Enhanced tumor delivery of gemcitabine via PEG-DSPE/TPGS mixed micelles

Bioactive polymers as stimulus-responsive anti-metastatic combination agents to treat pancreatic cancer

The intractable and devastating nature of pancreatic ductal adenocarcinoma (PDAC) necessitates an urgent need for novel therapies. This study presents the development of a novel polymer prodrug system for the combination treatment of PDAC, based on an optimized pharmacologically active anti-metastatic macromolecular carrier, PCQ, conjugated with gemcitabine (GEM). Structure-activity relationship evaluations showed that random PCQ copolymers exhibited superior anti-migratory activity compared to the gradient PCQ analogs. GEM was incorporated into the random PCQ copolymers using disulfide linker to prepare a reduction-responsive prodrug, PCQ(r)6-SS-GEM12. The resultant therapeutic system presents a pharmacologically active delivery strategy that targets both the proliferative and the metastatic phenotype in PDAC. The PCQ(r)6-SS-GEM12 prodrug demonstrated a selective release of GEM under the reductive tumor environment leading to a significant inhibition of tumor growth with pronounced anti-metastatic effect. Collectively, our data show that the combination of anti-metastatic PCQ and cytotoxic GEM-based reduction-responsive prodrug polymer offers an innovative strategy to treat PDAC.

Tailoring the Composition of HA/PEG Mixed Nano-Assemblies for Anticancer Drug Delivery

Self-assembling amphiphilic polymers represent highly promising materials with emerging applications across various fields. In these polymers, the presence of hydrophilic and hydrophobic segments within their structure drives the self-assembly process in aqueous environments, leading to organized structures capable of incorporating lipophilic drugs. Their high chemical versatility enables the design of tailored structures to meet specific requirements, such as the active targeting ability, thereby broadening their potential applications. In this work, a polyethylene glycol-phospholipid conjugate was employed to form nanocarriers loaded with a lipophilic derivative of gemcitabine. To achieve nano-assemblies actively targeted towards cancer cells overexpressing the hyaluronic acid (HA) receptor CD44, a HA-phospholipid conjugate was co-formulated in various molar ratios (1%, 10%, and 20%). All formulations exhibited a mean diameter below 130 nm, a negative zeta potential (approximately -30 mV), and a high encapsulation efficiency (above 90%). These nano-assemblies demonstrated stability during storage and effectively released the encapsulated drug in a cell culture medium. Upon incubation with cancer cells, the nano-assemblies were internalized via a CD44 endocytosis-mediated mechanism, with the extent of internalization depending on the HA conjugate content. Consistently, cell viability studies revealed that the nanocarriers decorated with higher amounts of HA exerted a higher cytotoxicity, enabling a fine tuning of the nano-assembly properties.

Improved Antitumor Efficiency of N4 -Tetradecyloxycarbonyl Gemcitabine-Loaded Liposomes for Pancreatic Cancer Chemotherapy

Background

Gemcitabine (Gem) is one of the first-line chemotherapy drugs for pancreatic cancer treatment. However, its short half-life in plasma and adverse effects limited its broader application.

Methods

A novel Gem derivative (N4 -tetradecyloxycarbonyl gemcitabine, tcGem) was synthesized and encapsulated into liposomes (LipotcGem) to overcome the above shortcomings.

Results

LipotcGem has been successfully formulated, with the average size of 115 nm, zeta potential values of -36 mV, encapsulation efficiency of up to 98%, and drug loading capacity of 8.1%. Compared to Gem, LipotcGem improved in vitro antitumor activity significantly, as evidenced by the lower IC50, the higher percentage of apoptotic cells, the stronger ability to inhibit cell migration and invasion due to the higher cellular accumulation (100 times). Additionally, the endocytosis of LipotcGem was mainly mediated by caveolae, and was then processed in the lysosome, where tcGem was released and hydrolyzed into Gem. LipotcGem inhibited tumor growth by 70% in subcutaneous xenograft model and 90% in orthotopic xenograft model, respectively. LipotcGem suppressed tumor metastasis and prolonged survival without perceptible systemic toxicity, which may be caused by the longer t1/2 in vivo (3.5 times, 5.23 vs 1.46 h) and more enrichment in tumor tissue (750 times).

Conclusion

LipotcGem significantly increased the anti-tumor efficiency and decreased the toxicity for chemotherapy of pancreatic cancer.

Cancer cell membrane-modified Soluplus® micelles for gemcitabine delivery to pancreatic cancer using a prodrug approach

Pancreatic cancer (PC) is one of the most lethal malignancies worldwide and its incidence is increasing. Chemotherapy is often associated to limited efficacy, poor targeting and systemic toxicity. In this work, the hydrophilic gemcitabine (GEM), widely used in PC treatment alone or in combination, was conjugated with vitamin E succinate (VES) and encapsulated in Soluplus® micelles. This prodrug approach facilitated encapsulation of the anticancer drug into the self-assembled copolymer micelles. Soluplus®/VES-GEM micelles were optimized regarding the ratio of the components and the preparation process. The micelles were small-sized (<80 nm), monodisperse, and highly stable, efficiently retaining the conjugate drug and showing significant antiproliferative activity against BxPC3 cell line. To improve biofunctionalization and targeting properties of prepared Soluplus®/VES-GEM micelles, biomimetic modification with PC cell membrane was further attempted by co-extruding PC cell membrane (BxPC3) nanovesicles with Soluplus®/VES-GEM micelles. Several protocols were attempted to prepare the BxPC3-modified Soluplus®/VES-GEM micelles and the outcomes were analyzed in detail. Overall, the results pave the way to innovative PC-targeted nanotherapies by maximizing GEM encapsulation in hydrophobic compartments with high stability and affinity. The results also highlight the need of higher resolution techniques to characterize cell membrane coating of nanocarriers bearing highly hydrophilic shells.

Innovative Encapsulation Strategies for Food, Industrial, and Pharmaceutical Applications

Bioactive metabolites obtained from fruits and vegetables as well as many drugs have various capacities to prevent or treat various ailments. Nevertheless, their efficiency, in vivo, encounter many challenges resulting in lower efficacy as well as different side effects when high doses are used resulting in many challenges for their application. Indeed, demand for effective treatments with no or less unfavorable side effects is rising. Delivering active molecules to a particular site of action within the human body is an example of targeted therapy which remains a challenging field. Developments of nanotechnology and polymer science have great promise for meeting the growing demands of efficient options. Encapsulation of active ingredients in nano-delivery systems has become as a vitally tool for protecting the integrity of critical biochemicals, improving their delivery, enabling their controlled release and maintaining their biological features. Here, we examine a wide range of nano-delivery techniques, such as niosomes, polymeric/solid lipid nanoparticles, nanostructured lipid carriers, and nano-emulsions. The advantages of encapsulation in targeted, synergistic, and supportive therapies are emphasized, along with current progress in its application. Additionally, a revised collection of studies was given, focusing on improving the effectiveness of anticancer medications and addressing the problem of antimicrobial resistance. To sum up, this paper conducted a thorough analysis to determine the efficacy of encapsulation technology in the field of drug discovery and development.

