Synthesis and characterization of pH-responsive N-naphthyl-N,O-succinyl chitosan micelles for oral meloxicam delivery

Long-Acting Drug Delivery Technologies for Meloxicam as a Pain Medicine

Meloxicam, a selective COX-2 inhibitor, has demonstrated clinical effectiveness in managing inflammation and acute pain. Although available in oral and parenteral formulations such as capsule, tablet, suspension, and solution, frequent administration is necessary to maintain therapeutic efficacy, which can increase adverse effects and patient non-compliance. To address these issues, several sustained drug delivery strategies such as oral, transdermal, transmucosal, injectable, and implantable drug delivery systems have been developed for meloxicam. These sustained drug delivery strategies have the potential to improve the therapeutic efficacy and safety profile of meloxicam, thereby reducing the frequency of dosing and associated gastrointestinal side effects. The choice of drug delivery system will depend on the desired release profile, the target site of inflammation, and the mode of administration. Overall, meloxicam sustained delivery systems offer better patient compliance, and reduce the side effects, thereby improving the clinical applications of this drug. Herein, we discuss in detail different strategies for sustained delivery of meloxicam.

Drug Polymeric Carrier of Aceclofenac Based on Amphiphilic Chitosan Micelles

Amphiphilic micelles based on chitosan (CS) were applied as drug carriers of aceclofenac (ACF) as a potential method to induce its bioavailability and therapeutic efficiency. N-octyl-N,O-succinyl CS (OSCS), an amphiphilic CS derivative, was successfully synthesized and loaded physically by ACF at different pH values and using different dosages of ACF, forming ACF-loaded polymeric micelles (PMs). The obtained PMs and ACF-loaded PMs were characterized by different analytical techniques, including AFM, TEM, DLS, UV-vis spectrophotometry, 1H NMR spectroscopy, and FT-IR spectroscopy. The pH 5 sample with a 30% ACF/polymer ratio showed the highest ACF loading capacity (LC) and entrapment efficiency (EE). In vitro release behaviors of pure ACF and ACF-loaded PMs at each release point indicated that the release profile of pH-responsive PMs loaded with ACF demonstrated quicker release rates (94% after 480 min) compared to the release behavior noticed for free ACF (59.56% after 480 min). Furthermore, the release rates exhibit a notable rise when the pH is increased from 1.2 to 4.7. In the carrageenan-induced inflammation model of paw edema in rats, it has been demonstrated that the injection of ACF-loaded PMs (at a dose of 10 mg/kg) resulted in a strengthened inflammatory activity compared to the injection of free ACF at equivalent dosages as well as at time intervals. However, the use of ACF-loaded PMs for a duration of 6 h displayed a notable reduction of paw edema, with an inhibition percentage of 85.09%, in contrast to the 74.9% inhibition percentage observed for the free ACF medication.

The Commonly Used Stabilizers for Phytochemical-Based Nanoparticles: Stabilization Effects, Mechanisms, and Applications

Phytochemicals, such as resveratrol, curcumin, and quercetin, have many benefits for health, but most of them have a low bioavailability due to their poor water solubility and stability, quick metabolism, and clearance, which restricts the scope of their potential applications. To overcome these issues, different types of nanoparticles (NPs), especially biocompatible and biodegradable NPs, have been developed. NPs can carry phytochemicals and increase their solubility, stability, target specificity, and oral bioavailability. However, NPs are prone to irreversible aggregation, which leads to NP instability and loss of functions. To remedy this shortcoming, stabilizers like polymers and surfactants are incorporated on NPs. Stabilizers not only increase the stability of NPs, but also improve their characteristics. The current review focused on discussing the state of the art in research on synthesizing phytochemical-based NPs and their commonly employed stabilizers. Furthermore, stabilizers in these NPs were also discussed in terms of their applications, effects, and underlying mechanisms. This review aimed to provide more references for developing stabilizers and NPs for future research.

