Introduction:
The therapeutic efficacy of perorally administered drugs is often obscured by their poor oral bioavailability (BA) and low metabolic stability in the gastrointestinal tract (GIT). Solid ...lipid nanoparticles (SLNs) have emerged as potential BA enhancer vehicles for various Class II, III and IV drug molecules.
Area covered:
This review examines the recent advancements in SLN technology, with regards to oral drug delivery. The discussion critically examines the effect of various key constituents on SLN absorption and their applications in oral drug delivery. The relationship between the complexity of absorption (and various factors involved during absorption, including particle size), stability and the self-emulsifying ability of the lipids used has been explored.
Expert opinion:
The protective effect of SLNs, coupled with their sustained/controlled release properties, prevents drugs/macromolecules from premature degradation and improves their stability in the GIT. An extensive literature survey reveals that direct peroral administration of SLNs improves the BA of drugs by 2- to 25-fold. Overall, the ease of large-scale production, avoidance of organic solvents and improvement of oral BA make SLNs a potential BA enhancer vehicle for various Class II, III and IV drugs.
Abstract The present investigation consists in the development and characterization of CoQ10 loaded PLGA nanoparticles (CoQ10-NPs, size < 100 nm) by a scalable emulsion-diffusion-evaporation method. ...Thermal and crystallinity analysis collectively corroborated that CoQ10 was entrapped into the NPs in amorphous form. The lyophilized CoQ10-NPs were found to be stable for a period of 6 months (at room temperature). In vitro cell culture studies indicated that CoQ10-NPs significantly quenched ROS with nearly 10 fold higher efficacy than free CoQ10. Further, positively charged CoQ10-NPs were localized in two major sources of ROS generation: mitochondria and lysosomes. CoQ10-NPs showed improved oral bioavailability (4.28 times) as compared to free CoQ10. Finally remarkably higher hepatoprotective and anti-inflammatory activity of CoQ10-NPs as compared to free CoQ10 was observed due to mitigation of deleterious effects associated with the generation of free radicals. As elucidated by live noninvasive animal imaging, the higher anti-inflammatory activity of CoQ10-NPs can be attributed to significant accumulation of these NPs in the inflamed tissues.
A novel, inexpensive biofunctionalization approach is adopted to develop a multimodal and theranostic nanoagent, which combines cancer‐targeted magnetic resonance/optical imaging and pH‐sensitive ...drug release into one system. This multifunctional nanosystem, based on an ultrasmall superparamagnetic iron oxide (USPIO) nanocore, is modified with a hydrophilic, biocompatible, and biodegradable coating of N‐phosphonomethyl iminodiacetic acid (PMIDA). Using appropriate spacers, functional molecules, such as rhodamine B isothiocyanate, folic acid, and methotrexate, are coupled to the amine‐derivatized USPIO–PMIDA support with the aim of endowing simultaneous targeting, imaging, and intracellular drug‐delivering capability. For the first time, phosphonic acid chemistry is successfully exploited to develop a stealth, multifunctional nanoprobe that can selectively target, detect, and kill cancer cells overexpressing the folate receptor, while allowing real‐time monitoring of tumor response to drug treatment through dual‐modal fluorescence and magnetic resonance imaging.
In at the kill: Phosphonate‐grafted iron oxide nanoparticles are bioconjugated with targeting agents, dyes, and chemotherapeutic drugs to develop a multimodal and theranostic nanoagent, which can target, image, and kill folate receptor‐overexpressed cancer cells (see picture).
•We developed and validated Carboxymethyl-dextran coated iron oxide nanoparticles (CION).•We disseminated a step-by-step protocol of our one-pot, cost-efficient synthesis protocol.•We performed ...several experiments in vivo, demonstrating the use of CION for functional and structural MRI applications.
