Pharmacokinetics, biodistribution, efficacy and safety of N-octyl-O-sulfate chitosan micelles loaded with paclitaxel

Synergistic effect of quercetin and pH-responsive DEAE-chitosan carriers as drug delivery system for breast cancer treatment

Amphiphilic chitosans, which may self-assemble in aqueous solution to form nanoaggregates with different conformations depending to the environmental pH, can be used as drug transport and delivery agents, when the target pH differs from the delivery medium pH. In this study, quercetin, a bioactive flavonoid, was encapsulated in a pH-responsive system based on amphiphilic chitosan. The hydrophilic reagent 2-chloro-N,N-diethylethylamine hydrochloride (DEAE), also known to inhibit the proliferation of cancer cells, was used as a grafting agent. Drug loading experiments (DL ∼5%) showed a quercetin entrapment efficiency of 73 and 78% for the aggregates. The sizes of blank aggregates measured by dynamic light scattering (DLS) varied from 169 to 263nm and increased to ∼410nm when loaded with quercetin. The critical aggregation concentration, zeta potential and morphology of the aggregates were determined. pH had a dominant role in the release process and Fickian diffusion was the controlling factor in drug release according to the Korsmeyer-Peppas mathematical model. In vitro studies indicated that the DEAE-modified chitosan nanoaggregates showed a synergistic effect with quercetin on the control of the viability of MCF-7 cells. Therefore, DEAE-modified chitosan nanoaggregates with pH-sensibility can be used as optimized nanocarriers in cancer therapy.

Size optimization and in vitro biocompatibility studies of chitosan nanoparticles

Chitosan (CS), an amino polysaccharide has fascinating scientific applications due to its many flexible properties. The advantages of Chitosan tend to increase when it was modified. Thus, in the present research work, to improve the properties of chitosan, it was converted into chitosan nanoparticles (CS-NPs) through the ionic gelation method using sodium tripoyphosphate (TPP) and sodium hexametaphosphate (SHMP) as a crosslinker. The size optimization was done by varying the parameters such as crosslinker concentration, agitation method and rate, agitation time, temperature and drying method. The prepared samples were characterized using FTIR, TGA, XRD, SEM, TEM and DLS. Also the prepared CS-NPs with TPP and SHMP had been evaluated in vitro for determining its hemocompatibility, biodegradability, serum stability, cytotoxicity and cell viability. The results showed the significant participation of all the parameters in obtaining the nanoparticles in 20-30nm and 5-10nm for CS-NPs-TPP air dried and freeze dried samples and around 60-80nm and 20-30nm for CS-NPs-SHMP air dried and freeze dried samples. The in vitro biological studies revealed that the nanoparticles are non-toxic with a good degree of biodegradability, blood compatibility and stability.

Self-assembled liposomes of dual paclitaxel-phospholipid prodrug for anticancer therapy

In this report, a newly liposomal formulation of paclitaxel (PTX) based on dual paclitaxel succinate glycerophosphorylcholine (Di-PTX-GPC) prodrug was developed. The Di-PTX-GPC prodrug was synthesized by conjugating PTX with GPC through esterification under N,N'-carbonyldiimidazole (CDI) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalytic system. Di-PTX-GPC liposomes were prepared by thin film method and characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The results indicated that the liposomes have an average diameter of 157.9nm with well-defined spherical morphology. In vitro drug release studies confirmed that the Di-PTX-GPC liposomes have controlled release profile of PTX at a weakly acidic environment, which formulates them suitable for sustained drug delivery. Additionally, in vitro cellular uptake analysis and cytotoxicity evaluation showed that Di-PTX-GPC liposomes were internalized successfully into tumor cells to induce the apoptosis against MCF-7, HeLa and HepG-2 cells. In vivo pharmacokinetics study revealed that such liposomal formulation of Di-PTX-GPC has longer retention half-life in bloodstream, which subsequently leads to slight accumulate in tumor sites due to enhanced permeability and retention (EPR) effect. More importantly, Di-PTX-GPC liposomes demonstrated good in vivo anticancer activities compared to Taxol with reduced adverse effects. Conclusively, these results suggest that Di-PTX-GPC liposomes could be an effective PTX delivery vehicles in clinical cancer chemotherapy.

