β-Lapachone and Paclitaxel Combination Micelles with Improved Drug Encapsulation and Therapeutic Synergy as Novel Nanotherapeutics for NQO1-Targeted Cancer Therapy

Enhanced Chemodynamic Therapy Mediated by a Tumor-Specific Catalyst in Synergy with Mitophagy Inhibition Improves the Efficacy for Endometrial Cancer

Chemodynamic therapy (CDT) relies on the tumor microenvironment (e.g., high H2 O2 level) responsive Fenton-like reactions to produce hydroxyl radicals (·OH) against tumors. However, endogenous H2 O2 is insufficient for effective chemodynamic responses. An NAD(P)H: quinone oxidoreductase 1 (NQO1)high catalase (CAT)low therapeutic window for the use of NQO1 bioactive drug β-lapachone (β-Lap) is first identified in endometrial cancer (EC). Accompanied by NADH depletion, NQO1 catalyzes β-Lap to produce excess H2 O2 and initiate oxidative stress, which selectively suppress NQO1high EC cell proliferation, induce DNA double-strand breaks, and promote apoptosis. Moreover, shRNA-mediated NQO1 knockdown or dicoumarol rescues NQO1high EC cells from β-Lap-induced cytotoxicity. Arginine-glycine-aspartic acid (RGD)-functionalized iron-based metal-organic frameworks (MOF(Fe)) further promote the conversion of the accumulated H2 O2 into highly oxidative ·OH, which in turn, exacerbates the oxidative damage to RGD-positive target cells. Furthermore, mitophagy inhibition by Mdivi-1 blocks a powerful antioxidant defense approach, ultimately ensuring the anti-tumor efficacy of stepwise-amplified reactive oxygen species signals. The tumor growth inhibition rate (TGI) is about 85.92%. However, the TGI of MOF(Fe)-based synergistic antitumor therapy decreases to only 50.46% in NQO1-deficient KLE tumors. Tumor-specific chemotherapy and CDT-triggered therapeutic modality present unprecedented therapeutic benefits in treating NQO1high EC.

Enzymatic drug release cascade from polymeric prodrug nanoassemblies enables targeted chemotherapy

Cancer drug delivery systems often suffer from premature drug leakage during transportation and/or inefficient drug release within cancer cells. We present here a polymeric prodrug nanoassembly that addresses these problems simultaneously. This nanoassembly comprises a polymeric prodrug with novel trivalent phenylboronate moieties for drug conjugation via ether linkages, as well as β-lapachone (Lapa). While the ether linkage enables nearly no drug release under physiological conditions, the Lapa molecules can induce the reactive oxygen species (ROS) burst specifically in cancer cells via NAD(P)H: quinone oxidoreductase-1 catalysis, which triggers the cleavage of the ether bonds and thus cascade amplification drug release in cancer cells. As a result, the nanoassemblies exhibit much higher cytotoxicity against cancer cells than normal cells, and also increased therapeutic efficacy and reduced side effects compared to the clinically used irinotecan. We anticipate that this strategy can be applied to other drug delivery platforms to enable more precise drug release.

A novel multifunctional nanoparticles formed by molecular recognition between AS1411 aptamer and redox-responsive paclitaxel-nucleoside analogue prodrug for combination treatment of β-lapachone and paclitaxel

Despite its high antitumor activity, the clinical application of chemotherapy is greatly impeded by lacking of specific accumulation and poor solubility. To address the above challenges, we designed a AS1411 aptamer modified nanoparticles based on molecular recognition of nucleobases. Firstly, a redox sensitive Paclitaxel-SS-Zidovudine (PZ) prodrug was synthesized. Then PZ/β-lapachone/AS1411/DSPE-PEG nanoparticles were prepared and AS1411 aptamer was connected through molecular recognition between the nucleoside analogue Zidovudine (ZDV) and the thymine on aptamer. DSPE-PEG (DP) was incorporated into nanoparticles to prolong the residence time of nanoparticles in the blood circulation. Furthermore, to realize the combination treatment, β-lapachone (LAP) has been incorporated into nanoparticles with high drug loading efficiency through the interaction of π-π stacking force and H-bonding between LAP and Paclitaxel (PTX). LAP can generate abundant exogenous reactive oxygen species (ROS) via the bioactivation of NAD(P)H: quinone oxidoreductase-1 (NQO1). Moreover, the connection of Zidovudine (ZDV) and AS1411 through molecular recognition of nucleobases further optimized the nanoparticles with high affinity to nucleolin which overexpressed on tumor cell membrane, thereby inducing the specific accumulation of nanoparticles in tumor sites. In vivo and in vitro studies showed that the obtained nanoparticles of PZ/LAP/AS1411/DP exhibited better tumor growth inhibition and lower systemic side effects. Herein, we have rationally conducted a novel self-codelivery system for effectively synergistic antitumor treatment.