Oral Delivery of Photopolymerizable Nanogels Loaded with Gemcitabine for Pancreatic Cancer Therapy: Formulation Design, and in vitro and in vivo Evaluations

Background

Gemcitabine (GEM) faces challenges of poor oral bioavailability and extensive first-pass metabolism. Currently, only injectable formulations are available for clinical use. Hence, there is an urgent demand for the development of advanced, efficacious, and user-friendly dosage forms to maintain its status as the primary treatment for pancreatic ductal adenocarcinoma (PDAC). Nanogels (NGs) offer a novel oral drug delivery system, ideal for hydrophilic compounds like GEM. This study aims to develop NGs tailored for GEM delivery, with the goal of enhancing cellular uptake and gastrointestinal permeability for improved administration in PDAC patients.

Methods

We developed cross-linked NGs via photopolymerization of methacryloyl for drug delivery of GEM. We reveal characterization, cytotoxicity, and cellular uptake studies in Caco-2 and MIA PaCa-2 cells. In addition, studies of in vitro permeability and pharmacokinetics were carried out to evaluate the bioavailability of the drug.

Results

Our results show NGs, formed via photopolymerization of methacryloyl, had a spherical shape with a size of 233.91±7.75 nm. Gemcitabine-loaded NGs (NGs-GEM) with 5% GelMA exhibited efficient drug loading (particle size: 244.07±19.52 nm). In vitro drug release from NGs-GEM was slower at pH 1.2 than pH 6.8. Cellular uptake studies indicated significantly enhanced uptake in both MIA PaCa-2 and Caco-2 cells. While there was no significant difference in GEM's AUC and Cmax between NGs-GEM and free-GEM groups, NGs-GEM showed markedly lower dFdU content (10.07 hr∙μg/mL) compared to oral free-GEM (19.04 hr∙μg/mL) after oral administration (p<0.01), highlighting NGs' efficacy in impeding rapid drug metabolism and enhancing retention.

Conclusion

In summary, NGs enhance cellular uptake, inhibit rapid metabolic degradation of GEM, and prolong retention after oral administration. These findings suggest NGs-GEM as a promising candidate for clinical use in oral pancreatic cancer therapy.

Recent advances in drug delivery and targeting for the treatment of pancreatic cancer

Despite significant treatment efforts, pancreatic ductal adenocarcinoma (PDAC), the deadliest solid tumor, is still incurable in the preclinical stages due to multifacet stroma, dense desmoplasia, and immune regression. Additionally, tumor heterogeneity and metabolic changes are linked to low grade clinical translational outcomes, which has prompted the investigation of the mechanisms underlying chemoresistance and the creation of effective treatment approaches by selectively targeting genetic pathways. Since targeting upstream molecules in first-line oncogenic signaling pathways typically has little clinical impact, downstream signaling pathways have instead been targeted in both preclinical and clinical studies. In this review, we discuss how the complexity of various tumor microenvironment (TME) components and the oncogenic signaling pathways that they are connected to actively contribute to the development and spread of PDAC, as well as the ways that recent therapeutic approaches have been targeted to restore it. We also illustrate how many endogenous stimuli-responsive linker-based nanocarriers have recently been developed for the specific targeting of distinct oncogenes and their downstream signaling cascades as well as their ongoing clinical trials. We also discuss the present challenges, prospects, and difficulties in the development of first-line oncogene-targeting medicines for the treatment of pancreatic cancer patients.

Gemcitabine-Vitamin E Prodrug-Loaded Micelles for Pancreatic Cancer Therapy

Pancreatic cancer (PC) is an aggressive cancer subtype presenting unmet clinical challenges. Conventional chemotherapy, which includes antimetabolite gemcitabine (GEM), is seriously undermined by a short half-life, its lack of targeting ability, and systemic toxicity. GEM incorporation in self-assembled nanosystems is still underexplored due to GEM's hydrophilicity which hinders efficient encapsulation. We hypothesized that vitamin E succinate-GEM prodrug (VES-GEM conjugate) combines hydrophobicity and multifunctionalities that can facilitate the development of Pluronic® F68 and Pluronic® F127 micelle-based nanocarriers, improving the therapeutic potential of GEM. Pluronic® F68/VES-GEM and Pluronic® F127/VES-GEM micelles covering a wide range of molar ratios were prepared by solvent evaporation applying different purification methods, and characterized regarding size, charge, polydispersity index, morphology, and encapsulation. Moreover, the effect of sonication and ultrasonication and the influence of a co-surfactant were explored together with drug release, stability, blood compatibility, efficacy against tumour cells, and cell uptake. The VES-GEM conjugate-loaded micelles showed acceptable size and high encapsulation efficiency (>95%) following an excipient reduction rationale. Pluronic® F127/VES-GEM micelles evidenced a superior VES-GEM release profile (cumulative release > 50%, pH = 7.4), stability, cell growth inhibition (<50% cell viability for 100 µM VES-GEM), blood compatibility, and extensive cell internalization, and therefore represent a promising approach to leveraging the efficacy and safety of GEM for PC-targeted therapies.

PEGylated Strontium Sulfite Nanoparticles with Spontaneously Formed Surface-Embedded Protein Corona Restrict Off-Target Distribution and Accelerate Breast Tumour-Selective Delivery of siRNA

As transporters of RNAi therapeutics in preclinical and clinical studies, the application of nanoparticles is often hindered by their susceptibility to opsonin-mediated clearance, poor biological stability, ineffectual targeting, and undesirable effects on healthy cells. Prolonging the blood circulation time while minimizing the off-target distribution and associated toxicity is indispensable for the establishment of a clinically viable delivery system for therapeutic small interfering RNAs (siRNAs). Herein, we report a scalable and straightforward approach to fabricate non-toxic and biodegradable pH-responsive strontium sulfite nanoparticles (SSNs) wrapped with a hydrophilic coating material, biotinylated PEG to lessen unforeseen biological interactions. Surface functionalization of SSNs with PEG led to the generation of small and uniformly distributed particles with a significant affinity towards siRNAs and augmented internalization into breast cancer cells. A triple quadrupole liquid chromatography-mass spectrometry (LC-MS) was deployed to identify the proteins entrapped onto the SSNs, with the help of SwissProt.Mus_musculus database. The results demonstrated the reduction of opsonin proteins adsorption owing to the stealth effect of PEG. The distribution of PEGylated SSNs in mice after 4 h and 24 h of intravenous administration in breast tumour-bearing mice was found to be significantly less to the organs of the reticuloendothelial system (RES) and augmented accumulation in the tumour region. The anti-EGFR siRNA-loaded PEG-SSNs exerted a significant inhibitory effect on tumour development in the murine breast cancer model without any significant toxicity to healthy tissues. Therefore, PEGylated SSNs open up a new avenue for tumour-selective efficient delivery of siRNAs in managing breast cancer.

