Preparation and Evaluation of Stearylamine-Bearing Pemetrexed Disodium-Loaded Cationic Liposomes In Vitro and In Vivo.

Pemetrexed disodium (PMX) stands out in the treatment of non-small cell lung cancer (NSCLC), but with short half-life and toxic side effects. This study was to design cationic liposomes for targeting delivery PMX to the lungs. The PMX cationic liposome was prepared by thin-film hydration using stearylamine (SA) as the positive component of charge-regulating charge. Then, the PMX cationic liposome (SA-PMX-Lips) was characterized by particle size, morphology, entrapment efficiency (EE), and drug loading (DL). Finally, the drug release behavior in vitro, the pharmacokinetic study, and tissue distribution of SA-PMX-Lips were evaluated separately, with PMX solution (PMX-Sol) and PMX liposome (PMX-Lips) as the control. According to results, SA-PMX-Lips were spherical and the particle size was 219.7 ± 4.97 nm with a narrow polydispersity index (PDI) (0.231 ± 0.024) and a positive zeta potential 22.2 ± 0.52 mV. Its EE was 92.39 ± 1.94% and DL was 9.15 ± 0.07%. The results of in vitro and in vivo experiments showed that SA-PMX-Lips released slowly, prolonged retention time and increased the value of AUC. More notably, SA-PMX-Lips could improve the accumulation of drugs in the lungs and the relative uptake rate (Re) was 2.35 in the lungs, which indicated its lung targeting. In summary, SA-PMX-Lips showed the potential for the effective delivery of PMX and the treatment of NSCLC.

Co-delivery of pemetrexed and miR-21 antisense oligonucleotide by lipid-polymer hybrid nanoparticles and effects on glioblastoma cells.

Combination therapy using anticancer drugs and nucleic acid is a more promising strategy to overcome multidrug resistance in cancer and to enhance apoptosis. In this study, lipid-polymer hybrid nanoparticles (LPNs), which contain both pemetrexed and miR-21 antisense oligonucleotide (anti-miR-21), have been developed for treatment of glioblastoma, the most aggressive type of brain tumor. Prepared LPNs have been well characterized by particle size distribution and zeta potential measurements, determination of encapsulation efficiency, and in vitro release experiments. Morphology of LPNs was determined by transmission electron microscopy. LPNs had a hydrodynamic size below 100 nm and exhibited sustained release of pemetrexed up to 10 h. Encapsulation of pemetrexed in LPNs increased cellular uptake from 6% to 78%. Results of confocal microscopy analysis have shown that co-delivery of anti-miR-21 significantly improved accumulation of LPNs in the nucleus of U87MG cells. Nevertheless, more effective cytotoxicity results could not be obtained due to low concentration of anti-miR-21, loaded in LPNs. We expect that the effective drug delivery systems can be obtained with higher concentration of anti-miR-21 for the treatment of glioblastoma.

Enhanced oral absorption of pemetrexed by ion-pairing complex formation with deoxycholic acid derivative and multiple nanoemulsion formulations: preparation, characterization, and in vivo oral bioavailability and anticancer effect.

OBJECTIVE: The current study sought to design an oral delivery system of pemetrexed (PMX), a multitargeted antifolate antimetabolite, by enhancing its intestinal membrane permeability. MATERIALS AND METHODS: PMX was ionically complexed with a permeation enhancer such as Nα-deoxycholyl-l-lysyl-methylester (DCK) and prepared as an amorphous solid dispersion by mixing with dispersants such as 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and poloxamer 188 (P188), forming an HP-beta-CD/PMX/DCK/P188; the complex was incorporated into multiple water-in-oil-in-water nanoemulsions in a supersaturated state (HP-beta-CD/PMX/DCK/P188-NE). RESULTS: After complex formation, the partition coefficient and in vitro membrane permeability of PMX were markedly increased, but it showed similar cytotoxic and inhibitory effects on cancer cell proliferation/migration. Furthermore, the intestinal membrane permeability and epithelial cell uptake of PMX were synergistically improved after HP-beta-CD/PMX/DCK/P188 was incorporated into a nanoemulsion with a size of 14.5±0.45 nm. The in vitro permeability of HP-beta-CD/PMX/DCK/P188-NE across a Caco-2 cell monolayer was 9.82-fold greater than that of free PMX, which might be attributable to the partitioning of PMX to the epithelial cells being facilitated via specific interaction of DCK with bile acid transporters, as well as the enhanced lipophilicity accompanied by surfactant-induced changes in the intestinal membrane structure and fluidity. Therefore, the oral bioavailability of HP-beta-CD/PMX/DCK/P188-NE in rats was evaluated as 26.8%±2.98% which was 223% higher than that of oral PMX. Moreover, oral HP-beta-CD/PMX/DCK/P188-NE significantly suppressed tumor growth in Lewis lung carcinoma cell-bearing mice, and the tumor volume was maximally inhibited by 61% compared with that in the control group. CONCLUSION: These results imply that HP-beta-CD/PMX/DCK/P188-NE is an effective and promising delivery system for enhancing the oral absorption of PMX. Thus, there is the potential for new medical applications, including applications in metronomic cancer treatment.

