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Photothermal therapy is a promising approach for antitumor application although regrettably restricted by available photothermal agents. Physical entrapment of organic near-infrared dyes into nanosystems was extensively studied to reverse the dilemma. However, problems still remained, such as drug bursting and leakage. We developed here an amphiphilic prodrug conjugate by chemically modifying indocyanine green derivative (ICG-COOH) and paclitaxel (PTX) to hyaluronic acid (HA) backbone for integration of photothermal-chemotherapy and specific tumor imaging. The prepared ICG-HA-PTX conjugates could self-assemble into nanomicelles to improve the stability and reduce systemic toxicity of the therapeutic agents. The high local concentration of ICG-COOH in nanomicelles resulted in fluorescence self-quenching, leading to no fluorescence signal being detected in circulation. When the nanomicelles reached the tumor site via electron paramagnetic resonance effect and HA-mediated active targeting, the overexpressed esterase in tumor cells ruptured the ester linkage between drugs and HA, achieving tumor-targeted therapy and specific imaging. A series of in vitro and in vivo experiments demonstrated that the easily prepared ICG- HA-PTX nanomicelles with high stability, smart release behavio r, and excellent tumor targeting ability showed formidable synergy in tumor inhibition, which provided new thoughts in developing an organic near-infrared-dye-based multifunctional delivery system for tumor theranostics.

Metastatic cancer is difficult to defeat with current treatments due to lack of etiological therapeutics and efficient delivery platforms. Employing tumor microenvironment in programming intelligent nanosystems has attracted considerable attention for combinative antitumor therapy. Herein, we proposed a core-shell based drug depot consisting of micellar core and crosslinked-gel shell for site-specific shuttling of paclitaxel (PTX) and KIAA1199 specific shRNA (shKIAA). Poly (e-caprolactone) were grafted with branched polyethylenimine (PEI-PCL) as micellar core, into which hydrophobic PTX was embedded; while shKIAA, a reliable RNAi regimen for metastatic cell inhibition was condensed with PEI through electrostatic interaction; and then photo-crosslinked hyaluronic acid (m-HA) was further coated as shell. The nanoscale drug depot shared HAase-triggered charge switching and desirable release profile. Upon reaching tumor region, HA shell was degraded by concentrated HAase, and facilitated drug shuttling to individual subcellular targeting site. Rapid intracellular trafficking of micellar core achieved endo/lysosomal escape and cytoplasmic liberation. The half-maximal inhibitory concentration (IC 50 ) of "nanodepot" toward human breast cancer cell line MDA-MB-231 was 0.016 μg/mL (PTX concentration), approximately 3-fold decrease compared to that of monotherapy group (0.043 μg/mL). The tumor weight inhibition (TWI) is 83.30% in xenografted MDA-MB-231 tumor model and metastasis was effectively inhibited in 4T1 orthotopic tumors. Moreover, knockdown of KIAA1199 via sustainable RNAi affected a broad range of cellular functions including apoptosis, migration and invasion. Collectively, tumor environment differentiated spatiotemporal co-delivery fashion holds a great promise for combinative treatment with enhanced efficacy on metastatic cancer cases., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Lung cancer is the primary cause of cancer-related death worldwide. A redox-sensitive nanocarrier system was developed for tumor-targeted drug delivery and sufficient drug release of the chemotherapeutic agent paclitaxel (PTX) for improved lung cancer treatment., Methods: The redox-sensitive nanocarrier system constructed from a hyaluronic acid-disulfide-vitamin E succinate (HA-SS-VES, HSV) conjugate was synthesized and PTX was loaded in the delivery system. The physicochemical properties of the HSV nanoparticles were characterized. The redox-sensitivity, tumor-targeting and intracellular drug release capability of the HSV nanoparticles were evaluated. Furthermore, in vitro and in vivo antitumor activity of the PTX-loaded HSV nanoparticles was investigated in a CD44 over-expressed A549 tumor model., Results: This HSV conjugate was successfully synthesized and self-assembled to form nanoparticles in aqueous condition with a low critical micelle concentration of 36.3 μg mL -1 . Free PTX was successfully entrapped into the HSV nanoparticles with a high drug loading of 33.5% (w/w) and an entrapment efficiency of 90.6%. Moreover, the redox-sensitivity of the HSV nanoparticles was confirmed by particle size change of the nanoparticles along with in vitro release profiles in different reducing environment. In addition, the HA-receptor mediated endocytosis and the potency of redox-sensitivity for intracellular drug delivery were further verified by flow cytometry and confocal laser scanning microscopic analysis. The antitumor activity results showed that compared to redox-insensitive nanoparticles and Taxol ® , PTX-loaded redox-sensitive nanoparticles exhibited much greater in vitro cytotoxicity and apoptosis-inducing ability against CD44 over-expressed A549 tumor cells. In vivo, the PTX-loaded HSV nanoparticles possessed much higher antitumor efficacy in an A549 mouse xenograft model and demonstrated improved safety profile. In summary, our PTX-loaded redox-sensitive HSV nanoparticles demonstrated enhanced antitumor efficacy and improved safety of PTX., Conclusion: The results of our study indicated the redox-sensitive HSV nanoparticle was a promising nanocarrier for lung cancer therapy., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Herein, thioglycolic acid modified N-octyl-O, N'-glycol chitosan (N-mercapto acetyl-N'-octyl-O, N″-glycol chitosan, abbreviated as SH-OGC) was synthesized to improve the oral bioavailability of paclitaxel (PTX). PTX was readily solubilized into the hydrophobic inner core of SH-OGC. Pharmacokinetic studies demonstrated that the bioavailability of PTX was greatly enhanced when delivered by SH-OGC compared to Taxol ® or non-sulfhydrylated OGC micelles. Caco-2 cell experiments confirmed PTX or rhodamine-123-loaded SH-OGC demonstrated effective cellular accumulation via caveola-mediated endocytosis along with the inhibition of P-gp efflux. Furthermore, Caco-2 transport studies demonstrated that the mechanistic basis of SH-OGC efficacy was attributed to P-gp inhibition, enhanced permeability of tight junctions and clathrin-mediated transcytosis across the endothelium. In addition, SH-OGC exhibited increased intestinal retention through thiol-mediated mucoadhesion compared with OGC according to results of mucoadhesion evaluation on freshly excised rat intestine. In summary, SH-OGC micelles may present as a promising delivery vehicle for enhancing the oral bioavailability of P-gp substrates., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Currently, the most prominent barrier to the success of orally delivered paclitaxel (PTX) is the extremely limited bioavailability of delivered therapeutic. In light of this issue, an amphiphilic sulfhydrylated N-deoxycholic acid-N,O-hydroxyethyl chitosan (TGA-DHC) was synthesized to improve the oral bioavailability of PTX. First, TGA-DHC demonstrated substantial loading of PTX into the inner hydrophobic core. A desirable enhancement in the bioavailability of PTX by TGA-DHC was verified by pharmacokinetic studies on rats against Taxol and non-sulfhydrylated DHC micelles. Moreover, cellular uptake studies revealed significant accumulation of TGA-DHC micelles encapsulating PTX or rhodamine-123 into Caco-2 cells via clathrin/caveolae-mediated endocytosis and inhibition of P-gp efflux of substrates. The results of the Caco-2 transport study further confirmed the mechanistic basis of TGA-DHC efficacy; which was attributed to permeabilized tight junctions, clathrin-mediated transcytosis across the endothelium, and inhibition of P-gp. Finally, in vitro mucoadhesion investigations on freshly excised rat intestine intuitively confirmed increased intestinal retention of drug-loaded TGA-DHC through thiol-mediated mucoadhesion. TGA-DHC has demonstrated the capability to overcome what is perhaps the most prominent barrier to oral PTX efficacy, low bioavailability, and serves as a prominent platform for oral delivery of P-gp substrates.