Self-assembled block copolymer biomaterials for oral delivery of protein therapeutics

Protein therapeutics have guided a transformation in disease treatment for various clinical conditions. They have been successful in numerous applications, but administration of protein therapeutics has been limited to parenteral routes which can decrease patient compliance as they are invasive and painful. In recent years, the synergistic relationship of novel biomaterials with modern protein therapeutics has been crucial in the treatment of diseases that were once thought of as incurable. This has guided the development of a variety of alternative administration routes, but the oral delivery of therapeutics remains one of the most desirable due to its ease of administration. This review addresses important aspects of micellar structures prepared by self-assembled processes with applications for oral delivery. These two characteristics have not been placed together in previous literature within the field. Therefore, we describe the barriers for delivery of protein therapeutics, and we concentrate in the oral/transmucosal pathway where drug carriers must overcome several chemical, physical, and biological barriers to achieve a successful therapeutic effect. We critically discuss recent research on biomaterials systems for delivering such therapeutics with an emphasis on self-assembled synthetic block copolymers. Polymerization methods and nanoparticle preparation techniques are similarly analyzed as well as relevant work in this area. Based on our own and others' research, we analyze the use of block copolymers as therapeutic carriers and their promise in treating a variety of diseases, with emphasis on self-assembled micelles for the next generation of oral protein therapeutic systems.

Fucoidan-based nanomaterial and its multifunctional role for pharmaceutical and biomedical applications

Fucoidans are promising sulfated polysaccharides isolated from marine sources that have piqued the interest of scientists in recent years due to their widespread use as a bioactive substance. Bioactive coatings and films, unsurprisingly, have seized these substances to create novel, culinary, therapeutic, and diagnostic bioactive nanomaterials. The applications of fucoidan and its composite nanomaterials have a wide variety of food as well as pharmacological properties, including anti-oxidative, anti-inflammatory, anti-cancer, anti-thrombic, anti-coagulant, immunoregulatory, and anti-viral properties. Blends of fucoidan with other biopolymers such as chitosan, alginate, curdlan, starch, etc., have shown promising coating and film-forming capabilities. A blending of biopolymers is a recommended approach to improve their anticipated properties. This review focuses on the fundamental knowledge and current development of fucoidan, fucoidan-based composite material for bioactive coatings and films, and their biological properties. In this article, fucoidan-based edible bioactive coatings and films expressed excellent mechanical strength that can prolong the shelf-life of food products and maintain their biodegradability. Additionally, these coatings and films showed numerous applications in the biomedical field and contribute to the economy. We hope this review can deliver the theoretical basis for the development of fucoidan-based bioactive material and films.

Solution properties of N-(2-allyl-butyl ether)-O-carboxymethyl chitosan and N-(2-allyl-isooctyl ether)-O-carboxymethyl chitosan

pH-sensitive and amphiphilic chitosan derivatives can be used as hydrophobic drug carriers, and their rheological properties play a key role in their performance. In this paper, two pH-responsive and amphiphilic chitosan derivatives, N-(2-allyl-butyl glycidyl ether)-O-carboxymethyl chitosan (HBCC) and N-(2-ethylhexyl glycidyl ether)-O-carboxymethyl chitosan (H2ECC) were synthesized, and their rheological properties were studied. The influence of parameters including concentrations of HBCC and H2ECC, the degree of substitution, solution pH, and [Ca²⁺] on the rheological properties were investigated. The results showed that the overlap and entanglement concentration of HBCC and H2ECC was ca. 1.7 wt% and 5 wt%, respectively. The dilute and semidilute solutions showed Newtonian behavior. Above 5 wt%, strong networks formed, and shear-thinning behavior appeared at high shear rates (>10 s^-1) for entangled solutions. A high degree of substitution and pH near the isoelectric points of HBCC and H2ECC corresponded to a low viscosity and viscoelasticity. In addition, Ca²⁺ played a shielding effect on the -COO^- groups at low concentrations (<10 mmol/L), whereas it acted as a cross-linker when [Ca²⁺] ≥ 20 mmol/L. The intermolecular hydrogen bonds were examined by molecular dynamics simulations. The results provide new information related to the application of HBCC and H2ECC for hydrophobic drug packaging and transportation.