Microgels and Nanogels for the Delivery of Poorly Water-Soluble Drugs

While microgels and nanogels are most commonly used for the delivery of hydrophilic therapeutics, the water-swollen structure, size, deformability, colloidal stability, functionality, and physicochemical tunability of microgels can also offer benefits for addressing many of the barriers of conventional vehicles for the delivery of hydrophobic therapeutics. In this review, we describe approaches for designing microgels with the potential to load and subsequently deliver hydrophobic drugs by creating compartmentalized microgels (e.g., core-shell structures), introducing hydrophobic domains in microgels, leveraging host-guest interactions, and/or applying "smart" environmentally responsive materials with switchable hydrophobicity. In particular, the challenge of promoting hydrophobic drug loading without compromising the inherent advantages of microgels as delivery vehicles and ensuring practically relevant release kinetics from such structures is highlighted, with an eye toward the practical translation of such vehicles to the clinic.

β-lapachone: A Promising Anticancer Agent with a Unique NQO1 Specific Apoptosis in Pancreatic Cancer

Cancer, one of the major health problems all over the world, requires more competent drugs for clinical use. One recent possible chemotherapeutic drug under research is β-lapachone. β- lapachone (1,2-naphthoquinone) has promising activity against those tumors showing raised levels of Nicotinamide di-phosphate Quinone Oxidoreductases-1 (NQO1). NQO1 is found to be up-regulated in pancreatic tumor cells, and thus β-lapachone could generate cytotoxicity in various cancers like pancreatic tumors. β-lapachone harborage independent growth and clonogenic cell survival in agar. The cell-killing effects of β-lapachone can be stopped by using dicumarol, an inhibitor of NAD(P)H Quinone Oxidoreductases-1. In previously established pancreatic cancer xenografts in mice, β- lapachone inhibited the tumor growth when given orally rather than when combined with cyclodextrin to improve its bioavailability.

Recent Advances and Challenges in Controlling the Spatiotemporal Release of Combinatorial Anticancer Drugs from Nanoparticles

To overcome cancer, various chemotherapeutic studies are in progress; among these, studies on nano-formulated combinatorial drugs (NFCDs) are being actively pursued. NFCDs function via a fusion technology that includes a drug delivery system using nanoparticles as a carrier and a combinatorial drug therapy using two or more drugs. It not only includes the advantages of these two technologies, such as ensuring stability of drugs, selectively transporting drugs to cancer cells, and synergistic effects of two or more drugs, but also has the additional benefit of enabling the spatiotemporal and controlled release of drugs. This spatial and temporal drug release from NFCDs depends on the application of nanotechnology and the composition of the combination drug. In this review, recent advances and challenges in the control of spatiotemporal drug release from NFCDs are provided. To this end, the types of combinatorial drug release for various NFCDs are classified in terms of time and space, and the detailed programming techniques used for this are described. In addition, the advantages of the time and space differences in drug release in terms of anticancer efficacy are introduced in depth.

A pH-Responsive Charge-Reversal Drug Delivery System with Tumor-Specific Drug Release and ROS Generation for Cancer Therapy

INTRODUCTION

Poor cell uptake and incomplete intracellular drug release are the two major challenges for polymeric prodrug-based drug delivery systems (PPDDSs) in cancer treatment.

METHODS

Herein, a PPDDS with pH-induced surface charge-reversal and reactive oxygen species (ROS) amplification for ROS-triggered self-accelerating drug release was developed, which was formed by encapsulating a ROS generation agent (vitamin K3 (VK3)) in pH/ROS dual-sensitive polymetric prodrug (PEG-b-P(LL-g-TK-PTX)-(LL-g-DMA)) based micelle nanoparticles (denoted as PVD-NPs).