The effective combination of drugs promoting antiangiogenesis and apoptosis effects has proven to be a promising collaborative tumor antidote; and the codelivery of small interfering RNA (siRNA) and chemotherapy agents within one efficient vehicle has gained more attention over single regimen administration. Herein, vascular endothelial growth factor specific siRNA (siVEGF) and paclitaxel (PTX) were introduced as therapeutic companions and coencapsulated into naturally mimic high-density lipoproteins (rHDL/siVEGF-PTX), so that various mechanisms of treatment can occur simultaneously. The terminal nanoparticles share capacity of specific-targeting to tumor cells overexpressed scavenger receptor class B type I (SR-BI) and deliver siVEGF and PTX into cytoplasm by a nonendocytosis mechanism. By exchanging HDL core lipids with hydrophobic therapeutics, rHDL/siVEGF-PTX possessed particle size of ∼160 nm, surface potential of ∼-20 mV, and desirable long-term storage stability. In vitro results confirmed that the parallel activity of siVEGF and PTX displayed enhanced anticancer efficacy. The half-maximal inhibitory concentration (IC 50 ) of rHDL/siVEGF-PTX toward human breast cancer MCF-7 cell is 0.26 μg/mL (PTX concentration), which presents a 14.96-fold increase in cytotoxicity by taking Taxol as comparison. Moreover, in vivo results further demonstrated that rHDL/siVEGF-PTX performed enhanced tumor growth inhibition via natural targeting pathway, accompanied by remarkable inhibition of neovascularization in situ caused by siVEGF silencing in down-regulation of VEGF proteins. On the premise of effective drug codelivery, rHDL/siVEGF-PTX demonstrated high tumor targeting for collaborative antitumor efficacy without side effects after systemic administration, and this bioinspired strategy could open an avenue for exploration of combined anticancer therapy.

Tyroservatide (YSV) is a tripeptide that has been approved for clinical testing, as a new anticancer drug. In the current study, YSV-stearic acid (YSV-SA) was inserted into the surface of d-alpha-tocopheryl polyethylene glycol 1000 succinate monoester (TPGS)-modified paclitaxel (PTX) liposomes (TP-Lip) to form YSV-conjugated TP-Lip (TYP-Lip). Both in vivo imaging and in vitro cell uptake analysis indicated that these modifications could increase tumor-targeting and cell uptake of the liposomes. Optimal antitumor effects were achieved via tail vein injections of TYP-Lip in MB-231 tumor-bearing nude mice. Overall, the formed TYP-Lip not only achieved a synergistic anticancer effect through YSV and PTX, but also improved tumor-targeting and exhibited further antitumor capabilities. These results indicated that combining biological (YSV) and chemotherapeutic (PTX) agents is an efficient combinatorial delivery strategy for enhanced tumor targeting and synergistic antitumor effects., (Copyright © 2016 Elsevier Inc. All rights reserved.)