Overcoming multidrug resistance by intracellular drug release and inhibiting p-glycoprotein efflux in breast cancer

Doxorubicin (DOX) is limited to use in clinical practice because of poor targeting, serious side effects and multidrug resistance (MDR). Vitamin E and its derivatives are currently considered as hydrophobic material that can reverse tumor MDR by suppressing the action of p-glycoprotein (p-gp). Therefore, reduction-sensitive amphiphilic heparosan polysaccharide-cystamine-vitamin E succinate (KSV) copolymers were designed to reverse breast cancer MDR cells. The spherical micelles (DOX/KSV) micelles which had suitable particle size presented redox-sensitive release character. Simultaneously, DOX-loaded reduction insensitive heparosan-adipic dihydrazide-vitamin E succinate (KV) micellar system was designed as a control. DOX/KSV and DOX/KV micelles had the higher capability to overcome tumor MDR than that free DOX. However, DOX/KSV had the highest amount of cellular uptake which might be caused by the synergistic intracellular drug release and inhibition of p-gp expression. The mechanism experiments revealed that DOX/KSV could be fast disassembled to release DOX after internalization into tumor cells. Moreover, DOX/KSV produced more ROS than free DOX and DOX/KV resulting in enhanced anticancer effect. In vivo tumor-bearing mice study suggested that DOX/KSV micelles could efficiently enhance antitumor effect by overcoming tumor MDR and reduce toxicity of DOX. The DOX/KSV micelles could synergistically increase the therapeutic effect of chemotherapeutic drug on tumor MDR cells.

Chitosan Derivatives and Their Application in Biomedicine

Chitosan is a product of the deacetylation of chitin, which is widely found in nature. Chitosan is insoluble in water and most organic solvents, which seriously limits both its application scope and applicable fields. However, chitosan contains active functional groups that are liable to chemical reactions; thus, chitosan derivatives can be obtained through the chemical modification of chitosan. The modification of chitosan has been an important aspect of chitosan research, showing a better solubility, pH-sensitive targeting, an increased number of delivery systems, etc. This review summarizes the modification of chitosan by acylation, carboxylation, alkylation, and quaternization in order to improve the water solubility, pH sensitivity, and the targeting of chitosan derivatives. The applications of chitosan derivatives in the antibacterial, sustained slowly release, targeting, and delivery system fields are also described. Chitosan derivatives will have a large impact and show potential in biomedicine for the development of drugs in future.

Redox-responsive biocompatible nanocarriers based on novel heparosan polysaccharides for intracellular anticancer drug delivery

Heparosan is a natural precursor of heparin biosynthesis in mammals. It is stable in blood circulation but can be degraded in lysosomes, showing good biocompatibility and long circulation features. So heparosan can be designed as anticancer drug carriers to increase tumor selectivity and improve the therapeutic effect. A novel redox-sensitive heparosan-cystamine-vitamin E succinate (KSV) micelle system was constructed for intracellular delivery of doxorubicin (DOX). Simultaneously, the redox-insensitive heparosan-adipic acid dihydrazide-vitamin E succinate copolymer (KV) was synthesized as control. DOX-loaded micelles (DOX/KSV) with an average particle size of 90-120 nm had good serum stability and redox-triggered depolymerization. In vitro drug release test showed that DOX/KSV micelles presented obvious redox-triggered release behavior compared with DOX/KV. Cytotoxicity and cell uptake were investigated using MGC80-3 tumor cells and COS7 fibroblast-like cells. The cell survival rate of blank micelles was more than 90%, and the cytotoxicity of DOX/KSV in MGC80-3 cells was higher than in COS7 cells, indicating that the carrier has better biocompatibility and less toxicity side effect. The cytotoxicity of DOX/KSV against MGC80-3 cells was significantly greater than that of free DOX and DOX/KV. Furthermore, compared with DOX/KV in MGC80-3 cells, DOX/KSV micelles uptook more anticancer drugs and then released DOX faster into the cell nucleus. The micelles were endocytosed by multiple pathways, but clathrin-mediated endocytosis was the main pathway. Therefore, heparosan polysaccharide could be a potential option as anticancer carrier for enhancing efficacy and mitigating toxicity.