RESULTS

The surface charge of the PVD-NPs can change from negative to positive for enhanced cell uptake in response to tumor extracellular acidity pH. After internalization by cancer cells, PVD-NPs demonstrate dual drug release in response to intracellular ROS-rich conditions. In addition, the released VK3 can produce ROS under the catalysis by NAD(P)H:quinone oxidoreductase-1, which facilitates tumor-specific ROS amplification and drug release selectively in cancer cells to enhance chemotherapy.

CONCLUSION

Both in vitro and in vivo experiments demonstrated that the PVD-NPs showed significant antitumor activity in human prostate cancer.

Polymeric micelles loading with ursolic acid enhancing anti-tumor effect on hepatocellular carcinoma

Ursolic acid (UA) is widely found in many dietary plants, which has been proved to be effective in cancer therapy. But unfortunately its hydrophobic property limits its clinical application. Polymer micelles (PMs) are constructed from amphiphilic block copolymers that tend to self-assemble and form the unique core-shell structure consisting of a hydrophilic corona outside and a hydrophobic inner core. PMs could entrap the hydrophobic substance into its hydrophobic inner core for solubilizing these poorly water-soluble drugs and it is widely applied as a novel nano-sized drug delivery system. This study aimed to develop the drug delivery system of UA-loaded polymer micelles (UA-PMs) to overcome the disadvantages of UA in clinical application thus enhancing antitumor effect on hepatocellular carcinoma. UA-PMs was prepared and characterized for the physicochemical properties. It was investigated the cell-growth inhibition effect of UA-PMs against the human hepatocellular carcinoma cell line HepG2 and human normal liver cell line L-02. UA-PMs was evaluated about the in vivo toxicity and the antitumor activity. We took a diblock copolymer of methoxy poly (ethylene glycol)-poly(L-lactic acid) (mPEG-PLA) as carrier material to prepare UA-PMs by the thin-film dispersion method. MTT assay and wound-healing assay were investigated to assess the inhibition effect of UA-PMs against HepG2 cells on cell-growth and cell-migration. Further, we chose KM mice for the acute toxicity experiment and assessed the antitumor effect of UA-PMs on the H22 tumor xenograft. UA-PMs could markedly inhibit the proliferation and migration of HepG2 cells. In vivo study showed that UA-PMs could significantly inhibit the growth of H22 xenograft and prolong the survival time of tumor-bearing mice. It demonstrated that UA-PMs possess great potential in liver cancer therapy and may enlarge the application of UA in clinical therapy.

Tailored Design of an ROS-Responsive Drug Release Platform for Enhanced Tumor Therapy via "Sequential Induced Activation Processes"

The reactive oxygen species (ROS)-responsive intelligent drug delivery system has developed rapidly in recent years. However, because of the low concentration of ROS in most types of tumor cells, it is not possible to rapidly and effectively stimulate the drug delivery system to release the active drug. Here, we introduced "sequential induced activation processes" for efficient tumor therapy by designing a new ROS-responsive drug release platform. β-Lapachone, a positively charged nitrogen mustard (NM) prodrug, and two diblock molecules (mPEG-AcMH and PAsp-AcMH) are self-assembled to form prodrug primary micelles, which are further aggregated into nanoparticles that facilitate drug codelivery. When administered by intravenous injection, the nanoparticles reach the tumor site and enter the tumor cells by endocytosis. The β-lapachone released in the tumor cells induces a large amount of H₂O₂, and the ROS-responsive NM prodrug is activated to form activated NM, quinone methide, and boric acid under the induction of H₂O₂. The activated NM leads to tumor cell apoptosis.

Self-Strengthened Oxidation-Responsive Bioactivating Prodrug Nanosystem with Sequential and Synergistically Facilitated Drug Release for Treatment of Breast Cancer

Although environment-sensitive prodrug-based nanoparticles (NPs) have developed rapidly, lots of prodrug NPs still show poor selectivity and efficiency of parent drug bioactivation because of tumor heterogeneity. Herein, self-strengthened bioactivating prodrug-based NPs are fabricated via co-encapsulation of oxidation-responsive thioether-linked linoleic acid-paclitaxel conjugates (PTX-S-LA) and β-lapachone (LPC) into polymeric micelles (PMs). Following cellular uptake, PMs first release LPC to significantly elevate the reactive oxidative species (ROS) level through NAD(P)H: quinone oxidoreductase-1 (NQO1) catalysis. Then, NQO1-generated ROS in combination with endogenous high ROS levels in tumor cells could synergistically facilitate PTX-S-LA to release the active cytotoxic agent PTX. Such a novel prodrug nanosystem exhibits self-strengthened prodrug bioactivation, ultraselective release, and cytotoxicity between cancer and normal cells, prolonged circulation time, and enhanced tumor accumulation, leading to high antitumor efficiency and superior biosafety. Our findings pave the new way for the rational design of oxidation-responsive prodrug NPs for high-efficacy cancer chemotherapy.