A novel tLyP-1-HA-PTX conjugate is designed for combining the solubilization capacity of Paclitaxel (PTX) and tumor tissue targeting - penetration effect of hyaluronic acid (HA) as well as cell penetration peptide (tLyP-1). In addition, through modifying by tLyP-1, the anticancer scope of tLyP-1-HA-PTX conjugate was expanded from tumor cells expressing CD44 receptors to those of expressing NRP1 receptors. In vitro antitumor ability of tLyP-1-HA-PTX conjugate and cellular uptake tests were conducted to testify the tumor-targeting behavior of the conjugates. The results showed that both HA-PTX and tLyP-1-HA-PTX conjugates gained better solubility, better stability and specific tumor sites ability and showed high safety in vitro cytotoxicity tests. The tLyP-1-HA-PTX conjugate was especially endowed with efficient cell-penetrating and tumor NRP1 receptor targeting ability and compensate for the decreasing of uptake caused by suppression of CD44 receptor, which is more significant when NRP1 receptor is highly expressed., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In the past decades, reconstituted high density lipoprotein (rHDL) has been successfully developed as a drug carrier since the enhanced HDL-lipids uptake is demonstrated in several human cancers. In this paper, rHDL, for the first time, was utilized to co-encapsulate two hydrophobic drugs: an anticancer drug, paclitaxel (PTX), and a new reversal agent for P-gp (P-glycoprotein)-mediated multidrug resistance (MDR) of cancer, N-cyano-1-[(3,4-dimethoxyphenyl)methyl]-3,4-dihydro-6,7-dimethoxy-N'-octyl-2(1H)-isoquinoline-carboximidamide (HZ08). We proposed this drug co-delivery strategy to reverse PTX resistance. The study aimed to develop a biomimetic nanovector, reconstituted high density lipoprotein (rHDL), mediating targeted PTX-HZ08 delivery for cancer therapy. Using sodium cholate dialysis method, we successfully formulated dual-agent co-delivering rHDL nanoparticles (PTX-HZ08-rHDL NPs) with a typical spherical morphology, well-distributed size (~100nm), high drug encapsulation efficiency (approximately 90%), sustained drug release properties and exceptional stability even after storage for 1month or incubation in 10% fetal bovine serum (FBS) DMEM for up to 2days. Results demonstrated that PTX-HZ08-rHDL NPs significantly enhanced anticancer efficacy in vitro, including higher cytotoxicity and better ability to induce cell apoptosis against both PTX-sensitive and -resistant MCF-7 human breast cancer cell lines (MCF-7 and MCF-7/PTX cells). Mechanism studies demonstrated that these improvements could be correlated with increased cellular uptake of PTX mediated by scavenger receptor class B type I (SR-BI) as well as prolonged intracellular retention of PTX due to the HZ08 mediated drug-efflux inhibition. In addition, in vivo investigation showed that the PTX-HZ08-rHDL NPs were substantially safer, have higher tumor-targeted capacity and have stronger antitumor activity than the corresponding dosage of paclitaxel injection. These findings suggested that rHDL NPs could be an ideal tumor-targeted nanovector for simultaneous transfer of insoluble anticancer drug and drug resistance reversal agents. The PTX-HZ08-rHDL NPs co-delivery system might be a new promising strategy to overcome tumor drug resistance., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this study, a simple and green approach 'bioinspired disassembly-reassembly strategy' was employed to reconstitute lipoprotein nanoparticles (RLNs) using whole-components of endogenous ones (contained dehydrated human lipids and native apolipoproteins). These RLNs were engineered to mimic the configuration and properties of natural lipoproteins for efficient drug delivery. In testing therapeutic targeting to microtubules, paclitaxel (PTX) was reassembled into RLNs to achieve improved targeted anti-carcinoma treatment and minimize adverse effects, demonstrating ultimately more applicable than HDL-like particles which are based on exogenous lipid sources. We have characterized that apolipoprotein-decoration of PTX-loaded RLNs (RLNs-PTX) led to favoring uniformly dispersed distribution, increasing PTX-encapsulation with a sustained-release pattern, while enhancing biostability during blood circulation. The innate biological RLNs induced efficient intracellular trafficking of cargos in situ via multi-targeting mechanisms, including scavenger receptor class B type I (SR-BI)-mediated direct transmembrane delivery, as well as other lipoprotein-receptors associated endocytic pathways. The resulting anticancer treatment from RLNs-PTX was demonstrated a half-maximal inhibitory concentration of 0.20μg/mL, cell apoptosis of 18.04% 24h post-incubation mainly arresting G2/M cell cycle in vitro, and tumor weight inhibition of 70.51% in vivo. Collectively, green-step assembly-based RLNs provided an efficient strategy for mediating tumor-targeted accumulation of PTX and enhanced anticancer efficacy., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Rapid blood clearance and premature burst release are inherent drawbacks of conventional nanoparticles, resulting in poor tumor selectivity. iRGD peptide is widely recognized as an efficient cell membrane penetration peptide homing to αVβ3 integrins. Herein, core-shell nanocapsules (NCs) and iRGD-modified NCs (iRGD-NCs) with high drug payload for paclitaxel (PTX) were prepared to enhance the antitumor activities of chemotherapy agents with poor water solubility. Improved in vitro and in vivo tumor targeting and penetration were observed with NCs and iRGD-NCs; the latter exhibited better antitumor activity because iRGD enhanced the accumulation and penetration of NCs in tumors. The NCs were cytocompatible, histocompatible, and non-toxic to other healthy tissues. The endocytosis of NCs was mediated by lipid rafts in an energy-dependent manner, leading to better cytotoxicity of PTX against cancer cells. In contrast with commercial product, PTX-loaded NCs (PTX-NCs) increased area under concentration-time curve (AUC) by about 4-fold, prolonged mean resident time (MRT) by more than 8-fold and reduced the elimination rate constant by greater than 68-fold. In conclusion, the present nanocarriers with high drug-loading capacity represent an efficient tumor-targeting drug delivery system with promising potential for cancer therapy.

A redox-sensitive micellar system constructed from an O,N-hydroxyethyl chitosan-octylamine (HECS-ss-OA) conjugate with disulfide linkages between the hydrophobic alkyl chains and hydrophilic chitosan backbone was synthesized for triggered intracellular delivery of hydrophobic paclitaxel (PTX). In aqueous environments, conjugates formed micelles with high PTX loading (>30%). Mechanistically, the sensitivity of HECS-ss-OA micelles to reducing environments was investigated using the parameters of in vitro release and particle size. Intracellular release of nile red fluorescence alongside cytotoxicity studies further confirmed the potency of redox-sensitive micelles for intracellular drug delivery compared with redox-insensitive micelles. Additionally, an in vivo study confirmed the efficacy of PTX-loaded micelles in tumor-bearing mice with superior antitumor efficacy and diminished systemic toxicity when compared with the redox-insensitive micelles and a PTX solution. These results demonstrate the potential of redox-sensitive HECS-ss-OA micelles for intracellular trafficking of lipophilic anticancer drugs.