Biodegradable reduction-responsive polymeric micelles for enhanced delivery of melphalan to retinoblastoma cells

Melphalan (MEL) is an effective chemotherapeutic agent for treatment of retinoblastoma (Rb) which is the most common childhood malignancy. However, the inherent cardiopulmonary toxicity and hazardous integration limit its therapeutic effect on RB. N-Acetylheparosan (AH), a natural heparin-like polysaccharide in mammals with long circulation effect and good biocompatibility, was linked by d-α-tocopherol acid succinate (VES) via and cystamine (CYS) to synthesize reduction-responsive N-acetylheparosan-CYS-Vitamin E succinate (AHV) copolymers. In addition, CYS was replaced by adipic acid dihydrazide (ADH) to obtain a control of non-reduction-responsive polymers N-acetylheparosan-ADH-Vitamin E succinate (ADV). MEL-loaded AHV micelles (MEL/AHV) as well as ADV micelles (MEL/ADV) were prepared with small particle size and high drug loading content. In vitro drug release showed that MEL/AHV micelles presented obvious reduction-triggered release behavior compared with MEL/ADV. In vitro antitumor effects were investigated using WERI-Rb-1 retinoblastoma cells. Cytotoxicity experiments showed that the IC₅₀ of MEL/AHV was significantly lower than that of free MEL and MEL/ADV, suggesting that MEL/AHV enhanced the cytotoxicity against retinoblastoma cells. Furthermore, MEL/AHV micelles were more easily uptaken by multiple pathways compared with MEL/ADV and free MEL. Therefore, MEL/AHV might be a potential delivery system for enhanced delivery of melphalan to Rb cells.

pH-Responsive Polypeptide-Based Smart Nano-Carriers for Theranostic Applications

Smart nano-carriers have attained great significance in the biomedical field due to their versatile and interesting designs with different functionalities. The initial stages of the development of nanocarriers mainly focused on the guest loading efficiency, biocompatibility of the host and the circulation time. Later the requirements of less side effects with more efficacy arose by attributing targetability and stimuli-responsive characteristics to nano-carriers along with their bio- compatibility. Researchers are utilizing many stimuli-responsive polymers for the better release of the guest molecules at the targeted sites. Among these, pH-triggered release achieves increasing importance because of the pH variation in different organ and cancer cells of acidic pH. This specific feature is utilized to release the guest molecules more precisely in the targeted site by designing polymers having specific functionality with the pH dependent morphology change characteristics. In this review, we mainly concert on the pH-responsive polypeptides and some interesting nano-carrier designs for the effective theranostic applications. Also, emphasis is made on pharmaceutical application of the different nano-carriers with respect to the organ, tissue and cellular level pH environment.

Catechol-Functionalized Succinyl Chitosan for Novel Mucoadhesive Drug Delivery

The objective of this research was to synthesized and evaluated a mucoadhesive catechol-bearing succinyl chitosan (Cat-SCS) as an innovative mucoadhesive substance for a mucoadhesive drug delivery system. Succinyl chitosan (SCS) was synthesized via ring-opening reactions with succinic anhydride. The Cat-SCS was then synthesized by reacting SCS with dopamine with the existence of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC) and N-hydroxysulfosuccinimide (NHS). The successful functionalization of catechol onto chitosan backbone was verified using nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). Mucoadhesion studies were performed using rheology measurement and ex-vivo mucoadhesion test. The findings exposed that the synthesized Cat-SCS exhibited excellent mucoadhesive properties which was better than the intact CS. Further indirect studies verified the occurrence of polymer-mucin glycoproteins interactions. The catechol content of catechol moiety on the Cat-SCS was determined to be 0.377 using the 1H NMR. The cytotoxicity test indicated the biocompatibility of the obtained polymer on human gingival fibroblast cells (HGF cells). Therefore, these results could advocate the capacity to use of Cat-SCS as an innovative mucoadhesive platform for mucoadhesive drug delivery.