Multimodal targeting of glioma with functionalized nanoparticles

The most common and aggressive primitive intracranial tumor of the central nervous system is the glioma. The blood–brain barrier (BBB) has proven to be a significant obstacle to the effective treatment of glioma. To effectively treat glioma, different ways have been used to cross the BBB to deliver drugs to the brain. Drug delivery through nanocarriers proves to be an effective and non-invasive technique for the treatment of glioma and has great potential in the treatment of glioma. In this review, we will provide an overview of nanocarrier-mediated drug delivery and related glioma therapy. Nanocarrier-mediated drug delivery techniques to cross the BBB (liposomes, micelles, inorganic systems, polymeric nanoparticles, nanogel system, and biomimetic nanoparticles) are explored. Finally, the use of nanotherapeutic approaches in the treatment of glioblastoma including chemotherapy, radiotherapy, photothermal therapy, gene therapy, glioma genome editing, immunotherapy, chimeric antigen receptor (CAR) T-cells, immune checkpoint modulators, immune photothermal therapy, vaccine-based immunotherapy, and combination therapy is summarized. Furthermore, this article offers various views on the clinical applicability of nanomedicine.

Preliminary Study on the Therapeutic Effect of Doxorubicin-Loaded Targeting Nanoparticles on Glioma

Doxorubicin (DOX) is an anthracycline anticancer drug, which is often associated with drug resistance and cytotoxicity. More unfortunately, the biological barrier in the human environment can weaken the efficacy of DOX, such as the blood-brain barrier (BBB). This work attempts to make efforts to solve this problem. We used polyethylene glycol distearoylphosphatidylethanolamine (PEG-DSPE) as a nanocarrier and DOX as a model drug to construct a composite nanodrug (TF-PEG-DSPE/DOX NPs) by coupling transferrin (TF). The results of glioma experiments show that the nanodrug can effectively penetrate BBB to achieve an antitumor effect.

Emerging pro-drug and nano-drug strategies for gemcitabine-based cancer therapy

Gemcitabine has been extensively applied in treating various solid tumors. Nonetheless, the clinical performance of gemcitabine is severely restricted by its unsatisfactory pharmacokinetic parameters and easy deactivation mainly because of its rapid deamination, deficiencies in deoxycytidine kinase (DCK), and alterations in nucleoside transporter. On this account, repeated injections with a high concentration of gemcitabine are adopted, leading to severe systemic toxicity to healthy cells. Accordingly, it is highly crucial to fabricate efficient gemcitabine delivery systems to obtain improved therapeutic efficacy of gemcitabine. A large number of gemcitabine pro-drugs were synthesized by chemical modification of gemcitabine to improve its biostability and bioavailability. Besides, gemcitabine-loaded nano-drugs were prepared to improve the delivery efficiency. In this review article, we introduced different strategies for improving the therapeutic performance of gemcitabine by the fabrication of pro-drugs and nano-drugs. We hope this review will provide new insight into the rational design of gemcitabine-based delivery strategies for enhanced cancer therapy.

Nanomedicine in Pancreatic Cancer: Current Status and Future Opportunities for Overcoming Therapy Resistance

Simple Summary

Despite access to a vast arsenal of anticancer agents, many fail to realise their full therapeutic potential in clinical practice. One key determinant of this is the evolution of multifaceted resistance mechanisms within the tumour that may either pre-exist or develop during the course of therapy. This is particularly evident in pancreatic cancer, where limited responses to treatment underlie dismal survival rates, highlighting the urgent need for new therapeutic approaches. Here, we discuss the major features of pancreatic tumours that contribute to therapy resistance, and how they may be alleviated through exploitation of the mounting and exciting promise of nanomedicines; a unique collection of nanoscale platforms with tunable and multifunctional capabilities that have already elicited a widespread impact on cancer management.

Abstract

The development of drug resistance remains one of the greatest clinical oncology challenges that can radically dampen the prospect of achieving complete and durable tumour control. Efforts to mitigate drug resistance are therefore of utmost importance, and nanotechnology is rapidly emerging for its potential to overcome such issues. Studies have showcased the ability of nanomedicines to bypass drug efflux pumps, counteract immune suppression, serve as radioenhancers, correct metabolic disturbances and elicit numerous other effects that collectively alleviate various mechanisms of tumour resistance. Much of this progress can be attributed to the remarkable benefits that nanoparticles offer as drug delivery vehicles, such as improvements in pharmacokinetics, protection against degradation and spatiotemporally controlled release kinetics. These attributes provide scope for precision targeting of drugs to tumours that can enhance sensitivity to treatment and have formed the basis for the successful clinical translation of multiple nanoformulations to date. In this review, we focus on the longstanding reputation of pancreatic cancer as one of the most difficult-to-treat malignancies where resistance plays a dominant role in therapy failure. We outline the mechanisms that contribute to the treatment-refractory nature of these tumours, and how they may be effectively addressed by harnessing the unique capabilities of nanomedicines. Moreover, we include a brief perspective on the likely future direction of nanotechnology in pancreatic cancer, discussing how efforts to develop multidrug formulations will guide the field further towards a therapeutic solution for these highly intractable tumours.

Gemcitabine-retinoid prodrug loaded nanoparticles display in vitro antitumor efficacy towards drug-resilient human PANC-1 pancreatic cancer cells

The treatment of pancreatic cancer with gemcitabine is hampered by its rapid metabolism in vivo, the dense stroma around the tumor site which prevents the drug from reaching the cancerous cells and drug resistance. To address these challenges, this study describes the preparation of a retinoid prodrug of gemcitabine, GemRA (gemcitabine conjugated to retinoic acid), and its formulation into a nanoparticulate system applicable for pancreatic cancer treatment. Retinoic acid targets stellate cells which are part of the stroma and can thus augment the delivery of gemcitabine. GemRA dissolved in dimethylsulfoxide presented efficacy towards PANC-1 (human) and mT4 (mouse) pancreatic cancer cell lines but its poor solubility in aqueous solution affects its applicability. Thus, the preparation of the nanoparticles was initially attempted through self-assembly of GemRA, which resulted in the formation of unstable aggregates that precipitated during preparation. As a result, encapsulation of the drug into micelles of polyethylene glycol-retinoic acid (PGRA) amphiphilic conjugates was accomplished and resulted in successful incorporation of GemRA into nanoparticles of ca. 33 nm by dynamic light scattering and 25 nm by transmission electron microscopy. The nanoparticles had good stability in aqueous media and protected gemcitabine from the enzymatic action of cytidine deaminase, which converts gemcitabine to its inactive metabolite upon circulation. Cellular uptake of the nanoparticles by PANC-1 cells was confirmed by fluorescence spectroscopy and flow cytometry. Treatment of PANC-1 cells in vitro with the prodrug-loaded nanoparticles resulted in a significant reduction in cell viability (IC50 ca. 5 μM) compared to treatment with gemcitabine (IC50 > 1000 μM). The ability of the GemRA-loaded nanoparticles to induce cellular apoptosis of treated PANC-1 cells was ascertained via a TUNEL assay suggesting these nanoparticles are effective in pancreatic cancer treatment.

