Self-assembled micelles based on gambogenic acid-phospholipid complex for sustained-release drug delivery.

Objective: To improve the water solubility and enhance the oral bioavailability of gambogenic acid (GNA). Methods: GNA-phospholipid complex (GNA-PLC) micelles were successfully prepared by anti-solvent method. Results: The encapsulation efficiency of GNA-PLC micelles can reach 99.33 % (w/w). The average particle size of the GNA-PLC micelles was 291.23 nm which was approximate agreed with the transmission electron microscopy (TEM). In vitro release profile showed the GNA-PLC and GNA-PLC micelles have significant sustained-release of GNA compared with crude GNA. Pharmacokinetic parameters indicated that the area under concentration-time curve (AUC0→t) of GNA in cases of GNA-PLC and GNA-PLC micelles are 2.04- and 3.92-fold higher than crude GNA, respectively. Conclusions: The better water solubility and higher bioavailability of GNA in GNA-PLC micelles with significant sustained-release of GNA endow the nanoparticle with great potential in GNA delivery system.

Preparation, preliminary pharmacokinetics and brain tissue distribution of Tanshinone IIA and Tetramethylpyrazine composite nanoemulsions.

Objective: Tanshinone IIA (TSN) and Tetramethylpyrazine (TMP) were combined in a composite, oil-in-water nanoemulsions (TSN/TMP O/W NEs) was prepared to prolong in vitro and vivo circulation time, and enhance the bioavailability of TSN. Material and methods: Physicochemical characterization of TSN/TMP O/W NEs was characterized systematically. The in vitro dissolution and in vivo pharmacokinetic experiments of TSN/TMP O/W NEs were also evaluated. Result: A formulation was optimized, yielding a 32.5 nm average particle size, an encapsulation efficiency of over 95 %, and were spherical in shape as shown by TEM. TSN/TMP O/W NEs were shown to extend the release and availability in vitro compared to raw compounds. In pharmacokinetic study, the AUC0→∞ and t1/2 of the TSN/TMP O/W NEs were 481.50 mg/L*min and 346.39 min higher than TSN solution, respectively. Brain tissue concentration of TSN was enhanced with TSN/TMP O/W NEs over raw TSN and even TSN O/W NEs. Conclusions: Therefore, nanoemulsions are an effective carrier to increase encapsulation efficiency of drugs, improve bioavailability and brain penetration for TSN - which is further enhanced by pairing with the co-delivery of TMP, providing a promising drug delivery.

In vitro/in vivo evaluation of pH-sensitive Gambogenic acid loaded Zein nanoparticles with polydopamine coating.

As one of the active pharmaceutical ingredients in Gamboge, Gambogenic acid (GNA) has shown diverse anti-tumor activities. To reduce the vascular irritation of GNA and improve its water solubility, tumor targeting, and bioavailability, GNA loaded Zein nanoparticles (GNA@Zein NPs) was further coated by polydopamine (PDA) to develop GNA@Zein-PDA NPs by anti-solvent precipitation and surface modification. The results showed that particle size and Zeta potential of GNA@Zein-PDA NPs were about 310 nm and -40.8 mV with core-shell morphology confirmed by TEM. GNA@Zein-PDA NPs increased the water solubility of GNA by more than 700 times and showed pH-sensitive release behavior in PBS with pH 6.86. In vitro cytotoxicity tests showed that GNA@Zein-PDA NPs had higher inhibitory activity on HepG2 cells than free GNA, and their IC50 were 1.59 µg/mL and 9.89 µg/mL, respectively. Additionally, the hemolysis and vascular irritation assay showed that GNA@Zein-PDA NPs had good cytocompatibility and reduced the irritation of GNA to blood vessels. Moreover, the in vivo pharmacokinetic experiments exhibited that the Cmax and AUC0-t of GNA@Zein-PDA NPs were significantly improved approximately by 2.09-fold and 3.48-fold over that of GNA, respectively. In conclusion, GNA@Zein-PDA NPs solve many defects of GNA and provide a tumor-targeting drug delivery for GNA.

Preparation, characterization and preliminary pharmacokinetic study of pH-sensitive Hydroxyapatite/Zein nano-drug delivery system for doxorubicin hydrochloride.

OBJECTIVES: Zein nanoparticles (Zein NPs) were used as a hydroxyapatite (HA) biomineralization template to generate HA/Zein NPs. Doxorubicin hydrochloride (DOX) was loaded on HA/Zein NPs (HA/Zein-DOX NPs) to improve its pH-sensitive release, bioavailability and decrease cardiotoxicity. METHODS: HA/Zein-DOX NPs were prepared by phase separation and biomimetic mineralization method. Particle size, polydispersity index (PDI), Zeta potential, transmission electron microscope, X-ray diffraction and Fourier-transform infrared spectroscopy of HA/Zein-DOX NPs were characterized. The nanoparticles were then evaluated in vitro and in vivo. KEY FINDINGS: The small PDI and high Zeta potential demonstrated that HA/Zein-DOX NPs were a stable and homogeneous dispersed system and that HA was mineralized on Zein-DOX NPs. HA/Zein-DOX NPs showed pH-sensitive release. Compared with free DOX, HA/Zein-DOX NPs increased cellular uptake which caused 7 times higher in-vitro cytotoxicity in 4T1 cells. Pharmacokinetic experiments indicated the t1/2ß and AUC0- t of HA/Zein-DOX NPs were 2.73- and 3.12-fold higher than those of DOX solution, respectively. Tissue distribution exhibited HA/Zein-DOX NPs reduced heart toxicity with lower heart targeting efficiency (18.58%) than that of DOX solution (37.62%). CONCLUSION: In this study, HA/Zein-DOX NPs represented an antitumour drug delivery system for DOX in clinical tumour therapy with improved bioavailability and decreased cardiotoxicity.

