ET AAS evaluation of the stability and pH-sensitivity of, pH-sensitive stealth liposomes containing cisplatin in mouse plasma

The effect of free and encapsulated cisplatin into long-circulating and pH-sensitive liposomes on IEC-6 cells during wound healing in the presence of host-microbiota

OBJECTIVES

To circumvent cisplatin (CDDP) toxic effects and improve the antitumoural effect, our research group developed long-circulating and pH-sensitive liposomes containing CDDP (SpHL-CDDP). This study aimed to evaluate whether SpHL-CDDP is associated with intestinal protection under in-vitro conditions in the presence of host-microbiota, compared with free CDDP.

METHODS

The cytotoxicity of CDDP and SpHL-CDDP were evaluated by colorimetric MTT and sulforhodamine B (SRB) assays. Epithelial proliferation was assessed by using an in-vitro wounding model in the presence of host-microbiota with intestinal epithelial cell line 6 (IEC-6) monolayers. Cytokines were determined by ELISA.

KEY FINDINGS

Reduced cytotoxicity of SpHL-CDDP in IEC-6 cells (minimum of 1.3-fold according to the IC50 values) was observed when compared with CDDP. The presence of microbiota or CDDP reduced the wound healing. The association of microbiota and SpHL-CDDP improved the wound healing and cell number in IEC-6 cells when compared with control. These beneficial results can be associated with increased IL-6 and IL-10 levels induced by SpHL-CDDP which were affected by the presence of microbiota.

CONCLUSIONS

These results indicate that the presence of microbiota associated with SpHL-CDDP provided less intestinal cellular damages compared with CDDP and constitutes a promising candidate for clinical use.

Analytical methods for the quantification of cisplatin, carboplatin, and oxaliplatin in various matrices over the last two decades

Background:

Platinum derivatives including cisplatin and its later generations carboplatin, and oxaliplatin remain the most largely used drugs in the therapy of malignant diseases. They exert notable anticancer activity towards numerous types of solid tumors such as gastric, colorectal, bladder, ovary, and several others. The chemotherapeutic activity of these compounds, however, is associated with many unwanted side effects and drug resistance problems limiting their application and effectiveness. Proper dosage is still an inherent problem, as these drugs are usually prescribed in small doses.

Objective:

Several analytical methods have been reported for the accurate quantification of cisplatin, carboplatin, and oxaliplatin and their metabolites either alone or in combination with other chemotherapeutic drugs, in different matrices such as pharmaceutical formulations, biological fluids, cancer cells, and environmental samples. The main goal of this review is to systematically study the analytical methods already used for the analysis of cisplatin, carboplatin, and oxaliplatin in various matrices during the last two decades.

Results and Conclusion:

In the literature, reviews showed that numerous analytical methods such as electroanalytical, UV-visible spectrophotometry, chromatographic, fluorescence, atomic absorption spectrophotometry, and other spectroscopic methods combined with mass spectrometry were used for the determination of these compounds in various matrices.

Co-Encapsulation of Fisetin and Cisplatin into Liposomes for Glioma Therapy: From Formulation to Cell Evaluation

(1) Background: Glioblastoma (GBM) is the most frequent cerebral tumor. It almost always relapses and there is no validated treatment for second-line GBM. We proposed the coencapsulation of fisetin and cisplatin into liposomes, aiming to (i) obtain a synergistic effect by combining the anti-angiogenic effect of fisetin with the cytotoxic effect of cisplatin, and (ii) administrate fisetin, highly insoluble in water. The design of a liposomal formulation able to encapsulate, retain and deliver both drugs appeared a challenge. (2) Methods: Liposomes with increasing ratios of cholesterol/DOPC were prepared and characterized in term of size, PDI and stability. The incorporation of fisetin was explored using DSC. The antiangiogneic and cytotoxic activities of the selected formulation were assayed in vitro. (3) Results: We successfully developed an optimized liposomal formulation incorporating both drugs, composed by DOPC/cholesterol/DODA-GLY-PEG2000 at a molar ratio of 75.3/20.8/3.9, with a diameter of 173 ± 8 nm (PDI = 0.12 ± 0.01) and a fisetin and cisplatin drug loading of 1.7 ± 0.3% and 0.8 ± 0.1%, respectively, with a relative stability over time. The maximum incorporation of fisetin into the bilayer was determined at 3.2% w/w. Then, the antiangiogenic activity of fisetin was maintained after encapsulation. The formulation showed an additive effect of cisplatin and fisetin on GBM cells; (4) Conclusions: The developed co-loaded formulation was able to retain the activity of fisetin, was effective against GBM cells and is promising for further in vivo experimentations.