Emerging insights on drug delivery by fatty acid mediated synthesis of lipophilic prodrugs as novel nanomedicines

Many drug molecules that are currently in the market suffer from short half-life, poor absorption, low specificity, rapid degradation, and resistance development. The design and development of lipophilic prodrugs can provide numerous benefits to overcome these challenges. Fatty acids (FAs), which are lipophilic biomolecules constituted of essential components of the living cells, carry out many necessary functions required for the development of efficient prodrugs. Chemical conjugation of FAs to drug molecules may change their pharmacodynamics/pharmacokinetics in vivo and even their toxicity profile. Well-designed FA-based prodrugs can also present other benefits, such as improved oral bioavailability, promoted tumor targeting efficiency, controlled drug release, and enhanced cellular penetration, leading to improved therapeutic efficacy. In this review, we discuss diverse drug molecules conjugated to various unsaturated FAs. Furthermore, various drug-FA conjugates loaded into various nanostructure delivery systems, including liposomes, solid lipid nanoparticles, emulsions, nano-assemblies, micelles, and polymeric nanoparticles, are reviewed. The present review aims to inspire readers to explore new avenues in prodrug design based on the various FAs with or without nanostructured delivery systems.

Intestinal OCTN2- and MCT1-targeted drug delivery to improve oral bioavailability

Various drug transporters are widely expressed throughout the intestine and play important roles in absorbing nutrients and drugs, thus providing high quality targets for the design of prodrugs or nanoparticles to facilitate oral drug delivery. In particular, intestinal carnitine/organic cation transporter 2 (OCTN2) and mono-carboxylate transporter protein 1 (MCT1) possess high transport capacities and complementary distributions. Therefore, we outline recent developments in transporter-targeted oral drug delivery with regard to the OCTN2 and MCT1 proteins in this review. First, basic information of the two transporters is reviewed, including their topological structures, characteristics and functions, expression and key features of their substrates. Furthermore, progress in transporter-targeting prodrugs and nanoparticles to increase oral drug delivery is discussed, including improvements in the oral absorption of anti-inflammatory drugs, antiepileptic drugs and anticancer drugs. Finally, the potential of a dual transporter-targeting strategy is discussed.

Gemcitabine loaded autologous exosomes for effective and safe chemotherapy of pancreatic cancer

Pancreatic cancer remains one of the most highly lethal diseases with very poor prognosis. Gemcitabine (GEM) is the first-line chemotherapeutic drug for pancreatic cancer treatment but is associated with significant side effects when administered systemically. Exosomes have emerged as attractive candidates for drug delivery for their high delivery efficiency and biocompatibility. Here, GEM was loaded into autologous exosomes to formulate ExoGEM for targeted chemotherapy of pancreatic cancer. Autologous exosomes facilitate cellular uptake of GEM and contributed to significantly increased cytotoxic effect of GEM, while heterologous cellular uptake showed less efficiency. Autologous exosomes showed targeting ability to pancreatic cancer in biodistribution study, and GEM concentration in tumor site was increased via ExoGEM delivery. ExoGEM treatment, in tumor-bearing mice, significantly suppressed tumor growth, with prolonged survival in a dose-response manner, but caused minimal damage to normal tissues. More importantly, tumors in several mice treated with ExoGEM were disappeared without recurrence. Autologous exosomes are safe and effective vehicles for targeted delivery of GEM against pancreatic cancer. This delivery strategy may have implications for personalized chemotherapy of pancreatic cancer. STATEMENT OF SIGNIFICANCE: Exosomes are efficient delivery vehicles in intracellular communication. Moreover, potential tropism of autologous exosomes to the tumor microenvironment make them competitive delivery vehicles. The use of cancer-derived exosomes for drug delivery and superior targeting efficacy and enhanced anticancer efficacy of therapeutics have been evidenced. Gemcitabine is a mainstay for pancreatic treatment. However, poor cellular uptake and low targeting effects of gemcitabine often lead to severe systemic toxicity. Therefore, to overcome this limitation, we herein loaded gemcitabine into autologous pancreatic cancer-derived exosomes for the targeted chemotherapy of pancreatic cancer.

Lipid-drug conjugates and associated carrier strategies for enhanced antiretroviral drug delivery

Mortality rate of patients infected with HIV-1 has been significantly reduced by using HAART. However, the virus to date has not been eradicated. Transmission of HIV-1 infection through sexual intercourse remains an ongoing challenge, with increased risk of infection occurring in women. Interestingly, ARV drugs can be chemically linked with lipids to produce lipid-drug conjugates (LDCs). This alters pharmacokinetic properties of ARV drugs and thereby resulting in improved effectiveness. Although LDCs can be administered without a delivery carrier, they are usually incorporated into suitable delivery systems such as lipid nanoparticles, polymeric nanoparticles, micelles, liposomes, emulsions, and carbon nanotubes. Given that LDCs have the potential to improve oral bioavailability, lipophilicity, toxicity, and drug targeting, it is of our great interest to review strategies of lipid-drug conjugation together with their delivery systems for enhanced antiretroviral efficacy.

A novel gemcitabine derivative-loaded liposome with great pancreas-targeting ability

Gemcitabine (Gem) is a standard first-line treatment for pancreatic cancer (PC). However, its chemotherapeutic efficacy is hampered by various limitations such as short half-life, metabolic inactivation, and lack of tumor localizing. We previously synthesized a lipophilic Gem derivative (Gem formyl hexadecyl ester, GemC16) that exhibited improved antitumor activity in vitro. In this study, a target ligand N,N-dimethyl-1,3-propanediamine was conjugated to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[hydroxyl succinimidyl (polyethylene glycol-2000)] (DSPE-PEG-NHS) to form DSPE-PEG-2N. Then, pancreas-targeting liposomes (2N-LPs) were prepared using the film dispersion-ultrasonic method. GemC16-loaded 2N-LPs displayed near-spherical shapes with an average size distribution of 157.2 nm (polydispersity index (PDI) = 0.201). The encapsulation efficiency of GemC16 was up to 97.3% with a loading capacity of 8.9%. In human PC cell line (BxPC-3) and rat pancreatic acinar cell line (AR42J), cellular uptake of 2N-LPs was significantly enhanced compared with that of unmodified PEG-LPs. 2N-LPs exhibited more potent in vitro cytotoxicity against BxPC-3 and AR42J cell lines than PEG-LPs. After systemic administration in mice, 2N-LPs remarkably increased drug distribution in the pancreas. In an orthotopic tumor mouse model of PC, GemC16-bearing liposomes were more effective in preventing tumor growth than free GemC16. Among these treatments, 2N-LPs showed the best curative effect. Together, 2N-LPs represent a promising nanocarrier to achieve pancreas-targeting drug delivery, and this work would provide new ideas for the chemotherapy of PC.

3,5,4'-trimethoxy-trans-stilbene loaded PEG-PE micelles for the treatment of colon cancer

Background

3,5,4′-trimethoxy-trans-stilbene (BTM) is a methylated derivative of resveratrol. To improve the pharmaceutical properties of BTM, BTM loaded PEG-PE micelles (BTM@PEG-PE) were fabricated and its anti-cancer efficacy against colon cancer was evaluated.

