Wettability and contact angle affect precorneal retention and pharmacodynamic behavior of microspheres.

In the present study, we describe the development of betaxolol hydrochloride and montmorillonite with ion exchange in a single formulation to create a novel micro-interactive dual-functioning sustained-release delivery system (MIDFDS) for the treatment of glaucoma. Betaxolol hydrochloride molecule was loaded onto the montmorillonite by ion exchange and MIDFDS formation was confirmed by XPS data. MIDFDS showed similar physicochemical properties to those of Betoptic, such as particle size, pH, osmotic pressure, and rheological properties. Nevertheless, the microdialysis and intraocular pressure test revealed better in vivo performance of MIDFDS, such as pharmacokinetics and pharmacodynamics. With regards to wettability, MIDFDS had a larger contact angle (54.66 ± 5.35°) than Betoptic (36.68 ± 1.77°), enabling the MIDFDS (2.93 s) to spread slower on the cornea than Betoptic (2.50 s). Moderate spreading behavior and oppositely charged electrostatic micro-interactions had a comprehensive influence on micro-interactions with the tear film residue, resulting in a longer precorneal retention time. Furthermore, MIDFDS had a significant sustained-release effect, with complete release near the cornea. The dual-functioning sustained-release carrier together with prolonged pre-corneal retention time (80 min) provided sufficiently high drug concentrations in the aqueous humor to achieve a more stable and long-term IOP reduction for 10 h. In addition, cytotoxicity and hemolysis tests showed that MIDFDS had better biocompatibility than Betoptic. The dual-functioning microspheres presented in this study provide the possibility for improved compliance due to low cytotoxicity and hemolysis, which suggests promising clinical implications.

Surfactant Assisted Rapid-Release Liposomal Strategies Enhance the Antitumor Efficiency of Bufalin Derivative and Reduce Cardiotoxicity.

BACKGROUND: BF211, a derivative of bufalin (BF), shows significantly improved solubility and potent antitumor efficiency compared to BF. Unfortunately, the unwanted toxicity such as cardiotoxicity caused by unspecific distribution has hindered its clinical use. METHODS: PEGylated BF211 liposomes (BF211@Lipo) were designed and optimizely prepared based on the pre-prescription research. In vitro and in vivo cardiotoxicity was evaluated. In vivo pharmacokinetics and biodistribution of BF211@Lipo were investigated. In vivo antitumor activity and toxicity were evaluated in HepG2 cell xenograft models. The rapid-release triggered by Poloxamer 188 (P188) was assessed in vitro and in vivo. RESULTS: The optimized BF211@Lipo displayed a spherical morphology with a size of (164.6 ± 10.3) nm and a high encapsulation efficiency of (93.24 ± 2.15) %. The in vivo concentration-time curves of BF211 loaded in liposomes showed a prolonged half-life in plasma and increased tumor accumulation. No obvious abnormality in electrocardiograms was observed in guinea pigs even at 9 mg/kg. Moreover, to improve the efficient release of BF211@Lipo, a surfactant-assisted rapid-release strategy was developed, and the release-promoting mechanism was revealed by the fluorescence resonance energy transfer (FRET) and fluorescence nanoparticle tracking analysis (fl-NTA) technology. Sequential injection of BF211@Lipo and P188 could ignite the "cold" liposomes locally in tumor regions, facilitating the burst release of BF211 and enhancing the therapeutic index. CONCLUSION: Our progressive efforts that begin with preparation technology and dosage regimen enable BF211 to like a drug, providing a promising nano platform to deliver the cardiac glycosides and alleviate the side effects by decreasing unspecific biodistribution.

[Structural Chinese medicine: new research field on pharmacodynamic substance basis of traditional Chinese medicine].

