Mitochondria-targeted dual-channel colorimetric and fluorescence chemosensor for detection of Sn2+ ions in aqueous solution based on aggregation-induced emission and its bioimaging applications.

Several fluorescence and colorimetric chemosensory for Sn2+ detection in an aqueous media have been reported, but applications remain limited for discriminative Sn2+ detection in live human cells and zebrafish larvae. Herein, a mitochondria-targeted Sn2+ "turn-on" colorimetric and fluorescence chemosensor, 2CTA, with an aggregation-induced emission (AIE) response was developed. The sensing of Sn2+ was enabled by a reduction-enabled binding pathway, with the conversion of -CË­O groups to -C-OH groups at the naphthoquinone moiety. The color changed from light maroon to milky white in a buffered aqueous solution. The chemosensor 2CTA possessed the excellent characteristics of good water solubility, fast response (less than 10 s), and high sensitivity (79 nM) and selectivity for Sn2+ over other metal ions, amino acids, and peptides. The proposed binding mechanism was experimentally verified by means of FT-IR and NMR studies. The chemosensor 2CTA was successfully employed to recognize Sn2+ in live human cells and in zebrafish larvae. In addition, a colocalization study proved that the chemosensor had the ability to target mitochondria and overlapped almost completely with MitoTracker Red. Furthermore, a bioimaging study of live cells demonstrated the discriminative detection of Sn2+ in human cancer cells and the practical applications of 2CTA in biological systems.

Lipid Nanoparticles Improve the Uptake of α-Asarone Into the Brain Parenchyma: Formulation, Characterization, In Vivo Pharmacokinetics, and Brain Delivery.

Treatment of brain-related diseases is one of the most strenuous challenges in drug delivery research due to numerous hurdles, including poor blood-brain barrier penetration, lack of specificity, and severe systemic toxicities. Our research primarily focuses on the delivery of natural therapeutic compound, α-asarone, for the treatment of brain-related diseases. However, α-asarone has poor aqueous solubility, bioavailability, and stability, all of which are critical issues that need to be addressed. This study aims at formulating a lipid nanoparticulate system of α-asarone (A-LNPs) that could be used as a brain drug delivery system. The physicochemical, solid-state properties, stability, and in vitro and in vivo studies of the A-LNPs were characterized. The release of α-asarone from the A-LNPs was prolonged and sustained. After intravenous administration of A-LNPs or free α-asarone, significantly higher levels of α-asarone from the A-LNPs were detected in murine plasma and brain parenchyma fractions, confirming the ability of A-LNPs to not only maintain a therapeutic concentration of α-asarone in the plasma, but also transport α-asarone across the blood-brain barrier. These findings confirm that lipid nanoparticulate systems enable penetration of natural therapeutic compound α-asarone through the blood-brain barrier and may be a candidate for the treatment of brain-related diseases.

N,N,N-trimethyl chitosan embedded in situ Pluronic F127 hydrogel for the treatment of brain tumor.

The malignant gliomas are most destructive brain tumor having low drug response. The thermosensitive hydrogel from pluronic F127 (PF127) and N,N,N-trimethyl chitosan (TMC) is developed as a drug delivery system for anticancer drug docetaxel (DTX) to the glioblastoma multiforme. The influence of TMC on morphology, physico-chemical, mechanical, and release properties of PF127 based thermosensitive hydrogel is investigated here. The hydrogels shows porous network as shown by scanning electron microscopy and TMC addition hindered close packing of PF127 layers in the gel system leaving more pores on the surface. TEM images demonstrate micelle formation by PF127-TMC with diameters of about 50 nm. MTT assay result shows that DTX loaded PF127-TMC hydrogel is more capable of killing U87MG cell than free DTX and DTX loaded PF-127. Hydrogels retain sustained release of DTX under different pH conditions more than one month. Furthermore, in vivo experiments are carried out by creating xenograft tumor model on the head of BALB/c nude mice for checking tumor suppression by PF127-TMC/DTX hydrogel. Overall, the hydrogels shows sustained release of DTX on different pH with tumor suppression suggests that it can be used for treating tumor.

Recent developments in solid lipid nanoparticle and surface-modified solid lipid nanoparticle delivery systems for oral delivery of phyto-bioactive compounds in various chronic diseases.

Solid lipid nanoparticle (SLN) delivery systems have a wide applicability in the delivery of phyto-bioactive compounds to treat various chronic diseases, including diabetes, cancer, obesity and neurodegenerative diseases. The multiple benefits of SLN delivery include improved stability, smaller particle size, leaching prevention and enhanced lymphatic uptake of the bioactive compounds through oral delivery. However, the burst release makes the SLN delivery systems inadequate for the oral delivery of various phyto-bioactive compounds that can treat such chronic diseases. Recently, the surface-modified SLN (SMSLN) was observed to overcome this limitation for oral delivery of phyto-bioactive compounds, and there is growing evidence of an enhanced uptake of curcumin delivered orally via SMSLNs in the brain. This review focuses on different SLN and SMSLN systems that are useful for oral delivery of phyto-bioactive compounds to treat various chronic diseases.