pH-responsive artemisinin dimer in lipid nanoparticles are effective against human breast cancer in a xenograft model

Artemisinin (ART), a well-known antimalaria drug, also exhibits anticancer activities. We previously reported a group of novel dimeric artemisinin piperazine conjugates (ADPs) possessing pH-dependent aqueous solubility and a proof-of-concept lipid nanoparticle formulation based on natural egg phosphatidylcholine (EPC). EPC may induce allergic reactions in individuals sensitive to egg products. Therefore, the goal of this report is to develop ADP-synthetic lipid particles suitable for in vivo evaluation. We found that ADP binds to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) with greater than 90% efficiency and forms drug-lipid particles (d ∼ 80 nm). Cryo-electron microscopy of the ADP drug-lipid particles revealed unilamellar vesicle-like structures. Detailed characterization studies show insertion of the ADP lead compound, ADP109, into the DPPC membrane and the presence of an aqueous core. Over 50% of the ADP109 was released in 48 hours at pH4 compared with less than 20% at neutral. ADP109-lipid particles exhibited high potency against human breast cancer, but was tolerated well by nontumorigenic cells. In MDA-MB-231 mouse xenograft model, lipid-bound ADP109 particles were more effective than paclitaxel in controlling tumor growth. Cellular uptake studies showed endocytosis of the nanoparticles and release of core-trapped marker throughout the cytosol at 37°C. These results demonstrate, for the first time, the in vivo feasibility of lipid-bound ART dimer for cancer chemotherapy.

Improvement of the antiproliferative effect of rapamycin on tumor cell lines by poly (monomethylitaconate)-based pH-sensitive, plasma stable liposomes

pH-responsive polymers produce liposomes with pH-sensitive property which can release their encapsulated drug under mild acidic conditions found inside the cellular endosomes, inflammatory tissues and cancerous cells. The aim of this study was preparing pH-sensitive and plasma stable liposomes in order to enhance the selectivity and antiproliferative effect of Rapamycin. In the present study we used PEG-poly (monomethylitaconate)-CholC6 (PEG-PMMI-CholC6) copolymer and Oleic acid (OA) to induce pH-sensitive property in Rapamycin liposomes. pH-sensitive liposomal formulations bearing copolymer PEG-PMMI-CholC6 and OA were characterized in regard to physicochemical stability, pH-responsiveness and stability in human plasma. The ability of pH-sensitive liposomes in enhancing the cytotoxicity of Rapamycin was evaluated in vitro by using colon cancer cell line (HT-29) and compared with its cytotoxicity on human umbilical vein endothelial cell (HUVEC) line. Both formulations were found to release their contents under mild acidic conditions rapidly. However, unlike OA-based liposomes, the PEG-PMMI-CholC6 bearing liposomes preserved their pH-sensitivity in plasma. Both types of pH-sensitive Rapamycin-loaded liposomes exhibited high physicochemical stability and could deliver antiproliferative agent into HT-29 cells much more efficiently in comparison with conventional liposomes. Conversely, the antiproliferative effect of pH-sensitive liposomes on HUVEC cell line was less than conventional liposomes. This study showed that both OA and PEG-PMMI-CholC6-based vesicles could submit pH-sensitive property, however, only PEG-PMMI-CholC6-based liposomes could preserve pH-sensitive property after incubation in plasma. As a result pH-sensitive PEG-PMMI-CholC6-based liposomal formulation can improve the selectivity, stability and antiproliferative effect of Rapamycin.