Anticancer Drug Methotrexate Research Articles

Thermo-triggered drug delivery from polymeric micelles of poly(N-isopropylacrylamide-co-acrylamide)-b-poly(n-butyl methacrylate) for tumor targeting

Novel temperature-sensitive micelles, possessing a core-shell structure, were successfully fabricated and evaluated as possible systems for targeting anticancer drugs to solid tumors. The amphiphilic block copolymer poly( N-isopropylacrylamide- co-acrylamide)-b-poly( n-butyl methacrylate) was used to achieve a stimuli-responsive on/off release and spatial specificity. The anticancer drug methotrexate, which is poorly water soluble, was used as the model. Fourier transform–infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, gel-permeation chromatography, and critical micelle concentration were used to evaluate the successful synthesis of block copolymers with a lower critical solution temperature ~40°C. Based on transmission electron microscope images, the micelles are spherical particles with narrow size distribution. The thermally triggered release of methotrexate was observed in vitro. Quartz crystal microbalance with dissipation was used to investigate the interactions of the polymeric micelles with bovine serum albumin, to illustrate protein adsorption and cell attachment. Cytotoxicity studies were conducted on Lewis lung carcinoma cells, and the anticancer activity of methotrexate-loaded micelles was significantly enhanced in combination with hyperthermia. The thermo-sensitive characteristics of the micelles make them applicable as smart drug delivery systems, when combined with localized hyperthermia.

Methotrexate-conjugated AgInS2/ZnS quantum dots for optical imaging and drug delivery

The ability to conjugate drugs with quantum dots (QDs) offers excellent prospects in pharmacotherapy for the improvement of diagnosis and treatment of human diseases. Here, we report a facile strategy to prepare dual-functional nanomaterials consisting of QDs and an anticancer drug. Hydrophilic AgInS2/ZnS QDs were obtained through an ultrasonication process by introducing the amphiphilic polymer, poly(maleic anhydride-alt-1-octadecene) (PMAO). Subsequently, the anticancer drug methotrexate (MTX) was covalently coupled to the surface of the AgInS2/ZnS QDs by carbodiimide chemistry. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell proliferation assay indicated that these hydrophilic PMAO-coated AgInS2/ZnS QDs exhibited negligible cytotoxicity. Human cervical (HeLa) cancer cells had >80% cell viability after 24h at concentrations of up to 300μg/mL. Confocal laser scanning microscopy revealed that the AgInS2/ZnS QDs conjugated with MTX were taken up effectively by HeLa cells. In addition, this nanomaterial was shown to have a dose-dependent antiproliferative effect in cancer cells by the MTT assay. These important features suggest that AgInS2/ZnS QDs conjugated with MTX might be a novel candidate for cancer therapeutics and diagnosis in future.

Electrochemically controlled release of anticancer drug methotrexate using nanostructured polypyrrole modified with cetylpyridinium: Release kinetics investigation

A new simple strategy for direct electrochemical incorporation of chemotherapeutic methotrexate (MTX) into conductive polypyrrole (PPy) has been suggested for an electrochemically controlled loading and release system. Electropolymerization of MTX doped polypyrrole yielded poor quality with low efficiency of doping, but a well-doped, nanostructure and increased capacity of drug loading (24.5mgg−1) has been obtained in the presence of cetylpyridinium (CP) as a modifier. When CP was preloaded onto PPy, the hydrophobic surface of the PPy serves as a backbone to which the hydrophobic chain of the CP can be attached. Electrostatic interaction between cationic CP with anionic MTX and aromatic interaction between pyridinium head of CP with pyrimidine and pyrazine rings of MTX increases drug doping. Then release kinetics were investigated at various applied potentials and temperatures. Kinetics analysis based on Avrami's equation showed that the drug release was controlled and accelerated by increasing temperature and negative potential and sustained by increasing positive potential. At open circuit condition, the release parameter (n) represented a diffusive mechanism and at applying electrochemical potentials, a first-order mode. Activation energy parameters (Ea, ΔG≠, ΔH≠ and ΔS≠) and half-life time (t1/2) of drug release are also analyzed as a function of applied potential. The nanostructured polymer films (PPy/CP/MTX) were characterized by several techniques: scanning electron microscopy, Furrier transforms Infrared, UV-vis spectroscopy. Overall, our results demonstrate that the PPy/CP/MTX films, combined with electrical stimulation, permit a programmable release of MTX by altering the interaction strength between the PPy/CP and MTX.

