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The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution.

Pellach M, Margel S - Chem Cent J (2011)

Bottom Line: Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems.We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system.Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Bar-Ilan University, Ramat Gan 52900, Israel. shlomo.margel@mail.biu.ac.il.

ABSTRACT
Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character.The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

No MeSH data available.


Related in: MedlinePlus

A scheme explaining the increased solubility of fluorescein in organic solvents and in water. In the organic phase the hydrogen bonds depicted can "protect" the hydrophilic hydroxyl groups, and in the aqueous phase, the salts formed are soluble.
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Figure 2: A scheme explaining the increased solubility of fluorescein in organic solvents and in water. In the organic phase the hydrogen bonds depicted can "protect" the hydrophilic hydroxyl groups, and in the aqueous phase, the salts formed are soluble.

Mentions: Fluorescein has been of great interest to the scientific community due to its interesting chemical properties, its high quantum yield, availability and low costs, as well as its lack of toxicity and approval for in vivo clinical applications [12-14]. Fluorescein is an organic fluorescent molecule with molecular weight 332.3 Da, consisting of 3,6-Dihydroxyxanthane, of which the hydroxyl groups give the molecule lipophobic character and two hydrogen bond (H-bond) donors, and phthalolactone, which despite the H-bond acceptors, is largely hydrophobic (structure shown in Figure 2). It is soluble in acetone, slightly soluble in ethanol, but not significantly soluble in other common organic solvents or in (neutral) water [15]. As well as the lipophobic and hydrophobic properties, lack of solubility may be attributed to the pi-stacking interactions between the fluorescein molecules, also held together by H-bonding between hydroxyl groups.


The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution.

Pellach M, Margel S - Chem Cent J (2011)

A scheme explaining the increased solubility of fluorescein in organic solvents and in water. In the organic phase the hydrogen bonds depicted can "protect" the hydrophilic hydroxyl groups, and in the aqueous phase, the salts formed are soluble.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285059&req=5

Figure 2: A scheme explaining the increased solubility of fluorescein in organic solvents and in water. In the organic phase the hydrogen bonds depicted can "protect" the hydrophilic hydroxyl groups, and in the aqueous phase, the salts formed are soluble.
Mentions: Fluorescein has been of great interest to the scientific community due to its interesting chemical properties, its high quantum yield, availability and low costs, as well as its lack of toxicity and approval for in vivo clinical applications [12-14]. Fluorescein is an organic fluorescent molecule with molecular weight 332.3 Da, consisting of 3,6-Dihydroxyxanthane, of which the hydroxyl groups give the molecule lipophobic character and two hydrogen bond (H-bond) donors, and phthalolactone, which despite the H-bond acceptors, is largely hydrophobic (structure shown in Figure 2). It is soluble in acetone, slightly soluble in ethanol, but not significantly soluble in other common organic solvents or in (neutral) water [15]. As well as the lipophobic and hydrophobic properties, lack of solubility may be attributed to the pi-stacking interactions between the fluorescein molecules, also held together by H-bonding between hydroxyl groups.

Bottom Line: Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems.We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system.Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Bar-Ilan University, Ramat Gan 52900, Israel. shlomo.margel@mail.biu.ac.il.

ABSTRACT
Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character.The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

No MeSH data available.


Related in: MedlinePlus