Encapsulation in a rapid-release liposomal formulation enhances the anti-tumor efficacy of pemetrexed in a murine solid mesothelioma-xenograft model.

We recently developed a PEG-coated liposome encapsulating the anti-folate drug pemetrexed (PMX). Such liposomal formulations have shown potent cytotoxic effects against malignant pleural mesothelioma (MPM) cells in vitro. In the present study, we investigated the pharmacokinetics, bio-distribution and in vivo anti-tumor efficacy of two liposomal PMX formulations with different drug release rates in a murine mesothelioma-xenograft model. Liposomes with different PMX release rates were prepared via manipulating liposomal membrane fluidity through incorporating either a solid-phase (HSPC) or a fluid-phase (POPC) phospholipid. Both liposomal PMX formulations showed prolonged plasma pharmacokinetics and were accumulated to a similar extent in tumors and other tissues, presumably, due to surface modification with polyethylene glycol (PEG). In a murine mesothelioma-xenograft model, interestingly, PMX encapsulated in a fast-release POPC liposome produced superior tumor growth suppression compared with either free PMX or PMX encapsulated in a slow-release HSPC liposome. Such in vivo anti-tumor efficacy was accomplished mainly by a potent induction of apoptosis within tumor tissue by the released PMX from POPC liposomes. Our results clearly emphasize the therapeutic efficacy of liposomal PMX over free PMX in conquering aggressive solid tumors such as malignant mesothelioma. A guarantee of the targeted delivery of PMX to tumor cells helps overcome some of the major shortcomings encountered with the use of free PMX.

Advanced therapeutic approach for the treatment of malignant pleural mesothelioma via the intrapleural administration of liposomal pemetrexed.

Malignant pleural mesothelioma (MPM) is an aggressive cancer that proliferates in the pleural cavity. Pemetrexed (PMX) in combination with cisplatin is currently the approved standard care for MPM, but a dismal response rate persists. Recently, we prepared various liposomal PMX formulations using different lipid compositions and evaluated their in vitro cytotoxicity against human mesothelioma cells (MSTO-211H). In the present study, we investigated the in vivo therapeutic effect of our liposomal PMX formulations using an orthotopic MPM tumor mouse model. PMX encapsulated within either cholesterol-containing (PMX/Chol CL) or cholesterol-free (PMX/Non-Chol CL) cationic liposome was intrapleurally injected into tumor-bearing mice. PMX encapsulated in cholesterol-free liposomes (PMX/Non-Chol CL) drastically inhibited the tumor growth in the pleural cavity, while free PMX and PMX encapsulated in cholesterol-containing liposomes (PMX/Chol CL) barely inhibited the tumor growth. The enhanced in vivo anti-tumor efficacy of PMX/Non-Chol CL was credited, on the one hand, for prolonging the retention of cationic liposomes in the pleural cavity via their electrostatic interaction with the negatively charged membranes of tumor cells, but on the other hand, it was charged with contributing to a higher drug release from the "fluid" liposomal membrane following intrapleural administration. This therapeutic strategy of direct intrapleural administration of liposomal PMX, along with the great advances in CL-guided therapeutics, might be a promising therapeutic approach to conquering the poor prognosis for MPM.

Synergistic activity of combination therapy with PEGylated pemetrexed and gemcitabine for an effective cancer treatment.

Combination therapy in cancer is now opted as a potential therapeutic strategy for cancer treatment. However, effective delivery of drugs in combination at the tumor site is marred by low bioavailability and systemic toxicity of individual drugs. Polymer therapeutics is indeed an upcoming approach for the combinational drug delivery in favor of better cancer management. Hence, the objective of our investigation was to develop a dual drug PEGylated system that carries two chemotherapeutic drugs simultaneously for effective treatment of cancer. In this regard, we have synthesized Pem-PEG-Gem, wherein pemetrexed (Pem) and gemcitabine (Gem) are conjugated to a heterobifunctional polyethylene glycol (PEG) polymer for the effective treatment of Non-Small Cell Lung Cancer (NSCLC). Our results demonstrate enhanced bioavailability of the individual drugs in Pem-PEG-Gem in comparison with the drugs in their native form. The developed Pem-PEG-Gem showed enhanced cell death with respect to their native counterparts when treated singly or in combination against NSCLC cells. This might be attributed to better cellular internalization through the process of macropinocytosis and synergistic cytotoxic action of Pem-PEG-Gem in NSCLC cells. Hence, we propose the above dual drug based polymer therapeutic approach suitable for better clinical application in the treatment of NSCLC.