Methods

BTM@PEG-PE micelles were prepared by the solvent evaporation method and were characterized by nuclear magnetic resonance (NMR), size, zeta potential, polymer disperse index (PDI) and transmission electron microscopy (TEM). Cellular uptake, cell viability assay, caspase-3 activity assay and flow cytometry were performed to evaluate the cell internalization and anti-cancer efficacy of BTM@PEG-PE micelles in vitro. Pharmacokinetic profiles of BTM and BTM@PEG-PE micelles were compared and in vivo anti-cancer therapeutic efficacy and safety of BTM@PEG-PE micelles on CT26 xenograft mice were evaluated.

Results

BTM was successfully embedded in the core of PEG-PE micelles, with a drug loading capacity of 5.62±0.80%. PEG-PE micelles facilitated BTM entering to the CT26 cells and BTM@PEG-PE micelles exerted enhanced anti-cancer efficacy against CT26 cells. BTM@PEG-PE micelles showed prolonged half-life and increased bioavailability. More importantly, BTM@PEG-PE micelles treatment suppressed tumor growth in tumor-bearing mice and prolonged survival with minimal damage to normal tissues.

Conclusion

Altogether, the BTM@PEG-PE micelles might be a promising strategy to enhance the pharmacokinetic and pharmacodynamic potentials of BTM for colon cancer therapy.

Puerarin-loaded PEG-PE micelles with enhanced anti-apoptotic effect and better pharmacokinetic profile

Puerarin (PUE) is the most abundant isoflavonoid in kudzu root. It is widely used as a therapeutic agent for the treatment of cardiovascular diseases. However, the short elimination half-life, poor-bioavailability, and acute intravascular hemolysis of PUE are the main obstacles to its widespread clinical applications. Whereas PEG-PE micelles possess the ability to release medicine slowly, enhance the cellular uptake of drugs and improve their biocompatibility. Therefore, it was aim to fabricate puerarin-loaded PEG-PE (PUE@PEG-PE) micelles to improve the pharmaceutical properties of drugs. It can be observed from the TEM images that PUE@PEG-PE micelles appeared obvious core-shell structure and remained well-dispersed without aggregation and adhesion. PUE was successfully embedded in the core of PEG-PE micelles, which was confirmed by FT-IR and ¹H NMR spectra. In vitro studies showed that PUE@PEG-PE micelles exhibited a sustained release behavior in pH 7.4 PBS buffer and decreased hemolysis rate of PUE. Compared with PUE, PUE@PEG-PE micelles showed a 3.2-fold increase in the half-life of PUE and a 1.58-fold increase in bioavailability. In addition, the PUE@PEG-PE micelles exerted enhanced protective effect against isoprenaline-induced H9c2 cells apoptosis compared with PUE, as evident by decreased percentage of Hoechst-positive cells, Caspase 3 activity, Bax expression, and increased Bcl-2 expression. Notably, the PEG-PE micelles exhibited favorable cellular uptake efficiency on H9c2 cells, and this may account for their enhanced anti-apoptotic effect of the incorporated drug. Altogether, the PUE@PEG-PE micelles were not only able to control the drug release but also offered promise to enhance the pharmacokinetic and pharmacodynamic potential of PUE.

Stereocomplex Prodrugs of Oligo(lactic acid) n-Gemcitabine in Poly(ethylene glycol)- block-poly(d,l-lactic acid) Micelles for Improved Physical Stability and Enhanced Antitumor Efficacy

Herein we demonstrate the formation of stereocomplex prodrugs of oligo(l-lactic acid) _n-gemcitabine (o(LLA) _n-GEM) and oligo(d-lactic acid) _n-gemcitabine (o(DLA) _n-GEM) for stable incorporation in poly(ethylene glycol)- block-poly(d,l-lactic acid) (PEG- b-PLA) micelles. O(LLA) _n or o(DLA) _n was attached at the amino group (4-( N)) of GEM via an amide linkage. When n = 10, a 1:1 mixture of o(LLA)₁₀-GEM and o(DLA)₁₀-GEM (o(L+DLA)₁₀-GEM) was able to form a stereocomplex with a distinctive crystalline pattern. Degradation of o(L+DLA)₁₀-GEM was driven by both backbiting conversion and esterase contribution, generating primarily o(L+DLA)₁-GEM and GEM. O(L+DLA)₁₀-GEM stably loaded in PEG- b-PLA micelles in the size range of 140-200 nm with an unexpected elongated morphology. The resulting micelles showed improved physical stability in aqueous media and inhibited backbiting conversion of o(L+DLA)₁₀-GEM within micelles. Release of o(L+DLA)₁₀-GEM from micelles was relatively slow, with a t_1/2 at ca. 60 h. Furthermore, weekly administration of o(L+DLA)₁₀-GEM micelles i.v. displayed potent antitumor activity in an A549 human non-small-cell lung carcinoma xenograft model. Thus, stereocomplexation of isotactic o(LLA) _n and o(DLA) _n acts as a potential prodrug strategy for improved stability and sustained drug release in PEG- b-PLA micelles.

PEGylation of Carbonate Apatite Nanoparticles Prevents Opsonin Binding and Enhances Tumor Accumulation of Gemcitabine

pH sensitives carbonate apatite (CA) has emerged as a targeted delivery vehicle for chemotherapeutics agent with tremendous potential to increase the effectivity of breast cancer treatment. The major challenge for intravenous delivery of drug-incorporated nanoparticles is their rapid opsonization, resulting in accumulation within the organs of reticuloendothelial system, such as liver and spleen. Therefore, surface modification by polyethylene glycol was implemented to improve the half-life of drug-particle complexes and enhance their uptake by target tissues. A simple, rapid, and sensitive triple quadrupole liquid chromatography-mass spectrometry method was developed and validated for quantification of gemcitabine in plasma, various organs and tumor tissues of mice with breast carcinoma, whereas sodium dodecyl sulfate-polyacrylamide gel electrophoresis, quadrupole-time of flight liquid chromatography-mass spectrometry and analysis by SwissProt.Mus_musculus database were performed for protein separation, identification, and homology search by comparing the de novo sequence tag. PEGylated CA exhibited almost 6-fold increase in gemcitabine accumulation in tumor with significant reduction in other organs within 1 h of intravenous administration, compared to free drug. In addition, plasma drug amount was found to be higher in PEGylated particles, implying their role in prolonging blood circulation time of particle-bound gemcitabine. Investigation of protein corona composition demonstrated notable reduction in opsonin interactions after PEGylation of CA particles. Overall, the results indicate that the composition and dynamics of protein corona subjected to alteration by PEGylation play crucial roles in affecting successful nanoparticle-based targeted delivery of a cytotoxic drug.