Synthesis, cytotoxicity and liver targeting of 3-O-ß-D-Galactosylated Resveratrol.

OBJECTIVES: Resveratrol (Res), a naturally occurring polyphenol, has shown pharmacological activities in treatment of liver diseases. However, the application of Res was limited by its poor bioavailability and liver targeting. Herein, 3-O-ß-D-Galactosylated Resveratrol (Gal-Res) was synthesized by structural modification of Res to enhance bioavailability and liver targeting. METHODS: The Gal-Res was characterized by IR, 1 H-NMR spectra and MS. The in vitro antitumour experiments, in vivo pharmacokinetics and biodistribution studies were evaluated. RESULTS: Gal-Res was successfully synthesized in our study. Compared to Res, Gal-Res resulted in enhanced cytotoxicity in HepG2 cells. After intravenous injection of normal SD rats, Gal-Res significantly improved the bioavailability of Res and the Cmax and AUC0-t of Gal-Res were 3.186 and 3.929 time than that of Res. In addition, in the study of liver targeting, the relative uptake rate (Re ) of Gal-Res in the liver (2.006) is the largest. The drug targeting efficiency (Te ; 38.924%) of Gal-Res was greater than that of Res. These showed that Gal-Res could significantly improve the distribution ability of Res in liver. CONCLUSIONS: On the whole, Gal-Res increased cellular uptake to HepG2 cells, bioavailability and liver targeting, providing its future clinical application in the treatment of liver diseases.

Preparation, physicochemical characterization and pharmacokinetics of paeoniflorin-phospholipid complex.

In order to enhance lipophilicity and oral bioavailability of paeoniflorin (PF), this study developed paeoniflorin-phospholipid complex (PF-PLC) by solvent-evaporation method. The optimum preparation technology of PF-PLC was screened by the combination of single factor and orthogonal experiment. The physicochemical properties of PF-PLC were evaluated via differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and oil-water partition coefficient study (lgP). The result of FTIR spectra indicated that there was some strong hydrogen bond interaction and good compatibility between the phospholipid molecule and PF in the complex. DSC and XRD structure analysis showed that PF was in form of amorphous structure in PF-PLC, and lgP of PF-PLC was enhanced, suggesting that the lipophilicity of PF-PLC was higher than that of PF. In vitro release of PF-PLC showed slower release than PF solution with its cumulative release rate of 93.81% at 24 h compared to 93.43% of PF at 1.5 h. In pharmacokinetic experiments, the AUC and Cmax of the PF-PLC were 1.97-fold and 2.5-fold higher than PF solution. These results suggested that PF-PLC could enhance lipophilicity and oral bioavailability of PF and provide a promising delivery system for the application of PF.

Preparation and preliminary pharmacokinetics study of GNA-loaded zein nanoparticles.

OBJECTIVES: Gambogenic acid (GNA), one of the main active ingredients isolated from Garcinia cambogia, has shown diverse antitumour activities. However, short biological half-life and low oral bioavailability severely limit its clinical application. Here, we developed GNA-loaded zein nanoparticles (GNA-ZN-NPs) based on phospholipid complex and zein nanoparticles to prolong the circulation time and enhance oral bioavailability of GNA. METHODS: The physicochemical properties of GNA-ZN-NP were characterized in details. The in vitro release profile, in vivo pharmacokinetic experiments and tissue distribution of GNA-ZN-NPs were also evaluated. KEY FINDINGS: The particle size, PDI and encapsulation efficiency of GNA-ZN-NPs were 102.90 nm, 0.027 and 76.35 ± 0.64%, respectively. The results of SEM, FTIR, DSC and XRD demonstrated that GNA-ZN-NPs were prepared successfully. The in vitro dissolution of GNA-ZN-NPs exhibited controlled release compared with raw GNA solution. The pharmacokinetic study showed that the AUC of GNA-ZN-NPs was significantly increased, and the t1/2 and MRT values of GNA-ZN-NPs were 3.21-fold and 2.19-fold higher than that of GNA solution. Tissue distribution results illustrated that GNA-ZN-NPs showed hepatic-targeting properties. CONCLUSION: GNA-ZN-NPs significantly enhanced the oral bioavailability and prolonged half-life of GNA, providing a promising oral drug delivery system to improve in vivo pharmacokinetic behaviour of GNA.

Preparation, preliminary pharmacokinetic and brain targeting study of metformin encapsulated W/O/W composite submicron emulsions promoted by borneol.

Metformin hydrochloride (Met) is the first-line drug to treat type 2 diabetes and has shown high efficiency in reducing Alzheimer's disease in recent studies. Herein, a borneol W/O/W composite submicron emulsion containing Met (B-Met-W/O/W SE) was prepared, expecting longer in-vivo circulation time, better bioavailability and brain targeting of Met drug. In the optimized formulation, the mean droplets size, polydispersity index and encapsulation efficiency of the composite were 386.5 nm, 0.219 and 87.26%, respectively. FTIR analysis confirmed that Met interacted with carriers in B-Met-W/O/W SE. Compared with Met free drug, in-vitro release of Met in B-Met-W/O/W SE delivery system was much slower. In pharmacokinetic studies in rats, the AUC, MRT and t1/2 of the B-Met-W/O/W SE system were respectively 1.27, 2.49 and 4.02-fold higher than Met free drug system. The drug-targeting index of B-Met-W/O/W SE system to the brain tissue was also higher than that of Met free drug system and Met-W/O/W SE system. These results indicated that B-Met-W/O/W SE drug delivery system is a promising candidate in treating clinical Alzheimer's disease.