Retention profiles

Several groups investigated the use of liposomes for the intra-pulmonary delivery. Farr et al. (1985) showed that the deposition of aerosolized liposomes in the human lung depends on the aerosol particle size. Short-term retention profiles for MLVs and SUVs deposited in the lung were indicative of clearance via the mucociliary transport mechanism. 

Ethylene oxide sterilized laonofilaments of copolymer II-A and a poly(p-dioxanone) were compared in terms of their in-vivo absorption and BSR (breaking strength retention) profiles. The BSR and absorption studies were conducted in rats according to the procedures described elsewhere. The comparative data of these studies are given in Table V. 

A similar cell-retention profile was also observed on the surface of poly [iV-methyl-lV-(4-vinylphenethyl)ethylenediamine(AVEMA)-co-HEMA] (HAV) [115]. 

Filtrate volume (mL) Figure 5.1. Filter retention profile. 

These retention profiles could be described by the following equation as a function of eluent pH and analyte [54],... 

Thus, a reference polymer imprinted with benzylamine, as a stationary phase, was prepared and used to validate the model. pH-curves of the product of solute and MIP ionization (a a ) and of the retention profiles of benzylamine and (/ ,S)-(1) on the benzylamine-selective cationic-imprinted polymer stationary phase showed excellent agreement (see Fig. 9.29b). 

In addition to the usual ligands described above, selective ligands for a series of metal ions can be introduced. An example is the ligand 8-hydroxyquinolin (oxine). Figure 12 shows the retention profiles of the complexation of poly(ethylenimin)-oxine with Fe(III) ions at different pH, when compared to the properties of the precursor poly(ethylenimin). 

The retention profiles of the water-soluble polymer the poly (ethylenediamine tetra-acetic acid-co-lactose) clearly show that the polymer has a strong binding ability for iron and chromium, as it exhibited a strong metal complexation with Cr(III) and Fe(III) with retention values of 100%. In contrast, Co(II), Ni(II), Cu(II), Zn(II), Sr(III), Cd(II), Pb(II), and Al(III) showed lower retention values (20-80%). Thus, the enrichment of Cr(III) and Fe(III) from the other metal ions can be achieved. 

Figure 16. Retention profiles of poly(ethylenediamine tetraacetic acid-co-lactose) (1 wt%)...

Because of (a) the overlaps of the spectral and retention time vectors, and (b) the noise in the data, there will in general be a r2utge of possible K s which can transform the U and V sets to sets with all-positive elements. Thus the estimates for the spectral vectors will have some degree of ambiguity in them. The exact degree of uncertainty has been shown to be dependent on the degree of overlap of the spectra and retention profiles and whether there are regions in the time, detector... 

We now come to the most difficult (and prevalent I ) analytical situation where one has a mixture of unresolved components in the chromatogram, some of which are known u1d some of which are unknown. In this case, one wishes to (a) quantitate the knowns and (b) obtain the spectra and retention profiles of the unknowns for qualitative identification. We believe that "Rank Annihilation", developed by Davidson (30), is an excellent approach to performing this type of analysis. The technique can be described qualitatively as follows. The data is assumed to be represented by Equation 13. Thus, the rank of M is equal to the number of components, both knowns and unknowns. Now, suppose that we have for the kth cos nent, a calibration matrix Then, if we subtract the correct amount of from M, the... 

Figure 6. A. Retention profile for the B. Retention profile for the second mixture.

The results from the decon sition of these data into their three con nents is Illustrated in Figure 12 B-D. The absorption spectrum and the retention profiles along the x juid y axes are all shown for each of the three components. The spectra obtained superimposed nearly exactly on those of the pure components. 

Segmented Copolyesters with Prolonged Strength Retention Profiles... 

Composition of the amorphous initiator for the polyaxial crystalline systems can be easily adjusted to provide biomaterials for constructing devices with a broad range of strength retention profiles. 

Greisler and co-workers have examined the use of commercial absorbable fibers for the production of absorbable vascular grafts. Using multifilament yam of 90/10 poly(glycolide-co-/-lactide) and monofilaments of poly-p-diox-anone to produce totally absorbable grafts was shown to be impractical. This is because of the insufficient strength retention profile of these grafts postoperatively. 

Using Equations 9.9 and 9.6 in the MDPE, one can solve for and graphically interpret the retentate profile for a specified CS. 

Hexane and a Cig column [654] were conditions also used for this separation. A triphenyl colunm (A = 320 run) and a hexane mobile phase were used to study the temperature effects on the retention of fullerenes. For the range of 30-70°C, little or no change in the retention profile occurred [655]. Unlike the study presented above, mixtures of 5-15% ethyl elher in pentane on a phenyl colutiui (A = 330run) successfully separated Cgo and C70 fullerenes but could not separate the higher molecular weight species [656]. Plots of bA versus percent ethyl er in pentane were shown for Cso and C70 fullerenes. 

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