Novel methods of antiepileptic drug delivery -- polymer-based implants

Intrahippocampal Supramolecular Assemblies Directed Bioorthogonal Liberation of Neurotransmitters to Suppress Seizures in Freely Moving Mice

The precise delivery of anti-seizure medications (ASM) to epileptic loci remains the major challenge to treat epilepsy without causing adverse drug reactions. The unprovoked nature of epileptic seizures raises the additional need to release ASMs in a spatiotemporal controlled manner. Targeting the oxidative stress in epileptic lesions, here the reactive oxygen species (ROS) induced in situ supramolecular assemblies that synergized bioorthogonal reactions to deliver inhibitory neurotransmitter (GABA) on-demand, are developed. Tetrazine-bearing assembly precursors undergo oxidation and selectively self-assemble under pathological conditions inside primary neurons and mice brains. Assemblies induce local accumulation of tetrazine in the hippocampus CA3 region, which allows the subsequent bioorthogonal release of inhibitory neurotransmitters. For induced acute seizures, the sustained release of GABA extends the suppression than the direct supply of GABA. In the model of permanent damage of CA3, bioorthogonal ligation on assemblies provides a reservoir of GABA that behaves prompt release upon 365 nm irradiation. Incorporated with the state-of-the-art microelectrode arrays, it is elucidated that the bioorthogonal release of GABA shifts the neuron spike waveforms to suppress seizures at the single-neuron precision. The strategy of in situ supramolecular assemblies-directed bioorthogonal prodrug activation shall be promising for the effective delivery of ASMs to treat epilepsy.

Status of Polymer Fused Deposition Modeling (FDM)-Based Three-Dimensional Printing (3DP) in the Pharmaceutical Industry

Additive manufacturing (AM) or 3D printing (3DP) is arguably a versatile and more efficient way for the production of solid dosage forms such as tablets. Of the various 3DP technologies currently available, fused deposition modeling (FDM) includes unique characteristics that offer a range of options in the production of various types of tablets. For example, amorphous solid dispersions (ASDs), enteric-coated tablets or poly pills can be produced using an appropriate drug/polymer combination during FDM 3DP. The technology offers the possibility of evolving personalized medicines into cost-effective production schemes at pharmacies and hospital dispensaries. In this review, we highlight key FDM features that may be exploited for the production of tablets and improvement of therapy, with emphasis on gastrointestinal delivery. We also highlight current constraints that must be surmounted to visualize the deployment of this technology in the pharmaceutical and healthcare industries.

Fabrication of ethosuximide loaded alginate/polyethylene oxide scaffolds for epilepsy research using 3D-printing method

Epilepsy is a medical condition that causes seizures and impairs the mental and physical activities of patients. Unfortunately, over one-third of patients do not receive adequate relief from oral Antiepileptic Drugs (AEDs) and continue to experience seizures. In addition to that, long term usage of Antiepileptic Drugs can cause a range of side effects. To overcome this problem, the precision of 3D printing technology is combined with the controlled release capabilities of biodegradable polymers, allowing for tailored and localized AED delivery to specific seizure sites. As a result of this novel technique, therapeutic outcomes can be enhanced, side effects of AEDs are minimized, and patient-specific dosage forms can be created. This study focused on the use of ethosuximide, an antiepileptic drug, at different concentrations (10, 13, and 15 mg) loaded into 3D-printed sodium alginate and polyethylene oxide scaffolds. The scaffolds contained varying concentrations (0.25%, 0.50%, and 0.75% w/v) and had varying pores created by 3D patterning sizes from 159.86 ± 19.9 µm to 240.29 ± 10.7 µm to optimize the releasing system for an intracranial administration. The addition of PEO changed the Tg and Tm temperatures from 65°C to 69°C and from 262°C to 267°C, respectively. Cytotoxicity assays using the human neuroblastoma cell line (SH-SY5Y) showed that cell metabolic activity reached 130% after 168 h, allowing the cells to develop into mature neural cells. In vitro testing demonstrated sustained ethosuximide release lasting 2 hours despite crosslinking with 3% CaCl2. The workpaves the way for the use of ethosuximide -loaded scaffolds for treating epilepsy.