Formulation and Pharmacokinetics of HSA-core and PLGA-shell Nanoparticles for Delivering Gemcitabine

Gemcitabine-loaded core-shell nanoparticles (CSNPs), comprised of a cross-linked HSA-core and PLGA-shell, were prepared through a modified double emulsification method, and the processing parameters were systematically investigated. The optimized CSNPs had a particle size of 241 ± 36.2 nm and an encapsulation efficiency of 41.52%. The core-shell structure was characterized by optical microscope (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The amorphous nature of the encapsulated drug was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). An in vitro release study demonstrated that the CSNPs had an improved sustained release profile controlled by erosion of materials in combination with drug diffusion. In vivo pharmacokinetics of CSNPs obtained a bigger area under concentration-time curve (AUC), t _1/2, and C _max compared to free drug solution. The results suggest that HSA-PLGA-based CSNPs can be a promising carrier for the sustained release of gemcitabine.

Combination of Oxaliplatin and Vit.E-TPGS in Lipid Nanosystem for Enhanced Therapeutic Efficacy in Colon Cancers

PURPOSE

The main aim of present study was to prepare the oxaliplatin (OXL)-loaded D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS)-based lipid nanoparticles to enhance the anticancer effect in colon cancer cells.

METHODS

The nanoparticles were nanosized and spherical shaped and exhibited controlled release kinetics. Flow cytometer and confocal laser scanning microscopy (CLSM) showed a remarkable uptake of nanoparticles in cancer cells in a time-dependent manner.

RESULTS

The presence of TPGS remarkably increased the anticancer effect of OXL in HT-29 colon cancer cells. The IC50 value of free OXL was 4.25 μg/ml whereas IC50 value of OXL-loaded TPGS-based lipid nanoparticles (OXL/TLNP) was 1.12 μg/ml. The 3-fold lower IC50 value of OXL/TLNP indicates the superior anticancer effect of nanoparticle-based OXL. Consistently, OXL/TLNP induced a remarkable apoptosis of cancer cells. Approximately, ~52% of cells were in early apoptosis phase and ~13% of cells were in late apoptosis phase indicating the potent anticancer effect of the formulations. The findings from this study provide novel insights into the use of TPGS and lipid nanoparticle together for the better antitumor effect in colon cancers. Future studies will involve the detailed in vitro and in vivo studies on clinically relevant animals.

Optimization of Weight Ratio for DSPE-PEG/TPGS Hybrid Micelles to Improve Drug Retention and Tumor Penetration

PURPOSE

To enhance therapeutic efficacy and prevent phlebitis caused by Asulacrine (ASL) precipitation post intravenous injection, ASL-loaded hybrid micelles with size below 40 nm were developed to improve drug retention and tumor penetration.

METHODS

ASL-micelles were prepared using different weight ratios of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethyleneglycol-2000 (DSPE-PEG₂₀₀₀) and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) polymers. Stability of micelles was optimized in terms of critical micelle concentration (CMC) and drug release properties. The encapsulation efficiency (EE) and drug loading were determined using an established dialysis-mathematic fitting method. Multicellular spheroids (MCTS) penetration and cytotoxicity were investigated on MCF-7 cell line. Pharmacokinetics of ASL-micelles was evaluated in rats with ASL-solution as control.

RESULTS

The ASL-micelles prepared with DSPE-PEG₂₀₀₀ and TPGS (1:1, w/w) exhibited small size (~18.5 nm), higher EE (~94.12%), better sustained in vitro drug release with lower CMC which may be ascribed to the interaction between drug and carriers. Compared to free ASL, ASL-micelles showed better MCTS penetration capacity and more potent cytotoxicity. Pharmacokinetic studies demonstrated that the half-life and AUC values of ASL-micelles were approximately 1.37-fold and 3.49-fold greater than that of free ASL.

CONCLUSIONS

The optimized DSPE-PEG₂₀₀₀/TPGS micelles could serve as a promising vehicle to improve drug retention and penetration in tumor.

A sequential enzyme-activated and light-triggered pro-prodrug nanosystem for cancer detection and therapy

A sequential enzyme-activated and light-triggered pro-prodrug has been developed for cancer biomarker detection and on-demand therapy.

A novel strategy to achieve effective drug delivery: exploit cells as carrier combined with nanoparticles

Cell-mediated drug delivery systems employ specific cells as drug vehicles to deliver drugs to targeted sites. Therapeutics or imaging agents are loaded into these cells and then released in diseased sites. These specific cells mainly include red blood cells, leukocytes, stem cells and so on. The cell acts as a Trojan horse to transfer the drug from circulating blood to the diseased tissue. In such a system, these cells keep their original properties, which allow them to mimic the migration behavior of specific cells to carry drug to the targeted site after in vivo administration. This strategy elegantly combines the advantages of both carriers, i.e. the adjustability of nanoparticles (NPs) and the natural functions of active cells, which therefore provides a new perspective to challenge current obstacles in drug delivery. This review will describe a fundamental understanding of these cell-based drug delivery systems, and discuss the great potential of combinational application of cell carrier and NPs.

Encapsulating a Hydrophilic Chemotherapeutic into Rod-like Nanoparticles of a Genetically Encoded Asymmetric Triblock Polypeptide Improves its Efficacy

Encapsulating hydrophilic chemotherapeutics into the core of polymeric nanoparticles can improve their therapeutic efficacy by increasing their plasma half-life, tumor accumulation and intracellular uptake, and by protecting them from premature degradation. To achieve these goals, we designed a recombinant asymmetric triblock polypeptide (ATBP) that self-assembles into rod-shaped nanoparticles, and which can be used to conjugate diverse hydrophilic molecules, including chemotherapeutics, into their core. These ATBPs consist of three segments: a biodegradable elastin-like polypeptide, a hydrophobic Tyrosine-rich segment, and a short Cysteine-rich segment, that spontaneously self-assemble into rod-shaped micelles. Covalent conjugation of a structurally diverse set of hydrophilic small molecules, including a hydrophilic chemotherapeutic -gemcitabine- to the Cysteine residues also leads to formation of nanoparticles over a range of ATBP concentrations. Gemcitabine-loaded ATBP nanoparticles have significantly better tumor regression compared to free drug in a murine cancer model. This simple strategy of encapsulation of hydrophilic small molecules by conjugation to an ATBP can be used to effectively deliver a range of water-soluble drugs and imaging agents in vivo.

Dual Enzymatic Reaction-Assisted Gemcitabine Delivery Systems for Programmed Pancreatic Cancer Therapy

Dual enzymatic reactions were introduced to fabricate programmed gemcitabine (GEM) nanovectors for targeted pancreatic cancer therapy. Dual-enzyme-sensitive GEM nanovectors were prepared by conjugation of matrix metalloproteinase-9 (MMP-9) detachable poly(ethylene glycol) (PEG), cathepsin B-cleavable GEM, and targeting ligand CycloRGD to CdSe/ZnS quantum dots (QDs). The GEM nanovectors decorated with a PEG corona could avoid nonspecific interactions and exhibit prolonged blood circulation time. After GEM nanovectors were accumulated in tumor tissue by the enhanced permeability and retention (EPR) effect, the PEG corona can be removed by overexpressed MMP-9 in tumor tissue and RGD would be exposed, which was capable of facilitating cellular internalization. Once internalized into pancreatic cancer cells, the elevated lysosomal cathepsin B could further promote the release of GEM. By employing dual enzymatic reactions, the GEM nanovectors could achieve prolonged circulation time while maintaining enhanced cellular internalization and effective drug release. The proposed mechanism of the dual enzymatic reaction-assisted GEM delivery system was fully investigated both in vitro and in vivo. Meanwhile, compared to free GEM, the deamination of GEM nanovectors into inactive 2',2'-difluorodeoxyuridine (dFdU) could be greatly suppressed, while the concentration of the activated form of GEM (gemcitabine triphosphate, dFdCTP) was significantly increased in tumor tissue, thus exhibiting superior tumor inhibition activity with minimal side effects.