Since its approval by the FDA, Abraxane™ has been established as a clinical standard of paclitaxel (PTX)-based therapy against a variety of cancers. Despite success, Abraxane™ is still limited by suboptimal biodistribution, unfavorable pharmacokinetics and chronic toxicities from chloroform used during preparation. Accordingly, a PTX-loaded nanosuspension based on human serum albumin (HSA) with PEG modifiers (PTX-PEG-HSA) has been developed to optimize the in-vivo biodistribution, pharmacokinetics and safety of PTX over traditional PTX-HSA nanosuspensions prepared using the accepted method for Abraxane™. Results of in-vivo pharmacokinetic (PK) studies indicated PTX-PEG-HSA achieved prolonged blood circulation, illustrated by an 8.8-fold and 4.8-fold increase in area-under-the-curve (AUC) of PTX over Taxol® and PTX-HSA, while the mean residence time (MRT) of PTX in PTX-PEG-HSA was increased by 3.2-fold and 1.5-fold, respectively. HSA mediated active targeting further suppressed non-specific distribution of PTX to normal tissues, which permitted enhanced antitumor efficacy in S180 mice over Taxol® and PTX-HSA. Safety of intravenously administered PTX-PEG-HSA was confirmed through lower hemolytic activity, a 2.2-fold and 1.2-fold increase in LD50 (113.4 mg/kg) over Taxol® and PTX-HSA alongside the absence of local venous irritation. Studies herein suggest the therapeutic and clinical applicability of PTX-PEG-HSA for tumor specific therapy., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A redox-sensitive prodrug, octreotide(Phe)-polyethene glycol-disulfide bond-paclitaxel [OCT(Phe)-PEG-ss-PTX], was successfully developed for targeted intracellular delivery of PTX. The formulation emphasizes long-circulation-time polymer-drug conjugates, combined targeting based on EPR and OCT-receptor mediated endocytosis, sharp redox response, and programmed drug release. The nontargeted redox-sensitive prodrug, mPEG-ss-PTX, and the targeted insensitive prodrug, OCT(Phe)-PEG-PTX, were also synthesized as controls. These polymer-PTX conjugates, structurally confirmed by 1H NMR, exhibited approximately 23,000-fold increase in water solubility over parent PTX and possessed drug contents ranging from 11% to 14%. The redox-sensitivity of the objective OCT(Phe)-PEG-ss-PTX prodrug was verified by in vitro PTX release profile in simulated reducing conditions, and the SSTRs-mediated endocytosis was demonstrated by flow cytometry and confocal laser scanning microscopy analyses. Consequently, compared with mPEG-PTX and OCT(Phe)-PEG-PTX, the OCT(Phe)-PEG-ss-PTX exhibited much stronger cyotoxicity and apoptosis-inducing ability against NCI-H446 tumor cells (SSTRs overexpression), whereas a comparable cytotoxicity of these prodrugs was obtained against WI-38 normal cells (no SSTRs expression). Finally, the in vivo studies on NCI-H466 tumor-bearing nude mice demonstrated that the OCT(Phe)-PEG-ss-PTX possessed superior tumor-targeting ability and antitumor activity over mPEG-PTX, OCT(Phe)-PEG-PTX and Taxol, as well as minimal collateral damage. This targeted redox-sensitive polymer-PTX prodrug system is promising in tumor therapy.

In this study, a novel redox-sensitive micellar system constructed from a hyaluronic acid-based amphiphilic conjugate (HA-ss-(OA-g-bPEI), HSOP) was successfully developed for tumor-targeted co-delivery of paclitaxel (PTX) and AURKA specific siRNA (si-AURKA). HSOP exhibited excellent loading capacities for both PTX and siRNA with adjustable dosing ratios and desirable redox-sensitivity independently verified by morphological changes of micelles alongside in vitro release of both drugs in different reducing environments. Moreover, flow cytometry and confocal microscopy analysis confirmed that HSOP micelles were capable of simultaneously delivering PTX and siRNA into MDA-MB-231 breast cancer cells via HA-receptor mediated endocytosis followed by rapid transport of cargoes into the cytosol. Successful delivery and transport amplified the synergistic effects between the drugs while leading to substantially greater antitumor efficacy when compared with single drug-loaded micelles and non-sensitive co-loaded micelles. In vivo investigation demonstrated that HSOP micelles could effectively accumulate in tumor sites and possessed the greatest antitumor efficacy over non-sensitive co-delivery control and redox-sensitive single-drug controls. These findings indicated that redox-sensitive HSOP co-delivery system holds great promise for combined drug/gene treatment for targeted cancer therapy., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In this study, a novel PTX prodrug, octreotide(Phe)-polyethene glycol-paclitaxel [OCT(Phe)-PEG-PTX], was successfully synthesized and used for targeted cancer therapy. A nontargeting conjugate, mPEG-PTX, was also synthesized and used as a control. Chemical structures of OCT(Phe)-PEG-PTX and mPEG-PTX were confirmed using (1) H nuclear magnetic resonance and circular dichroism. The drug contents in both the conjugates were 12.0% and 14.0%, respectively. Compared with the parent drug (PTX), OCT(Phe)-PEG-PTX, and mPEG-PTX prodrugs showed a 20,000- and 30,000-fold increase in water solubility, respectively. PTX release from mPEG-PTX and OCT(Phe)-PEG-PTX exhibited a pH-dependent profile. Moreover, compared with mPEG-PTX, OCT(Phe)-PEG-PTX exhibited significantly stronger cytotoxicity against NCI-H446 cells (SSTR overexpression) but comparable cytotoxicity against WI-38 cells (no SSTR expression). Results of confocal laser scanning microscopy revealed that the targeting prodrug labeled with fluorescence probe was selectively taken into tumor cells via SSTR-mediated endocytosis. In vivo investigation of prodrugs in nude mice bearing NCI-H446 cancer xenografts confirmed that OCT(Phe)-PEG-PTX prodrug exhibited stronger antitumor efficacy and lower systemic toxicity than mPEG-PTX and commercial Taxol. These results suggested that OCT(Phe)-PEG-PTX is a promising anticancer drug delivery system for targeted cancer therapy., (© 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.)