Ultrasound trapping and navigation of microrobots in the mouse brain vasculature

The intricate and delicate anatomy of the brain poses significant challenges for the treatment of cerebrovascular and neurodegenerative diseases. Thus, precise local drug delivery in hard-to-reach brain regions remains an urgent medical need. Microrobots offer potential solutions; however, their functionality in the brain remains restricted by limited imaging capabilities and complications within blood vessels, such as high blood flows, osmotic pressures, and cellular responses. Here, we introduce ultrasound-activated microrobots for in vivo navigation in brain vasculature. Our microrobots consist of lipid-shelled microbubbles that autonomously aggregate and propel under ultrasound irradiation. We investigate their capacities in vitro within microfluidic-based vasculatures and in vivo within vessels of a living mouse brain. These microrobots self-assemble and execute upstream motion in brain vasculature, achieving velocities up to 1.5 µm/s and moving against blood flows of ~10 mm/s. This work represents a substantial advance towards the therapeutic application of microrobots within the complex brain vasculature.

Three Dimensional Printing and Its Applications Focusing on Microneedles for Drug Delivery

Microneedles (MNs) are considered to be a novel smart injection system that causes significantly low skin invasion upon puncturing, due to the micron-sized dimensions that pierce into the skin painlessly. This allows transdermal delivery of numerous therapeutic molecules, such as insulin and vaccines. The fabrication of MNs is carried out through conventional old methods such as molding, as well as through newer and more sophisticated technologies, such as three-dimensional (3D) printing, which is considered to be a superior, more accurate, and more time- and production-efficient method than conventional methods. Three-dimensional printing is becoming an innovative method that is used in education through building intricate models, as well as being employed in the synthesis of fabrics, medical devices, medical implants, and orthoses/prostheses. Moreover, it has revolutionary applications in the pharmaceutical, cosmeceutical, and medical fields. Having the capacity to design patient-tailored devices according to their dimensions, along with specified dosage forms, has allowed 3D printing to stand out in the medical field. The different techniques of 3D printing allow for the production of many types of needles with different materials, such as hollow MNs and solid MNs. This review covers the benefits and drawbacks of 3D printing, methods used in 3D printing, types of 3D-printed MNs, characterization of 3D-printed MNs, general applications of 3D printing, and transdermal delivery using 3D-printed MNs.

Recent advancements to enhance the therapeutic efficacy of antiepileptic drugs

Epilepsy is a multifactorial neurological disorder characterized by recurrent or unprovoked seizures. Over the past two decades, many new antiepileptic drugs (AEDs) were developed and are in use for the treatment of epilepsy. However, drug resistance, drug-drug interaction and adverse events are common problems associated with AEDs. Antiepileptic drugs must be used only if the ratio of efficacy, safety, and tolerability of treatment are favorable and outweigh the disadvantages including treatment costs. The application of novel drug delivery techniques could enhance the efficacy and reduce the toxicity of AEDs. These novel techniques aim to deliver an optimal concentration of the drug more specifically to the seizure focus or foci in the CNS without numerous side-effects. The purpose of this article is to review the recent advancements in antiepileptic treatment and summarize the novel modalities in the route of administration and drug delivery, including gene therapy, for effective treatment of epilepsy.

Polymeric long-acting drug delivery systems (LADDS) for treatment of chronic diseases: Inserts, patches, wafers, and implants

Non-oral long-acting drug delivery systems (LADDS) encompass a range of technologies for precisely delivering drug molecules into target tissues either through the systemic circulation or via localized injections for treating chronic diseases like diabetes, cancer, and brain disorders as well as for age-related eye diseases. LADDS have been shown to prolong drug release from 24 h up to 3 years depending on characteristics of the drug and delivery system. LADDS can offer potentially safer, more effective, and patient friendly treatment options compared to more invasive modes of drug administration such as repeated injections or minor surgical intervention. Whilst there is no single technology or definition that can comprehensively embrace LADDS; for the purposes of this review, these systems include solid implants, inserts, transdermal patches, wafers and in situ forming delivery systems. This review covers common chronic illnesses, where candidate drugs have been incorporated into LADDS, examples of marketed long-acting pharmaceuticals, as well as newly emerging technologies, used in the fabrication of LADDS.

Electrohydrodynamic atomisation driven design and engineering of opportunistic particulate systems for applications in drug delivery, therapeutics and pharmaceutics

