Disposition of orally administered a promising chemotherapeutic agent flavopiridol in the intestine

Analytical Quality-by-Design-Based Systematic Optimization of RP-HPLC Method Conditions to Analyze Simultaneously Chloroquine Phosphate and Flavopiridol in Stress-Induced Combined Drug Solution and Pharmaceutical Emulsions

A design of experiments (DoE)-driven RP-HPLC method conditions was employed to analyze simultaneously chloroquine (CQ) phosphate and flavopiridol (FLAP) in emulsions and solution. After subjecting the various critical method attributes to preliminary risk assessment and screening by Pareto-chart-based fractional factorial design, the 17 runs were produced in Box-Behnken design for optimization. Analysis of variance, lack of fit, prediction equations, 3D response surface plots and contour plots were used to evaluate the critical analytical attributes such as retention time, tailing factor and theoretical plate count. The optimized RP-HPLC method conditions include 262 nm as detection wavelength, 37°C temperature for column, 20-μl injection volume, 1-ml/min flow rate and mobile phase mixture [70:30 ratio of 0.4% triethylamine in methanol&sodium phosphate buffer (11 mM, pH 3.0)]. The studied validation parameters were found within the ICH-prescribed limits. Exposing the combined drug solution at oxidative stress condition resulted to diminish the FLAP recovery value (53.39 ± 0.86) and arrival of an extra chromatographic peak. However, the % drug entrapment efficiency values of 96.22 ± 2.47 and 85.86 ± 3.66, respectively, were noticed for CQ phosphate and FLAP in emulsions. Thus, DoE-driven approach could be helpful for systematically optimizing RP-HPLC method conditions.

Sodium cholate-enhanced polymeric micelle system for tumor-targeting delivery of paclitaxel

PURPOSE

Polymeric micelles are attractive nanocarriers for tumor-targeted delivery of paclitaxel (PTX). High antitumor efficacy and low toxicity require that PTX mainly accumulated in tumors with little drug exposure to normal tissues. However, many PTX-loaded micelle formulations suffer from low stability, fast drug release, and lack of tumor-targeting capability in the circulation. To overcome these challenges, we developed a micellar formulation that consists of sodium cholate (NaC) and monomethoxy poly (ethylene glycol)-block-poly (d,l-lactide) (mPEG-PDLLA).

METHODS

PTX-loaded NaC-mPEG-PDLLA micelles (PTX-CMs) and PTX-loaded mPEG-PDLLA micelles (PTX-Ms) were formulated, and their characteristics, particle size, surface morphology, release behavior in vitro, pharmacokinetics and in vivo biodistributions were researched. In vitro and in vivo tumor inhibition effects were systematically investigated. Furthermore, the hemolysis and acute toxicity of PTX-CMs were also evaluated.

RESULTS

The size of PTX-CMs was 53.61±0.75 nm and the ζ-potential was -19.73±0.68 mV. PTX was released much slower from PTX-CMs than PTX-Ms in vitro. Compared with PTX-Ms, the cellular uptake of PTX-CMs was significantly reduced in macrophages and significantly increased in human cancer cells, and therefore, PTX-CMs showed strong growth inhibitory effects on human cancer cells. In vivo, the plasma AUC0-t of PTX-CMs was 1.8-fold higher than that of PTX-Ms, and 5.2-fold higher than that of Taxol. The biodistribution study indicated that more PTX-CMs were accumulated in tumor than PTX-Ms and Taxol. Furthermore, the significant antitumor efficacy of PTX-CMs was observed in mice bearing BEL-7402 hepatocellular carcinoma and A549 lung carcinoma. Results from drug safety assessment studies including acute toxicity and hemolysis test revealed that the PTX-CMs were safe for in vivo applications.

CONCLUSION

These results strongly revealed that NaC-mPEG-PDLLA micelles can tumor-target delivery of PTX and enhance drug penetration in tumor, suggesting that NaC-mPEG-PDLLA micelles are promising nanocarrier systems for anticancer drugs delivery.