The research on the pharmacodynamic substance basis of traditional Chinese medicine(TCM) is a key scientific issue for the inheritance and development of TCM. At present, a large number of remarkable achievements have been made in the field of chemical components in Chinese medicine, however, another important aspect, namely the physical structure and mode of action of the multi-component assembly of TCM, has not been clearly understood and deeply studied. From the bottleneck of restricting material ba-sic research, we objectively analyzed the common cause of the existing problems. Based on the new discoveries and advances of active substances from TCM emerging in recent years, we extracted and summarized the concept of structural Chinese medicine, elaborated the basic ideas, main features and research modes, hoping to provide theoretical and practical references for the study on the pharmacodynamic substance basis and other research fields of TCM.

Preparation and evaluation of oral self-microemulsifying drug delivery system of Chlorophyll.

OBJECTIVE: This study was aimed at improving the water solubility and oral bioavailability of Chl by self-microemulsifying drug delivery system (Chl-SMEDDS). METHODS: Compatibility experiments, pseudo-ternary phase diagram and central composite design were used to optimize the formulation. The selected systems were further evaluated for physical characteristics, including particle size, zeta potential, and appearance. The stability, in vitro dispersion test, and in vivo intestinal perfusion experiments were used to evaluate the SMEDDS. RESULTS: The optimal composition of Chl-SMEDDS included: Labrafil M 1944 CS (35%), kolliphor RH 40 (46%), Transcutol HP (19%) and 60 mg/g Chl. The appearance of water emulsified Chl-SMEDDS was green and transparent. The particle size, ζ-potential, and transmission electron microscopy studies showed that spherical globules of Chl-SMEDDS with a size of about 22.82 ± 1.29 nm and a negative surface charge of -24.21 ± 3.45 mV were obtained. Chl-SMEDDS could remain stable at 25 °C and 4 °C for at least 6 months. The dispersion test showed that Chl-SMEDDS dispersed spontaneously to form microemulsion after disintegration of capsule shell and 90% drug dispersed in just 30 min in pH 1.2 HCl without any drug precipitation during the test period. In vivo intestinal perfusion experiment revealed that the main absorption site for Chl-SMEDDS was duodenum. CONCLUSIONS: This study indicates that SMEDDS formulation could be an effective strategy for the oral administration of Chl.

Micro-interaction of mucin tear film interface with particles: The inconsistency of pharmacodynamics and precorneal retention of ion-exchange, functionalized, Mt-embedded nano- and microparticles.

Physiological reflexes and anatomical barriers render traditional eye drop delivery inefficient. We previously reported that drug-loaded nanoparticles and microspheres prepared from montmorillonite and Eudragit polymers exhibited good sustained-release and lowered intraocular pressure. Here, we compared the performance of optimized formulations to select the most suitable formulation for glaucoma therapy. We found that the microspheres had much higher encapsulation efficiency and drug loading than nanoparticles. Moreover, cytocompatibility experiments demonstrated that nanoparticles showed more severe cytotoxicity than microspheres, probably due to their smaller particles, enhanced cell uptake, and intracellular solubility. Interestingly, the pre-corneal retention time of nanoparticles reflected a clear advantage over microspheres, while the duration of the pharmacological effect of nanoparticles was not as good as that of microspheres: compared with the nanoparticle depressurization duration of only 8 h, the microspheres continuously depressurized for 12 h. The slower release of the microspheres and its micro-interaction mechanism with the discontinuous mucin layer of the tear film led to the inconsistency between duration of pharmacodynamics and fluorescence ocular retention time. In summary, the lower cytotoxicity and longer pharmacological effect of microspheres indicate their potential advantages for glaucoma applications.

Lactoferrin/phenylboronic acid-functionalized hyaluronic acid nanogels loading doxorubicin hydrochloride for targeting glioma.