MiR-21 is required for anti-tumor immune response in mice: an implication for its bi-directional roles

Here we show that miR-21, a microRNA known for its oncogenic activity, is also essential for mediating immune responses against tumor. Knockout of miR-21 in mice slowed the proliferation of both CD4⁺ and CD8⁺ cells, reduced their cytokine production and accelerated the grafted tumor growth. Further investigations indicated that miR-21 could activate CD4⁺ and CD8⁺ T cells via the PTEN/Akt pathway in response to stimulations. Taken together, these data suggest the key functions of miR-21 in mediating anti-tumor immune response and thereby uncover a bi-directional role of this traditionally known 'oncomiR' in tumorigenesis. Our study may provide new insights for the design of cancer therapies targeting microRNAs, with an emphasis on the dynamic and possibly unexpected role of these molecules.

Plaque-hyaluronidase-responsive high-density-lipoprotein-mimetic nanoparticles for multistage intimal-macrophage-targeted drug delivery and enhanced anti-atherosclerotic therapy

Increasing evidence has highlighted the pivotal role that intimal macrophage (iMΦ) plays in the pathophysiology of atherosclerotic plaques, which represents an attractive target for atherosclerosis treatment. In this work, to address the insufficient specificity of conventional reconstituted high-density lipoprotein (rHDL) for iMΦ and its limited cholesterol efflux ability, we designed a hyaluronan (HA)-anchored core-shell rHDL. This nanoparticle achieved efficient iMΦ-targeted drug delivery via a multistage-targeting approach, and excellent cellular cholesterol removal. It contained a biodegradable poly (lactic-co-glycolic acid) (PLGA) core within a lipid bilayer, and apolipoprotein A-I (apoA-I) absorbing on the lipid bilayer was covalently decorated with HA. The covalent HA coating with superior stability and greater shielding was favorable for not only minimizing the liver uptake but also facilitating the accumulation of nanoparticles at leaky endothelium overexpressing CD44 receptors in atherosclerotic plaques. The ultimate iMΦ homing was achieved via apoA-I after HA coating degraded by hyaluronidase (HAase) (abundant in atherosclerotic plaque). The multistage-targeting mechanism was revealed on the established injured endothelium-macrophage co-culture dynamic system. Upon treatment with HAase in vitro, the nanoparticle HA-(C)-PLGA-rHDL exhibited a greater cholesterol efflux capacity compared with conventional rHDL (2.43-fold). Better targeting efficiency toward iMΦ and attenuated liver accumulation were further proved by results from ex vivo imaging and iMΦ-specific fluorescence localization. Ultimately, HA-(C)-PLGA-rHDL loaded with simvastatin realized the most potent anti-atherogenic efficacies in model animals over other preparations. Thus, the HAase-responsive HDL-mimetic nanoparticle was shown in this study to be a promising nanocarrier for anti-atherogenic therapy, in the light of efficient iMΦ-targeted drug delivery and excellent function of mediating cellular cholesterol efflux.

Mechanism of hard-nanomaterial clearance by the liver

The liver and spleen are major biological barriers to translating nanomedicines because they sequester the majority of administered nanomaterials and prevent delivery to diseased tissue. Here we examined the blood clearance mechanism of administered hard nanomaterials in relation to blood flow dynamics, organ microarchitecture and cellular phenotype. We found that nanomaterial velocity reduces 1,000-fold as they enter and traverse the liver, leading to 7.5 times more nanomaterial interaction with hepatic cells relative to peripheral cells. In the liver, Kupffer cells (84.8 ± 6.4%), hepatic B cells (81.5 ± 9.3%) and liver sinusoidal endothelial cells (64.6 ± 13.7%) interacted with administered PEGylated quantum dots, but splenic macrophages took up less material (25.4 ± 10.1%) due to differences in phenotype. The uptake patterns were similar for two other nanomaterial types and five different surface chemistries. Potential new strategies to overcome off-target nanomaterial accumulation may involve manipulating intra-organ flow dynamics and modulating the cellular phenotype to alter hepatic cell interactions.

