Methotrexate-loaded SLNs prepared by coacervation technique: in vitro cytotoxicity and in vivo pharmacokinetics and biodistribution

A Comprehensive Review of the Strategies to Reduce Retinoid-Induced Skin Irritation in Topical Formulation

Currently, retinoids are known for their abundant benefits to skin health, ranging from reducing signs of aging and decreasing hyperpigmentation to treating acne. However, it cannot be denied that there are various side effects associated with the use of retinoids on the skin, one of which is irritation. Several approaches can be employed to minimize the irritation caused by retinoids. This review article discusses topical retinoid formulation technology strategies to reduce skin irritation effects. The methodology used in this study is a literature review of 21 reference journals. The sources used in compiling this review are from PubMed, Scopus, ScienceDirect, and MEDLINE. The findings obtained indicate that the following methods can be used to lessen retinoid-induced irritation in topical formulations: developing drug delivery systems in the formulation, such as encapsulating retinoids, transforming retinoids into nanoparticles, forming complexes (e.g., with cyclodextrin), and binding retinoids with carriers (e.g., polymers, NLC, SLN), adding ingredients with anti-irritation activity, skin barrier improvement, and increased skin hydration to retinoid formulations (e.g., combinations of glucosamine, trehalose, ectoine, sucralfate, omega-9, and 4-t-butylcyclohexanol, addition of ethanolic bark extract of Alstonia scholaris R. Br).

Combinational strategy using albumin-based nanoparticles to enable synergetic anti-rheumatic efficacy and reduced hepatotoxicity

Methotrexate (MTX) is recognized as the golden standard for rheumatoid arthritis (RA) treatment. However, it can cause liver damage in long-term application. Although nanomedicines can target to inflamed sites, most of them tend to accumulate in liver. Glycyrrhizinic acid (GA) holds potential to reverse MTX-associated hepatotoxicity. The combination of GA and MTX might achieve a synergistic anti-inflammatory efficacy and reduced hepatotoxicity. As MTX and GA have totally different in vivo performance, it is necessary to co-encapsulate them in one carrier to coordinate their in vivo fates. Here, we co-delivered MTX and GA to arthritic joints using a human serum albumin-based nanoparticle (HSN). We found the dual drug-loaded albumin nanoparticles (HSN/MTX/GA) could preferentially distribute in inflamed joints, where GA can extend MTX retention by inhibiting the expression of efflux pumps for MTX, thereby exerting synergistic therapeutic effect. In liver tissues, GA was able to reverse the MTX-induced liver damage by activating anti-oxidant defense Nrf2/HO-1 and anti-apoptosis Bcl-2/Bax signaling. We offer a combinational strategy to effectively overcome the MTX-induced hepatotoxicity and enhance the anti-rheumatic efficacy simultaneously. Furthermore, we verified the underlying mechanism about how GA cooperated with MTX in vivo for the first time. Our findings can provide valuable insights for long-term treatment of RA.

Evaluation of methotrexate encapsulated polymeric nanocarrier for breast cancer treatment

Herein, Methotrexate-loaded chitosan nanoparticles (Meth-Cs-NPs) was formulated through single-step self-assembly by incorporating the ionic-gelation method. Chitosan was cross-linked with Methotrexate via a sodium tripolyphosphate (STPP) where 49 % Methotrexate was loaded in the nanoparticles (∼143 nm) and zeta potential of 34 ± 3 mV with an entrapment efficiency of 87 %. The efficacy of nanoparticles was assessed for chemically induced breast cancer treatment in the Sprague Dawley rats model. These Meth-Cs-NPs followed the Korsmeyer-Peppas model in-vitro release kinetics. Nanoparticles were further evaluated for in-vitro efficacy on triple-negative breast cancer (MDA-MB-231) cell lines. The MTT assay studies revealed that even slight exposure to Meth-Cs-NPs (IC₅₀ = 15 µg/mL) caused 50 % cell death in 24 h. Further, hemocompatibility studies of Meth-Cs-NPs were performed, deciphered that Meth-Cs-NPs were biocompatible (hemolysis < 2 %). Additional cellular uptake was evaluated by confocal imaging. Moreover, an in-vivo pharmacokinetic study of nanoparticles in rats displayed increased plasma concentration of the drug and retention time, whereas a decrease in cellular clearance compared to free Methotrexate. Further, anti-tumor efficacy studies revealed that nanoparticles could reduce tumor volume from 1414 mm³→385 mm³ compared to free Methotrexate (1414 mm³→855 mm³). The current study presents encouraging prospects of Meth-Cs-NPs to be used as a viable breast cancer treatment modality.