Self-assembly Polyrotaxanes Nanoparticles as Carriers for Anticancer Drug Methotrexate Delivery

Abstract α-Cyclodextrin/poly(ethylene glycol) (α-CD/PEG) polyrotaxane nanoparticles were prepared via a self-assembly method. Anticancer drug methotrexate (MTX) was loaded in the nanoparticles. The interaction between MTX and polyrotaxane was investigated. The formation, morphology, drug release and in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles were studied. The results show that the MTX could be efficiently absorbed on the nanoparticles, and hydrogen bonds were formed between MTX and α-CDs. The typical channel-type stacking assembly style of polyrotaxane nanoparticles was changed after MTX was loaded. The mean diameter of drug loaded polyrotaxane nanoparticles were around 200 nm and the drug loading content was as high as about 20%. Drug release profiles show that most of the loaded MTX was released within 8 hours and the cumulated release rate was as high as 98%. The blank polyrotaxane nanoparticles were nontoxicity to cells. The in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles was higher than that of free MTX.

Self-assembly Polyrotaxanes Nanoparticles as Carriers for Anticancer Drug Methotrexate Delivery

α-Cyclodextrin/poly(ethylene glycol) (α-CD/PEG) polyrotaxane nanoparticles were prepared via a self-assembly method. Anticancer drug methotrexate (MTX) was loaded in the nanoparticles. The interaction between MTX and polyrotaxane was investigated. The formation, morphology, drug release and in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles were studied. The results show that the MTX could be efficiently absorbed on the nanoparticles, and hydrogen bonds were formed between MTX and α-CDs. The typical channel-type stacking assembly style of polyrotaxane nanoparticles was changed after MTX was loaded. The mean diameter of drug loaded polyrotaxane nanoparticles were around 200 nm and the drug loading content was as high as about 20%. Drug release profiles show that most of the loaded MTX was released within 8 hours and the cumulated release rate was as high as 98%. The blank polyrotaxane nanoparticles were nontoxicity to cells. The in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles was higher than that of free MTX.

Protective effect of peroxisome proliferator activator receptor (PPAR)-α and -γ ligands against methotrexate-induced nephrotoxicity

Context: The anticancer drug methotrexate (MTX) may cause multi-organ toxicities, including nephrotoxicity.Objective: To investigate effects of peroxisome proliferator activator receptor (PPAR)-α and -γ agonists; fenofibrate (FEN) and pioglitazone (PIO), in MTX-induced nephrotoxicity in rats.Methods: Rats were given FEN or PIO (150 or 5 mg/kg/day, respectively) orally for 15 days. MTX was injected as a single dose of 20 mg/kg, i.p. at day 11 of experiment, with or without either PPAR agonists.Results: MTX induced renal toxicity, assessed by increase in serum urea and creatinine as well as histopathological alterations. MTX caused renal oxidative/nitrosative stress, indicated by decrease in GSH and catalase with increase in malondialdehyde and nitric oxide (NOx) levels. In addition, MTX increased renal level of the pro-inflammatory cytokine; tumor necrosis factor (TNF)-α and up-regulated the expression of both the inflammatory and apoptotic markers; NF-κB and caspase 3. Pre-administration of FEN or PIO to MTX-treated rats improved renal function and reversed oxidative/nitrosative parameters. Interestingly, pre-administration of PIO, but not FEN, decreased renal TNF-α level and NF-κB expression compared to MTX alone. Furthermore, PIO had more significant effect than FEN on reversing MTX-induced renal caspase 3 expression.Discussion: Both FEN and PIO conferred protection against MTX-induced nephrotoxicity through comparable amelioration of oxidative/nitrosative stress. FEN lacked any effect on TNF-α/NF-κB, which was reflected on its less improvement on renal histopathology and apoptosis.Conclusion: At indicated dosage, PPAR-γ ligand; PIO shows better improvement of MTX-induced nephrotoxicity compared to PPAR-α ligand; FEN due to differential effect on TNF-α/NF-κB inflammatory pathway.