Herein, lactoferrin (Lf)/phenylboronic acid (PBA)-functionalized hyaluronic acid nanogels crosslinked with disulfide-bond crosslinker was developed as a reduction-sensitive dual-targeting glioma therapeutic platform for doxorubicin hydrochloride (DOX) delivery (Lf-DOX/PBNG). Spherical Lf-DOX/PBNG with optimized physicochemical properties was obtained, and it could rapidly release the encapsulated DOX under high glutathione concentration. Moreover, enhanced cytotoxicity, superior cellular uptake efficiency, and significantly improved brain permeability of Lf-DOX/PBNG were observed in cytological studies compared with those of DOX solution, DOX-loaded PBA functionalized nanogels (DOX/PBNG), and Lf modified DOX-loaded nanogels (Lf-DOX/NG). The pharmacokinetic study exhibited that the area under the curve of DOX/PBNG, Lf-DOX/NG, and Lf-DOX/PBNG increased by 8.12, 4.20 and 4.32 times compared with that of DOX solution, respectively. The brain accumulation of Lf-DOX/PBNG was verified in biodistribution study to be 12.37 and 4.67 times of DOX solution and DOX/PBNG, respectively. These findings suggest that Lf-DOX/PBNG is an excellent candidate for achieving effective glioma targeting.

A combination of receptor mediated transcytosis and photothermal effect promotes BBB permeability and the treatment of meningitis using itraconazole.

Fungal infections of the central nervous system (CNS) may lead to life-threatening meningitis. Itraconazole (ITZ) is an effective antifungal agent that can be used to treat various fungal infections; however, its poor solubility along with poor permeability of the blood-brain barrier (BBB) prevents it from treating meningitis. Receptor mediated transcytosis (RMT) shows modest efficacy in BBB crossing, while affinity and saturability of interactions between ligands and receptors account for the limited efficacy of RMT in crossing the BBB. Mild hyperthermia could temporarily disrupt the BBB to increase its permeability. Therefore, we speculated that the combination of mild hyperthermia with RMT could potentially increase BBB permeability of ITZ leading to improved efficacy in fungal meningitis. Here, we have constructed for the first time, apolipoprotein E (Apo E) mimicked peptide COG1410 modified polydopamine (PDA)-coated bovine serum albumin nanoparticles (ApoE-PDA@ITZ-NPs). Different levels of COG1410-modified NPs were prepared and characterized. ApoE-PDA@ITZ-NPs have a superior photothermal effect under 808 nm light irradiation and exhibited favorable plasma stability and photothermal stability. Moreover, the cellular uptake of nanoparticles increased with an increase in COG1410. H-ApoE-PDA@ITZ-NPs increased cellular uptake and in vitro BBB permeability by 4.2-fold and 4.8-fold, respectively, compared to the ITZ-NPs. Live imaging implied that H-ApoE-PDA@ITZ-NPs could significantly increase the distribution of ITZ in the brain under 808 nm light irradiation. Histopathological analysis of periodic acid-Schiff-stained brain sections of the H-ApoE-PDA@ITZ-NP treated C. albicans meningitis model indicated that H-ApoE-PDA@ITZ-NPs showed superior antifungal activity after 808 nm light irradiation. Hence, we report ApoE-PDA@ITZ-NPs in tandem with 808 nm irradiation as a novel strategy of RMT combination with a photothermal effect in enhancing BBB permeability to facilitate drug accumulation in the brain region and enhance the therapeutic efficacy of ITZ in meningitis.

The enhancement of N-acetylcysteine on intestinal absorption and oral bioavailability of hydrophobic curcumin.

To solve the low oral bioavailability of curcumin (CUR) due to the limits imposed by gastrointestinal (GI) barrier, we constructed a nano delivery system to evaluate the effect of N-acetyl-L-cysteine (NAC) on intestinal absorption and oral bioavailability of CUR. CUR was first encapsulated in bovine serum albumin nanoparticles (CUR-BSA-NPs), and then was further modified by NAC (CUR-NBSA-NPs). In situ single-pass intestinal perfusion assay demonstrated that CUR-NBSA-NPs displayed excellent permeation and absorption rates in GI tract. Additionally, the distribution study in GI tract revealed that more NBSA-NPs were absorbed by intestinal segments compared to the BSA nanoparticles. Plasma concentration-time curves in rats showed that AUC0-t, Cmax and MRT0-t values of CUR after oral administration of CUR-NBSA-NPs were increased to 3.25-, 4.42-, and 1.43-fold compared with that of CUR suspension. In conclusion, NAC promotes oral absorption of CUR, thereby improving its oral bioavailability.