Redox-Sensitive Micelles Based on O,N-Hydroxyethyl Chitosan-Octylamine Conjugates for Triggered Intracellular Delivery of Paclitaxel

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

From Diagnosis to Treatment: Clinical Applications of Nanotechnology in Thoracic Surgery

Nanotechnology is an emerging field with potential as an adjunct to cancer therapy, particularly thoracic surgery. Therapy can be delivered to tumors in a more targeted fashion, with less systemic toxicity. Nanoparticles may aid in diagnosis, preoperative characterization, and intraoperative localization of thoracic tumors and their lymphatics. Focused research into nanotechnology's ability to deliver both diagnostics and therapeutics has led to the development of nanotheranostics, which promises to improve the treatment of thoracic malignancies through enhanced tumor targeting, controlled drug delivery, and therapeutic monitoring. This article reviews nanoplatforms, their unique properties, and the potential for clinical application in thoracic surgery.

Inhalable, large porous PLGA microparticles loaded with paclitaxel: preparation, in vitro and in vivo characterization

Large porous particles (LPPs) could be used as a useful carrier for non-invasive delivery to the deep lung. Pulmonary delivery of paclitaxel-loaded LPPs (PTX-LPPs) can help to eliminate the highly complicated and harmful solvent used in PTX parenteral formulations. PTX-LPPs with mass median aerodynamic diameter (MMAD) of 5.74 ± 0.09 μm, high encapsulation efficiency and good aerosolisation properties were produced using ammonium bicarbonate as porogen. Cytotoxicity of PTX-LPPs on A549 and Calu-6 cell lines was comparable with Free-PTX. Endotracheal administration of PTX-LPPs in rats exhibited PTX plasma concentration in the therapeutic range which lasted 4-fold longer than i.v. injection. The bioavailability was measured as 51 ± 7.1%. The lung targeting efficiency (Te) of PTX-LPPs was 11.9-fold higher than i.v. administration. PTX-LPPs could deliver a higher PTX to lung with a non-toxic plasma level in a longer duration which shows their pulmonary delivery suitability.

Polymeric Micelles: Recent Advancements in the Delivery of Anticancer Drugs

Nanotechnology, in health and medicine, extensively improves the safety and efficacy of different therapeutic agents, particularly the aspects related to drug delivery and targeting. Among various nano-carriers, polymer based macromolecular approaches have resulted in improved drug delivery for the diseases like cancers, diabetes, autoimmune disorders and many more. Polymeric micelles consisting of hydrophilic exterior and hydrophobic core have established a record of anticancer drug delivery from the laboratory to commercial reality. The nanometric size, tailor made functionality, multiple choices of polymeric micelle synthesis and stability are the unique properties, which have attracted scientists and researchers around the world to work upon in this opportunistic drug carrier. The capability of polymeric micelles as nano-carriers are nowhere less significant than nanoparticles, liposomes and other nanocarriers, as per as the commercial feasibility and presence is concerned. In fact polymeric micelles are among the most extensively studied delivery platforms for the effective treatment of different cancers as well as non-cancerous disorders. The present review highlights the sequential and recent developments in the design, synthesis, characterization and evaluation of polymeric micelles to achieve the effective anticancer drug delivery. The future possibilities and clinical outcome have also been discussed, briefly.

