Development of arsenic trioxide sustained-release pellets for reducing toxicity and improving compliance.

Arsenic trioxide (ATO) is first-line drug for acute promyelocytic leukemia. Clinically, the continuously slow intravenous infusion is adopted to maintain effective blood concentration and reduce toxic effects, but it causes poor patient' compliance for a considerable infusion period. To overcome these disadvantages, we developed an oral ATO sustained-release preparation which was constructed via the ATO core pellets prepared by extrusion spheronization and followed by a coating membrane by fluid-bed technology. The prepared coated pellets displayed a round surface and uniform particle size. All in vitro release profiles of ATO pellets in different pH media and rotation speeds had no statistical difference. Importantly, the coated pellets can release completely in 12 h without obvious burst release. There was no distinct change in appearance and release behaviors in stability experiments. In vivo pharmacokinetics was studied by one-time intragastric administration of rats. Compared with free drug, the AUC0-∞ of the ATO coated pellets was 2.3-fold higher, indicating the oral bioavailability was significantly increased. Cmax decreased by about a half and Tmax extended about 15 h. In particularly, the ATO level at 96 h only decreased about 20% of Cmax , suggesting that the ATO sustained-release preparation could not only decrease the peak concentration, but also maintain a relatively constant blood concentration for a long period. Further, the in vivo absorption could be well predicted by in vitro release experiments. Therefore, the ATO sustained-release preparation formulated by the mature preparation technology, possessing satisfactory stability and improving bioavailability, had great application potentials for industrialization.

Efficiency of Different Treatment Regimens Combining Anti-tumor and Anti-inflammatory Liposomes for Metastatic Breast Cancer.

Nanomedicines such as liposomes have been widely exploited in the treatment of tumors, and are also involved in combination therapies to enhance anti-tumor efficacy and reduce side effects. However, few studies have systematically discussed the significance and optimized regimens for nanomedicine-based combination therapy. In this study, we used anti-inflammatory and anti-tumor liposomes for co-administration, and compared three regimens: intermittent, metronomic, or sequential administration (IA, MA, and SA). The anti-inflammatory liposome HA/TN-CCLP was constructed in our previous research, which co-loaded curcumin (CUR) and celecoxib (CXB), modified with TAT-NBD peptide (TN) and finally coated with hyaluronic acid (HA), thereby inhibiting NF-κB and STAT3 pathways in the treatment of metastatic breast cancer. Furthermore, doxorubicin liposomes with and without TN modification (namely TN-DOXLP and DOXLP) were constructed and administrated with HA/TN-CCLP. The anti-tumor and anti-metastasis efficacy of different regimens was investigated. Results showed that in vitro cytotoxicity of DOXLP and TN-DOXLP was significantly enhanced when combined with HA/TN-CCLP. In vivo experiments also revealed the superiority of three combination therapies in inhibiting tumor growth, prolonging the survival of tumor-bearing mice, inducing apoptosis, and reducing lung metastases. In particular, the combination therapy could reduce MDSCs (Gr-1+/CD11b+) and CSCs (CD44+/CD24+) infiltration, which are two important factors in tumor metastasis and recurrence. Among three regimens, sequential administration (SA) showed the best therapeutic outcome and was especially effective for the inhibition of CSCs. In general, the results demonstrated that combination therapy, particularly the sequential administration of anti-inflammatory and anti-tumor liposome, was superior to monotherapy in inhibiting the development and metastasis of inflammation-related tumors.

Tumor-permeable smart liposomes by modulating the tumor microenvironment to improve the chemotherapy.

Low levels of accumulation and permeability in tumors are two primary reasons for the limited efficacy of conventional antineoplastic nanodrugs. In the present study, based on an original corosolic acid liposome (CALP) carrier with the functions of cell penetration, tumor permeability and anti-inflammation developed by our previous work, a versatile PTX/CALP was achieved by CALP loading paclitaxel (PTX). Compared to conventional PTX liposomes (PTX/LP) prepared by cholesterol and phospholipid, PTX/CALP exhibited extremely increasing cellular uptake and cytotoxicity in vitro, and in vivo enhancing the accumulation and permeability of tumor, thus significantly improving the antitumor efficacy. Further evidence indicated that PTX/CALP conspicuously promoted the recruitment of CD8+ T cells as well as reduced the infiltration of regulatory T cells and M2 macrophages into tumor by inducing enhanced immunogenic cell death (ICD) and down-regulating the inflammation level. Therefore, the improvement of efficacy was also attributed to the superiorities of PTX/CALP in modulating the inflammatory and immunosuppressive tumor microenvironment. Overall, the smart PTX liposomes based on the multi-functional CALP carrier without any modification could overcome the harsh tumor biological barriers, enhance the induction of ICD and then achieve satisfactory efficacy, suggesting its promising potentials in industrial transfer and clinical application.

Macrophage-biomimetic anti-inflammatory liposomes for homing and treating of aortic dissection.