Determination of six chemotherapeutic agents in municipal wastewater using online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry

Due to the increased consumption of chemotherapeutic agents, their high toxicity, carcinogenicity, their occurrence in the aquatic environment must be properly evaluated. An analytical method based on online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry was developed and validated. A 1mL injection volume was used to quantify six of the most widely used cytotoxic drugs (cyclophosphamide, gemcitabine, ifosfamide, methotrexate, irinotecan and epirubicin) in municipal wastewater. The method was validated using standard additions. The validation results in wastewater influent had coefficients of determination (R2) between 0.983 and 0.998 and intra-day precision ranging from 7 to 13% (expressed as relative standard deviation %RSD), and from 9 to 23% for inter-day precision. Limits of detection ranged from 4 to 20ngL−1 while recovery values were greater than 70% except for gemcitabine, which is the most hydrophilic compound in the selected group and had a recovery of 47%. Matrix effects were interpreted by signal suppression and ranged from 55 to 118% with cyclophosphamide having the highest value. Two of the target anticancer drugs (cyclophosphamide and methotrexate) were detected and quantified in wastewater (effluent and influent) and ranged from 13 to 60ngL−1. The proposed method thus allows proper monitoring of potential environmental releases of chemotherapy agents.

Self-assembled, redox-sensitive, H-shaped pegylated methotrexate conjugates with high drug-carrying capability for intracellular drug delivery

A novel prodrug of pegylated methotrexate conjugates (PMCs) with a high drug-carrying capability and a redox sensitive drug release mechanism was reported for intracellular drug delivery. The PMC was structured in a H-shape with four molecules of anticancer drug methotrexate (MTX) linked to both ends of the PEG main chain via disulfide linkers, resulting in the conjugates with a high and constant drug loading efficiency of up to 26 wt%. The amphiphilic property of PMCs enables them to self-assemble into nanoparticles in aqueous solution, while the cleavable disulfide linkers allow the conjugated MTX to exert its therapeutic activity due to the fast cleavage of disulfide linkers when exposed to the intracellular concentration of glutathione (GSH). Cell proliferation assays performed with HepG2 cancer cells confirmed the pharmacological efficacy.

β-Cyclodextrin-Bearing Gold Glyconanoparticles for the Development of Site Specific Drug Delivery Systems

Three novel gold nanoparticles containing multiple long, flexible linkers decorated with lactose, β-cyclodextrin, and both simultaneously have been prepared. The interaction of such nanoparticles with β-d-galactose-recognizing lectins peanut agglutinin (PNA) and human galectin-3 (Gal-3) was demonstrated by UV-vis studies. Gal-3 is well-known to be overexpressed in several human tumors and can act as a biorecognizable target. This technique also allowed us to estimate their loading capability toward the anticancer drug methotrexate (MTX). Both results make these glyconanoparticles potential site-specific delivery systems for anticancer drugs.

Biotin-Encoded and Fe<sub>3</sub>O<sub>4</sub>-Loaded Polymeric Nano Micelles: Preparation, Optimization and In Vitro Characterization