Incorporation of ion exchange functionalized-montmorillonite into solid lipid nanoparticles with low irritation enhances drug bioavailability for glaucoma treatment.

Montmorillonite-loaded solid lipid nanoparticles with good biocompatibility, using Betaxolol hydrochloride as model drug, were prepared by the melt-emulsion sonication and low temperature-solidification methods and drug bioavailability was significantly improved in this paper for the first time to application to the eye. The appropriate physical characteristics were showed, such as the mean particle size, Zeta potential, osmotic pressure, pH values, entrapping efficiency (EE%) and drug content (DC%), all showed well suited for possible ocular application. In vitro release experiment indicated that this novel system could continuously release 57.83% drugs within 12 h owing to the dual drug controlled-release effect that was achieved by ion-exchange feature of montmorillonite and structure of solid lipid nanoparticles. Low irritability and good compatibility of nanoparticles were proved by both CAM-TBS test and cytotoxicity experiment. We first discovered from the results of Rose Bengal experiment that the hydrophilicity of the drug-loaded nanoparticles surface was increased during the loading and releasing of the hydrophilic drug, which could contribute to prolong the ocular surface retention time of drug in the biological interface membrane of tear-film/cornea. The results of in vivo pharmacokinetic and pharmacodynamics studies further confirmed that increased hydrophilicity of nanoparticles surface help to improve the bioavailability of the drug and reduce intraocular pressure during administration. The results suggested this novel drug delivery system could be potentially used as an in situ drug controlled-release system for ophthalmic delivery to enhance the bioavailability and efficacy.

Co-Encapsulation of Mitoxantrone and ß-Elemene in Solid Lipid Nanoparticles to Overcome Multidrug Resistance in Leukemia.

Multidrug resistance (MDR) due to P-glycoprotein (P-gp) overexpression is a major obstacle to successful leukemia chemotherapy. The combination of anticancer chemotherapy with a chemosensitizer of P-gp inhibitor is promising to overcome MDR, generate synergistic effects, and maximize the treatment effect. Herein, we co-encapsulated a chemotherapeutic drug of mitoxantrone (MTO) and a P-gp inhibitor of ß-elemene (ßE) in solid lipid nanoparticles (MTO/ßE-SLNs) for reversing MDR in leukemia. The MTO/ßE-SLNs with about 120 nm particle size possessed good colloidal stability and sustained release behavior. For the cellular uptake study, doxorubicin (DOX) was used as a fluorescence probe to construct SLNs. The results revealed that MTO/ßE-SLNs could be effectively internalized by both K562/DOX and K562 cells through the pathway of caveolate-mediated endocytosis. Under the optimized combination ratio of MTO and ßE, the in vitro cytotoxicity study indicated that MTO/ßE-SLNs showed a better antitumor efficacy in both K562/DOX and K562 cells than other MTO formulations. The enhanced cytotoxicity of MTO/ßE-SLNs was due to the increased cellular uptake and blockage of intracellular ATP production and P-gp efflux by ßE. More importantly, the in vivo studies revealed that MTO/ßE-SLNs could significantly prolong the circulation time and increase plasma half-life of both MTO and ßE, accumulate into tumor and exhibit a much higher anti-leukemia effect with MDR than other MTO formulations. These findings suggest MTO/ßE-SLNs as a potential combined therapeutic strategy for overcoming MDR in leukemia.

