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In situ precipitation: a novel approach for preparation of iron-oxide magnetoliposomes.

Xia S, Li P, Chen Q, Armah M, Ying X, Wu J, Lai J - Int J Nanomedicine (2014)

Bottom Line: Single-factor analysis and orthogonal-design experiments were applied to determinate the effects of alkalization pH, temperature, duration, and initial Fe concentration on encapsulation efficiency and drug loading.The iron-oxide cores were confirmed as Fe3O4 by X-ray diffraction and demonstrated a superparamagnetic response.In situ precipitation could be a simple and efficient approach for the preparation of iron-oxide magnetoliposomes.

View Article: PubMed Central - PubMed

Affiliation: Yiwu Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People's Republic of China.

ABSTRACT

Background: Conventional methods of preparing magnetoliposomes are complicated and inefficient. A novel approach for magnetoliposomes preparation was investigated in the study reported here.

Methods: FeCl3/FeCl2 solutions were hydrated with lipid films to obtain liposome-encapsulated iron ions by ultrasonic dispersion. Non-encapsulated iron ions were removed by dialysis. NH3·H2O was added to the system to adjust the pH to a critical value. Four different systems were prepared. Each was incubated at a different temperature for a different length of time to facilitate the permeation of NH3·H2O into the inner phase of the liposomes and the in situ formation of magnetic iron-oxide cores in the liposomes. Single-factor analysis and orthogonal-design experiments were applied to determinate the effects of alkalization pH, temperature, duration, and initial Fe concentration on encapsulation efficiency and drug loading.

Results: The magnetoliposomes prepared by in situ precipitation had an average particle size of 168±14 nm, zeta potential of -26.2±1.9 mV and polydispersity index of 0.23±0.06. The iron-oxide cores were confirmed as Fe3O4 by X-ray diffraction and demonstrated a superparamagnetic response. Encapsulation efficiency ranged from 3% to 22%, while drug loading ranged from 0.2 to 1.58 mol Fe/mol lipid. The optimal conditions for in situ precipitation were found to be an alkalization pH of 12, temperature of 60°C, time of 60 minutes, and initial Fe concentration of 100 mM Fe(3+) + 50 mM Fe(2+).

Conclusion: In situ precipitation could be a simple and efficient approach for the preparation of iron-oxide magnetoliposomes.

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Related in: MedlinePlus

The effect of alkalization pH.Abbreviations: Fe(t), the amount of total iron in the liposomes after alkalization; Fe(f), the amount of free iron ions in the liposomes after alkalization.
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f5-ijn-9-2607: The effect of alkalization pH.Abbreviations: Fe(t), the amount of total iron in the liposomes after alkalization; Fe(f), the amount of free iron ions in the liposomes after alkalization.

Mentions: The EE and drug loading reached their maximum at pH 12. The total Fe concentrations in liposomes after alkalization (Fe[t]) were very close at pH 10–12, but decreased significantly at pH 13. The free iron-ion concentrations in the liposomes (Fe[f]) decreased significantly as the pH increased (as shown in Table 1 and Figure 5).


In situ precipitation: a novel approach for preparation of iron-oxide magnetoliposomes.

Xia S, Li P, Chen Q, Armah M, Ying X, Wu J, Lai J - Int J Nanomedicine (2014)

The effect of alkalization pH.Abbreviations: Fe(t), the amount of total iron in the liposomes after alkalization; Fe(f), the amount of free iron ions in the liposomes after alkalization.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043714&req=5

f5-ijn-9-2607: The effect of alkalization pH.Abbreviations: Fe(t), the amount of total iron in the liposomes after alkalization; Fe(f), the amount of free iron ions in the liposomes after alkalization.
Mentions: The EE and drug loading reached their maximum at pH 12. The total Fe concentrations in liposomes after alkalization (Fe[t]) were very close at pH 10–12, but decreased significantly at pH 13. The free iron-ion concentrations in the liposomes (Fe[f]) decreased significantly as the pH increased (as shown in Table 1 and Figure 5).

Bottom Line: Single-factor analysis and orthogonal-design experiments were applied to determinate the effects of alkalization pH, temperature, duration, and initial Fe concentration on encapsulation efficiency and drug loading.The iron-oxide cores were confirmed as Fe3O4 by X-ray diffraction and demonstrated a superparamagnetic response.In situ precipitation could be a simple and efficient approach for the preparation of iron-oxide magnetoliposomes.

View Article: PubMed Central - PubMed

Affiliation: Yiwu Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People's Republic of China.

ABSTRACT

Background: Conventional methods of preparing magnetoliposomes are complicated and inefficient. A novel approach for magnetoliposomes preparation was investigated in the study reported here.

Methods: FeCl3/FeCl2 solutions were hydrated with lipid films to obtain liposome-encapsulated iron ions by ultrasonic dispersion. Non-encapsulated iron ions were removed by dialysis. NH3·H2O was added to the system to adjust the pH to a critical value. Four different systems were prepared. Each was incubated at a different temperature for a different length of time to facilitate the permeation of NH3·H2O into the inner phase of the liposomes and the in situ formation of magnetic iron-oxide cores in the liposomes. Single-factor analysis and orthogonal-design experiments were applied to determinate the effects of alkalization pH, temperature, duration, and initial Fe concentration on encapsulation efficiency and drug loading.

Results: The magnetoliposomes prepared by in situ precipitation had an average particle size of 168±14 nm, zeta potential of -26.2±1.9 mV and polydispersity index of 0.23±0.06. The iron-oxide cores were confirmed as Fe3O4 by X-ray diffraction and demonstrated a superparamagnetic response. Encapsulation efficiency ranged from 3% to 22%, while drug loading ranged from 0.2 to 1.58 mol Fe/mol lipid. The optimal conditions for in situ precipitation were found to be an alkalization pH of 12, temperature of 60°C, time of 60 minutes, and initial Fe concentration of 100 mM Fe(3+) + 50 mM Fe(2+).

Conclusion: In situ precipitation could be a simple and efficient approach for the preparation of iron-oxide magnetoliposomes.

Show MeSH
Related in: MedlinePlus