Diblock copolymers of poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) bearing a biotin ligand, were self-assembled into micelles. Superparamagnetic iron oxide (SPIO) nanoparticles and an anticancer drug methotrexate (MTX) were coencapsulated within the micelles less than 100 nm in diameters. The preparation process was optimized by a systematic multi-objective-optimization approach in terms of the encapsulation ratio (ER %, Y1), drug-loading efficiency (DL %, Y2) and the percentage of MTX precipitated from the drug-loaded mixed micelles after 30min and 6h incubation at 37ºC (MTX precipitated %, Y3 and Y4) of the resulting nanocarriers. A combination of the stirring rate, ultrasonic power and drug/polymer ratio, accounted for nearly 79% of the variation in drug-loading efficiency. The final entrapment ratio, loading efficiency and MTX % precipitated corresponding to the optimal conditions were 70.938, 5.665 and 6.885 respectively. Moreover, in vitro release behavior of MTX was also investigated. The result shows, MTX is physically entrapped inside B-PEG-PCL self-aggregated nanoparticlesis. Keywords: Biotin, Drug delivery, Nano micelle, Optimization, Plackett-Burman, SoCl2.

In situ synthesized BSA capped gold nanoparticles: Effective carrier of anticancer drug Methotrexate to MCF-7 breast cancer cells

The proficiency of MTX loaded BSA capped gold nanoparticles (Au-BSA-MTX) in inhibiting the proliferation of breast cancer cells MCF-7 as compared to the free drug Methotrexate (MTX) is demonstrated based on MTT and Ki-67 proliferation assays. In addition, DNA ladder gel electrophoresis studies, flow cytometry and TUNEL assay confirmed the induction of apoptosis by MTX and Au-BSA-MTX in MCF-7 cells. Notably, Au-BSA-MTX was found to have higher cytotoxicity on MCF-7 cells compared with an equivalent dose of free MTX. The enhanced activity is attributed to the preferential uptake of Au-BSA-MTX particles by MCF-7 cells due to the presence of BSA that acts as a source of nutrient and energy to the rapidly proliferating MCF-7 cells. Moreover, the targeting ability of the drug MTX to the over expressed folate receptors on MCF-7 cells also contributes to the enhanced uptake and activity. Taken together, these results unveil that Au-BSA-MTX could be more effective than free drug for cancer treatment.

Reduction-degradable PEG-b–PAA-b–PEG triblock copolymer micelles incorporated with MTX for cancer chemotherapy

Reduction-breakable core–shell type polymeric micelles from reduction-degradable amphiphilic polyethylene glycol-b–polyamide amine-b–polyethylene glycol triblock copolymers (PEG-b–PAA-b–PEG) were prepared as new drug carriers of methotrexate (MTX) for cancer chemotherapy. The PEG-b–PAA-b–PEG copolymers were synthesized in a simple one-step process under mild condition through Michael addition. Spherical micelles with diameters ranging from 65 to 123nm were successfully fabricated from the copolymers. These micelles could effectively encapsulate the anti-cancer drug MTX in the core with drug loading content around 13%. The incorporation of MTX resulted in a little size increase but did not influence the morphology of micelles. The drug was hardly released from the micelles in normal condition without DDT as the reductant, but fast released up to 100% within 24h when the structure of micelle core was broken in the presence of DTT, thus provided a potential tool for tumor targeting delivery of MTX using the higher concentration of reductant in tumor tissues. The proliferation inhibition experiments demonstrate that MTX-encapsulated micelles show significant cytotoxicity to KB, HepG2 and 4T1 tumor cells, especiallythe 4T1 cells.