Folate Receptor-Targeting and Reactive Oxygen Species-Responsive Liposomal Formulation of Methotrexate for Treatment of Rheumatoid Arthritis.

Multifunctional nanomedicines with active targeting and stimuli-responsive drug release function utilizing pathophysiological features of the disease are regarded as an effective strategy for treatment of rheumatoid arthritis (RA). Under the inflammatory environment of RA, activated macrophages revealed increased expression of folate receptor and elevated intracellular reactive oxygen species (ROS) level. In this study, we successfully conjugated folate to polyethylene glycol 100 monostearate as film-forming material and further prepared methotrexate (MTX) and catalase (CAT) co-encapsulated liposomes, herein, shortened to FOL-MTX&CAT-L, that could actively target to activated macrophages. Thereafter, elevated intracellular hydrogen peroxide, the main source of ROS, diffused into liposomes and encapsulated CAT catalyzed the decomposition of hydrogen peroxide into oxygen and water. Continuous oxygen-generation inside liposomes would eventually disorganize its structure and release the encapsulated MTX. We characterized the in vitro drug release, cellular uptake and cytotoxicity studies as well as in vivo pharmacokinetics, biodistribution, therapeutic efficacy and safety studies of FOL-MTX&CAT-L. In vitro results revealed that FOL-MTX&CAT-L possessed sufficient ROS-sensitive drug release, displayed an improved cellular uptake through folate-mediated endocytosis and exhibited a higher cytotoxic effect on activated RAW264.7 cells. Moreover, in vivo results showed prolonged blood circulation time of PEGylated liposomes, enhanced accumulation of MTX in inflamed joints of collagen-induced arthritis (CIA) mice, reinforced therapeutic efficacy and minimal toxicity toward major organs. These results imply that FOL-MTX&CAT-L may be used as an effective nanomedicine system for RA treatment.

BSA Nanoparticles Modified with N-Acetylcysteine for Improving the Stability and Mucoadhesion of Curcumin in the Gastrointestinal Tract.

A major obstacle to the clinical use of curcumin (CUR) is its reduced bioavailability because of the drug's hydrophobic nature, low intestinal absorption, and rapid metabolism. In this study, a novel oral drug delivery system was constructed for improving the stability and enhancing mucoadhesion of CUR in the gastrointestinal (GI) tract. First, CUR was encapsulated in the bovine serum albumin nanoparticles (CUR-BSA-NPs). Then, N-acetyl cysteine (NAC)-modified CUR-BSA-NPs (CUR-NBSA-NPs) were obtained. The average particle size and zeta potential of CUR-NBSA-NPs were 251.6 nm and -30.66 mV, respectively; encapsulation efficiency and drug loading were 85.79 and 10.9%, respectively. CUR-NBSA-NPs exhibited a sustained release property and prominently enhanced stability in simulated GI conditions. Additionally, enhanced mucoadhesion of CUR-NBSA-NPs was also observed. An MTT study showed that the CUR-NBSA-NPs were safe for oral administration. Overall, NAC-modified BSA-NPs may potentially serve as an oral vehicle for improving CUR stability in the GI tract and enhancing mucoadhesion.

The enhancing effect of N-acetylcysteine modified hyaluronic acid-octadecylamine micelles on the oral absorption of paclitaxel.