Polymeric Micelles: Recent Advancements in the Delivery of Anticancer Drugs

Nanotechnology, in health and medicine, extensively improves the safety and efficacy of different therapeutic agents, particularly the aspects related to drug delivery and targeting. Among various nano-carriers, polymer based macromolecular approaches have resulted in improved drug delivery for the diseases like cancers, diabetes, autoimmune disorders and many more. Polymeric micelles consisting of hydrophilic exterior and hydrophobic core have established a record of anticancer drug delivery from the laboratory to commercial reality. The nanometric size, tailor made functionality, multiple choices of polymeric micelle synthesis and stability are the unique properties, which have attracted scientists and researchers around the world to work upon in this opportunistic drug carrier. The capability of polymeric micelles as nano-carriers are nowhere less significant than nanoparticles, liposomes and other nanocarriers, as per as the commercial feasibility and presence is concerned. In fact polymeric micelles are among the most extensively studied delivery platforms for the effective treatment of different cancers as well as non-cancerous disorders. The present review highlights the sequential and recent developments in the design, synthesis, characterization and evaluation of polymeric micelles to achieve the effective anticancer drug delivery. The future possibilities and clinical outcome have also been discussed, briefly.

Curcumin-loaded PLGA nanoparticles conjugated with anti- P-glycoprotein antibody to overcome multidrug resistance

BACKGROUND

The encapsulation of curcumin (Cur) in polylactic-co-glycolic acid (PLGA) nanoparticles (Cur- NPs) was designed to improve its solubility and stability. Conjugation of the Cur-NPs with anti-P-glycoprotein (P-gp) antibody (Cur-NPs-APgp) may increase their targeting to P-gp, which is highly expressed in multidrug- resistance (MDR) cancer cells. This study determined whether Cur-NPs-APgp could overcome MDR in a human cervical cancer model (KB-V1 cells) in vitro and in vivo.

MATERIALS AND METHODS

First, we determined the MDR- reversing property of Cur in P-gp-overexpressing KB-V1 cells in vitro and in vivo. Cur-NPs and Cur-NPs-APgp, in the range 150-180 nm, were constructed and subjected to an in vivo pharmacokinetic study compared with Cur. The in vitro and in vivo MDR-reversing properties of Cur-NPs and Cur-NPs-APgp were then investigated. Moreover, the stability of the NPs was determined in various solutions.

RESULTS

The combined treatment of paclitaxel (PTX) with Cur dramatically decreased cell viability and tumor growth compared to PTX treatment alone. After intravenous injection, Cur-NPs-APgp and Cur-NPs could be detected in the serum up to 60 and 120 min later, respectively, whereas Cur was not detected after 30 min. Pretreatment with Cur-NPs-APgp, but not with NPs or Cur-NPs, could enhance PTX sensitivity both in vitro and in vivo. The constructed NPs remained a consistent size, proving their stability in various solutions.

CONCLUSIONS

Our functional Cur-NPs-APgp may be a suitable candidate for application in a drug delivery system for overcoming drug resistance. The further development of Cur-NPs-APgp may be beneficial to cancer patients by leading to its use as either as a MDR modulator or as an anticancer drug.

Improved antitumor effect of paclitaxel administered in vivo as pH and glutathione-sensitive nanohydrogels

Most antitumor drugs usually affect not only rapidly dividing cells, such as those in tumors, but also highly proliferative cells in normal tissues. This nonspecific drawback could be successfully solved by using nanocarriers as controlled drug delivery systems. In this work, pH and redox-responsive nanohydrogels (NG) based on N-isopropylacrilamide (NIPA), N-hydroxyethyl acrylamide (HEEA) 2-acrylamidoethyl carbamate (2AAECM) and N,N'-cystaminebisacrylamide (CBA) as crosslinker were evaluated as bioreducible paclitaxel (PTX) nanocarriers for improving the accumulation of the drug within the tumor tissue and avoiding its conventional side effects. A single dose of PTX solution, unloaded-NHA 80/15/5CBA NG and PTX-loaded NHA 80/15/5-CBA NG (30 mg/kg PTX equivalent) were subcutaneously injected in female athymic nude mice bearing HeLa human tumor xenografts. PTX-loaded nanohydrogels showed higher antitumor activity than free PTX, as tumor evolution and Ki67 detection demonstrated. Histological tumor images revealed a higher content of defective mitotic figures and apoptotic bodies in PTX- treated tumors than in control or unloaded NG treated tumor samples. Nanohydrogels injection did not change any biochemical blood parameters, which means no liver or kidney damage after NG injection. However, differences in antioxidant defenses in MPS systems (liver, kidney and spleen) were observed among treatments, which may indicate an oxidative stress response after PTX injection.