Effect of the linear aliphatic amine functionalization on in vitro transfection efficiency of chitosan nanoparticles

The aim of this study is to prepare the long linear aliphatic amine pendant group-functionalized chitosan based nanoparticulate gene carrier system with improved properties for the efficient transfection. The amine functionalized chitosan (MChi) was synthesized by using N-(2-hydroxyethyl)ethylenediamine (HE-EDA) and characterized for the first time. The nanoparticles of MChi (nMChi) were prepared by ionic gelation method, and their particle size, polydispersity (PDI), zeta potential (mV), gene binding capacity and cytotoxicity were determined. Green Fluorescent Protein circular plasmid DNA (pEGFN1) loaded nanoparticles (gnMChi) were used in the transfection studies. The results showed that nMChi with a particle size of 102.9 nm and zeta potential of 41.9 ± 5.63 mV was non-toxic, had high transfection efficiency in Human Embryonic Kidney 293 and Primary Ovine Fibroblast cell lines and would be used as an efficient gene carrier system.

Apoptosis Induction and Antimigratory Activity of Andrographolide Analog (3A.1)-Incorporated Self-Assembled Nanoparticles in Cancer Cells

Andrographolide analog, namely 19-tert-butyldiphenylsilyl-8,17-epoxy andrographolide (or 3A.1) has been reported to be a potential anticancer agent for several types of cancer. Due to its poor aqueous solubility, 3A.1 was incorporated within self-assembly polymeric nanoparticles made of naphthyl-grafted succinyl chitosan (NSC), octyl-grafted succinyl chitosan (OSC), and benzyl-grafted succinyl chitosan (BSC). These 3A.1-loaded nanoparticles were nanosized (< 200 nm) and spherical in shape with a negative surface charge. 3A.1-loaded nanoparticles were produced using a dropping method, which 40% initial drug adding exhibited the highest entrapment efficiency. The release of 3A.1 from the 3A.1-loaded nanoparticles displayed a delayed release pattern. Under acidic conditions (pH 1.2), there was no free drug release. After the pH was adjusted to 6.8, a high cumulative 3A.1 release was obtained which was dependent on the hydrophobic moieties. These 3A.1-loaded pH-sensitive nanoparticles proved to be beneficial for specifically delivering anticancer drugs to the targeted colon cancer sites. In vitro anticancer activity against HT-29 found that the 3A.1-loaded nanoparticles had significantly lower IC₅₀ than that of the free drug and promoted apoptosis. Additionally, in vitro wound-healing migration on HN-22 revealed that free 3A.1 and the 3A.1-loaded nanoparticles inhibited cell motility compared with untreated cells. These pH-sensitive amphiphilic chitosan nanoparticles may be promising nanocarriers for oral anticancer drug delivery to colorectal cancer cells. Graphical abstract ᅟ.