In-vivo anticancer efficacy of self-targeted methotrexate-loaded polymeric nanoparticles in solid tumor-bearing rat

Here, cytotoxicity and antitumor efficacy against a chemically (N-methyl-N-nitrosourea) generated mammary tumor in rats were assessed using methotrexate-loaded chitosan nanoparticles (Meth-Cs-NPs). Meth-Cs-NPs intravenous administrated resulted in noticeably decreased tumor incidence, multiplicity, and weight. Further, kidney function tests for the treated groups resulted in noticeably decreased ALP (Meth-Cs-NPs; 244 ± 15, diseases control; 403 ± 14 U/L), Creatinine (Meth-Cs-NPs; 0.81 ± 0.05, diseases control; 2 ± 0.05 mg/dl), and Urea (Meth-Cs-NPs; 56.62 ± 5, diseases control; 113 ± 6 mg/dl) levels, close to a normal control group. Similarly, liver function tests showed significantly decreased serum biomarkers, SGPT (Meth-Cs-NPs; 40 ± 1.8, diseases control; 84 ± 1.9 U/L) and SGOT (Meth-Cs-NPs; 15 ± 2, diseases control; 55 ± 4 U/L) levels in treated groups as compared to the untreated group (diseases control). From the results, pro-inflammatory cytokines were also markedly reduced in the treated group such as, TNF-α (Meth-Cs-NPs; 17.31 ± 1.15, diseases control; 36.9 ± 5 pg/mL), IL-1β (Meth-Cs-NPs; 433.3 ± 66.5, diseases control; 1540 ± 131.1 pg/mL), and IL-6 (Meth-Cs-NPs; 1515 ± 53, diseases control; 2200.6 ± 69 pg/mL) levels. Whereas Meth-Cs-NPs not only helped in lowering tumor multiplicity rates but also decrease inflammation. The studies could be successfully performed in chemically induced mammary tumors due to their easy, quick tumor growth and low mortality rates in rat models. According to the current study, Meth-Cs-NPs have high treatment potency and represent a possible therapeutic alternative for breast cancer treatment.

Co-Crystalline Solid Solution Affords a High-Soluble and Fast-Absorbing Form of Praziquantel

Praziquantel (PZQ) is a chiral class-II drug, and it is used as a racemate for the treatment of schistosomiasis. The knowledge of several cocrystals with dicarboxylic acids has prompted the realization of solid solutions of PZQ with both enantiomers of malic acid and tartaric acid. Here, the solid form landscape of such a six-component system has been investigated. In the process, two new cocrystals were structural-characterized and three non-stoichiometric, mixed crystal forms identified and isolated. Thermal and solubility analysis indicates a fourfold solubility advantage for the newly prepared solid solutions over the pure drug. In addition, a pharmacokinetic study was conducted in rats, which involved innovative mini-capsules for the oral administration of the solid samples. The available data indicate that the faster dissolution rate of the solid solutions translates in faster absorption of the drug and helps maintain a constant steady-state concentration.

Role of folate-conjugated glycol-chitosan nanoparticles in modulating the activated macrophages to ameliorate inflammatory arthritis: in vitro and in vivo activities