Aortic dissection (AD) is a life-threatening disease featured by the dissection of intimal layer and the formation of a blood-filled false lumen within the aortic wall. Recent studies revealed that the formation and progression of AD lesions is closely related to vascular inflammation and macrophage infiltration. However, the potential efficacy of anti-inflammatory therapy on the prevention and treatment of AD has not been extensively investigated. Herein, we proposed a biomimetic anti-inflammatory liposome (PM/TN-CCLP) co-loaded with curcumin and celecoxib (CC), modified with cell-penetrating TAT-NBD fusion peptide (TN), and further camouflaged by isolated macrophage plasma membrane (PM), as a potential nanotherapy for AD. In vitro results showed that PM/TN-CCLP exhibited low cytotoxicity and elevated cellular uptake by inflammatory macrophages, and prominently inhibited the transendothelial migration, inflammatory responses and ROS generation of macrophages. Moreover, the PM/TN-CCLP treatment significantly prevented the H2O2-induced smooth muscle cell apoptosis. In vivo experiments were performed on the acute and chronic AD mouse models, respectively. The results verified the elevated accumulation of PM-camouflaged liposome at the aorta lesions. Further, the anti-inflammatory liposomes, especially PM/TN-CCLP, could reduce the rupture rate of dissection, prevent the loss of elastic fibers, and reduce MMP-9 expression as well as macrophage infiltration in the aortic lesions. Notably, as compared with free drugs and TN-CCLP, the PM/TN-CCLP treatment displayed the longest survival period along with the minimal aortic injury on both acute and chronic AD mice. Taken together, the present study suggested that the macrophage-biomimetic anti-inflammatory nanotherapy would be a promising strategy for the prevention and therapy of aortic dissection.

A practical strategy to subcutaneous administered in-situ gelling co-delivery system of arsenic and retinoic acid for the treatment of acute promyelocytic leukemia.

Arsenic trioxide (ATO) combined with all trans retinoic acid (ATRA) is the first choice for the treatment of low and medium risk acute promyelocytic leukemia (APL). Clinical studies reported that the combination of ATO and ATRA could achieve a significant curative effect. However, the retinoic acid syndrome, serious drug resistance and the short half-life in vivo which lead to frequent and large dose administration limit the application of ATRA. In addition, the preparations of arsenic are conventional injections and tablets in clinic, which has poor patients' compliance caused by frequent long-term administration and serious side effects. In order to overcome the above limitations, a phospholipid phase separation gel (PPSG) loaded with ATO and ATRA was developed. ATO+ATRA-PPSG (AAP), as a biodegradable sustained-release delivery system, was the first achievement of co-delivery of hydrophilic ATO and lipophilic ATRA with high drug loading which is the main problem in the application of nano preparation. The prepared PPSG displayed high safety and biocompatibility. The drug in PPSG was released slowly and continuously in vivo and in vitro for up to 10 d, which could reduce the side effects caused by the fluctuation of blood drug concentration and solve the problem of the long treatment cycle and frequent administration. In vivo pharmacokinetics depicted that PPSG could improve the bioavailability, decrease the peak concentration, and prolong the t1/2 of ATO and ATRA. Particularly, AAP significantly inhibited the tumor volume, extended the survival period of tumor-bearing mice, and promoted the differentiation of APL cells into normal cells. Therefore, ATO+ATRA-PPSG not only could co-load hydrophilic ATO and lipophilic ATRA according to the clinical dosage, but also possessed the sustained-release and long-acting treatment effect which was expected to reduce administration time and ameliorate compliance of patients. Thus, it had great potential for clinical transformation and application.

Cell-penetrating corosolic acid liposome as a functional carrier for delivering chemotherapeutic drugs.

Corosolic acid (CA), a natural pentacyclic triterpenoid, exhibits antitumor and synergistic therapy effect with chemotherapeutic drugs mainly through inhibiting STAT3 activation. In this study, it is found that CA possesses cholesterol-like properties in liposome by regulating membrane phase behavior to form stable cholesterol-free CA liposomes (CALP). Compared with traditional cholesterol liposomes (CHOLP), CALP exhibit stronger membrane fusion and higher cellular uptake, and other functions including inhibition of STAT3 activation and suppression of the recruitment of macrophages to tumor microenvironment. Therefore, CALP is used as a functional carrier, and doxorubicin-loaded CALP (DOX/CALP) based on PEGylated liposomal doxorubicin (DOXILⓇ) are prepared by replacing its cholesterol with CA. The physicochemical properties and biological activities are compared with those of doxorubicin-loaded cholesterol liposomes (DOX/LP). Both DOX/CALP and DOX/LP possess approximately similar physical properties and exhibit high stability and low drug leakage as shown by the published data of DOXILⓇ. Nevertheless, it is noteworthy that DOX/CALP displays higher in vitro cellular uptake and tumor spheroid permeation along with stronger cytotoxicity against tumor cells than DOX/LP. Despite DOX/CALP has the same PK parameters, normal tissue biodistribution, and safety profile as DOX/LP, the results of an in vivo study in 4T1-bearing mice indicate that the DOX/CALP treatment group exhibit higher tumor accumulation, more significant tumor growth inhibition, and longer life span than the DOX/LP group. Overall, DOX/CALP is a representative example of CA-doped liposomes, suggesting that CALP as a functional drug carrier for solving low efficacy of present liposomal drugs might have promising application potential. STATEMENT OF SIGNIFICANCE: An original drug delivery nanocarrier, corosolic acid liposome (CALP), was developed in this study. It was found that CA possesses cholesterol-like function to regulate phospholipid membrane phase behavior. By replacing the cholesterol with CA, the liposomes were converted into high cellular uptake carriers, possessing anti-inflammatory activity and synergism with chemotherapeutic drugs. The variability of CALP formulations enabled to deliver therapeutic agents. The use of CALP to deliver doxorubicin not only significantly enhanced the therapeutic efficacy compared with the classic PEGylated liposomal doxorubicin, but also maintained the improved safety. Because CALP can be obtained by conventional liposome preparation methods, its use as functional drug carriers for solving low efficacy of present liposomal drugs would have promising application potential.