Development of a selective and sensitive LC-MS/MS method for the quantification of α-asarone in mouse plasma and its application to pharmacokinetic studies.

A simple, sensitive and selective liquid chromatography-tandem mass spectrometric method was developed and validated for the quantification of α-asarone in mouse plasma with its application to pharmacokinetic studies. An electrospray ionization (ESI) with multiple reaction monitoring (MRM) mode was used to monitor the precursor-product ion transitions of 209.1 > 193.9 m/z for α-asarone and 157.8 > 114.0 m/z for allantoin. Chromatographic separation was acquired on a Sepax BR-C18 (5 µm, 120 Š1.0 × 100 mm) column with an isocratic mobile phase consisting of methanol and 0.1% formic acid (80:20, v/v). The developed bioanalytical method was successfully validated according to the United States Food and Drug Administration (US FDA) guidelines for linearity, selectivity, accuracy, precision, recovery, matrix effect, and stability. The validated method was successfully applied to a pharmacokinetics study of α-asarone along with a combination of pharmacokinetic techniques, including small-volume serial blood sampling in mice, reducing drug doses and the number of animals used, using a simple protein precipitation method and less solvent consumption will enable its use in further bioequivalence studies.

Wasabia japonica is a potential functional food to prevent colitis via inhibiting the NF-κB signaling pathway.

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC), are prevalent and debilitating health problems worldwide. Many types of drugs are used to treat IBDs, but they exhibit adverse effects such as vomiting, nausea, abdominal pain, diarrhea, etc. In order to overcome the limitations of current therapeutic drugs, scientists have searched for functional foods from natural resources. In this study, we investigated the anti-colitic effects of Wasabia japonica extract in a DSS-induced colitis model. Wasabi japonica is a plant of the Brassicaceae family that has recently been reported to exhibit properties of detoxification, anti-inflammation, and induction of apoptosis in cancer cells. In this study, we generated wasabi ethanol extract (WK) and assessed its anti-colitic effect. In addition, in order to improve delivery of the extract to the colon, WK was coated with 5% Eudragit S100 (WKE), after which the anti-colitic effects of WKE were assessed. In conclusion, WK prevented development of colitis through inhibition of the NF-kB signaling pathway and recovery of epithelial tight junctions. In addition, the anti-colitic effect of WK was enhanced by improving its delivery to the colon by coating the WK with Eudragit S100. Therefore, we suggest that wasabi can be used as a new functional food to prevent IBDs due to its anti-colitic effect.

Validated LC-MS/MS method for simultaneous quantification of resveratrol levels in mouse plasma and brain and its application to pharmacokinetic and brain distribution studies.

A rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine resveratrol levels in plasma and brain tissue in mice for supporting pharmacokinetic and brain distribution studies. Analytes were separated using a Sepax BR-C18 analytical column (5µm, 120Å, 1.0×100mm) and eluted using an isocratic elution mobile phase acetonitrile and 0.01% formic acid [60:40, v/v] at a flow rate of 0.1mL/min. Precursor and product ion transitions for analyte resveratrol m/z 226.9>184.8 and curcumin m/z 367.1>148.9 were monitored using triple quadrupole mass spectrometer with multiple reaction monitoring (MRM) in negative ionization mode. The method was validated with respect to accuracy, within- and between-day precision, linearity, limit of quantification, recovery, and matrix effects of analyte. The inter- and intra-day accuracy and precision were within the range of the US Food and Drug Administration (FDA) acceptance criteria, for both matrices. The method was also successfully applied to pharmacokinetic and brain distribution studies of resveratrol after intravenous administration of free resveratrol and resveratrol-loaded solid lipid nanoparticles to mice. The combined use of serial blood sampling, small sample volume, simple extraction, and capillary depletion method drastically improved resveratrol analysis from biological matrices.

Improved oral delivery of resveratrol from N-trimethyl chitosan-g-palmitic acid surface-modified solid lipid nanoparticles.