Increased Intestinal Absorption of Genistein by Coadministering Verapamil in Rats

Combination of genistein (GT) and verapamil, a P-glycoprotein (P-gp) inhibitor, can increase GT absorption in situ perfusion technology in rat. To date, little information is yet available about the effect of verapamil on oral absorption of GT in vivo. In this study, a simple and reproducible HPLC-UV method was developed and validated for determination of total GT in rat plasma. Based on this, a pharmacokinetic experiment was designed to characterize biopharmaceutical properties of GT with or without coadministration of verapamil (10.0, 20.0, 30.0 mg/kg) in rats. The coadministration of verapamil (30.0 mg/kg) with GT caused a significant increase of the maximum GT plasma concentration (1.31-fold vs. GT, P < 0.05) and area under the curve (1.39-fold vs. GT, P < 0.05). Our data show that verapamil would increase intestinal absorption of GT in rat, suggesting there is some drug-nutrition interaction between verapamil and GT.

Anti prostate cancer using PEGylated bombesin containing, cabazitaxel loading nano-sized drug delivery system

CONTEXT

Prostate cancer (PCa) is the second most-frequently diagnosed cancer in men. Cabazitaxel was approved for the treatment of patients with hormone-refractory metastatic prostate cancer previously treated with a docetaxel-containing regimen.

OBJECTIVE

In this study, bombesin (BN), a ligand reported to specifically target GRP overexpressing prostate tumor, was applied for the construction of lipid-polymer hybrid nanoparticles (LPNs), and used for the targeted delivery of cabazitaxel (CAB) to prostate cancer.

METHODS

BN-polyethylene glycol-1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (BN-PEG-DSPE) was synthesized. CAB loaded, BN-PEG-DSPE contained LPNs (BN-CAB-LPNs) were prepared. Their particle size, zeta potential and drug encapsulation efficiency (EE) were evaluated. In vitro cytotoxicity study of BN-CAB-LPNs was tested in LNCaP human prostatic cancer cell line (LNCaP cells). In vivo anti-tumor efficacy of the carriers was evaluated on mice bearing prostate cancer model.

RESULTS

The optimum BN-CAB-LPNs formulations had a particle size of 184.9 nm and a 26.5 mV positive surface charge. The growth of LNCaP cells in vitro was obviously inhibited. BN-CAB-LPNs also displayed better anti-tumor activity than the other formulations in vivo.

CONCLUSION

The results demonstrated that BN-CAB-LPNs can sufficiently deliver CAB to the cancer cells and enhance the anti-tumor capacity. Thus, BN-CAB-LPNs can be proved to be a superior nanomedicine which can achieve better therapeutic efficacy of prostate tumor.

Interactions of cyclin-dependent kinase inhibitors AT-7519, flavopiridol and SNS-032 with ABCB1, ABCG2 and ABCC1 transporters and their potential to overcome multidrug resistance in vitro

PURPOSE

ATP-binding cassette (ABC) transporters play an important role in multidrug resistance (MDR) toward anticancer drugs. Here, we evaluated interactions of cyclin-dependent kinase inhibitors (CDKi) AT-7519, flavopiridol and SNS-032 with the following ABC transporters in vitro: P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2) and multidrug resistance-associated protein 1 (ABCC1).

METHODS

Inhibitory potency of studied CDKi to the transporters was evaluated by accumulation assays using fluorescent substrates and MDCKII cells overexpressing human ABCB1, ABCG2 or ABCC1. Resistance of transporter-expressing cells to the CDKi was evaluated by XTT proliferation assay. Observed interactions of CDKi were verified by ATPase assay in ABC transporter-expressing Sf9 membrane vesicles. Combination index analysis was additionally performed in ABC transporter-expressing cancer cell lines, HepG2 and T47D.

RESULTS

Flavopiridol showed a significant inhibitory potency toward ABCG2 and ABCC1. SNS-032 also decreased ABCG2-mediated efflux, while AT-7519 failed to inhibit ABCB1, ABCG2 or ABCC1. Both flavopiridol and SNS-032 showed synergistic antiproliferative effects in combination with relevant ABC transporter substrates such as daunorubicin and topotecan in cancer cells. ABCB1 was found to confer significant resistance to AT-7519 and SNS-032, but not to flavopiridol. In contrast, ABCG2 and ABCC1 conferred resistance to flavopiridol, but not to AT-7519 and SNS-032.

CONCLUSION

Our data provide detailed information on interactions of flavopiridol, SNS-032 and AT-7519 with ABC transporters, which may help elucidate the pharmacokinetic behavior and toxicity of these compounds. Moreover, we show the ability of flavopiridol and SNS-032, but not AT-7519, to overcome ABC transporter-mediated MDR.