About 40% of the marketed drugs and 70-90% of new drug candidates are insoluble in water and therefore poorly bioavailable, which significantly compromises their therapeutic effects. A formulation of nanosuspensions achieved by reducing the pure drug particle size down to seb-micron range is one of the most promising approaches to overcome the insolubility. However, the nanosuspension formulations are subject to instability because of nucleation and particle growth. Therefore, a stabilizer is needed to be incorporated into the nanosuspension formulation during the preparation process to suppress the aggregation of drug particles. β-LG, a globular protein, is broken by heat-induced denaturation, and its hydrophobic area is exposed, which allows it to associate with organic particles. PTX, an insoluble drug, is widely used for the clinical treatment of human cancer. However, this drug's clinical application is greatly limited by intrinsic defects including poor solubility, adverse side effects, and poor tumor penetration. In this study, we prepared β-LG-stabilized PTX nanosuspensions (PTX-NS) by coating the protein onto nanoscaled drug particles, investigating the stabilization effect of β-LG on PTX-NS, and evaluating its in vitro and in vivo performance. PTX-NS with a diameter of approximately 200 nm was easily prepared. β-LG produced significantly stabilized effect on PTX-NS via the interaction between the hydrophobic area of the protein and the hydrophobic surface of the drug particles, which resulted in a conformational change of the protein, the loss of both secondary and tertiary structures, and the transition of Trp residues to a less hydrophobic condition. Importantly, unlike other conventional nanoparticles, PTX-NS could directly translocated across the membrane into the cytosol in an energy-independent manner, without entrapment within the endosomal-lysosomal system. Moreover, compared with Taxol, PTX-NS increased AUC and Cmax by 26- and 16-fold, respectively, and prolonged T1/2 by 314-fold. As expected, PTX-NS had better in vitro and in vivo antitumor activity compared to PTX alone. Additionally, β-LG is cyto- and bio-compatible, and PTX-NS is not toxic to healthy tissues. In conclusion, the present study has suggested the high potency of globular proteins, such as β-LG, as novel biomaterials for nanosuspension platform to improve the drug delivery for disease treatment.

Tumor-targeted drug delivery and microenvironment-responsive drug release are attractive strategies in cancer treatment. Our previous study demonstrated that redox-sensitive micelles based on hyaluronic acid-deoxycholic acid (HA-ss-DOCA) conjugates exhibited excellent drug-loading capacities (34.1%) for paclitaxel (PTX) and rapid drug release in response to reducing agent, glutathione. In the present study, the physicochemical and biological properties of PTX-loaded HA-ss-DOCA (PTX-HA-ss-DOCA) micelles were investigated further. The micelles have an average size of about 120 nm and a zeta potential of about -36 mV. Transmission electron microscopy and wide-angle X-ray diffraction analysis demonstrated redox-sensitive degradation of micelles in the presence of glutathione. Moreover, the encapsulated payload was effectively released from HA-ss-DOCA micelles into cytoplasm and then rapidly transported into nuclei. In vitro cytotoxicity and cell apoptosis assay further revealed that HA significantly improved the tumor-specific drug delivery of HA-ss-DOCA micelles via receptor-mediated endocytosis, while efficient intracellular drug release and transportation lead to marked inhibition of tumor cell growth, as compared to Taxol(®) and insensitive micelles. More importantly, PTX-HA-ss-DOCA micelles demonstrated superior in vivo antitumor activity compared with Taxol(®) and insensitive control, and decreased systemic toxicity. Herein we present data which provide valuable insight into the design and development of tumor-specific drug delivery systems., (Copyright © 2015. Published by Elsevier B.V.)

To obtain efficient therapeutics, drug release into the cytosol is required because drug targets are often located in the cytosol or have active sites that require intracellular machinery in the cytosolic compartment. However, typical nanocarriers gain cellular entry by endocytic mechanisms, confining the internalized nanocarriers to the endosomal-lysosomal system, thus resulting in the rapid destruction of active drugs without release into the cytosol. Herein, hybrid nanoparticles (HNs) with a core-shell structure, which was based on nanoemulsion-templates stabilized by both β-lactoglobulin (β-LG) and lecithin, were developed. Additionally, its formation mechanism and structure were also studied. Importantly, the HNs could directly penetrate the cell membrane and enter the cytosol, without entrapment within the endosomal-lysosomal system via the lipid raft-like pathway, thus enhancing its antitumor activities. We therefore concluded that HNs are promising targeting delivery systems for drugs, especially for pharmaceutical proteins and gene-targeting drugs., (Copyright © 2014 Elsevier B.V. All rights reserved.)

An amphiphilic carboxymethyl chitosan-quercetin (CQ) conjugate was designed and synthesized for oral delivery of paclitaxel (PTX) to improve its oral bioavailability by increasing its water solubility and bypassing the P-gp drug efflux pumps. CQ conjugate had low critical micelle concentration (55.14 μg/mL), and could self assemble in aqueous condition to form polymeric micelles (PMs). PTX-loaded CQ PMs displayed a particle size of 185.8 ± 4.6 nm and polydispersity index (PDI) of 0.134 ± 0.056. The drug-loading content (DL) and entrapment efficiency (EE) were 33.62 ± 1.34% and 85.63 ± 1.26%, respectively. Moreover, PTX-loaded CQ PMs displayed similar sustained-release profile in simulated gastrointestinal fluids (pH 1.2/pH 6.8) and PBS (pH 7.4). In situ intestinal absorption experiment showed that PTX-loaded CQ PMs significantly improved the effective permeability of PTX as compared to verapamil (P < 0.01). Likewise, PTX-loaded CQ PMs significantly enhanced the oral bioavailability of PTX, resulting in strong antitumor efficacy against tumor xenograft models with better safety profile as compared to Taxol(®) and Taxol(®) with verapamil. Overall, the results implicate that CQ PMs are promising vehicles for the oral delivery of water-insoluble anticancer drugs., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

An amphiphilic hyaluronic acid (HA)-g-all-trans retinoid acid (HRA) conjugate was successfully developed as a tumor-targeting nanocarrier for potentially synergistic combination chemotherapy of all-trans retinoid acid (ATRA) and paclitaxel (PTX). The HRA conjugate was synthesized by an imine reaction between HA-COOH and ATRA-NH2. PTX-loaded HRA nanoparticles possessed a high loading capacity, nanoscale particle sizes, and good biocompatible characteristics. Cell viability assays indicated that PTX-loaded HRA nanoparticles exhibited concentration- and time-dependent cytotoxicity. Moreover, they displayed obvious superiority in inducing the apoptosis of tumor cells. Cellular uptake analysis suggested that HRA nanoparticles could be efficiently taken up by cells via endocytic pathway and transport into the nucleus, contributing to HA receptor-mediated endocytosis and ATRA-induced nuclear translocation, respectively. Moreover, in vivo imaging analysis indicated that the accumulation of DiR-loaded HRA nanoparticles in tumor was increased obviously after intravenous administration as compared to free DiR solution, which confirmed that the HRA nanoparticles could assist the drugs targeting to the tumor. Furthermore, PTX-loaded HRA nanoparticles exhibited greater tumor growth inhibition effect in vivo with reducing the toxicity. Therefore, HRA nanoparticles can be considered as a promising targeted codelivery system for combination cancer chemotherapy.