Synthesis, Characterization, and Antifungal Property of Hydroxypropyltrimethyl Ammonium Chitosan Halogenated Acetates

Hydroxypropyltrimethyl ammonium chitosan halogenated acetates were successfully synthesized from six different haloacetic acids and hydroxypropyltrimethyl ammonium chloride chitosan (HACC) with high substitution degree, which are hydroxypropyltrimethyl ammonium chitosan bromacetate (HACBA), hydroxypropyltrimethyl ammonium chitosan chloroacetate (HACCA), hydroxypropyltrimethyl ammonium chitosan dichloroacetate (HACDCA), hydroxypropyltrimethyl ammonium chitosan trichloroacetate (HACTCA), hydroxypropyltrimethyl ammonium chitosan difluoroacetate (HACDFA), and hydroxypropyltrimethyl ammonium chitosan trifluoroacetate (HACTFA). These chitosan derivatives were synthesized by two steps: first, the hydroxypropyltrimethyl ammonium chloride chitosan was synthesized by chitosan and 3-chloro-2-hydroxypropyltrimethyl ammonium chloride. Then, hydroxypropyltrimethyl ammonium chitosan halogenated acetates were synthesized via ion exchange. The structures of chitosan derivatives were characterized by Fourier transform infrared spectroscopy (FTIR), ¹H Nuclear magnetic resonance spectrometer (¹H NMR), 13C Nuclear magnetic resonance spectrometer (13C NMR), and elemental analysis. Their antifungal activities against Colletotrichum lagenarium, Fusarium graminearum, Botrytis cinerea, and Phomopsis asparagi were investigated by hypha measurement in vitro. The results revealed that hydroxypropyltrimethyl ammonium chitosan halogenated acetates had better antifungal activities than chitosan and HACC. In particular, the inhibitory activity decreased in the order: HACTFA > HACDFA > HACTCA > HACDCA > HACCA > HACBA > HACC > chitosan, which was consistent with the electron-withdrawing property of different halogenated acetates. This experiment provides a potential idea for the preparation of new antifungal drugs by chitosan.

Endogenous pH-responsive nanoparticles with programmable size changes for targeted tumor therapy and imaging applications

Nanotechnology-based antitumor drug delivery systems, known as nanocarriers, have demonstrated their efficacy in recent years. Typically, the size of the nanocarriers is around 100 nm. It is imperative to achieve an optimum size of these nanocarriers which must be designed uniquely for each type of delivery process. For pH-responsive nanocarriers with programmable size, changes in pH (~6.5 for tumor tissue, ~5.5 for endosomes, and ~5.0 for lysosomes) may serve as an endogenous stimulus improving the safety and therapeutic efficacy of antitumor drugs. This review focuses on current advanced pH-responsive nanocarriers with programmable size changes for anticancer drug delivery. In particular, pH-responsive mechanisms for nanocarrier retention at tumor sites, size reduction for penetrating into tumor parenchyma, escaping from endo/lysosomes, and swelling or disassembly for drug release will be highlighted. Additional trends and challenges of employing these nanocarriers in future clinical applications are also addressed.

Development of Chitosan-Based pH-Sensitive Polymeric Micelles Containing Curcumin for Colon-Targeted Drug Delivery

pH-sensitive N-naphthyl-N,O-succinyl chitosan (NSCS) and N-octyl-N,O-succinyl chitosan (OSCS) polymeric micelles carriers have been developed to incorporate curcumin (CUR) for colon-targeted drug delivery. The physical entrapment methods (dialysis, co-solvent evaporation, dropping, and O/W emulsion) were applied. The CUR-loaded micelles prepared by the dialysis method presented the highest loading capacity. Increasing initial amount of CUR from 5 to 40 wt% to polymer resulted in the increase in loading capacity of the polymeric micelles. Among the hydrophobic cores, there were no significant differences in the loading capacity of CUR-loaded micelles. The particle sizes of all CUR-loaded micelles were in the range of 120-338 nm. The morphology of the micelles changed after being contacted with medium with different pH values, confirming the pH-responsive properties of the micelles. The release characteristics of curcumin from all CUR-loaded micelles were pH-dependent. The percent cumulative release of curcumin from all CUR-loaded micelles in simulated gastric fluid (SGF) was limited to about 20%. However, the release amount was significantly increased after contacted with simulated intestinal fluid (SIF) (50-55%) and simulated colonic fluid (SCF) (60-70%). The released amount in SIF and SCF was significantly greater than the release of CUR from CUR powder. CUR-loaded NSCS exhibited the highest anti-cancer activity against HT-29 colorectal cancer cells. The stability studies indicated that all CUR-loaded micelles were stable for at least 90 days. Therefore, the colon targeted, pH-sensitive NSCS micelles may have potential to be a prospective candidate for curcumin delivery to the colon.