A micelle system based on hyaluronic acid (HA)-octadecylamine (OA) conjugate (HOA) functionalized with N-acetylcysteine (NAC) was constructed to yield NAC modified HOA conjugate (NHOA) for improving oral paclitaxel (PTX) delivery (PTX-NHOA). The average size of spherical PTX-NHOA micelles was 162.7 nm with a zeta potential of -27.6 mv. The encapsulation efficiency (EE) and drug loading (DL) of PTX-NHOA micelles were 92.64% and 6.96%, respectively. Additionally, NHOA micelles exihibited significantly higher cellular uptake in comparison with HOA micelles by caveolin-mediated and clathrin-mediated endocytosis. Higher permeation ability of NHOA micelles (2.75-fold and 1.32-fold, respectively) through cell monolayers of Caco-2/HT29 cells than that of Taxol and HOA micelles were also observed. The intestinal biodistribution result showed that NAC-modified micelles could enhance its adhesion to the intestinal surface and permeate deeply within the intestinal villi. The NHOA micelles were better absorbed in the duodenum, followed by the jejunum and the ileum. In vivo pharmacokinetic studies showed that AUC0-t value of PTX-NHOA micelles was about 5.92-fold and 2.47-fold higher compared to that of Taxol and PTX-HOA micelles, respectively. In a word, NHOA micelles is a promising drug delivery system in improving the oral absorption of insoluble drugs.

Preparation, intestinal segment stability, and mucoadhesion properties of novel thymopentin-loaded chitosan derivatives coated with poly (n-butyl) cyanoacrylate nanoparticles.

BACKGROUND: In order to develop a promising carrier for the oral delivery of proteins and peptide drugs, a novel bioadhesive nanocarrier of chitosan (CTS) derivatives coated with poly (n-butyl) cyanoacrylate nanoparticles (PBCA-NPs) was prepared in this study. METHODS: Three different thymopentin (TP5)-loaded nanoparticles were prepared in the present study. TP5-PBCA-NPs were developed by modifying an emulsion polymerization method, and CTS and chitosan-glutathione (CG) derivative-coated PBCA nanoparticles were obtained from the electrostatic interactions between CTS or CG with negatively charged PBCA nanoparticles. RESULTS: The particle sizes of TP5-PBCA-NPs, TP5-CTS-PBCA-NPs, and TP5-CG-PBCA-NPs were 212.3±6.9, 274.6±8.2, and 310.4±7.5 nm, respectively, while the respective zeta potentials were -22.6±0.76, 23.3±1.2, and 34.6±1.6 mV with encapsulation efficiencies of 79.37%±2.15%, 74.21%±2.13%, and 72.65%±1.48%, respectively. An everted intestinal ring method indicated that drug stability was remarkably improved after incorporation into the nanoparticles, especially the CG-coated nanoparticles. The mucus layer retention rates for CTS- and CG-coated nanoparticles were 1.43 and 1.83 times that of the uncoated nanoparticles, respectively, using ex vivo mucosa. The in vivo mucoadhesion study illustrated that the transfer of uncoated PBCA-NPs from the stomach to the intestine was faster than that of CTS-PBCA-NPs and CG-PBCA-NPs, while the CG-PBCA-NPs presented the best intestinal retentive characteristic. CONCLUSION: In summary, this study demonstrated the feasibility and benefit of orally delivering peptide drugs using novel CTS derivative-coated nanoparticles with optimal stability and bioadhesive properties.

Camouflaging Nanoparticles for Ratiometric Delivery of Therapeutic Combinations.

Combination therapy is a common clinical practice in the management of malignancies. Synergistic therapeutic outcomes are achieved only when tumor cells are exposed to drugs in an optimal ratio and sequence; therefore, carriers coencapsulating multiple drugs are widely pursued for their coordinated delivery. However, it is challenging to coload drugs with different physicochemical properties in a single carrier with specific ratios. It is not even beneficial to load them in one carrier if they need to be released at different times. We propose to load drugs into chemically compatible carriers separately, equalize different carriers by a simple, rapid, and versatile camouflage technique based on natural polyphenol tannic acid (TA), and administer them in desirable ratios and sequences. To demonstrate this potential, different nanoparticles (NPs) with different charges and material basis, such as polymeric (carboxyl-terminated or amine-terminated cationic polystyrene NPs or poly(lactic- co-glycolic acid (PLGA) NPs), inorganic (mesoporous silica NPs (MSNs)), and liposomal NPs, are camouflaged with TA layers and further modified with folate-conjugated polyethylene glycol to aid in the delivery to tumors. The camouflaged NPs show similar physicochemical properties and interactions with KB cells despite the difference in core platforms, and their mixtures interact with common cell targets in a ratiometric manner. In KB-tumor-bearing mice, the camouflaged PLGA NPs and MSNs show near-perfect colocalization in tumors. These results support that TA helps equalize different NPs with high versatility and enables their ratiometric delivery to common targets. This approach can relieve technical challenges in ratiometric codelivery or sequential delivery of therapeutic agents with distinct physicochemical properties.