Drug Promiscuity in PDB: Protein Binding Site Similarity Is Key

Drug repositioning applies established drugs to new disease indications with increasing success. A pre-requisite for drug repurposing is drug promiscuity (polypharmacology) – a drug’s ability to bind to several targets. There is a long standing debate on the reasons for drug promiscuity. Based on large compound screens, hydrophobicity and molecular weight have been suggested as key reasons. However, the results are sometimes contradictory and leave space for further analysis. Protein structures offer a structural dimension to explain promiscuity: Can a drug bind multiple targets because the drug is flexible or because the targets are structurally similar or even share similar binding sites? We present a systematic study of drug promiscuity based on structural data of PDB target proteins with a set of 164 promiscuous drugs. We show that there is no correlation between the degree of promiscuity and ligand properties such as hydrophobicity or molecular weight but a weak correlation to conformational flexibility. However, we do find a correlation between promiscuity and structural similarity as well as binding site similarity of protein targets. In particular, 71% of the drugs have at least two targets with similar binding sites. In order to overcome issues in detection of remotely similar binding sites, we employed a score for binding site similarity: LigandRMSD measures the similarity of the aligned ligands and uncovers remote local similarities in proteins. It can be applied to arbitrary structural binding site alignments. Three representative examples, namely the anti-cancer drug methotrexate, the natural product quercetin and the anti-diabetic drug acarbose are discussed in detail. Our findings suggest that global structural and binding site similarity play a more important role to explain the observed drug promiscuity in the PDB than physicochemical drug properties like hydrophobicity or molecular weight. Additionally, we find ligand flexibility to have a minor influence.

Hydroxyethylated graphene oxide as potential carriers for methotrexate delivery

In this study, we presented a simple approach to prepare hydroxyethylated graphene oxide (HE-GO) with high water solubility and physiological stability. The successful synthesis of HE-GO was confirmed by UV–Vis spectroscopy, Fourier transform infrared spectroscopy, and atomic force microscopy. The loading of anticancer drug methotrexate (MTX) onto this nanocarrier (MTX/HE-GO) was investigated. The results of in vitro drug release experiment showed that the rate of MTX release from MTX/HE-GO was pH dependent. Moreover, cell viability assay demonstrated that HE-GO loaded with MTX exhibits higher anticancer activity against human lung adenocarcinoma epithelial cell line than non-vehicle MTX.

Covalent conjugation of graphene oxide with methotrexate and its antitumor activity

Here, we have functionalized graphene oxide with anticancer drug methotrexate through amide bonding. A kinetics of the drug release from graphene oxide in physiological solution – phosphate buffered saline (PBS) containing different biocompatible polymers have been investigated. Dispersion of MTX-GO in poly sodium-4-styrene sulfonate and poly ethylene glycol resulted in increase of the release time. The material was characterized with transmission electron microscopy, atomic force microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. Furthermore, antineoplastic action against human breast adenocarcinoma cell line MCF7 of MTX-GO and empty graphene oxide was explored.

Influence of Human OATP1B1, OATP1B3, and OATP1A2 on the Pharmacokinetics of Methotrexate and Paclitaxel in Humanized Transgenic Mice

Organic anion-transporting polypeptide (OATP) drug uptake transporters are thought to play an important role in drug pharmacokinetics and toxicokinetics. We aimed to determine the influence of the individual human OATP1B1, OATP1B3, and OATP1A2 transporters on the in vivo disposition of the anticancer drugs methotrexate and paclitaxel by using liver-specific humanized OATP1A/1B transgenic mice. Wild-type, Slco1a/1b(-/-) (Oatp1a/1b knockout), Slco1a/1b(-/-);1B1(tg), Slco1a/1b(-/-);1B3(tg), and newly generated Slco1a/1b(-/-);1A2(tg) (humanized OATP1B1, OATP1B3, and OATP1A2 transgenic) mice were characterized biochemically and physiologically, and subsequently intravenously dosed with methotrexate or paclitaxel (2 or 10 mg/kg each) for pharmacokinetic analyses. Humanized OATP1B1, OATP1B3, and OATP1A2 transgenic mice all showed partial or complete rescue of increased plasma bilirubin levels, but also of the increased plasma levels and decreased liver and small intestinal accumulation of methotrexate observed in Slco1a/1b(-/-) mice. Furthermore, hepatic expression of OATP1B3 and OATP1A2, but not OATP1B1, resulted in increased liver uptake of paclitaxel (2 mg/kg). At 10 mg/kg, a modest effect of only OATP1A2 on paclitaxel liver uptake was observed. Human OATP1A/1B transporters play an important role in plasma and tissue distribution of the structurally diverse chemotherapeutics methotrexate (organic anion) and paclitaxel (hydrophobic, bulky). Variation in OATP1A/1B activity due to genetic variation and pharmacologic inhibition, or differences in tumor-specific expression levels might therefore affect plasma, tissue, and tumor levels of these drugs in patients, and hence their therapeutic efficacy. Humanized transgenic OATP1A/1B mice will provide excellent tools to further study these aspects in vivo for many (anticancer) drugs.

