Formulation and characterization of doxorubicin nanovesicles

Abstract

Ascorbyl palmitate formed vesicles in combination with cholesterol and a negatively charged lipid (dicetyl phosphate). Niosomes were prepared by the film hydration method, followed by sonication, in which aqueous doxorubicin solution (in phosphate buffer saline pH=7.4) was encapsulated in aqueous regions of lipid layers. Vesicle’s formation was confirmed by either scanning electron microscopy images or observation of unsonicated vesicles by light microscope. The percent efficiencies of doxorubicin encapsulation of the different formulations were determined by fluorescence spectrophotometry. Cholestrol content in niosomes did not exhibit any relation to vesicle size, zeta potential, percent entrapment, or release rate. Differential scanning calorimetric data of pure lipids, vesicle dispersion, and mixture of lipids confirmed the formation of niosomes.

Investigation of Formulation Variables and Excipient Interaction on the Production of Niosomes

“…7d was the flash point of Span 40. The melting points of each sample were compatible with literature data (23)(24)(25)(26). The physical mixture composed of PCT, DCP, cholesterol, and span 40 showed an endothermic peak of DCP at 77.57°C demonstrating that DCPs' crystal structure was protected (Fig.…”

Effect of Process Factors on the Properties of Doxycycline Nanovesicles

“…Previously reported DSC scans of AP, Ch and DCP showed melting endotherms at 116, 149 and 82 ºC, respectively [16]. DSC scans of various anhydrous fatty mixtures (AP, Ch and DCP) are shown in Fig.3A.…”

“…The first peak is due to simple melting of eutectic mixture and this was followed by three other peaks; the first two peaks could related to mesospheric transition, or may be smectic or cholestric phases. It was shown earlier [16] that with increase in Ch concentration in lipid mixture, an increase in the area of the fourth peak was observed which could be related to pure Ch. Increase in Ch concentration slightly decreased the main transition temperature.…”

“…Increase in Ch concentration slightly decreased the main transition temperature. The liquid crystalline state is a prerequisite for the formation of vesicles [16]. The DSC results show evidence for the formation of liquid crystals with ascorbyl palmitate, cholesterol and DCP anhydrous mixture.…”

“…If the zeta potential falls below a certain level, the emulsion droplets or colloids will aggregate as a result of the attractive forces. Conversely, a high zeta potential (either positive or negative), typically more than 30 mV, maintains a stable system [16].…”