Mutlifunctional nanoparticles prepared from arginine-modified chitosan and thiolated fucoidan for oral delivery of hydrophobic and hydrophilic drugs

Self-assembled nanoparticles (NPs) from arginine-modified chitosan (CS-N-Arg) and thiolated fucoidan (THL-fucoidan) were synthesized to enhance the transport of dextran and curcumin across intestinal epithelial cell layer. CS-N-Arg/THL-fucoidan NPs exhibited a pH-sensitive assembly-disassembly and drug release property. Evaluations of the NPs in enhancing the transport of a hydrophilic macromolecule (FITC-dextran) and a hydrophobic drug (curcumin) were investigated in Caco-2 cell monolayers. The cationic CS-N-Arg in the NPs induced disruption of intestinal epithelial tight junctions as indicated by the decrease of transepithelial electrical resistance (TEER). Permeation studies revealed that the NPs enhanced the paracellular permeation of macromolecular dextran through the monolayer barrier. In addition, the multifunctional NPs increased the permeability of rhodamine 123 because the thiomer THL-fucoidan in the NPs inhibited P-glycoprotein. Cellular uptake and permeability of curcumin encapsulated in the NPs were improved due to increasing their water solubility and stability.

Chitosan-based self-assembled nanocarriers coordinated to cisplatin for cancer treatment

Polymeric nanocarriers were prepared via a dialysis method using three chitosan derivatives, N-benzyl-N,O-succinyl chitosan (BSCT), N-naphthyl-N,O-succinyl chitosan (NSCT), and N-octyl-N-O-succinyl chitosan (OSCT) and were coordinated to cisplatin. The nanocarrier properties and cytotoxicity on the human carcinoma cells, HN22 (head and neck), were investigated. In addition, intracellular cisplatin accumulation, apoptosis induction and toxicity on renal cells were also evaluated. The findings revealed that the succinyl groups of the polymers were perfectly deprotonated and bound with cisplatin by co-ordinate bonds at pH 8.5. Among the derivatives, BSCT exhibited the highest cisplatin loading and release in simulated physiological medium. The cytotoxicities on HN22 cells of cisplatin-loaded BSCT nanocarriers were lower than that of free cisplatin, however, they presented a greater percentage of early apoptosis in HN22 cells and could decrease cisplatin induced renal cell death. In conclusion, the BSCT self-assembly nanocarrier might be a cisplatin carrier for sustained release, which provides prolonged antitumour treatment and reduced nephrotoxicity.

Polymeric nanocarriers were prepared using chitosan derivatives, and were coordinated to cisplatin.The nanocarrier properties and cytotoxicity on the human carcinoma cells, HN22, were investigated.

A novel controlled drug delivery system based on alginate hydrogel/chitosan micelle composites

In this study, we present a novel cross-linked unimolecular micelle based on chitosan. For controlling drug delivery via oral administration, emodin (EMO) encapsulated micelles were loaded into sodium alginate hydrogel matrix to construct the pH-sensitive hydrogel/micelle composites. The optimized formulation of micelle that consists of 8.06% CaCl₂, 1.71% chitosan and 26.52% β-GP was obtained by the combination of Box-Behnken experimental design and response surface methodology. The morphological analysis showed that the micelles exhibited a smaller diameter of about 80nm in aqueous solution, but dilated to 100-200nm in hydrogel owing to the formation of polyelectrolyte complexes. The physical characteristics in simulated digestive fluids were investigated, demonstrating that the ratio of hydrogel to micelle distinctly affected swelling, degradation and in vitro drug release behaviors. The hydrogel/micelle (1:1) exhibited a sustained-release profile, while hydrogel/micelle (3:1) exhibited a colon-specific profile. Their corresponding release mechanisms revealed that the release of drug from these two formulations followed a complex process, in which several mechanisms were involved or occurred simultaneously. These results demonstrated that the pH-sensitive hydrogel/micelle composites constructed with biocompatible materials can be a promising sustained-release or site-specific drug delivery system for instable or hydrophobic drugs.