Highlights of This Issue

The cytidine analogues 5-azacytidine and decitabine have a powerful molecular epigenetic effect: depletion of DNA-methyltransferase. This is an S-phase, DNA-replication dependent action, so treatment exposure time is likely a crucial determinant of efficacy, and genetic factors that influence cytidine analogue metabolism could potentially affect treatment outcomes. The ubiquitously expressed enzyme cytidine deaminase (CDA) rapidly inactivates 5-azacytidine/decitabine. Mahfouz and colleagues evaluated here for the first time the impact of pharmacogenetic factors that affect CDA enzyme activity/expression on 5-azacytidine/decitabine treatment outcomes. Interestingly and significantly, they found that gender had a substantially greater influence on CDA enzyme activity/expression than the well-known CDA SNP A79C, with a corresponding impact on overall survival in 5-azacytidine/decitabine-treated MDS patients. The identification of this pharmacogenetic factor and the mechanism by which it affects outcomes suggest rational methods for optimizing the clinical application of these unique oncotherapeutics.KRAS hyperactivation can occur through mutation or genomic amplification and defines a subset of lung tumors with poor prognosis and fewer therapeutic options. McCleland and colleagues utilize both functional and genomic techniques to identify genes that functionally cooperate with KRAS. These integrative approaches identify lactate dehydrogenase B (LDHB) as overexpressed and necessary for cell growth in the context of KRAS-hyperactive lung cancers. Consistent with a role for LDHB in glycolysis and tumor growth, lung cancers with high LDHB show an increased dependence on glycolysis and a worse patient outcome. These findings warrant further investigation of LDHB as a metabolic driver in KRAS-dependent lung cancer.Cancer chemotherapy is complicated by interindividual variation in drug response and toxicity and drug–drug interactions. Given their tissue distribution and broad substrate specificity, drug uptake transporters of the organic anion transporting polypeptide (OATP) family may play a marked role in these processes. Using humanized OATP1B1, OATP1B3, and OATP1A2 transgenic mice, van de Steeg and colleagues found that all 3 OATPs transport the anticancer drug methotrexate in vivo, whereas OATP1B3 and OATP1A2 transport paclitaxel. Variation in OATP1A/1B activity due to genetic variation or drug–drug interactions, and tumor-specific expression of OATPs, might therefore codetermine treatment efficacy and/or toxicity of these, and likely many other, anticancer drugs.There has been significant interest in fully understanding the ability of plasma VEGF-A to predict for patients who may respond favorably to bevacizumab, an antiangiogenesis agent approved for metastatic cancers including colorectal cancer (CRC), non–small cell lung cancer (NSCLC), and renal cell cancer (RCC). Previous studies have examined small cohorts or single clinical trials that are underpowered for retrospective subset analyses. To provide a more definitive answer, Hegde and colleagues evaluated VEGF-A levels in plasma from 1,816 patients from 5 randomized controlled trials in indications including CRC, NSCLC, and RCC. Using an assay that recognizes major isoforms of VEGF-A with equivalent sensitivities, this study provides robust data on prevalence of plasma VEGF-A in these indications. This study shows for the first time in a rigorous manner that plasma levels of total VEGF do not predict benefit from bevacizumab therapy in these indications.