Targeting the Oncogene KRAS Mutant Pancreatic Cancer by Synergistic Blocking of Lysosomal Acidification and Rapid Drug Release

Survival of KRAS mutant pancreatic cancer is critically dependent on reprogrammed metabolism including elevated macropinocytosis, autophagy, and lysosomal degradation of proteins. Lysosomal acidification is indispensable to protein catabolism, which makes it an exploitable metabolic target for KRAS mutant pancreatic cancer. Herein we investigated ultra-pH-sensitive micelles (UPSM) with pH-specific buffering of organelle pH and rapid drug release as a promising therapy against pancreatic cancer. UPSM undergo micelle-unimer phase transition at their apparent p K_a, with dramatically increased buffer capacity in a narrow pH range (<0.3 pH). Cell studies including amino acid profiling showed that UPSM inhibited lysosomal catabolism more efficiently than conventional lysosomotropic agents ( e. g., chloroquine) and induced cell apoptosis under starved condition. Moreover, pH-triggered rapid drug release from triptolide prodrug-loaded UPSM (T-UPSM) significantly enhanced cytotoxicity over non-pH-sensitive micelles (T-NPSM). Importantly, T-UPSM demonstrated superior safety and antitumor efficacy over triptolide and T-NPSM in KRAS mutant pancreatic cancer mouse models. Our findings suggest that the ultra-pH-sensitive nanoparticles are a promising therapeutic platform to treat KRAS mutant pancreatic cancer through simultaneous lysosomal pH buffering and rapid drug release.

Improving Drug Delivery of Micellar Paclitaxel against Non-Small Cell Lung Cancer by Coloading Itraconazole as a Micelle Stabilizer and a Tumor Vascular Manipulator

Although polymeric micelles of paclitaxel (PTX) significantly reduce excipient-induced toxicity compared with Taxol, they exhibit few clinical advantages in tumor inhibition and overall survival. To improve, itraconazole (ITA), an antifungal drug with potent anti-angiogenesis activity, is co-encapsulated together with PTX within the PEG-PLA micelles. The strong intermolecular interactions between the payloads inhibit drug crystallization and prevent drugs from binding with external proteins, render super-stable micelles upon dilution and exposure to biological environment, and enter the tumor cells through endocytosis. The co-encapsulated micelles show strong anti-proliferation potency against non-small-cell lung cancer (NSCLC) and even PTX resistant NSCLC cells in vitro and significantly improve the drug accumulation within the tumor in vivo. Compared with PTX monotherapy or combination therapy using individual PTX and ITA micelles, the co-encapsulated micelle demonstrates strikingly superior efficacy in tumor growth inhibition, recurrence prevention, and reversion of PTX resistance, in Kras mutant patient derived xenografts, orthotropic models, and paclitaxel-resistance subcutaneous models. Besides the pharmacokinetic improvement, therapeutic benefits are also contributed by angiogenesis inhibition and blood vessel normalization by ITA. Utilizing the pharmaceutical and pharmacological synergies between the therapeutic agents, a simple yet effective design of a combination cancer nanomedicine that is industrially scalable and clinically translatable is achieved.

Phase 1 study of ARQ 761, a β-lapachone analogue that promotes NQO1-mediated programmed cancer cell necrosis

BACKGROUND

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a two-electron oxidoreductase expressed in multiple tumour types. ARQ 761 is a β-lapachone (β-lap) analogue that exploits the unique elevation of NQO1 found in solid tumours to cause tumour-specific cell death.

METHODS

We performed a 3+3 dose escalation study of 3 schedules (weekly, every other week, 2/3 weeks) of ARQ 761 in patients with refractory advanced solid tumours. Tumour tissue was analysed for NQO1 expression. After 20 patients were analysed, enrolment was restricted to patients with NQO1-high tumours (H-score ≥ 200).