Activated macrophages are the primary targets in rheumatoid arthritis (RA) management. So, we report efficacious, dual-functional Methotrexate (MTX) loaded folate-conjugated pH-responsive glycol-chitosan nanoparticles (MFGCN) prepared by nano-precipitation and zero-order cross-linking reaction for targeting inflamed arthritic tissue. Physical characterization by DLS, SEM and TEM indicated a spherical, smooth morphology with a diameter ~ 300 nm. ¹H NMR and FTIR indicated folic acid conjugation to GC by zero-order cross-linkers. In vitro release kinetics in PBS showed pH-responsive and sustained release behaviour of MFGCN. Enhanced cellular uptake and cytotoxicity of MFGCN in LPS(+)RAW and activated peritoneal macrophages (Mϕ) were observed when compared to LPS(-)RAW cells. MFGCN-induced mitochondrial membrane potential (MMP) perturbations indicated apoptosis. Oxidative stress was evident by significant increase in ROS and RNS, 4 h post incubation with MFGCN. Negligible hemolysis by FGCN and MFGCN on rat RBC's indicated biocompatibility. In vivo biodistribution of MFGCN in adjuvant-induced arthritis (AIA) rats indicated RA targetability. Prolonged blood circulation coupled with higher concentrations of ^99mTc-MFGCN at the arthritic site was observed post 24 h of injection. The gamma scintigraphic image confirmed accumulation of radiolabelled MFGCN in arthritic paw when compared to the non-inflamed paw, confirming the selective uptake of ^99mTc-MFGCN by folate-overexpressing macrophages in the arthritic synovium thereby proving its targeted efficacy and theranostic potential. In AIA rats, MFGCN lowers arthritic signs, improves antioxidant response and decreases pro-inflammatory cytokines, suggesting its potential in targeting activated macrophages of synovium. Graphical abstract.

Solid lipid nanoparticles for hydrophilic drugs

Hydrophilic drugs are proficient therapeutic agents however, delivery of these drugs is a difficult task. Hence, developing an efficient drug delivery system may require a multipronged approach. Colloidal drug delivery systems such as emulsions, liposomes, nanoemulsions, polymeric nanoparticles, and niosomes are known to enhance drug entrapment, bioavailability, and to improve the pharmacokinetic profiles of hydrophilic drugs. However, issues such as drug leakage and burst release are frequently reported with such systems. Solid lipid nanoparticles (SLNs) were developed as an alternative to the traditional colloidal drug carriers to overcome these issues. Although SLNs have been widely studied as carriers for hydrophobic drugs, delivery of hydrophilic molecules remains a challenge. Hence, the current review focuses on different approaches that have been used for the delivery of hydrophilic drugs using SLNs. It not only discusses various modifications in the traditional methods for the synthesis but also emphasizes modifications of the hydrophilic drugs itself that can help in their efficient entrapment into SLNs drug carriers.

Polymeric Nanoscale Drug Carriers Mediate the Delivery of Methotrexate for Developing Therapeutic Interventions Against Cancer and Rheumatoid Arthritis

Methotrexate (MTX) is widely used as an anticancer and anti-inflammtory drug for treating various types of cancer and autoimmune diseases. The optimal dose of MTX is known to inhibit the dihydrofolatereductase that hinders the replication of purines. The nanobiomedicine has been extensively explored in the past decade to develop myriad functional nanostructures to facilitate the delivery of therapeutic agents for various medical applications. This review is focused on understanding the design and development of MTX-loaded nanoparticles alongside the inclusion of recent findings for the treatment of cancers. In this paper, we have made a coordinated effort to show the potential of novel drug delivery systems by achieving effective and target-specific delivery of methotrexate.

Lipid nanoparticles as vehicles for oral delivery of insulin and insulin analogs: preliminary ex vivo and in vivo studies

AIMS

Subcutaneous administration of insulin in patients suffering from diabetes is associated with the distress of daily injections. Among alternative administration routes, the oral route seems to be the most advantageous for long-term administration, also because the peptide undergoes a hepatic first-pass effect, contributing to the inhibition of the hepatic glucose output. Unfortunately, insulin oral administration has so far been hampered by degradation by gastrointestinal enzymes and poor intestinal absorption. Loading in lipid nanoparticles should allow to overcome these limitations.

METHODS

Entrapment of peptides into such nanoparticles is not easy, because of their high molecular weight, hydrophilicity and thermo-sensitivity. In this study, this objective was achieved by employing fatty acid coacervation method: solid lipid nanoparticles and newly engineered nanostructured lipid carriers were formulated. Insulin and insulin analog-glargine insulin-were entrapped in the lipid matrix through hydrophobic ion pairing.