Gelatin-based hydrogels with β-cyclodextrin as a dual functional component for enhanced drug loading and controlled release

In this paper, we demonstrate a simple and practical method to prepare chemically crosslinked gelatin-based hydrogels using β-cyclodextrin (β-CD) that plays a dual role as a crosslinker as well as a host molecule for enhanced binding of anticancer drug methotrexate (MTX), to achieve high drug loading level as well as controlled and sustained release of the anticancer drug. For this purpose, a series of novel β-CD-crosslinked gelatin-based hydrogels were synthesized and characterized. The β-CD content of the hydrogels was 11–15%, and the crosslinking degree was 21–36%. The gelatin-based hydrogels could swell well in PBS buffer. The hydrogels degraded hydrolytically and the degradation was accelerated by collagenase in PBS buffer. It was found that the higher water content resulted in faster biodegradation of the hydrogels regardless of the crosslinker used. Pyrene was used as a fluorescence probe to investigate the micro-environment of the gelatin-based hydrogels. Pyrene was well adsorbed in the β-CD-crosslinked hydrogels, and the pyrene molecules in the hydrogels were included and complexed within the hydrophobic cavities of the β-CD crosslinkers. The adsorption, loading, binding and complexation, and release of MTX in or from the hydrogels were investigated. MTX was adsorbed and loaded into the hydrogels by immersing the swollen hydrogel samples in MTX saturated aqueous solution. The loading of MTX in the hydrogels was confirmed by measuring the UV-vis spectra of the MTX-loaded hydrogels, the spectra indicated that the loaded MTX was complexed by β-CD in the β-CD-crosslinked hydrogels. Our data showed that the complexation of MTX with β-CD crosslinkers largely increased the loading level of MTX in the hydrogels. The complexation could also reduce the initial burst release effect, and then retard the release of the complexed MTX for a certain period, until the hydrogels started to hydrolytically degrade and all remained MTX was released. Due to the unique structures and properties, the β-CD-crosslinked gelatin-based hydrogels demonstrated an interesting multiphasic profile for controlled and sustained release of the MTX drug. Thus, the β-CD-crosslinked gelatin-based hydrogels may be utilized as a promising drug carrier for controlled and sustained release and localized delivery of anticancer drugs.

Interaction of anticancer drug methotrexate with DNA analyzed by electrochemical and spectroscopic methods

Electrochemical DNA biosensor was used to study the interaction of methotrexate (MTX) with DNA immobilized on the bare surface of glassy carbon electrode (GCE). The binding mechanism of MTX with DNA was elucidated by using constant current potentiometric technique further supported by UV–Visible and FT-IR studies. The decrease in guanine peak area was used as an analytical signal for the interaction of drug with DNA in acetate buffer solution at pH 4.2 (20% ethanol). The binding constant (K) value calculated for MTX was 3.821×105M−1. UV–Visible studies indicated hyperchromic and hypsochromic shifts in the maximum absorption bands of MTX after interaction with DNA. FT-IR investigations of MTX–DNA interaction revealed significant changes in the characteristic IR absorption bands of all the bases and phosphate groups of DNA. Furthermore, the shift of characteristics bands of CO, NH, CH and OH groups of MTX endow evidence for the interaction of MTX with DNA supporting the intercalative binding between them.

Biodegradable Hyperbranched Polyglycerol with Ester Linkages for Drug Delivery

Biodegradable hyperbranched polyglycerols (dHPGs) were synthesized through oxyanionic initiating hybrid polymerization of glycerol and glycidyl methacrylate. Due to the introduction of ester linkages into the hyperbranched polyglycerol backbone, dHPGs showed good biodegradability and low cytotoxicity. Benefiting from the existence of terminal hydroxyls and methacryloyl groups, both the anticancer drug methotrexate (MTX) and fluorescent probe Rhodamine-123 could be conjugated onto the surface of dHPGs easily. The resultant MTX-conjugated polymers (dHPG-MTXs) exhibited an amphiphilic character, resulting in the formation of micelles in an aqueous solution. The release of MTX from micelles was significantly faster at mildly acidic pH of 5.0 compared to physiological pH of 7.4. dHPG-MTX micelles could be efficiently internalized by cancer cells. MTT assay against cancer cells showed dHPG-MTXs micelles had high anticancer efficacy. On the basis of their good biodegradability and low cytotoxicity, dHPGs provide an opportunity to design excellent drug delivery systems.