Effects of phospholipid and polyethylene glycol monostearate (100) on the in vitro and in vivo physico-chemical characterization of poly(n-butyl cyanoacrylate) nanoparticles.

In this study, poly(n-butyl cyanoacrylate) nanoparticles (PBCA-NPs) modified with various amounts of soybean phospholipid (PC) and polyethylene glycol monostearate (S100) were prepared in order to investigate the effects of PC and S100 on the nanoparticles' physico-chemical properties, cytological properties and in vivo gastrointestinal absorption. Coumarin-6 (C6) was used as a fluorescent probe; C6-loaded PBCA-NPs modified with both PC and S100 (C6-PS-PBCA-NPs) were prepared using miniemulsion polymerization, and C6-loaded PBCA-NPs modified with either S100 (C6-S-PBCA-NPs) or PC (C6-P-PBCA-NPs) were used as references. All of the different NPs were shown to be stably dispersed and to have a small particle size. A cytotoxicity study indicated that all of the blank PBCA-NPs were safe and nontoxic. The uptake of NPs by Caco-2 cells was shown to be increased when the amount of PC was increased from 0% to 1.25% and the amount of S100 was increased from 0% to 0.725%. The use of a ligated intestinal loop model demonstrated that C6-PS-PBCA-NPs could rapidly penetrate a highly viscoelastic mucous layer, leading to an improvement in the absorption efficiency. During a pharmacokinetic study, C6-PS-PBCA-NPs improved the absorption of C6, as indicated by their higher Cmax and AUC0-t values compared with those of C6-S-PBCA-NPs or C6-P-PBCA-NPs. Overall, the results of this study indicate that PBCA-NPs modified with PC and S100 can enhance the absorption of orally administered drugs.

Local strategies and delivery systems for the treatment of malignant gliomas.

Glioma is one of the most common type of malignant tumours with high morbidity and mortality rates. Due to the particular features of the brain, such as blood-brain barrier or blood-tumour barrier, therapeutic agents are ineffective by systemic administration. The tumour inevitably recurs and devitalises patients. Herein, an overview of the localised gliomas treatment strategies is provided, including direct intratumoural/intracerebral injection, convection-enhanced delivery, and the implant of biodegradable polymer systems. The advantages and disadvantages of each therapy are discussed. Subsequently, we have reviewed the recent developments of therapeutic delivery systems aimed at transporting sufficient amounts of antineoplastic drugs into the brain tumour sites while minimising the potential side effects. To treat gliomas, localised and controlled delivery of drugs at their desired site of action is preferred as it reduces toxicity and increases treatment efficiency. Simultaneously, various drug delivery systems (DDS) have been used to enhance drug delivery to the brain. Use of non-conventional DDS for localised therapy has greatly expanded the spectrum of drugs available for the treatment of malignant tumours. Use smart DDS via localised delivery strategies, in combination with radiotherapy and multiple drug loading would serve as a promising approach to treat gliomas.

Tween 80-modified hyaluronic acid-ss-curcumin micelles for targeting glioma: Synthesis, characterization and their in vitro evaluation.