Glycyrrhetinic acid-graft-hyaluronic acid (HGA) conjugate was synthesized as a carrier for intravenous administration of paclitaxel (PTX), which combined hyaluronic acid (HA) and glycyrrhetinic acid (GA) as the active targeting ligands to liver tumor. In the present study, physicochemical characteristics, cellular uptake efficiency, and in vivo fates of HGA conjugates were investigated. HGA nanoparticles could readily load PTX with high efficiency up to 31.16 wt.% and entrapment efficiency to 92.02%. Moreover, PTX-loaded HGA nanoparticles exhibited more significant cytotoxicity to HepG2 cells than B16F10 cells due to simultaneously over-expressing HA and GA receptors. Meanwhile, the cellular uptake of nanoparticles was clearly enhanced in HepG2 and B16F10 cells compared to a normal fibroblast cell (HELF cells). In particular, more HGA nanoparticles were taken up by HepG2 cells than by B16F10 cells, which might be attributed to the affinity of multiple ligands of HA and GA to HepG2 cells. Furthermore, liver and tumor targeting activity of HGA nanoparticles was also confirmed by in vivo imaging analysis. The fluorescence signals of DiR-labeled HGA nanoparticles in tumor and liver were 2.88 and 1.83 folds stronger than that of the control, respectively. These results indicate HGA nanoparticles can be a potential drug carrier with "double target sites" for liver cancer therapy., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In order to enhance paclitaxel oral bioavailability, mixed polymeric micelles that comprised of pluronic copolymers and low molecular weight heparin-all-trans-retinoid acid (LHR) conjugate were developed. PTX-loaded mixed polymeric micelles (MPMs) were prepared by dialysis method with high drug loading 26.92 ± 2.08% and 25.82 ± 1.9% for F127/LHR and P188/LHR MPMs respectively, and were found to be spherical in shape with an average size of around 140 nm and a narrow size distribution. In vitro release study showed that pluronic/LHR MPMs exhibited delayed release characteristics compared to Taxol and faster drug release profile compared to LHR plain polymeric micelles (PPMs). The cytotoxic activity of PTX-loaded pluronic/LHR MPMs was slightly higher than LHR PPMs in MCF-7 cells (p<0.01). In situ effective permeability of PTX through rat small intestine was 5- to 6-fold higher with mixed micelles than that of Taxol. Moreover, pluronic/LHR MPMs achieved significantly higher AUC and C(max) level than both of LHR PPMs and Taxol. This enhancement might be due to the inhibition of both P-glycoprotein efflux system and cytochrome P450 metabolism by pluronic copolymers. The current results encourage further development of paclitaxel mixed polymeric micelles as an oral drug delivery system., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Amphiphilic low molecular weight heparin-all-trans-retinoid acid (LHR) conjugate, as a drug carrier for cancer therapy, was found to have markedly low toxicity and to form self-assembled nanoparticles for simultaneous delivery of paclitaxel (PTX) and all-trans-retinoid acid (ATRA) in our previous study. In the present study, PTX-loaded LHR nanoparticles were prepared and demonstrated a spherical shape with particle size of 108.9 nm. Cellular uptake analysis suggested rapid internalization and nuclear transport of LHR nanoparticles. In order to investigate the dynamic behaviors and targeting ability of LHR nanoparticles on tumor-bearing mice, near-infrared fluorescent (NIFR) dye DiR was encapsulated into the nanoparticles for ex vivo optical imaging. The results indicated that LHR nanoparticles could enhance the targeting and residence time in tumor site. Furthermore, in vivo biodistribution study also showed that the area under the plasma concentration time curve (AUC (0→inf)) values of PTX and ATRA for PTX-loaded LHR nanoparticles in tumor were 1.56 and 1.62-fold higher than those for PTX plus ATRA solution. Finally, PTX-loaded LHR nanoparticles demonstrated greater tumor growth inhibition effect in vivo without unexpected side effects, compared to PTX solution and PTX plus ATRA solution. These results suggest that PTX-loaded LHR nanoparticles can be considered as promising targeted delivery system for combination cancer chemotherapy to improve therapeutic efficacy and minimize adverse effects., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A targeted intracellular delivery system of paclitaxel (PTX) was successfully developed based on redox-sensitive hyaluronic acid-deoxycholic acid (HA-ss-DOCA) conjugates. The conjugates self-assembled into nano-size micelles in aqueous media and exhibited excellent drug-loading capacities (34.1%) and entrapment efficiency (93.2%) for PTX. HA-ss-DOCA micelles were sufficiently stable at simulated normal physiologic condition but fast disassembled in the presence of 20 mm reducing agent, glutathione. In vitro drug release studies showed that the PTX-loaded HA-ss-DOCA micelles accomplished rapid drug release under reducing condition. Intracellular release of fluorescent probe nile red indicated that HA-ss-DOCA micelles provide an effective approach for rapid transport of cargo into the cytoplasm. Enhanced cytotoxicity of PTX-loaded HA-ss-DOCA micelles further confirmed that the sensitive micelles are more potent for intracellular drug delivery as compared to the insensitive control. Based on flow cytometry and confocal microscopic analyses, observations revealed that HA-ss-DOCA micelles were taken up to human breast adenocarcinoma cells (MDA-MB-231) via HA-receptor mediated endocytosis. In vivo investigation of micelles in tumor-bearing mice confirmed that HA-ss-DOCA micelles possessed much higher tumor targeting capacity than the insensitive control. These results suggest that redox-sensitive HA-ss-DOCA micelles hold great potential as targeted intracellular delivery carriers of lipophilic anticancer drugs., (Copyright © 2011. Published by Elsevier Ltd.)