RESULTS

A total of 42 patients were treated. Median number of prior lines of therapy was 4. Maximum tolerated dose was 390 mg/m² as a 2-h infusion every other week. Dose-limiting toxicity was anaemia. The most common treatment-related adverse events were anaemia (79%), fatigue (45%), hypoxia (33%), nausea (17%), and vomiting (17%). Transient grade 3 hypoxia, reflecting possible methemoglobinaemia, occurred in 26% of patients. Among 32 evaluable patients, best response was stable disease (n = 12); 6 patients had tumour shrinkage. There was a trend towards improved efficacy in NQO1-high tumours (P = 0.06).

CONCLUSIONS

ARQ 761 has modest single-agent activity, which appears associated with tumour NQO1 expression. Principal toxicities include anaemia and possible methemoglobinaemia.

More Is Sometimes Less: Curcumin and Paclitaxel Formulations Using Poly(2-oxazoline) and Poly(2-oxazine)-Based Amphiphiles Bearing Linear and Branched C9 Side Chains

A known limitation of polymer micelles for the formulation of hydrophobic drugs is their low loading capacity (LC), which rarely exceeds 20 wt%. One general strategy to overcome this limitation is to increase the amphiphilic contrast, that is, to make the hydrophobic core of the micelles more hydrophobic. However, in the case of poly(2-oxazoline) (POx)-based amphiphilic triblock copolymers, a minimal amphiphilic contrast was reported to be beneficial. Here, this subject is revisited in more detail using long hydrophobic side chains that are either linear (nonyl) or branched (3-ethylheptyl). Two different backbones within the hydrophobic block are investigated, in particular POx and poly(2-oxazine) (POzi), for the solubilization and co-solubilization of the two highly water insoluble compounds, curcumin and paclitaxel. Even though high loading capacities can be achieved for curcumin using POzi-based triblock copolymers, the solubilization capacity of all investigated polymers with longer side chains is significantly lower compared to POx and poly(2-oxazine)s with shorter side chains. Although the even lower LC for paclitaxel can be somehow improved by co-formulating curcumin, this study corroborates that in the case of POx and POzi-based polymer micelles, an increased amphiphilic contrast leads to less drug solubilization.

Nanostructured lipid carriers co-delivering lapachone and doxorubicin for overcoming multidrug resistance in breast cancer therapy

BACKGROUND

Multidrug resistance is responsible for the poor outcome in breast cancer therapy. Lapa is a novel therapeutic agent that generates ROS through the catalysis of the NAD(P) H:quinone oxidoreductase-1 (NQO1) enzyme which significantly facilitate the intracellular accumulation of the co-delivered DOX to overcome MDR in cancer cells.

PURPOSE

Herein, in our study, nanostructured lipid carrier (NLC) co-delivering β-lapachone (Lapa) and doxorubicin (DOX) was developed (LDNLC) with the aim to overcome the multidrug resistance (MDR) in breast cancer therapy.

PATIENTS AND METHODS

Lapa and DOX were loaded into NLC to prepare LDNLC using melted ultrasonic dispersion method.

RESULTS

The well designed LDNLC was nanoscaled particles that exhibited preferable stability in physiological environment. In vitro cell experiments on MCF-7 ADR cells showed increased DOX retention as compared to DOX mono-delivery NLC (DNLC). In vivo anti-cancer assays on MCF-7 ADR tumor bearing mice model also revealed significantly enhanced efficacy of LDNLC than mono-delivery NLCs (DNLC and LNLC).

CONCLUSION

LDNLC might be a promising platform for effective breast cancer therapy.