Redox-sensitive micelles based onhydrophilic hyaluronic acid-ss-hydrophobic curcumin conjugate were designed as a novel delivery system for gliomas targeting. Furthermore, the obtained micelles were further functionalized with Tween 80 (CUR-THSC) for better brain penetration. Dynamic light scattering experiment and in vitro release study showed that the synthetic disulfide-linked conjugate possessed redox-sensitivity under high glutathione conditions. Spherical micelles with a mean particle size of 74.2 nm, negative zeta potential (-30.25 mV), high entrapment efficiency (94.12%) and drug loading (8.9%) were obtained. XRD analysis of micelles revealed amorphous form of the encapsulated drug. CUR-THSC micelles showed good plasma stability and did not induce any hemolysis in erythrocytes. In addition, highest cytotoxicity in G422 cells was observed compared to the free curcumin group and non-sensitive micelles group. These results indicate that the Tween 80-modified hyaluronic acid-ss-curcumin micelles could emerge as a promising platform for the delivery of curcumin in the treatment of gliomas.

N-acetylcysteine modified hyaluronic acid-paclitaxel conjugate for efficient oral chemotherapy through mucosal bioadhesion ability.

N-acetylcysteine modified hyaluronic acid-paclitaxel (NAC-HA-PTX) conjugate was designed to improve the water solubility and oral bioavailability of PTX through mucosal bioadhesion ability. The average size of spherical NAC-HA-PTX micelles was 187 nm with a zeta potential of -25.38 mV. Mucin adhesion study showed that the amount of mucin adhered to NAC-HA-PTX micelles was 1.98-fold greater than that of hyaluronic acid-paclitaxel (HA-PTX) micelles. The fluorescence micrographs showed that the biodistribution sequence of coumarin 6-loaded micelles in the gastrointestinal tract was duodenum > jejunum > ileum, and NAC-modified micelles significantly exhibited better mucoadhesive properties than the corresponding unmodified ones. The pharmacokinetic study showed that the area under the curve (AUC0-24h) of NAC-HA-PTX micelles was 2.32-fold and 2.56-fold higher compared to that of HA-PTX micelles and PTX solution (Taxol) after oral administration, respectively. NAC-HA-PTX micelles appear to be a promising drug delivery system to improve the bioavailability of insoluble drugs for efficient tumor therapy via oral administration.

Mitoxantrone-loaded chitosan/hyaluronate polyelectrolyte nanoparticles decorated with amphiphilic PEG derivates for long-circulating effect.

Poly (ethylene glycol) (PEG) and its derivatives are not only used to improve the stability of drug-loaded nanoparticles but also prolong their stay in blood for extended durations. We, hereby, report mitoxantrone loaded polyelectrolyte nanoparticles (MTO-PENPs) based on the hyaluronic acid (HA) and chitosan hydrochloride (HCS) complexed with amphiphilic PEG derivatives, carboxylated PEG (100) monostearate (PGMC, MTO-CPENPs) and D-tocopheryl PEG 1000 succinate (TPGS, MTO-TPENPs), to extend the in vivo circulation time. Maximum encapsulation efficiency (>95%) was observed at 40 mg/mL of PGMC or TPGS. TEM showed that PENPs preparations were spherical with an average diameter around 200 nm. Both MTO-CPENPs and MTO-TPENPs showed better stability than MTO-PENPs during storage at 4 °C, offered better control over the release of drug than simple PENPs, and showed pH-sensitivity with faster drug release in acidic conditions. MTO-CPENPs showed greater aversion from the protein adsorption and phagocytic uptake by macrophages but their cytotoxicity against the cancerous cells was poor of the all, and yet MTO-TPENPs showed good cytotoxicity against the MCF-7 cells. In the pharmacokinetic study, both MTO-CPENPs and MTO-TPENPs exhibited significant prolongation in blood circulation of drug compared to MTO-PENPs and MTO solution in rats after intravenous administration. However, MTO-TPENPs showed no statistically significant difference in plasma profile of MTO than the MTO-CPENPs. This indicates that there are underlying mechanisms that need to be explored to use the PEGylation in a way that could prolong stay of the nanoparticles in blood without compromising their interactions with target cells.