Preparation, characterization and release behavior of chitosan-coated nanoliposomes (chitosomes) containing olive leaf extract optimized by response surface methodology

Abstract

This study was dedicated to the optimization and preparation of chitosan-coated liposomes (chitosomes) as promising nanocarriers for retention of olive leaf extract optimized by Response surface methodology (RSM) based on central composite design. Accordingly, the best sample was chosen for further tests with the encapsulation efficiency, stability and electrical conductivity of 94%, 98% and 9.545 mS respectively. The average size of the optimal chitosome and nanoliposome were lower than 100 nm and the zeta potential was altered from a negative charge to positive after addition coating process with chitosan. Moreover, the differential scanning calorimetry of blank and loaded chitosome revealed the increase of fluidity and lower temperature of phase transition in loaded chitosome compared to blank one. FTIR spectra demonstrated that electrostatic interactions and hydrogen bonds occur between phospholipid polar groups, chitosan amine moieties and major olive leaf extract polyphenols including oleuropein and hydroxy tyrosol. Furthermore, the optimal loaded chitosome had the highest stability during 25 days at the temperature of 4 °C. Finally, the in vitro release tests were best fitted with Peppas-Sahlin and Kopcha models in food simulants and gastrointestinal simulated juice respectively revealing erosion-based release model.

Supplementary information: The online version contains supplementary material available at (10.1007/s13197-021-04972-2).

Keywords: Chitosome; Olive leaf extract; Optimization; Release; Response surface methodology.

Fig. 1

Surface plot of the a effect of extract and ultrasonication power on E.E., b extract and ultrasonication power, c extract and chitosan content, d ultrasonication power and chitosan content on the stability of chitosomes and e extract and ultrasonication power, f chitosan content and extract and g chitosan and ultrasonication power on the conductivity of chitosomes

Fig. 2

a Transmission electron microscopy (TEM), b field emission electron microscopy (FESEM) micrographs and c atomic force microscopy (AFM) images of chitosomes loaded with OLE

Fig. 3

FTIR spectra of blank nanoliposome olive leaf extract blank chitosome and chitosome loaded with OLE

Fig. 4

Leakage rates of the optimal loaded chitosome and liposome during storage at 4 °C and 25 °C for 25 days. The values are recorded as mean ± standard deviation (n = 3)

Fig. 5

In vitro release profile of the optimal OLE-loaded chitosome in a aqueous food simulant (AFS), b fatty food simulant (FFS), c simulated gastric juice (SGJ) and d simulated intestinal juice (SIJ)