Mixed micelles of lipoic acid-chitosan-poly(ethylene glycol) and distearoylphosphatidylethanolamine-poly(ethylene glycol) for tumor delivery

Many chemotherapeutics suffer from poor aqueous solubility and tissue selectivity. Distearoylphosphatidylethanolamine-poly(ethylene glycol) (DSPE-PEG) micelles are a promising formulation strategy for the delivery of hydrophobic anticancer drugs. However, storage and in vivo instability restrict their use. The aim of this study was to prepare mixed micelles, containing a novel polymer, lipoic acid-chitosan-poly(ethylene glycol) (LACPEG), and DSPE-PEG, to overcome these limitations and potentially increase cancer cell internalisation. Drug-loaded micelles were prepared with a model tyrosine kinase inhibitor and characterized for size, surface charge, stability, morphology, drug entrapment efficiency, cell viability (A549 and PC-9 cell lines), in vivo biodistribution, ex vivo tumor accumulation and cellular internalisation. Micelles of size 30-130nm with entrapment efficiencies of 46-81% were prepared. LACPEG/DSPE-PEG mixed micelles showed greater interaction with the drug (condensing to half their size following entrapment), greater stability, and a safer profile in vitro compared to DSPE-PEG micelles. LACPEG/DSPE-PEG and DSPE-PEG micelles had similar entrapment efficiencies and in vivo tumor accumulation levels, but LACPEG/DSPE-PEG micelles showed higher tumor cell internalisation. Collectively, these findings suggest that LACPEG/DSPE-PEG mixed micelles provide a promising platform for tumor delivery of hydrophobic drugs.

Nanotechnology for delivery of gemcitabine to treat pancreatic cancer

Pancreatic cancer (PC) is one of the most deadly and quickly fatal human cancers with a 5-year mortality rate close to 100%. Its prognosis is very poor, mainly because of its hostile biological behavior and late onset of symptoms for clinical diagnosis; these bring limitations on therapeutic interventions. Factors contributing for the difficulties in treating PC include: high rate of drug resistance, fast metastasis to different organs, poor prognosis and relapse of the tumor after therapy. After being approved by US FDA 1997, Gemcitabine (Gem) is the first line and the gold standard drug for all stages of advanced PC till now. However, its efficacy is unsatisfactory, mainly due to; its chemical instability and poor cellular uptake, resulting in an extremely short half-life and low bioavailability. To solve this drawbacks and increase the therapeutic outcome important progress has been achieved in the field of nanotechnology and offers a promising and effective alternative. This review mainly focus on the most commonly investigated nanoparticle (NP) delivery systems of Gem for PC treatment and the latest progresses achieved. Novel nanocarriers with better tumor targeting efficiencies and maximum treatment outcome to treat this deadly due are given much attention.

Lipid-Drug Conjugate for Enhancing Drug Delivery

Lipid-drug conjugates (LDCs) are drug molecules that have been covalently modified with lipids. The conjugation of lipids to drug molecules increases lipophilicity and also changes other properties of drugs. The conjugates demonstrate several advantages including improved oral bioavailability, improved targeting to the lymphatic system, enhanced tumor targeting, and reduced toxicity. Based on the chemical nature of drugs and lipids, various conjugation strategies and chemical linkers can be utilized to synthesize LDCs. Linkers and/or conjugation methods determine how drugs are released from LDCs and are critical for the optimal performance of LDCs. In this review, different lipids used for preparing LDCs and various conjugation strategies are summarized. Although LDCs can be administered without a delivery carrier, most of them are loaded into appropriate delivery systems. The lipid moiety in the conjugates can significantly enhance drug loading into hydrophobic components of delivery carriers and thus generate formulations with high drug loading and superior stability. Different delivery carriers such as emulsions, liposomes, micelles, lipid nanoparticles, and polymer nanoparticles are also discussed in this review.

Biodistribution of Self-Assembling Polymer-Gemcitabine Conjugate after Systemic Administration into Orthotopic Pancreatic Tumor Bearing Mice

Therapeutic efficacy of gemcitabine (GEM) is severely limited due to its rapid metabolism by enzymatic deamination in vivo. We recently determined its therapeutic efficacy before (F-GEM) and after conjugation to poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate) (mPEG-b-PCC-g-GEM-g-DC, abbreviated as P-GEM) in subcutaneous and orthotopic pancreatic tumor bearing mice. In this study, pharmacokinetic (PK) parameters and biodistribution profiles of F-GEM and P-GEM were determined after intravenous injection into orthotopic pancreatic tumor bearing NSG mice. To assess the short-term toxicity, the levels of hematological, hepatic, and renal injury markers were measured after 24 h postadministration into these mice. P-GEM was distributed to all the major organs, with higher accumulation in the liver, spleen, and tumor compared to F-GEM. Area under the curve (AUC), elimination half-life (t_1/2), and mean residence time (MRT) of P-GEM treated group were significantly higher compared to those of F-GEM treated group: 246,425 ± 1605 vs 83,591 ± 1844 ng/mL × h as AUC, 5.77 ± 2.02 vs 1.99 ± 0.09 h as t_1/2, and 4.45 ± 0.15 vs 1.12 ± 0.13 h as MRT. Further, P-GEM exhibited negligible systemic toxicity as evidenced by almost similar alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values for both P-GEM and F-GEM. These results suggest that P-GEM protects GEM from degradation and provides sustained drug release, resulting in enhanced GEM delivery to the tumor by more than 2.5-fold compared to F-GEM. Hence, P-GEM is a promising gemcitabine conjugated polymeric micelle for treating pancreatic cancer.

Synthesis, Characterization, and In Vitro and In Vivo Evaluations of 4-(N)-Docosahexaenoyl 2', 2'-Difluorodeoxycytidine with Potent and Broad-Spectrum Antitumor Activity

In this study, a new compound, 4-(N)-docosahexaenoyl 2′, 2′-difluorodeoxycytidine (DHA-dFdC), was synthesized and characterized. Its antitumor activity was evaluated in cell culture and in mouse models of pancreatic cancer. DHA-dFdC is a poorly soluble, pale yellow waxy solid, with a molecular mass of 573.3 Da and a melting point of about 96°C. The activation energy for the degradation of DHA-dFdC in an aqueous Tween 80–based solution is 12.86 kcal/mol, whereas its stability is significantly higher in the presence of vitamin E. NCI-60 DTP Human Tumor Cell Line Screening revealed that DHA-dFdC has potent and broad-spectrum antitumor activity, especially in leukemia, renal, and central nervous system cancer cell lines. In human and murine pancreatic cancer cell lines, the IC₅₀ value of DHA-dFdC was up to 10⁵-fold lower than that of dFdC. The elimination of DHA-dFdC in mouse plasma appeared to follow a biexponential model, with a terminal phase t_1/2 of about 58 minutes. DHA-dFdC significantly extended the survival of genetically engineered mice that spontaneously develop pancreatic ductal adenocarcinoma. In nude mice with subcutaneously implanted human Panc-1 pancreatic tumors, the antitumor activity of DHA-dFdC was significantly stronger than the molar equivalent of dFdC alone, DHA alone, or the physical mixture of them (1:1, molar ratio). DHA-dFdC also significantly inhibited the growth of Panc-1 tumors orthotopically implanted in the pancreas of nude mice, whereas the molar equivalent dose of dFdC alone did not show any significant activity. DHA-dFdC is a promising compound for the potential treatment of cancers in organs such as the pancreas.