Design and characteristics of gellan gum beads for modified release of meloxicam

The aim of the presented work was to design, formulate and evaluate the properties of low-acyl gellan macro beads with the potential application as carriers for oral delivery of meloxicam (MLX) in the prophylaxis of colorectal cancer. The beads were obtained by means of ionotropic gelation technique. Calcium chloride (1.0%, 9.0 × 10^-2 M) was used as the cross-linking agent. Nine different polymer, drug and surfactant (Tween^®80) mixtures were used for production of the beads. The quantitative compositions of the mixtures were generated with the application of the Design of Experiments (DoE) modulus from the STATISTICA Software. The prepared formulations revealed 7.2-27.0% of drug loading and 29.2-50.7% drug encapsulation efficiency. It turned out that 0.5% amount of gellan gum in the mixtures was not sufficient to obtain spherical beads. The morphology and surface of the dried beads were analyzed by SEM. Raman spectra confirmed that MLX did not undergo structural changes during production of the beads. The swelling behavior and degradation of the beads were evaluated in three simulated gastrointestinal fluids at different pH (1.2; 4.5; 6.8). The MLX in vitro release studies were conducted on USP apparatus IV, working in the open loop mode. The obtained results showed that MLX release from the dried beads was pH-dependent. The formulations obtained from mixtures containing 1.0 and 1.5% of gellan may be considered as oral dosage forms for MLX, intended to omit the stomach and release the drug in the distal parts of the gastrointestinal tract.

Facile fabrication of a magnetically smart PTX-loaded Cys–Fe3O4/CuS@BSA nano-drug for imaging-guided chemo-photothermal therapy

A PTX-loaded Cys-Fe₃O₄/CuS@BSA nano-drug was synthesized for MR and NIR imaging-guided chemo-photothermal combination therapy of cancer via a facile fabrication method.

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.

Development and evaluation of N-naphthyl-N,O-succinyl chitosan micelles containing clotrimazole for oral candidiasis treatment

Clotrimazole (CZ)-loaded N-naphthyl-N,O-succinyl chitosan (NSCS) micelles have been developed as an alternative for oral candidiasis treatment. NSCS was synthesized by reductive N-amination and N,O-succinylation. CZ was incorporated into the micelles using various methods, including the dropping method, the dialysis method, and the O/W emulsion method. The size and morphology of the CZ-loaded micelles were characterized using dynamic light scattering measurements (DLS) and a transmission electron microscope (TEM), respectively. The drug entrapment efficiency, loading capacity, release characteristics, and antifungal activity against Candida albicans were also evaluated. The CZ-loaded micelles prepared using different methods differed in the size of micelles. The micelles ranged in size from 120 nm to 173 nm. The micelles prepared via the O/W emulsion method offered the highest percentage entrapment efficiency and loading capacity. The CZ released from the CZ-loaded micelles at much faster rate compared to CZ powder. The CZ-loaded NSCS micelles can significantly hinder the growth of Candida cells after contact. These CZ-loaded NSCS micelles offer great antifungal activity and might be further developed to be a promising candidate for oral candidiasis treatment.

Tumor-targeted docetaxel-loaded hyaluronic acid-quercetin polymeric micelles with p-gp inhibitory property for hepatic cancer therapy

Herein, a novel targeted drug delivery nanosystem based on hyaluronic acid (HA) and quercetin (QU) was designed to improve the in vivo therapeutic efficacy of DTX on HC through HA-CD44 mediated targeting and QU-based p-gp efflux inhibition.