Natural Cationic Polymers for Advanced Gene and Drug Delivery

Gene and drug delivery is becoming more and more important in the treatment of complicated human diseases. Proper gene/drug delivery systems can effectively enhance therapeutic efficiency and minimize various side-effects. To date, a variety of delivery systems have been developed. Different from synthetic materials, natural polymers are abundant in nature, renewable, non-toxic, biocompatible and biodegradable. Owing to the presence of positive charges, natural cationic polymers have found important applications in many biological fields, such as drug/gene delivery and tissue engineering. In gene delivery, natural cationic polymers can condense nucleic acids, protect them from degradation, lower the immunogenicity and improve overall transfection efficiency. In drug delivery, cationic functional groups can alter the amphiphilic properties of the polymers to ensure their suitable applications for delivering hydrophobic or protein drugs. After simple chemical modification, the derivatives of natural cationic polymers show improved performance as functional delivery carriers. In this chapter, details on the chemical modification of natural cationic polymers and their applications in gene/drug delivery is discussed.

Lanreotide-conjugated PEG-DSPE micelles: an efficient nanocarrier targeting to somatostatin receptor positive tumors

Lanreotide is an octapeptide analog of endogenous somatostatin, specifically binding with tumors over-express somatostatin receptor 2 (SSTR2). In this study, we conjugated lanreotide to 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (poly-(ethylene glycol))-2000] (PEG-DSPE), constructed active targeted micelles (lanreotide-PM), characterized their in vitro and in vivo targeting effect, and explored the receptor mediated transportion. The uptake of lanreotide-PM was found to be related to the expression level of SSTR2 in different cell lines and the competitive inhibition phenomenon indicated that the cellular uptake of lanreotide-PM was via a receptor meditated mechanism. In vivo, more lanreotide-PM accumulated in SSTR2 high expression tumor xenografts, endocytosed by the tumor cells, induced more apoptosis of tumor cells, and suppressed tumor growth efficiently. In conclusion, lanreotide-modified micelles containing antitumor drugs provide a promising strategy for the treatment of SSTR-expressing tumors.

Biosafe nanoscale pharmaceutical adjuvant materials

Thanks to developments in the field of nanotechnology over the past decades, more and more biosafe nanoscale materials have become available for use as pharmaceutical adjuvants in medical research. Nanomaterials possess unique properties which could be employed to develop drug carriers with longer circulation time, higher loading capacity, better stability in physiological conditions, controlled drug release, and targeted drug delivery. In this review article, we will review recent progress in the application of representative organic, inorganic and hybrid biosafe nanoscale materials in pharmaceutical research, especially focusing on nanomaterial-based novel drug delivery systems. In addition, we briefly discuss the advantages and notable functions that make these nanomaterials suitable for the design of new medicines; the biosafety of each material discussed in this article is also highlighted to provide a comprehensive understanding of their adjuvant attributes.

The biocompatibility evaluation of mPEG-PLGA-PLL copolymer and different LA/GA ratio effects for biocompatibility