Superparamagnetic iron-oxide nanoparticles are robust contrast agents for magnetic resonance imaging (MRI) used for sensitive structural and functional mapping of the cerebral blood volume (CBV) when administered intravenously. To date, many CBV-MRI studies are conducted with Feraheme, manufactured for the clinical treatment of iron-deficiency. Unfortunately, Feraheme is currently not available outside the United States due to commercial and regulatory constraints, making CBV-MRI methods either inaccessible or very costly to achieve. To address this barrier, we developed a simple, one-pot recipe to synthesize Carboxymethyl-dextran coated Iron Oxide Nanoparticles, namely, “CION”, suitable for preclinical CBV-MRI applications. Here we disseminate a step-by-step instruction of our one-pot synthesis protocol, which allows CION to be produced in laboratories with minimal cost. We also characterized different CION-conjugations by manipulating polymer to metal stoichiometric ratio in terms of their size, surface chemistry, and chemical composition, and shifts in MR relaxivity and pharmacokinetics. We performed several proof-of-concept experiments in vivo, demonstrating the utility of CION for functional and structural MRI applications, including hypercapnic CO2 challenge, visual stimulation, targeted optogenetic stimulation, and microangiography. We also present evidence that CION can serve as a cross-modality research platform by showing concurrent in vivo optical and MRI measurement of CBV using fluorescent-labeled CION. The simplicity and cost-effectiveness of our one-pot synthesis method should allow researchers to reproduce CION and tailor the relaxivity and pharmacokinetics according to their imaging needs. It is our hope that this work makes CBV-MRI more openly available and affordable for a variety of research applications.
Several neuropsychiatric conditions, such as addiction and schizophrenia, may arise in part from dysregulated activity of ventral tegmental area dopaminergic (TH
) neurons, as well as from more ...global maladaptation in neurocircuit function. However, whether TH
activity affects large-scale brain-wide function remains unknown. Here we selectively activated TH
neurons in transgenic rats and measured resulting changes in whole-brain activity using stimulus-evoked functional magnetic resonance imaging. Applying a standard generalized linear model analysis approach, our results indicate that selective optogenetic stimulation of TH
neurons enhanced cerebral blood volume signals in striatal target regions in a dopamine receptor-dependent manner. However, brain-wide voxel-based principal component analysis of the same data set revealed that dopaminergic modulation activates several additional anatomically distinct regions throughout the brain, not typically associated with dopamine release events. Furthermore, explicit pairing of TH
neuronal activation with a forepaw stimulus of a particular frequency expanded the sensory representation of that stimulus, not exclusively within the somatosensory cortices, but brain-wide. These data suggest that modulation of TH
neurons can impact brain dynamics across many distributed anatomically distinct regions, even those that receive little to no direct TH
input.
The present study describes a systematic approach towards the design and development of novel, bio-functionalized, magneto-fluorescent nanoparticles for cancer-specific targeting. Biocompatible, ...hydrophilic, magneto-fluorescent nanoparticles with surface-pendant amine, carboxyl or aldehyde groups, to be later used for bio-conjugation, were designed using an aminophosphonic acid coupling agent. These magneto-fluorescent nanoparticles were further functionalized with folic acid, using diverse conjugation strategies. A series of new iron-oxide folate nanoconjugates with excellent aqueous dispersion stability and reasonably good hydrodynamic sizes under a wide range of physiological conditions were developed. These ultradispersed nanosystems were analyzed for their physicochemical properties and cancer-cell targeting ability, facilitated by surface modification with folic acid. The nanoparticle size, charge, surface chemistry, magnetic properties and colloidal stability were extensively studied using a variety of complementary techniques. Confocal microscopy, performed with folate receptor positive human cervical HeLa cancer cells, established that these non-cytotoxic iron-oxide folate nanoconjugates were effectively internalized by the target cells through receptor-mediated endocytosis. Cell-uptake behaviors of nanoparticles, studied using magnetically activated cell sorting (MACS), clearly demonstrated that cells over-expressing the human folate receptor internalized a higher level of these nanoparticle-folate conjugates than negative control cells.
Introduction:
In situ gel systems refer to a class of novel delivery vehicles, composed of natural, semisynthetic or synthetic polymers, which present the unique property of sol-gel conversion on ...receipt of biological stimulus.
Areas covered:
The present review summarizes the latest developments in in situ gel technology, with regard to ophthalmic drug delivery. Starting with the mechanism of ocular absorption, the review expands on the fabrication of various polymeric in situ gel systems, made up of two or more polymers presenting multi-stimuli sensitivity, coupled with other interesting features, such as bio-adhesion, enhanced penetration or sustained release. Various key issues and challenges in this area have been addressed and critically analyzed.