The overall goal of this study was to develop a micellar system of paclitaxel (PTX) to enhance its oral absorption. An amphiphilic chitosan derivative, N-deoxycholic acid-N, O-hydroxyethyl chitosan (DHC), was synthesized and characterized by FTIR, (1)H NMR, elemental analysis, and X-ray diffraction (XRD) techniques. The degree of substitution (DS) of hydroxyethyl group and deoxycholic acid group ranged from 89.5-114.5% and 1.11-8.17%, respectively. The critical micelle concentration (CMC) values of DHC decreased from 0.26 to 0.16 mg/mL as the DS of deoxycholic acid group increased. PTX was successfully loaded in DHC micelles with a high drug loading (31.68 ± 0.14%) and entrapment efficiency (77.57 ± 0.51%). The particle size of PTX-loaded DHC micelles ranged from 203.35 ± 2.19 to 236.70 ± 3.40 nm as the DS of deoxycholic acid group increased. After orally administration of PTX-loaded DHC micelles, the bioavailability was threefold compared with that of an orally dosed Taxol®. The single-pass intestinal perfusion studies (SPIP) showed that the intestinal absorption of micelles was via endocytosis involving a saturable process and a p-glycoprotein (P-gp)-independent way. All these indicated that the DHC micelles might be a promising tool for oral delivery of poorly water-soluble drugs., (© 2010 Wiley-Liss, Inc. and the American Pharmacists Association)

A new series of amphiphilically modified chitosan molecules with long alkyl chains as hydrophobic moieties and glycol groups as hydrophilic moieties (N-octyl-O-glycol chitosan, OGC) was synthesized for use as drug carriers. The chemical structure was characterized by Fourier transform infrared, (1)H nuclear magnetic resonance, and elemental analysis. OGC could easily self-assemble to form nanomicelles in an aqueous environment and exhibited a low critical micellar concentration of 5.3-32.5mg/L. The biocompatibility and low toxicity of OGC as excipient for the dosage forms aimed at i.v. administration were confirmed by hemolysis, acute toxicity and histopathological studies. Furthermore, the possibility of solubilizing paclitaxel (PTX), a water-insoluble antitumor drug, with OGC micelles was also explored. PTX was successfully loaded into OGC micelles by using a simple dialysis process. The drug-loading capacity of OGC and stability of drug-loaded micelles were significantly affected by the degree of substitution of alkyl chains. Moreover, a series of safety studies including hemolysis, hypersensitivity, maximum tolerated dose, acute toxicity, and organ toxicity revealed that the PTX-loaded OGC micelles had advantages over the commercially available injectable preparation of PTX (Taxol((R))), in terms of low toxicity levels and increased tolerated dose. Additionally, cytotoxicity studies showed that the PTX-loaded OGC micelles were comparable to the commercial formulation, but the blank micelles were far less toxic than the Cremophor EL vehicle. These results suggest that OGC is a promising carrier for injectable PTX micelles., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

A novel albumin derivative octyl modified serum albumin (OSA) which can form a core-shell structure in aqueous media by self-assembling due to core segregation and a combination of intermolecular forces has been synthesized. The chemical structure and physical properties of OSA were characterized by FTIR, (1)H NMR and TG. The degree of substitution (DS) was in the range of 52.4-69.7% and 48.9-65.8% determined by elemental analysis and fluorescamine assay, respectively. With the increase in the DS of octyl group, the critical micelle concentration (CMC) decreased from 30.1 to 14.7 mg/L because of the increasing hydrophobicity. In the light of the hydrophobic core as a microreservoir for poorly water-soluble drugs, paclitaxel (PTX) was successfully loaded into OSA micelles by the dialysis method with a high drug-loading (33.1 wt%) and entrapment efficiency (90.5%) due to the synergistic effect of micellar encapsulation and binding interaction between drug and OSA. Compared with PTX-loaded unmodified BSA preparation, PTX-loaded OSA micelles are characterized by small size, narrow size distribution, great drug-loading capacity and enhanced stability. The size of PTX-loaded micelles was in the range of 123.3-152.8 nm and smaller than their corresponding blank micelles. Hemolysis and cytotoxicity studies showed that OSA was safer than Tween-80 and Cremophor EL as an injectable pharmaceutic adjuvant for PTX. In terms of the greater drug-loading capacity and safer character, the novel albumin derivative OSA is a prospective injectable delivery system for PTX.

A simple, rapid, and sensitive liquid chromatography-mass spectrometry (MS)-MS method for quantitating paclitaxel in rat plasma is developed. Liquid-liquid extraction with tert-butyl methyl ether is used for sample preparation, and docetaxel is used as the internal standard. Paclitaxel and docetaxel are separated on a C18 column and quantitated using a triple-quadrupole MS operating in positive ion electrospray selective reaction monitoring mode with a total run time of 6.0 min. The peak area of the m/z 876.3 --> 307.9 transition of paclitaxel is measured versus that of the m/z 830.3 --> 549.1 transition of docetaxel to generate the standard curve. The standard curve is linear over the concentration range of 0.2008-1004 ng/mL for rat plasma. The method has high extraction recovery (> 90%) and accuracy (> 90%), with the intra- and interday precision < 15%. Frozen stability, freeze-and-thaw stability, extracted stability, and room temperature solution stability are also examined. This assay is used to support a pharmacokinetic study of paclitaxel self-assembled nanoliposome in rats.

A liquid chromatography/tandem triple-quadrupole mass spectrometry assay to quantify paclitaxel in rat tissue homogenates containing taxol or paclitaxel nanoliposome (PTX-NLP) was developed and validated. Liquid-liquid extraction with tert-butyl methyl ether was used for tissue sample preparation and docetaxel was used as the internal standard. Paclitaxel and docetaxel were separated on a 200 mm x 4.6 mm x 5 microm C(18) column and quantified using a triple-quadrupole mass spectrometer operating in positive ion electrospray selective reaction monitoring mode (ESI(+)-SRM) with a total run time of 6.0 min. The peak area of the m/z 876.3 --> 307.9 transition of paclitaxel is measured versus that of the m/z 830.3 --> 549.1 transition of docetaxel to generate the standard curves. The standard curves were linear over the concentration range of 0.2008-2008 ng/mL for different tissues. The method had high extraction recovery (>90%) and accuracy (>90%) with the intra-day and inter-day precision <15%. Frozen stability, freeze/thaw stability, extraction stability and solution stability at ambient temperature were examined, which indicated the tissue samples should be extracted within 5 days and avoid being frozen and thawed repeatedly over 5 times. Extracted samples after evaporation could be stored at -20 degrees C for 20 days without drug degradation and no degradation was also observed after solution samples were left to stand at ambient temperature for 24 h. This assay was used to support an in vivo biodistribution study of PTX-NLP in rats., (Copyright (c) 2006 John Wiley & Sons, Ltd.)