RESULTS

Bioactivity of lipid entrapped peptides was demonstrated through a suitable in vivo experiment. Ex vivo and in vivo studies were carried out by employing fluorescently labelled peptides. Gut tied up experiments showed the superiority of glargine insulin-loaded nanostructured lipid carriers, which demonstrated significantly higher permeation (till 30% dose/mL) compared to free peptide. Approximately 6% absolute bioavailability in the bloodstream was estimated for the same formulation through in vivo pharmacokinetic studies in rats. Consequently, a discrete blood glucose responsivity was noted in healthy animals.

CONCLUSIONS

Given the optimized ex vivo and in vivo intestinal uptake of glargine insulin from nanostructured lipid carriers, further studies will be carried out on healthy and diabetic rat models in order to establish a glargine insulin dose-glucose response relation.

Methotrexate-Loaded Solid Lipid Nanoparticles: Protein Functionalization to Improve Brain Biodistribution

Glioblastoma is the most common and invasive primary tumor of the central nervous system and normally has a negative prognosis. Biodistribution in healthy animal models is an important preliminary study aimed at investigating the efficacy of chemotherapy, as it is mainly addressed towards residual cells after surgery in a region with an intact blood⁻brain barrier. Nanoparticles have emerged as versatile vectors that can overcome the blood⁻brain barrier. In this experimental work, solid lipid nanoparticles, prepared using fatty acid coacervation, have been loaded with an active lipophilic ester of cytotoxic drug methotrexate, and functionalized with either transferrin or insulin, two proteins whose receptors are abundantly expressed on the blood⁻brain barrier. Functionalization has been achieved by grafting a maleimide moiety onto the nanoparticle's surface and exploiting its reactivity towards thiolated proteins. The nanoparticles have been tested in vitro on a blood⁻brain barrier cellular model and in vivo for biodistribution in Wistar rats. Drug metabolites, in particular 7-hydroxymethotrexate, have also been investigated in the animal model. The data obtained indicate that the functionalization of the nanoparticles improved their ability to overcome the blood⁻brain barrier when a PEG spacer between the proteins and the nanoparticle's surface was used. This is probably because this method provided improved ligand⁻receptor interactions and selectivity for the target tissue.

Lipid and TPGS based novel core-shell type nanocapsular sustained release system of methotrexate for intravenous application

Core shell nanocapsules present an interesting system for attaining high loading of drug. In an attempt, lipid and TPGS based novel core-shell nanocapsule were prepared to achieve high drug loading with sustained release of model hydrophilic drug methotrexate (MTX). Antisolvent nanoprecipitation was utilized for the formulation of nanoparticles. Optimized formulation depicted 223.6 ± 24.1 nm particle size, 0.243 ± 0.034 PDI, zeta potential -2.07 ± 0.51 mV and 15.03 ± 1.92%drug loading. In vitro release showed biphasic release for 12 h with initial burst phase followed by sustained release phase. Haemolytic study on RBCs revealed haemocompatible nature of MTX-TPGS nanoparticles compared to Biotrexate^® (Zydus). In vitro cell culture studies depicted 3 folds and 2.66 folds increase in cellular uptake of MTX at 10 μg/ml and 15 μg/ml respectively for developed nanoparticles with 3.81 folds decrease in IC₅₀ value as compared to Biotrexate^®. Higher apoptosis and increased lysosomal membrane permeability were also depicted by MTX-TPGS nanoparticles. 2.45 folds increase in AUC and 3.68 folds increase in T_1/2 was achieved in pharmacokinetic study. Significant reduction in tumor burden and serum biochemical parameters depicted efficacy and safety respectively of the formulation as compared to Biotrexate^®. RBCs morphology was retained after MTX-TPGS exposure proving its haemocompatibility in vivo.