Expert opinion:
The advent of in situ gel systems has inaugurated a new transom for 'smart' ocular delivery. By virtue of possessing stimuli-responsive phase transition properties, these systems can easily be administered into the eye, similar to normal eye drops. Their unique gelling properties endow them with special features, such as prolonged retention at the site of administration, followed by sustained drug release. Despite the superiority of these systems as compared with conventional ophthalmic formulations, further investigations are necessary to address the toxicity issues, so as to minimize regulatory hurdles during commercialization.
The present study reports the optimized synthesis, physicochemical characterization, and biological evaluation of a novel, multiwalled carbon nanotube-hyaluronic acid (MWCNT-HA) conjugate, complexed ...with an anticancer agent, Doxorubicin (DOX) via π–π stacking interaction. The therapeutic conjugate was concomitantly labeled with a near-infrared fluorescent dye, Alexa-Flour-647 (AF-647), and radiotracer Technetium-99m (99mTc) to track its whereabouts both in vitro and in vivo via optical and scintigraphic imaging techniques. Covalent functionalization of MWCNTs with HA facilitated their internalization into human lung adenocarcinoma, A549 cells via hyaluronan receptors (HR) mediated endocytosis. Internalized nanotubes showed lysosomal trafficking, followed by low pH-triggered DOX release under endolysosomal conditions. Consequently, DOX-loaded HA-MWCNTs exhibited 3.2 times higher cytotoxicity and increased apoptotic activity than free DOX in equivalent concentrations. Organ distribution studies in Ehlrich ascites tumor (EAT) bearing mice model indicated that tumor specific localization of 99mTc-MWCNT-HA-DOX is significantly higher than both free drug and nontargeted MWCNTs. Pharmacodynamic studies in chemically breast-cancer-induced rats showed that the tumor-growth inhibitory effect of HA-MWCNT-DOX was 5 times higher than free DOX in equivalent concentration. DOX delivered through HA-MWCNTs was devoid of any detectable cardiotoxity, hepatotoxicity, or nephrotoxicity. All these promising attributes make HA-MWCNTs a “smart” platform for tumor-targeted delivery of anticancer agents.
The present study reports the design, synthesis, and biological evaluation of a novel, intravenously injectable, theranostic prodrug based on multiwalled carbon nanotubes (MWCNTs) concomitantly ...decorated with a fluorochrome (Alexa-fluor, AF488/647), radionucleide (Technitium-99m), tumor-targeting module (folic acid, FA), and anticancer agent (methotrexate, MTX). Specifically, MTX was conjugated to MWCNTs via a serum-stable yet intracellularly hydrolyzable ester linkage to ensure minimum drug loss in circulation. Cell uptake studies corroborated the selective internalization of AF-FA-MTX-MWCNTs (1) by folate receptor (FR) positive human lung (A549) and breast (MCF 7) cancer cells through FR mediated endocytosis. Lysosomal trafficking of 1 enabled the conjugate to exert higher anticancer activity as compared to its nontargeted counterpart that was mainly restricted to cytoplasm. Tumor-specific accumulation of 1 in Ehlrich Ascites Tumor (EAT) xenografted mice was almost 19 and 8.6 times higher than free MTX and FA-deprived MWCNTs. Subsequently, the conjugate 1 was shown to arrest tumor growth more effectively in chemically breast tumor induced rats, when compared to either free MTX or nontargeted controls. Interestingly, the anticancer activities of the ester-linked CNT-MTX conjugates (including the one deprived of FA) were significantly higher than their amide-linked counterpart, suggesting that cleavability of linkers between drug and multifunctional nanotubes critically influence their therapeutic performance. The results were also supported by in silico docking and ligand similarity analysis. Toxicity studies in mice confirmed that all CNT-MTX conjugates were devoid of any perceivable hepatotoxicity, cardiotoxicity, and nephrotoxicity. Overall, the delivery property of MWCNTs, high tumor binding avidity of FA, optical detectability of AF fluorochromes, and radio-traceability of 99mTc could be successfully integrated and partitioned on a single CNT-platform to augment the therapeutic efficacy of MTX against FR overexpressing cancer cells while allowing a real-time monitoring of treatment response through multimodal imaging.
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