Despite the therapeutic effects of resveratrol, its clinical application is restricted by its poor oral bioavailability, low water solubility, and instability. Solid lipid nanoparticles (SLNs)-based drug delivery systems have been shown to provide excellent support for the delivery of hydrophobic drugs. The poor stability and burst release behavior in stomach acidic pH conditions of SLNs result in increased aggregation of the particles in the gastrointestinal environment, limiting the success of these particles as an oral delivery system for hydrophobic drugs. N-trimethyl chitosan (TMC) graft palmitic acid (PA) (TMC-g-PA) mucoadhesive copolymer was hypothesized to be a promising candidate for the surface modification of PA-decorated resveratrol-loaded SLNs to stabilize SLNs and circumvent all the above mentioned obstacles. TMC and TMC-g-PA copolymers were therefore synthesized and characterized by (1)H-nuclear magnetic resonance ((1)H NMR) and Fourier-transformed infra-red (FT-IR) spectroscopy. Resveratrol-loaded SLNs (SLRNs) that comprised Precirol ATO 5, PA, Gelucire 50/13, Tween 80, and resveratrol as well as TMC-g-PA SLRNs were formulated and characterized in terms of physicochemical properties, stability, cytotoxicity, and in vitro and in vivo effects. The in vitro release studies of TMC-g-PA SLRNs demonstrated negligible release of resveratrol in simulated gastric and sustained release in simulated intestinal conditions and the relative bioavailability of resveratrol was furthermore found to be 3.8-fold higher from TMC-g-PA SLRNs than that from resveratrol suspension. Overall, the findings reported here indicate that TMC-g-PA SLRNs represent a potential oral drug delivery system for resveratrol.

Enhanced oral delivery of curcumin from N-trimethyl chitosan surface-modified solid lipid nanoparticles: pharmacokinetic and brain distribution evaluations.

PURPOSE: Solid lipid nanoparticles (SLNs) have been proposed as a colloidal carrier system that could enhance the oral bioavailability of curcumin. However, a burst release of the loaded drug, which occurs in acidic environments, has been a main obstacle to the oral delivery of curcumin by using SLNs as a carrier system. We hypothesized that a quarternized chitosan derivative could be used for acid-resistant coating to stabilize the SLNs and circumvent the burst release. METHODS: N-trimethyl chitosan (TMC) was synthesized and determined by (1)H-NMR and FT-IR. To investigate the details of chitosan and TMC surface modification on SLCNs composed of palmitic acid, cholesterol, TPGS and curcumin, a number of factors such as optimized SLNs composition, solid state characterization, stability, cell viability, in vitro release in GI conditions, curcumin oral bioavailability and brain distribution studies, were evaluated. RESULTS: The TMC-SLCNs exhibited prolonged stability in room and refrigerated conditions, controlled drug release in simulated intestinal fluid, significantly higher oral bioavailability, and brain distribution of curcumin than free curcumin, chitosan and non-coated SLCNs. CONCLUSIONS: These finding suggests that the TMC-SLCNs is a promising nanocarrier system for oral delivery and brain distribution of curcumin.

A validated LC-MS/MS method for quantitative analysis of curcumin in mouse plasma and brain tissue and its application in pharmacokinetic and brain distribution studies.

Curcumin is a well-known multitherapeutic agent widely employed in neurodegenerative disorders and cancer. A selective, fast, and sensitive method employing liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the simultaneous determination of curcumin in mouse plasma and brain tissue, by using salbutamol as an internal standard. Triple quadrupole mass detection with multiple reaction monitoring (MRM) mode was used to monitor the ion transitions, m/z of 369>285 for curcumin, and m/z of 240>148 for salbutamol. The method was validated for recovery, accuracy, precision, linearity, and applicability. The lower limits of quantification (LLOQ) in both matrices were 2.5ng/mL. The inter-day and intra-day precisions and accuracy values were within the Food and Drug Administration (FDA) acceptance criteria, for both matrixes. The method was successfully applied in pharmacokinetics and brain distribution studies of curcumin after intravenous administration of free curcumin and curcumin-loaded solid lipid nanoparticles to mice. Furthermore, the application of this method along with serial blood sampling in mice has led to significant reduction in animal use and dosage and drastic improvement in speed, throughput, and quality of pharmacokinetic parameters.

N,N,N-Trimethyl chitosan nanoparticles for controlled intranasal delivery of HBV surface antigen.

Hepatitis B virus surface antigen (HBsAg) loaded N,N,N-trimethyl chitosan nanoparticles (N-TMC NPs) were formulated and studied for controlled intranasal delivery. The size and surface properties of the NPs can be tuned by modifying the concentration of N-TMC and found to be 66±13, 76±9 nm for 0.25 and 0.5 wt.% respectively. Loading of 380 and 760 µl of HBsAg yielded 143±33, 259±47 nm sized spherical N-TMC NPs with highest loading efficiency and capacity of 90-93%, and 96-97% respectively. In vitro drug release analysis ensured 93% cumulative release of HBsAg antigen over prolonged period (43 days). In vivo immunological study was performed using 6-8 weeks old female BALB mice and reveals adjuvants efficiency of NPs for antigen is highly stable and better than standard. Obtained results show that N-TMC NPs can be extensively used in controlled intra nasal delivery to treat various diseases including hepatitis B and allergic rhinitis.