PhytoNanotechnology: Enhancing Delivery of Plant Based Anti-cancer Drugs

Natural resources continue to be an invaluable source of new, novel chemical entities of therapeutic utility due to the vast structural diversity observed in them. The quest for new and better drugs has witnessed an upsurge in exploring and harnessing nature especially for discovery of antimicrobial, antidiabetic, and anticancer agents. Nature has historically provide us with potent anticancer agents which include vinca alkaloids [vincristine (VCR), vinblastine, vindesine, vinorelbine], taxanes [paclitaxel (PTX), docetaxel], podophyllotoxin and its derivatives [etoposide (ETP), teniposide], camptothecin (CPT) and its derivatives (topotecan, irinotecan), anthracyclines (doxorubicin, daunorubicin, epirubicin, idarubicin), and others. In fact, half of all the anti-cancer drugs approved internationally are either natural products or their derivatives and were developed on the basis of knowledge gained from small molecules or macromolecules that exist in nature. Three new anti-cancer drugs introduced in 2007, viz. trabectedin, epothilone derivative ixabepilone, and temsirolimus were obtained from microbial sources. Selective drug targeting is the need of the current therapeutic regimens for increased activity on cancer cells and reduced toxicity to normal cells. Nanotechnology driven modified drugs and drug delivery systems are being developed and introduced in the market for better cancer treatment and management with good results. The use of nanoparticulate drug carriers can resolve many challenges in drug delivery to the cancer cells that includes: improving drug solubility and stability, extending drug half-lives in the blood, reducing adverse effects in non-target organs, and concentrating drugs at the disease site. This review discusses the scientific ventures and explorations involving application of nanotechnology to some selected plant derived molecules. It presents a comprehensive review of formulation strategies of phytoconstituents in development of novel delivery systems like liposomes, functionalized nanoparticles (NPs), application of polymer conjugates, as illustrated in the graphical abstract along with their advantages over conventional drug delivery systems supported by enhanced biological activity in in vitro and in vivo anticancer assays.

Tumor Progression of Non-Small Cell Lung Cancer Controlled by Albumin and Micellar Nanoparticles of Itraconazole, a Multitarget Angiogenesis Inhibitor

Itraconazole (ITA), an old and widely prescribed antifungal drug with excellent safety profile, has more recently been demonstrated to be a multitarget antiangiogenesis agent affecting multiple angiogenic stimulatory signals and pathways, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor receptor 2 (VEGFR2) glycosylation, and mammalian target of rapamycin (mTOR). In this study, we developed two nanoparticle formulations, i.e., polymer micelles (IP2K) and albumin nanoparticles (IBSA), to solubilize the extremely hydrophobic and insoluble ITA to allow intravenous administration and pharmacokinetics (PK)/pharmacodynamics (PD) comparisons. Although none of the formulations showed strong antiproliferation potency against non-small cell lung cancer (NSCLC) cells in vitro, when administrated at the equivalent ITA dose to a NSCLC patient-derived xenograft (PDX) model, IBSA retarded while IP2K accelerated the tumor growth. We attributed the cause of this paradox to formulation-dependent PK and vascular manipulation: IBSA demonstrated a more sustained PK with a C_max of 60-70% and an AUC ∼2 times of those of IP2K, and alleviated the tumor hypoxia presumably through vascular normalization. In contrast, the high C_max of IP2K elevated tumor hypoxia through a strong angiogenesis inhibition, which could have aggravated cancer aggressiveness and accelerated tumor growth. Furthermore, IBSA induced minimal hepatic and hematologic toxicities compared to IP2K and significantly enhanced the in vivo tumor inhibition activity of paclitaxel albumin nanoparticles when used in combination. These findings suggest that formulation and pharmacokinetics are critical aspects to be considered when designing the ITA angiogenesis therapy, and IBSA could potentially be assessed as a novel and safe multitarget angiogenesis therapy to be used in combination with other anticancer agents.

A Tumor-Specific Cascade Amplification Drug Release Nanoparticle for Overcoming Multidrug Resistance in Cancers

A cascade amplification release nanoparticle (CARN) is constructed by the coencapsulation of β-lapachone and a reactive-oxygen-species (ROS)-responsive doxorubicin (DOX) prodrug, BDOX, in polymeric nanoparticles. Releasing β-lapachone first from the CARNs selectively increases the ROS level in cancer cells via NAD(P)H:quinone oxidoreductase-1 (NQO1) catalysis, which induces the cascade amplification release of DOX and overcomes multidrug resistance (MDR) in cancer cells, producing a remarkably improved therapeutic efficacy against MDR tumors with minimal side effects.

