Study on the stabilization mechanisms of wet-milled cepharanthine nanosuspensions using systematical characterization

Can the cavi-precipitation process be exploited to generate smaller size drug nanocrystal?

OBJECTIVE

Cavi-precipitation has the potential to generate drug nanocrystals very efficiently. Achieving smaller than 100 nm particle size for organic drug substances still remained a challenge. The objective of this study was to demonstrate if cavi-precipitation technology can be used to generate smaller than 100 nm drug nanocrystal particle.

SIGNIFICANCE

This study demonstrates that cavi-precipitation process can be used to generate drug nanocrystals of the model compound resveratrol (RVT) consists of crystallites of 30-50 nm size.

METHOD

RVT was dissolved in different organic solvents to prepare the solvent phase (S-phase). Several stabilizers were tested for the organic phase. A combination of SDS and PVP was used stabilizer system in the aqueous anti-solvent phase (AS-phase). The S-phase was added to the AS-phase inside the Emulsiflex C5 homogenizer. Nanosuspension was characterized by laser diffractometry (LD), photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). The solid state of the suspended particles was investigated by powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC).

RESULTS

It was found that DMSO, alone or in combination with acetone in the S-Phase generated the smallest size RVT nanocrystals. The optimum solvent (S) antisolvent (AS) ratio (S:AS) was found to be 3.6:56.4 (v:v). Span 20 was identified as the best stabilizer for the organic phase at a ratio (w:w) of 1:3 (Span 20:RVT). The particles precipitated from different solvents were predominantly crystalline.

CONCLUSIONS

The best sample had a mean particle size (LD) of 167 nm [d(0.5)] which was composed of smaller crystallites having 30-50 nm size (SEM).

Preparation and characterisation of tetrandrine nanosuspensions and in vitro estimate antitumour activity on A549 lung cancer cell line

Aim: The aim of this study was to improve solubility and antitumour ability in vitro of tetrandrine (Tet) via preparing nanosuspensions (NSs).Methods: The Tet-NSs were prepared by wet media milling. The Tet-CCS-NS was prepared with croscarmellose sodium (CCS) as single stabiliser. The Tet-HACC-TPGS-NS was manufactured with D-α-tocopheryl polyethylene glycol 1,000 succinate (TPGS) and hydroponically trimethyl ammonium chloride chitosan (HACC) as combined stabilisers. Physicochemical properties of the NSs such as particle size, surface morphologies, crystallinity and molecular interactions were investigated. In addition, the in vitro dissolution and antitumour activities using A549 human lung cancer cells were evaluated.Results: The mean particle sizes and Zeta potential of freshly prepared Tet-CCS-NS, Tet-HACC-TPGS-NS were 469.1 ± 14nm and 157.3 ± 5nm, -29.4 ± 0.26 mV and 23.3 ± 0.36 mV, respectively. In comparison to pure Tet, the cumulative dissolution of Tet-NSs were increased by 4 ∼ 5 times in 2 h. In vitro antitumour studies on Tet- NSs in A549 cells, the cell survival rate of the Tet-NSs at high concentration (30-50µg/ml) were less than 10% within 48 h. Meanwhile, Tet-NSs were revealed to induce A549 cells apoptosis and promote cell uptake.Conclusion: The present study has proved that the Tet-NSs can increase Tet solubility as well as improve Tet antitumour activity in vitro.