Lipid-Based Oral Formulation Strategies for Lipophilic Drugs

Partition coefficient (log P) is a key physicochemical characteristic of lipophilic drugs which plays a significant role in formulation development for oral administration. Lipid-based formulation strategies can increase lymphatic transport of these drugs and can enhance bioavailability many folds. The number of lipophilic drugs in pharmacopoeias and under discovery are continuously increasing and making the job of the formulation scientist difficult to develop suitable formulation of these drugs due to potent nature and water insolubility of these drugs. Recently, many natural and synthetic lipids are appearing in the market which are helpful in the development of lipid-based formulations of these types of drugs having enhanced solubility and bioavailability. One such reason for this enhanced bioavailability is the accessibility of the lymphatic transport as well as avoidance of first-pass effect. This review discusses the impact of lipophilicity in enhancing the intestinal lymphatic drug transport thereby reducing first-pass metabolism. The most appropriate strategy for developing a lipid-based formulation depending upon the degree of lipophilicity has been critically discussed and provides information on how to develop optimum formulation. Various formulation strategies are discussed in-depth by classifying lipid-based oral drug delivery systems with case studies of few marketed formulations with challenges and opportunities for the future of the formulations.

Effects of PEG surface density and chain length on the pharmacokinetics and biodistribution of methotrexate-loaded chitosan nanoparticles

Background

One of the most important aspects of drug delivery is extended nanoparticle (NP) residence time in vivo. Herein, we report a series of methotrexate (MTX)-loaded chito-san (CS) NPs coated with differently sized methoxy polyethylene glycol (mPEG) at different mPEG surface densities.

Materials and methods

MTX was incorporated into NPs (112.8–171.2 nm in diameter) prepared from the resulting mPEG-g-CS. The NPs had a zeta potential of +7.4–35.0 mV and MTX loading efficiency of 17.1%–18.4%. MTX/mPEG-g-CS NPs showed an initial burst release of MTX followed by a sustained-release profile in PBS at pH 7.4.

Results

The in vitro cellular uptake study showed that MTX accumulation in J774A.1 macrophage cells decreased with increasing the mPEG surface density or the mPEG molecular weight. The pharmacokinetic study on Sprague Dawley rats revealed an increase in AUC0–72 h (area under the plasma drug concentration–time curve over a period of 72 hours) with increasing the mPEG surface density or the mPEG molecular weight and a linear correlation between the mPEG surface density and AUC_{0–72 h}.

Conclusion

The biodistribution study on Institute of Cancer Research (ICR) mice revealed that MTX/mPEG-g-CS NPs significantly enhanced blood circulation time in the body and decreased accumulation in liver, spleen, and lung. These results suggest the potential of the mPEG-g-CS NPs as a promising candidate for drug delivery.

Solid lipid nanoparticles by coacervation loaded with a methotrexate prodrug: preliminary study for glioma treatment

AIM

Methotrexate-loaded biocompatible nanoparticles were tested for preliminary efficacy in glioma treatment.

MATERIALS & METHODS

Behenic acid nanoparticles, prepared by the coacervation method, were loaded with the ester prodrug didodecylmethotrexate, which was previously tested in vitro against glioblastoma human primary cultures. Nanoparticle conjugation with an ApoE mimicking chimera peptide was performed to obtain active targeting to the brain.

RESULTS & CONCLUSION

Biodistribution studies in healthy rats assessed the superiority of ApoE-conjugated formulation, which was tested on an F98/Fischer glioma model. Differences were observed in tumor growth rate (measured by MRI) between control and treated rats. In vitro tests on F98 cultured cells assessed their susceptibility to treatment, with consequent apoptosis, and allowed us to explain the apoptosis observed in glioma models.

Fucose decorated solid-lipid nanocarriers mediate efficient delivery of methotrexate in breast cancer therapeutics

The present study is designed to engineer fucose anchored methotrexate loaded solid lipid nanoparticles (SLNs) to target breast cancer. The developed nano-carriers were characterized with respect to particle size, PDI, zeta potential, drug loading and entrapment, in-vitro release etc. The characterized formulations were used to comparatively assess cellular uptake, cell-viability, apoptosis, lysosomal membrane permeability, bioavailability, biodistribution, changes in tumor volume and animal survival. The ex-vivo results showed greater cellular uptake and better cytotoxicity at lower IC50 of methotrexate in breast cancer cells. Further, we observed increased programmed cell death (apoptosis) with altered lysosomal membrane permeability and better rate of degradation of lysosomal membrane in-vitro. On the other hand, in-vivo evaluation showed maximum bioavailability and tumor targeting efficiency with minimum secondary drug distribution in various organs with formulated and anchored nano-carrier when compared with free drug. Moreover, sizeable reduction in tumor burden was estimated with fucose decorated SLNs as compared to that seen with free MTX and SLNs-MTX. Fucose decorated SLNs showed promising results to develop therapeutic interventions for breast cancer, and paved a way to explore this promising and novel nano-carrier which enables to address breast cancer.