Biomaterial poly(lactic-co-glycolic acid) (PLGA), a FDA-approved material for clinical application, showed broad prospects in the past, but gradually can no longer meet present clinical developments and requirements, which we synthesized monomethoxy(polyethylene glycol)-poly(D,L-lactic-co-glycolic acid)-poly(L-lysine) (mPEG-PLGA-PLL) (PEAL) and have had some relevant reports. But studies on biocompatibility and the impacts of LA and GA ratio (LA/GA=60/40, 70/30, and 80/20) in main material have not yet been reported. Hemolysis experiment indicates that the hemolysis rate of PEAL extraction medium is less than 5%. Whole blood clotting time (CT), plasma recalcification time, activated partial thromboplastin time, prothrombin time evaluations, and dynamic CT assay show that the anticoagulant time of PEAL copolymer for blood is longer than that under negative and positive control. Protein adsorption assay indicates that PEAL films adsorb less protein than PLGA films (p<0.01); but comparing with expanded polytetrafluoroethylene, the aforementioned difference is not significant (p>0.05). Complement activation test shows that PEAL surface does not induce complement activation. CCK8 measurement shows that the relative growth rates of Huh7, L02, and L929 cells co-incubated with PEAL nanoparticles (NPs) are more than 90%. PEAL NPs co-incubated with 5% foetal bovine serum or 2% bovine serum albumin, through dynamic light scattering assay, remain stable. Different concentrations of PEAL NPs co-incubated with zebrafish embryos at 6-72 h post fertilization show that comparing with negative control, 10, 100, or 500 μM of NPs for embryos development has no significant effects (p>0.05), only 1000 or 2000 μM of NPs has some effects (p<0.05). It is concluded that the PEAL copolymer, with excellent biocompatibility, proves to be a high-safety dose as drug carrier and implant candidate in vivo.

Polymeric micelles, a promising drug delivery system to enhance bioavailability of poorly water-soluble drugs

Oral administration is the most commonly used and readily accepted form of drug delivery; however, it is find that many drugs are difficult to attain enough bioavailability when administered via this route. Polymeric micelles (PMs) can overcome some limitations of the oral delivery acting as carriers able to enhance drug absorption, by providing (1) protection of the loaded drug from the harsh environment of the GI tract, (2) release of the drug in a controlled manner at target sites, (3) prolongation of the residence time in the gut by mucoadhesion, and (4) inhibition of efflux pumps to improve the drug accumulation. To explain the mechanisms for enhancement of oral bioavailability, we discussed the special stability of PMs, the controlled release properties of pH-sensitive PMs, the prolongation of residence time with mucoadhesive PMs, and the P-gp inhibitors commonly used in PMs, respectively. The primary purpose of this paper is to illustrate the potential of PMs for delivery of poorly water-soluble drugs with bioavailability being well maintained.

Advances in chitosan-based drug delivery vehicles

Within the past few years, chitosan-based drug delivery vehicles have become some of the most attractive to be studied. In contrast to all other polysaccharides, chitosan has demonstrated its unique characteristics for drug delivery platforms, including its active primary amino groups for chemical modification, simple and mild preparation methods for the encapsulation of biomolecules or drugs, mucoadhesion to facilitate transport across mucosal barriers and so on. In this review, an overview of the various types of chitosan-based drug delivery systems is provided, with special focus on polymeric drug conjugates and drug nanocarriers. The first part of the review is concerned with the development and applications of polymeric chitosan-drug conjugates. Then the chitosan-based nanocarrier systems as well as their preparation methods and applications are further discussed.

Toward the next-generation nanomedicines: design of multifunctional multiblock polyurethanes for effective cancer treatment

Specific accumulation of therapeutics at tumor sites to improve in vivo biodistribution and therapeutic efficacy of anticancer drugs is a major challenge for cancer therapy. Herein, we demonstrate a new generation of intelligent nanosystem integrating multiple functionalities in a single carrier based on multifunctional multiblock polyurethane (MMPU). The smart nanocarriers equipped with stealth, active targeting, and internalizable properties can ferry paclitaxel selectively into tumor tissue, rapidly enter cancer cells, and controllably release their payload in response to an intracellular acidic environment, thus resulting in an improved biodistribution and excellent antitumor activity in vivo. Our work provides a facile and versatile approach for the design and fabrication of smart intracellular targeted nanovehicles for effective cancer treatment, and opens a new era in the development of biodegradable polyurethanes for next-generation nanodelivery systems.

