Soy phosphatidylcholine

Soy phosphatidylcholine (SPC) was obtained from L. Meyer, Hamburg, Germany. Cholesterol (Fluka AG, Buchs, Switzerland) was recrystallized... 

In contrast to the conventional emulsions or macroemulsions described earlier are the disperse systems currently termeraiicroemulsions. The term was Lrst introduced by Schulman in 1959 to describe a visually transparent or translucent thermodynamically stable system, with much smaller droplet diameter (6-80 nm) than conventional emulsions. In addition to the aqueous phase, oily phase, and surfactant, they have a high proportion of a cosurfactant, such as an alkanol of 4-8 carbons or a nonionic surfactant. Whereas microemulsions have found applications in oral use (as described in the next chapter), parenteral use of microemulsions has been less common owing to toxicity concerns (e.g., hemolysis) arising from the high surfactant and cosolvent levels. In one example, microemulsions composed of PEG/ethanol/water/medium-chain triglycerides/Solutol HS15/soy phosphatidylcholine have been safely infused into rats at up to 0.5 mL/kg. On dilution into water, the microemulsion forms a o/w emulsion of 60-190 nm droplet size (Man Corswant et al., 1998). 

MPEG = methyl PEG HSPC = hydrogenated soy phosphatidylcholine DSPG = disteroylphosphatidyl-glycerol DOPC = dioleoylphosphatidylcholine DPPG = dipalmitoylphosphatidylglycerol. 

Hydrogenated soy phosphatidylcholine (HSPC) Distearoylphosphatidylglycerol (DSPG) L-a-Dimyristoylphos-phatidylcholine (DMPC) L-a-Dimyristoylphos-phatidylglycerol (DMPG) Phosphatidylglycerol... 

Phospholipids are essential components of cell membranes and liposomes, which are closed spherical vesicles with an inner aqueous core and an outer shell composed of phospholipid bilayer membranes. Depending on the level of hydrophobicity, moderately hydrophobic drugs can be solubilized by liposomes if the drug becomes encapsulated or intercalated within the liposome. The phospholipids in commercially available injectable formulations include hydrogenated soy phosphatidylcholine, dimyristoylphosphatidyl-choline, egg phosphatidylglycerol, distearoylphospha-tidylglycerol, and dimyristoylphosphatidylglycerol. 

Soy phosphatidylcholine (SPG, >98% purity) (Lipoid, Ludwigshafen, Germany). Store at -20 °C. Unfreeze in an exsiccator before us. 

The basic composition for the preparation of 5.0 mL liposomes was 1.0 g soy phosphatidylcholine (SPC, L. Meyer GmbH, Hamburg, Germany), 125 mg cholesterol (Fluka, Buchs, Switzerland) (see Note 1) and 6 mg D,L-a-tocopherol (Merck, Darmstadt, Germany) as antioxidant. 

Lipids are mixed together and solvent is removed using freeze-drying. Then an aqueous solution is introduced and the hpid cake around the vessel wall is reconstituted. This method works best for manufacture of neutral liposomes, as the hydro-phobic lipids readily dissolve in solvents such as chloroform and are deposited dry on the wall of the rotavapor vessel. Then the material to be encapsulated is dissolved in an aqueous solution and the dry film on the vessel wall is hydrated with this solution. The exact steps involved in the preparation of hydrogenated soy phosphatidylcholine (PHSPC)- and cholesterol-containing vesicles at a molar ratio of 60 to 40% are as listed here ... 

The antiviral activity of the oil obtained from Artemisia arborescens L was also studied by Sinico et al. (2005). They studied the influence of vesicle structure and composition on the antiviral activity, against herpes simplex virus type 1 (HSV-1), of the vesicle-incorporated oil, multilamellar vesicles (MLV), and small unilamellar vesicles (SUV) positively charged liposomes prepared by the film method and sonication. The liposomal incorporation of A. arborescens EO enhanced the in vitro antiherpetic activity mainly when vesicles were made with hydrogenated soy phosphatidylcholine. 

Amphotericin B liposome for injection Hydrogenated soy phosphatidylcholine, cholesterol, distearoylphosphatidylglycerol. Treatment of visceral leishmaniasis [264]... 

Figure 1.6. Doxorubicin in tumour-bearing mice, either as the free drug (open symbols/dashed lines) or in liposomes consisting of distearoylphosphatidylethanolamine-PEO/hydrogenated soy phosphatidylcholine/cholesterol (0.2 2 1 mol/mol) (filled symbols/continuous lines) (data from ref. (57))...

Hydrogenated soy phosphatidylcholine-cholesterol-BST liposomes injected into dairy cattle increased weekly milk production (Weiner et al, 1989). 

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