The ligand (s) anchored lipobrid nanoconstruct mediated delivery of methotrexate: an effective approach in breast cancer therapeutics

The present study was designed to engineer surface-anchored and methotrexate loaded lipobrid nano-constructs for targeting breast cancer. Ligands (fucose, galactose and mannose) anchored lipobrid nano-constructs were used to compare and assess delivery efficiency in breast cancer cell lines as well as in DMBA induced breast cancer animal model. The developed and characterized formulations were used to comparatively assess cellular uptake, cell-viability, apoptosis, lysosomal membrane permeability, bioavailability, bio-distribution, changes in tumor volume and animal survival. Our results show greater cellular uptake, cytotoxicity at low IC50, apoptosis with altered lysosomal membrane permeability and greater rate of degradation of lysosomal membrane. We saw better bioavailability and tumor targeting efficiency with minimum secondary organ drug distribution. The significant reduction was seen in tumor burden with ligand anchored lipobrids in comparison to plain and MTX-lipobrid formulations. In conclusion, fucose anchored MTX-lipobrid formulation showed promising results, and warrants to explore the development of therapeutic interventions for breast cancer.

Applied Nanotechnology and Nanoscience in Orthopedic Oncology

Nanomedicine is based on the fact that biological molecules behave similarly to nanomolecules, which have a size of less than 100 nm, and is now affecting most areas of orthopedics. In orthopedic oncology, most of the in vitro and in vivo studies have used osteosarcoma or Ewing sarcoma cell lineages. In this article, tumor imaging and treatment nanotechnology applications, including nanostructure delivery of chemotherapeutic agents, gene therapy, and the role of nano-selenium-coated implants, are outlined. Finally, the potential role of nanotechnology in addressing the challenges of drug and radiotherapy resistance is discussed. [Orthopedics. 2016; 39(5):280-286.].

Development and characterization of single step self-assembled lipid polymer hybrid nanoparticles for effective delivery of methotrexate

The present study was designed to develop methotrexate (MTX) loaded lipid polymer hybrid nanoparticles (LPHNPs) for spatial and controlled delivery of this drug.

Preparation and characterization of ascorbic acid loaded solid lipid nanoparticles and investigation of their apoptotic effects

In this paper, ascorbic acid (Vitamin C, AA) known as an antioxidant was successfully incorporated in solid lipid nanoparticles (SLNs) by hot homogenization and efficient delivery of AA to cancer cells. The obtained SLN formulations were characterized by Nano Zetasizer ZS and HPLC with the particle size being less than 250nm. AA-SLNs exhibited sustained release and high entrapment efficiency. According to MTT test results, AA-SLNs showed high cytotoxic activity compared to the free AA against H-Ras 5RP7 cells without damaging NIH/3T3 control cells. These results were supported by the Annexin V-PI and caspase-3 assay. Furthermore, as compared to the AA, AA-SLNs exhibited more efficient cellular uptake, accumulated in the cytoplasm and induced apoptosis which was observed by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Thus, the results of this study suggest that SLNs can be a potential nanocarrier system for AA.

Solid lipid nanoparticles for potential doxorubicin delivery in glioblastoma treatment: preliminary in vitro studies

The major obstacle to glioblastoma pharmacological therapy is the overcoming of the blood-brain barrier (BBB). In literature, several strategies have been proposed to overcome the BBB: in this experimental work, solid lipid nanoparticles (SLN), prepared according to fatty acid coacervation technique, are proposed as the vehicle for doxorubicin (Dox), to enhance its permeation through an artificial model of BBB. The in vitro cytotoxicity of Dox-loaded SLN has been measured on three different commercial and patient-derived glioma cell lines. Dox was entrapped within SLN thanks to hydrophobic ion pairing with negatively charged surfactants, used as counterions. Results indicate that Dox entrapped in SLN maintains its cytotoxic activity toward glioma cell lines; moreover, its permeation through hCMEC/D3 cell monolayer, assumed as a model of the BBB, was increased when the drug was entrapped in SLN. In conclusion, SLN proved to be a promising vehicle for the delivery of Dox to the brain in glioblastoma treatment.

