bubble point, SEM, mercury porosimetry, etc. Currently industry uses mercury intrusion porosimetry to characterize pore size distribution. Since mercury cannot differentiate between open and blind pores (closed at one end), mercury porosimetry does not generate the size distribution of pores available for flow. In pennoporometry the pores are first filed with a liquid and then the liquid in the pores available for flow is expelled with a second fluid. Since liquid expulsion is unidirectional, this gives an accurate representation of e quality of the filter [63]. 

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