Tyroservatide (YSV) is a tripeptide that has been approved for clinical testing, as a new anticancer drug. In the current study, YSV-stearic acid (YSV-SA) was inserted into the surface of d -alpha-tocopheryl polyethylene glycol 1000 succinate monoester (TPGS)-modified paclitaxel (PTX) liposomes (TP-Lip) to form YSV-conjugated TP-Lip (TYP-Lip). Both in vivo imaging and in vitro cell uptake analysis indicated that these modifications could increase tumor-targeting and cell uptake of the liposomes. Optimal antitumor effects were achieved via tail vein injections of TYP-Lip in MB-231 tumor-bearing nude mice. Overall, the formed TYP-Lip not only achieved a synergistic anticancer effect through YSV and PTX, but also improved tumor-targeting and exhibited further antitumor capabilities. These results indicated that combining biological (YSV) and chemotherapeutic (PTX) agents is an efficient combinatorial delivery strategy for enhanced tumor targeting and synergistic antitumor effects. [ABSTRACT FROM AUTHOR]

A liquid chromatography‐tandem triple‐quadrupole mass spectrometry assay to quantify palitaxel in rat tissue homogenates containing paclitaxel nanoliposome (PTX‐NLP) modified by PEO-PPO-PEO triblock copolymers was developed and validated. Liquid–liquid extraction with tert‐butyl methyl ether was used for preparation of tissue samples and docetaxel was used as the internal standard. Paclitaxel and docetaxel were separated on a 200 mm×4.6 mm×5 µm C 18 column and quantified using a triple‐quadrupole mass spectrometer operating in positive ion electrospray selective reaction monitoring mode (ESI + ‐SRM) with a total run time of 6.0 min. The peak area of the m/z 876.3→307.9 transition of paclitaxel is measured vs. that of the m/z 830.3→549.1 transition of docetaxel to generate the standard curves. The standard curves were linear over the concentration range of 0.2–2000 ng/mL for different tissues. The method had high extraction recovery (>90%) and accuracy (>90%) with the intraday and inter‐day precision [ABSTRACT FROM AUTHOR]

Abstract: Amphiphilically modified low molecular weight chitosan (LMWC) with long chain alkyl groups as hydrophobic moieties and carboxymethyl groups as hydrophilic moieties (N-octyl-N,O-carboxymethyl LMWC, OC-LMWC) was synthesized. Self-assembled polymeric micelles of OC-LMWC were prepared in aqueous environment. Critical micelle concentrations (CMC) of OC-LMWCs were varied from 8.7 to 27.7mg/l. Paclitaxel (PTX) was successfully encapsulated into the hydrophobic cores of the nanoparticles. The drug loading content and entrapment efficiency were higher to 32.17% (w/w) and 80.61%, respectively. Differential scanning calorimetry (DSC), transmission electron microscope (TEM) observation and dynamic light scattering (DLS) measurements were carried out to determination the physicochemical properties of the micelles. MTT assay showed that the in vitro cytotoxic effect of the PTX-loaded micelles was comparable to that of the commercial formulation, but the blank micelles were far less than the Cremophor EL® vehicle. These results suggested that OC-LMWC micelles were promising carriers for hydrophobic anticancer agents. [Copyright &y& Elsevier]

Modulation of tumor microenvironment (TME) has been indicated as an approach to improve efficacy of cancer therapy. Here, we proposed a nano co-delivery based combination therapy of paclitaxel (PTX) and silybin (SB) which can employ the synergistic effects through chemotherapy sensitization and microenvironment modulation. A dextran-based amphiphilic polymer (Dex-DOCA) was successfully developed for in vivo co-delivery and thus "synchronizing" the biodistribution, transport and release of PTX and SB. Resultantly, Dex-DOCA exhibited an excellent encapsulating efficiency for both PTX and SB with adjustable loading ratio for an optimal synergistic antitumor activity. Moreover, the co-loaded nanoparticles efficiently discharged the two drugs at the prospective dosage ratio specifically in acid endo/lysosome mimic environments. The results of in vitro cytotoxicity and cell apoptosis assays further confirmed the SB sensitized PTX potency. Finally, in vivo investigation demonstrated that the co-loaded nanoparticles could effectively accumulate in tumor sites by passive targeting, and inhibit tumor growth through an enhanced intratumoral penetration (resulted from stromal components eradication and tumor vessels normalization associated TME modulation), as well as a sensitization effect of SB on PTX cytotoxic chemotherapy. Unlabelled Image • A dextran-deoxycholic acid amphiphilic polymer (Dex-DOCA) was successfully synthesized. • Paclitaxel and silibinin could be co-loaded into Dex-DOCA at a controlled synergistic ratio. • (PTX+SB) NP "synchronized" the in vivo biodistribution, transport and release of PTX and SB within tumor. • (PTX+SB) NP improved intratumoral penetration of drugs by regulating TME. • (PTX+SB) NP maximized therapeutic outcomes through chemotherapy sensitization and TME modulation. [ABSTRACT FROM AUTHOR]

Abstract: As a novel nanocarrier for simultaneous delivery of multiple anticancer drugs, low molecular weight heparin-all-trans-retinoid acid (ATRA) (LHR) conjugate was developed. Amphiphilic LHR conjugate had markedly lower anticoagulant activity, and could self-assemble to form nanoparticles for loading hydrophobic drugs. The critical aggregation concentrations of LHR conjugates were varied from 407 to 40mg/L. Paclitaxel (PTX)-loaded LHR nanoparticles were prepared by the dialysis method, with particle sizes in the range of 228.0–108.9nm. The maximum drug-loading was as much as 33.1% with an entrapment efficiency of 93.1%. They displayed enhanced PTX-induced cytotoxicity to HepG2 cells compared to PTX solution. Hemolysis and cytotoxicity studies showed that LHR conjugate was a safe material for intravenous administration. Moreover, the pharmacokinetic profiles indicated that PTX-loaded LHR nanoparticles contributed to an extended circulation of PTX and ATRA. These results suggest that PTX-loaded LHR nanoparticles can be considered as promising anticancer drug delivery system for combination chemotherapy. [Copyright &y& Elsevier]