Intermolecular Interactions between Coencapsulated Drugs Inhibit Drug Crystallization and Enhance Colloidal Stability of Polymeric Micelles

Novel "pairs" of drugs possessing pharmacological synergies could be encapsulated into polymeric micelles and exert superb therapeutic effects in vivo upon intravenous administration, with the prerequisite that the micelles remain stable. NADP(H) quinone oxidoreductase 1 (NQO1) inhibitors, such as β-lapachone (LPC) and tanshinone IIA (THA), are structurally and pharmacologically similar molecules that are poorly water-soluble, crystallize extremely fast, and demonstrate synergistic anticancer effect when used together with paclitaxel (PTX). However, when coencapsulated with PTX in poly(ethylene glycol)-b-poly(d,l-lactic acid) (PEG-PLA) micelles, only PTX/LPC but not the PTX/THA pair yields satisfactory colloidal stability. To reveal the molecular mechanism contributing to the colloidal stability of the coencapsulated micelles, we investigated the molecular interactions of PTX/LPC and PTX/THA, through both experimental methods (crystallization kinetics, ¹³C NMR) and molecular dynamic simulation. We observed that PTX was capable of inhibiting LPC but not THA crystallization both in an aqueous environment and in the solid state, which could be attributed to the strong hetero-intermolecular interactions (π-π, H-bonding) between LPC and PTX, which disrupted the homo-intermolecular interactions between LPC molecules and thus formed a favorable miscible binary system. In comparison, the lack of a strong PTX/THA interaction left the strong THA/THA stacking interaction undisturbed and the fast THA crystallization tendency unrestrained. We conclude that the intermolecular interactions, i.e., the "pharmaceutical synergy", between the coencapsulated drugs critically control the colloidal stability of polymeric micelles and, therefore, should be evaluated when coencapsulated drug delivery systems are designed for optimal therapeutic benefits.

Pharmacokinetics and derivation of an anticancer dosing regimen for the novel anti-cancer agent isobutyl-deoxynyboquinone (IB-DNQ), a NQO1 bioactivatable molecule, in the domestic felid species

Isobutyl-deoxynyboquinone (IB-DNQ) is a selective substrate for NAD(P)H:quinone oxidoreductase (NQO1), an enzyme overexpressed in many solid tumors. Following activation by NQO1, IB-DNQ participates in a catalytic futile reduction/reoxidation cycle with consequent toxic reactive oxygen species generation within the tumor microenvironment. To elucidate the potential of IB-DNQ to serve as a novel anticancer agent, in vitro studies coupled with in vivo pharmacokinetic and toxicologic investigations in the domestic felid species were conducted to investigate the tractability of IB-DNQ as a translationally applicable anticancer agent. First, using feline oral squamous cell carcinoma (OSCC) as a comparative cancer model, expressions of NQO1 were characterized in not only human, but also feline OSCC tissue microarrays. Second, IB-DNQ mediated cytotoxicity in three immortalized feline OSCC cell lines were studied under dose-dependent and sequential exposure conditions. Third, the feasibility of administering IB-DNQ at doses predicted to achieve cytotoxic plasma concentrations and biologically relevant durations of exposure were investigated through pharmacokinetic and tolerability studies in healthy research felines. Intravenous administration of IB-DNQ at 1.0-2.0 mg/kg achieved peak plasma concentrations and durations of exposure reaching or exceeding predicted in vitro cytotoxic concentrations. Clinical adverse side effects including ptyalism and tachypnea exhibited during and post-IV infusion of IB-DNQ were transient and tolerable. Additionally, IB-DNQ administration did not produce acute or delayed-onset unacceptable hematologic, non-hematologic, or off-target oxidative toxicities. Collectively, the findings reported here within provide important safety and pharmacokinetic data to support the continued development of IB-DNQ as a novel anticancer strategy for NQO1 expressing cancers.

A recent trend of drug-nanoparticles in suspension for the application in drug delivery

Persistent development in nanomedicine has enabled successful nanosizing of most drug samples which, in turn, imparts remarkable properties to the drugs such as enhanced solubility and bioavailability for the applications in drug delivery. In this context, several review articles are available in scientific domain covering inorganic nanoparticles such as Au, Ag, SPIONs, Qdots, carbon nanotubes and graphene; however, this review covers the development of drug nanoparticles together with their possibilities and limitation from fabrication (bottom up vs top down) to application in drug delivery during the last 5 years. In addition, some distinguished studies and novel drug particles are presented in order to contribute significantly toward the understanding of drug nanocrystals and its use in drug delivery.

Recent trends in nano-based drug delivery systems for efficient delivery of phytochemicals in chemotherapy

The phytochemicals were found to become more soluble when delivered by the nanocarriers and exhibited a remarkable effect on the cancer cells compared to its free form.