Liposome concentration

Ma et al. [129] prepared a new pharmaceutical form, primaquine-liposome and determined the toxicity and the therapeutic efficacy of the primaquine liposome in mice. The LD50 of intravenous primaquine-liposome in mice was 2 3 times less than that of free primaquine. Primaquine liposome concentration in blood was higher... 

Talsma shows that peak 2 changes only from -39.8 °C to —40.4 °C (liposomes, liposomes concentration, buffer and cooling speed as in (I), but no mannitol) if the liposomes size is decreased from 0.87 pm to 0.14 pm. With small liposomes, the start of the homogeneous crystallization is delayed. This can also be deduced from the weakly performed crystallization (Fig. 3.19 (d), peak 3), if mannitol is only within the liposome. 

Fig. 4.17 Signal broadening (Avlj/2, mm) of various spin systems of chlorphentermine (a-c) at constant liposome concentration (1.2mg/mL) as a function of increasing NaCI concentration (0-6 mg/mL). The lowest symbols at zero NaCI concentration represent the control line width of the different proton resonance signals in the absence of both lecithin liposomes and NaCI. (Reprinted from Fig. 4 of ref. 135 with permission from Elsevier Science.)...

Determine the amount of RNA needed to obtain a 10-50 nM final concentration in the well for transfection. It is also possible to experimentally test several concentrations or N/P ratios in this step. The liposome concentration can be kept constant while varying the RNA amounts of visa versa (51). 

The molar ratio of cationic liposome to nucleic acid determines the proportion of electrostatic neutralization, which reflects the entire surface charge and the size of resulting lipoplexes (13). Therefore, lipoplex formation should be affected by experimental variables such as nucleic acid/cationic liposome concentration, time and medium for the complexation, the number and/or order of addition steps, and the presence of serum during lipoplex formation. In this section, we will present instructions to form lipoplexes and discuss the most important aspects to be considered in siRNA- or pDNA-lipoplex formation. 

Calculate the required volume of cationic liposome concentrated stock according to desired N/P ratio, and the total volume required before preparing the dilutions. 

It is not recommended to use culture medium in cationic liposome concentrated stock. They are composed of a mixture of essential salts, nutrients, and buffering agents that will inhibit the complex formation ability of siRNA and pDNA. 

Weigh each rat before treatment to calculate the group dose. Injection volume (-250 pi) is calculated with the average group body weight and the liposome concentration of 20 pmol total lipid/kg body weight. 

The basic characterization of the liposomes revolves around size determination, usually by DLS, and sample liposome concentration by phosphorous assay, neither of which will be described here. Indeed, the procedures of the DLS experiments highly depend on the type of apparatus used, while the Bartlett colorimetric assay of phosphorous content has frilly been described elsewhere (12-14). 

Optimizations-. Determine which hybridization buffer composition yields the least background and strongest signal (prepare hybridization buffers consisting of 0.2% (w/v) Ficoll Type 400, 0-10x SSC in 2x increments, and 0-30% (v/v) formamide in 5% increments, see Note 6), vary incubation time and temperature (5, 10, and 20min at 23°C or 41°C is recommended), and vary liposome concentrations. 

Doxorubicin Commercially available as a stable, lyophilized liposomal formulation rv administered liposomes concentrate in fenestrated capillaries such as liver, spleen, and the bone marrow. IV doxorubicin liposomes have been shown to reduce its cardiotoxicity... 

The quantity of lipid exchanged per milligram of protein was independent of the liposome concentration when the latter was in excess. In contrast, at low liposome concentrations, the quantity of lipid exchanged per milligram of protein increased with increasing liposome concentration. 

Add the liposomes directly into the RM compartment of the CECF reaction. For an initial screening, final liposome concentrations of 2-A mg/ml may be used (see Note 20). 

Fig. 2. Examples of the dynamin I colorimetric GTPase assay. (A) L-a-phosphatidyl-L-serine (PS) liposome concentration curve. Stimulation of dynamin I GTPase activity was measured as a function of PS concentration using the colorimetric assay. The curve reaches a plateau at about 30 /xg/ml PS in this experiment, but varies between PS preparations. The curve is representative of the level of optimal dynamin activity in the absorbance range 0.4-0.6 OD units. (B) Concentration-dependent effect of compound A on dynamin I GTPase activity stimulated by 40 /xg/ml PS. The effect of the drug alone at increasing concentrations is shown in the open bars. The stimulation by PS + Compound A is shown in the hatched bars. Compound A reduces PS-stimulated dynamin I GTPase activity (hatched bars), until at high concentrations there appears to be stimulation. The solid bars show a subtraction of the other values, which, after eliminating the effect of background phosphate, reveals the full inhibitory curve of compound A.

Paramagnetic liposomes can also act as very efficient T2 susceptibility agents. The typical transverse relaxivity values have been estimated from 10 to 10 mM s referred to the liposome concentration for 7 T and 298 K. These values make them comparable in efficacy to the gold standard iron-oxide nanoparticles. 

Figure 2 Effects of KCl (A) and liposome (B) concentrations on the SQS activity. The enzyme activity was determined in the absence and in the presence of 0.1, 0.2 and 0.5 M KCl. Different liposome concentrations (PC from 10 to 75pg) were added to the incubation medium containing 0.2 or 0.5M KCl.

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