Reduction-triggered breakable micelles of amphiphilic polyamide amine-g-polyethylene glycol for methotrexate delivery

Reduction-triggered breakable polymeric micelles incorporated with MTX were prepared using amphiphilic PAA-g-PEG copolymers having S-S bonds in the backbone. The micelles were spherical with diameters less than 70 nm. The micelles could encapsulate the hydrophobic MTX in the hydrophobic core. The drug loading content and drug loading efficiency of the micelles were highly dependent on the copolymer chemical structure, ranging from 2.9 to 7.5% and 31.9 to 82.5%, respectively. Both the drug loading content and drug loading efficiency increased along with more hydrophobic segments in the copolymers. In normal circumstance, these micelles were capable of keeping stable and hold most of the MTX in the core, stabilizing the incorporated MTX through the π-π stacking with the phenyl groups in the backbone of the copolymers. In reductive environments that mimicked the intracellular compartments, the entire MTX payload could be quickly released due to the reduction-triggered breakage of the micelles. These micelles showed good antiproliferative activity against several cancer cell lines, including KB, 4T-1 and HepG2, especially within the low drug concentration scope.

Nanoparticles containing insoluble drug for cancer therapy

Nanoparticle drug formulations have been extensively researched and developed in the field of drug delivery as a means to efficiently deliver insoluble drugs to tumor cells. By mechanisms of the enhanced permeability and retention effect, nanoparticle drug formulations are capable of greatly enhancing the safety, pharmacokinetic profiles and bioavailability of the administered treatment. Here, the progress of various nanoparticle formulations in both research and clinical applications is detailed with a focus on the development of drug/gene delivery systems. Specifically, the unique advantages and disadvantages of polymeric nanoparticles, liposomes, solid lipid nanoparticles, nanocrystals and lipid-coated nanoparticles for targeted drug delivery will be investigated in detail.

Nanoparticle delivery systems for cancer therapy: advances in clinical and preclinical research

Conventional anticancer drugs display significant shortcomings which limit their use in cancer therapy. For this reason, important progress has been achieved in the field of nanotechnology to solve these problems and offer a promising and effective alternative for cancer treatment. Nanoparticle drug delivery systems exploit the abnormal characteristics of tumour tissues to selectively target their payloads to cancer cells, either by passive, active or triggered targeting. Additionally, nanoparticles can be easily tuned to improve their properties, thereby increasing the therapeutic index of the drug. Liposomes, polymeric nanoparticles, polymeric micelles and polymer- or lipid-drug conjugate nanoparticles incorporating cytotoxic therapeutics have been developed; some of them are already on the market and others are under clinical and preclinical research. However, there is still much research to be done to be able to defeat the limitations of traditional anticancer therapy. This review focuses on the potential of nanoparticle delivery systems in cancer treatment and the current advances achieved.

Lipid nanoparticles: state of the art, new preparation methods and challenges in drug delivery

INTRODUCTION

Nanoparticles are rapidly developing as drug carriers because of their size-dependent properties. Lipid nanoparticles (LNPs) are widely employed in drug delivery because of the biocompatibility of the lipid matrix.

AREAS COVERED

Many different types of LNPs have been engineered in the last 20 years, the most important being solid lipid nanoparticles (SLNs), nanostrucured lipid carriers (NLCs), lipid-drug conjugates (LDCs) and lipid nanocapsules (LNCs). This review gives an overview of LNPs, including their physico-chemical properties and pharmacological uses. Moreover, it highlights the most important innovations in the preparation techniques of LNPs, aimed to encapsulate different molecules within the lipid matrix. Finally, it gives a short perspective on the challenges of drug delivery, which are a potential field of application for LNPs: cancer therapy, overcoming the blood-brain barrier and gene and protein delivery.

EXPERT OPINION

LNPs are a safe and versatile vehicles for drug and active delivery, suitable for different administration routes. New technologies have been developed for LNP preparation and studies are currently underway in order to obtain the encapsulation of different drugs and to deliver the active molecule to the site of action.