Tailoring polymeric micelles to optimize delivery to solid tumors

Block copolymer micelles have shown great potential in drug delivery systems, not only for overcoming the drawbacks of small agents such as water insolubility and wide distribution in normal tissues, but also for avoiding traditional nanoparticle formulation shortcomings, including in vivo instability and fast clearance from the blood. However, for translating micellar formulations to clinical practice, it is essential to overcome the many in vivo obstacles. Surmounting these barriers strongly depends on micellar physicochemical properties, which can be further optimized by the unique physiological aspects of solid tumors such as low pH, high temperature and the presence of abnormal vessels. Herein, based on the Flory parameter and scaling theory, the fundamental mechanisms and correlations in vitro/in vivo between self assembly, drug loading and release, stability, intracellular delivery and in vivo distribution, as well as micellar composition, size and microstructural tailoring are systematically revisited. The methods for enhancing micellar performance in solid tumors were consequently proposed through well-defined core-corona structure tailoring.

Odyssey of a cancer nanoparticle: from injection site to site of action

No chemotherapeutic drug can be effective until it is delivered to its target site. Nano-sized drug carriers are designed to transport therapeutic or diagnostic materials from the point of administration to the drug's site of action. This task requires the nanoparticle carrying the drug to complete a journey from the injection site to the site of action. The journey begins with the injection of the drug carrier into the bloodstream and continues through stages of circulation, extravasation, accumulation, distribution, endocytosis, endosomal escape, intracellular localization and-finally-action. Effective nanoparticle design should consider all of these stages to maximize drug delivery to the entire tumor and effectiveness of the treatment.

Biocompatibility of chitosan carriers with application in drug delivery

Chitosan is one of the most used polysaccharides in the design of drug delivery strategies for administration of either biomacromolecules or low molecular weight drugs. For these purposes, it is frequently used as matrix forming material in both nano and micron-sized particles. In addition to its interesting physicochemical and biopharmaceutical properties, which include high mucoadhesion and a great capacity to produce drug delivery systems, ensuring the biocompatibility of the drug delivery vehicles is a highly relevant issue. Nevertheless, this subject is not addressed as frequently as desired and even though the application of chitosan carriers has been widely explored, the demonstration of systems biocompatibility is still in its infancy. In this review, addressing the biocompatibility of chitosan carriers with application in drug delivery is discussed and the methods used in vitro and in vivo, exploring the effect of different variables, are described. We further provide a discussion on the pros and cons of used methodologies, as well as on the difficulties arising from the absence of standardization of procedures.

Enhanced bioavailability and efficiency of curcumin for the treatment of asthma by its formulation in solid lipid nanoparticles

Curcumin has shown considerable pharmacological activity, including anti-inflammatory, but its poor bioavailability and rapid metabolization have limited its application. The purpose of the present study was to formulate curcumin-solid lipid nanoparticles (curcumin-SLNs) to improve its therapeutic efficacy in an ovalbumin (OVA)-induced allergic rat model of asthma. A solvent injection method was used to prepare the curcumin-SLNs. Physiochemical properties of curcumin-SLNs were characterized, and release experiments were performed in vitro. The pharmacokinetics in tissue distribution was studied in mice, and the therapeutic effect of the formulation was evaluated in the model. The prepared formulation showed an average size of 190 nm with a zeta potential value of -20.7 mV and 75% drug entrapment efficiency. X-ray diffraction analysis revealed the amorphous nature of the encapsulated curcumin. The release profile of curcumin-SLNs was an initial burst followed by sustained release. The curcumin concentrations in plasma suspension were significantly higher than those obtained with curcumin alone. Following administration of the curcumin-SLNs, all the tissue concentrations of curcumin increased, especially in lung and liver. In the animal model of asthma, curcumin-SLNs effectively suppressed airway hyperresponsiveness and inflammatory cell infiltration and also significantly inhibited the expression of T-helper-2-type cytokines, such as interleukin-4 and interleukin-13, in bronchoalveolar lavage fluid compared to the asthma group and curcumin-treated group. These observations implied that curcumin-SLNs could be a promising candidate for asthma therapy.