Hyaluronic acid-coated, prodrug-based nanostructured lipid carriers for enhanced pancreatic cancer therapy

CONTEXT

Gemcitabine (GEM) and Baicalein (BCL) are reported to have anti-tumor effects including pancreatic cancer. Hyaluronic acid (HA) can bind to over-expressed receptors in various kinds of cancer cells.

OBJECTIVE

The aim of this study is to develop prodrugs containing HA, BCL and GEM, and construct nanomedicine incorporate GEM and BCL in the core and HA on the surface. This system could target the cancer cells and co-deliver the drugs.

METHODS

GEM-stearic acid lipid prodrug (GEM-SA) and hyaluronic acid-amino acid-baicalein prodrug (HA-AA-BCL) were synthesized. Then, GEM and BCL prodrug-based targeted nanostructured lipid carriers (HA-GEM-BCL NLCs) were prepared by the nanoprecipitation technique. The in vitro cytotoxicity studies of the NLCs were evaluated on AsPC1 pancreatic cancer cell line. In vivo anti-tumor effects were observed on the murine-bearing pancreatic cancer model.

RESULTS

HA-GEM-BCL NLCs were effective in entering pancreatic cancer cells over-expressing HA receptors, and showed cytotoxicity of tumor cells in vitro. In vivo study revealed significant tumor growth inhibition ability of HA-GEM-BCL NLCs in murine pancreatic cancer model.

CONCLUSION

It could be concluded that HA-GEM-BCL NLCs could be featured as promising co-delivery, tumor-targeted nanomedicine for the treatment of cancers.

Recent advances in drug delivery strategies for improved therapeutic efficacy of gemcitabine

Gemcitabine (2',2'-difluoro-2'-deoxycytidine; dFdC) is an efficacious anticancer agent acting against a wide range of solid tumors, including pancreatic, non-small cell lung, bladder, breast, ovarian, thyroid and multiple myelomas. However, short plasma half-life due to metabolism by cytidine deaminase necessitates administration of high dose, which limits its medical applicability. Further, due to its hydrophilic nature, it cannot traverse cell membranes by passive diffusion and, therefore, enters via nucleoside transporters that may lead to drug resistance. To circumvent these limitations, macromolecular prodrugs and nanocarrier-based formulations of Gemcitabine are gaining wide recognition. The nanoformulations based approaches by virtue of their controlled release and targeted delivery have proved to improve bioavailability, increase therapeutic efficacy and reduce adverse effects of the drug. Furthermore, the combination of Gemcitabine with other anticancer agents as well as siRNAs using nanocarriers has also been investigated in order to enhance its therapeutic potential. This review deals with challenges and recent advances in the delivery of Gemcitabine with particular emphasis on macromolecular prodrugs and nanomedicines.

Development and evaluation of vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate-mixed polymeric phospholipid micelles of berberine as an anticancer nanopharmaceutical

Berberine (Brb) is an active alkaloid occurring in various common plant species, with well-recognized potential for cancer therapy. Brb not only augments the efficacy of antineoplastic chemotherapy and radiotherapy but also exhibits direct antimitotic and proapoptotic actions, along with distinct antiangiogenic and antimetastatic activities in a variety of tumors. Despite its low systemic toxicity, several pharmaceutical challenges limit the application of Brb in cancer therapy (ie, extremely low solubility and permeability, very poor pharmacokinetics (PKs), and oral bioavailability). Among lipid-based nanocarriers investigated recently for Brb, stealth amphiphilic micelles of polymeric phospholipid conjugates were studied here as a promising strategy to improve Brb delivery to tumors. Specifically, physicochemically stable micelles made of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (PEG-PE) mixed with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) (PEG-succinate ester of vitamin E), in a 3:1 M ratio, increased Brb solubilization by 300%. Our PEG-PE/TPGS-mixed micelles firmly retained the incorporated Brb, displaying extended-release profile in simulated media, with up to 30-fold projected improvement in simulated PKs of Brb. Owing to the markedly better uptake of Brb-containing mixed micelles in vitro, our Brb-mixed micelles nanoformulation significantly amplified apoptosis and overall cytotoxic effectiveness against monolayer and spheroid cultures of human prostate carcinomas (16- to 18-fold lower half-maximal inhibitory concentration values in PC3 and LNPaC, respectively), compared to free Brb. Mixed PEG-PE/TPGS micelles represent a promising delivery platform for the sparingly soluble anticancer agent, Brb, encouraging further pharmaceutical development of this drug for cancer therapy.

How can nanomedicines overcome cellular-based anticancer drug resistance?

This review discusses the mechanisms of anticancer drug resistance according to its cellular level of action and outlines the nanomedicine-based strategies adopted to overcome it.

Chlorin e6-Encapsulated Polyphosphoester Based Nanocarriers with Viscous Flow Core for Effective Treatment of Pancreatic Cancer

Lack of effective treatment results in the low survival for patients with pancreatic cancer, and photodynamic therapy (PDT) with photosensitizers has emerged as an effective therapeutic option for treatment of various tumors by light-generated cytotoxic reactive oxygen species (ROS) to induce cell apoptosis or necrosis. However, the poor solubility, rapid blood clearance, and weak internalization of the photosensitizer seriously inhibit its anticancer efficacy. To overcome these obstacles, a polyphosphoester-based nanocarrier (NP-PPE) is employed as the carrier of the hydrophobic photosensitizer, chlorin e6 (Ce6), for photodynamic therapy. The Ce6-encapsulated nanocarrier (NP-PPE/Ce6) significantly promoted the cellular internalization of Ce6, enhanced the generation of ROS in the tumor cells after irradiation. Therefore, the cellular phototoxicity of NP-PPE/Ce6 against BxPC-3 pancreatic cancer cells was markedly enhanced than that of free Ce6 in vitro. Furthermore, NP-PPE/Ce6 improved accumulation of Ce6 in tumor tissue and treatment with NP-PPE/Ce6 significantly enhanced antitumor efficacy in human BxPC-3 pancreatic cancer xenografts. These results suggest that using a polyphosphoester-based nanocarrier as the delivery system for a photosensitizer has great potential for PDT of pancreatic cancer.