Electrohydrodynamic atomisation (EHDA) technologies have evolved significantly over the past decade; branching into several established and emerging healthcare remits through timely advances in the engineering sciences and tailored conceptual process designs. More specifically for pharmaceutical and drug delivery spheres, electrospraying (ES) has presented itself as a high value technique enabling a plethora of different particulate structures. However, when coupled with novel formulations (e.g. co-flows) and innovative device aspects (e.g., materials and dimensions), core characteristics of particulates are manipulated and engineered specifically to deliver an application driven need, which is currently lacking, ranging from imaging and targeted delivery to controlled release and sensing. This demonstrates the holistic nature of these emerging technologies; which is often overlooked. Parametric driven control during particle engineering via the ES method yields opportunistic properties when compared to conventional methods, albeit at ambient conditions (e.g., temperature and pressure), making this extremely valuable for sensitive biologics and molecules of interest. Furthermore, several processing (e.g., flow rate, applied voltage and working distance) and solution (e.g., polymer concentration, electrical conductivity and surface tension) parameters impact ES modes and greatly influence the production of resulting particles. The formation of a steady cone-jet and subsequent atomisation during ES fabricates particles demonstrating monodispersity (or near monodispersed), narrow particle size distributions and smooth or textured morphologies; all of which are successfully incorporated in a one-step process. By following a controlled ES regime, tailored particles with various intricate structures (hollow microspheres, nanocups, Janus and cell-mimicking nanoparticles) can also be engineered through process head modifications central to the ES technique (single-needle spraying, coaxial, multi-needle and needleless approaches). Thus, intricate formulation design, set-up and combinatorial engineering of the EHDA process delivers particulate structures with a multitude of applications in tissue engineering, theranostics, bioresponsive systems as well as drug dosage forms for specific delivery to diseased or target tissues. This advanced technology has great potential to be implemented commercially, particularly on the industrial scale for several unmet pharmaceutical and medical challenges and needs. This review focuses on key seminal developments, ending with future perspectives addressing obstacles that need to be addressed for future advancement.

Microemulsion-Based Media in Nose-to-Brain Drug Delivery

Nose-to-brain drug delivery has recently attracted enormous attention as an alternative to other delivery routes, including the most popular oral one. Due to the unique anatomical features of the nasal cavity, drugs administered intranasally can be delivered directly to the central nervous system. The most important advantage of this approach is the ability to avoid the blood-brain barrier surrounding the brain and blocking the entry of exogenous substances to the central nervous system. Moreover, selective brain targeting could possibly avoid peripheral side effects of pharmacotherapy. The challenges associated with nose-to-brain drug delivery are mostly due to the small volume of the nasal cavity and insufficient drug absorption from nasal mucosa. These issues could be minimized by using a properly designed drug carrier. Microemulsions as potential drug delivery systems offer good solubilizing properties and the ability to enhance drug permeation through biological membranes. The aim of this review is to summarize the current status of the research focused on microemulsion-based systems for nose-to-brain delivery with special attention to the most extensively investigated neurological and psychiatric conditions, such as neurodegenerative diseases, epilepsy, and schizophrenia.

Bypassing the Blood-Brain Barrier: Direct Intracranial Drug Delivery in Epilepsies

Epilepsies are common chronic neurological diseases characterized by recurrent unprovoked seizures of central origin. The mainstay of treatment involves symptomatic suppression of seizures with systemically applied antiseizure drugs (ASDs). Systemic pharmacotherapies for epilepsies are facing two main challenges. First, adverse effects from (often life-long) systemic drug treatment are common, and second, about one-third of patients with epilepsy have seizures refractory to systemic pharmacotherapy. Especially the drug resistance in epilepsies remains an unmet clinical need despite the recent introduction of new ASDs. Apart from other hypotheses, epilepsy-induced alterations of the blood-brain barrier (BBB) are thought to prevent ASDs from entering the brain parenchyma in necessary amounts, thereby being involved in causing drug-resistant epilepsy. Although an invasive procedure, bypassing the BBB by targeted intracranial drug delivery is an attractive approach to circumvent BBB-associated drug resistance mechanisms and to lower the risk of systemic and neurologic adverse effects. Additionally, it offers the possibility of reaching higher local drug concentrations in appropriate target regions while minimizing them in other brain or peripheral areas, as well as using otherwise toxic drugs not suitable for systemic administration. In our review, we give an overview of experimental and clinical studies conducted on direct intracranial drug delivery in epilepsies. We also discuss challenges associated with intracranial pharmacotherapy for epilepsies.

Anti-seizure therapy with a long-term, implanted intra-cerebroventricular delivery system for drug-resistant epilepsy: A first-in-man study

BACKGROUND

A clinical feasibility study was undertaken at a single center of long-term intra-cerebroventricular drug delivery of the anti-seizure medication valproic acid, into the cerebrospinal fluid (CSF) in order to treat drug resistant focal seizures, using an implantable infusion system. The primary objective was to establish the dose range of VPA administered in this manner. Secondarily, safety, pharmacokinetics (PK) and a preliminary estimate of effectiveness were evaluated.

METHODS

In this single arm study, five adult subjects, with 29-234 focal onset seizures per month from a seizure focus involving the mesial temporal lobe were implanted with the system (clinicaltrials.gov identifier NCT02899611). Oral valproic acid (VPA) had previously been ineffective in all subjects. Post-surgery, pharmacokinetic studies of CSF infused VPA were performed. Valproic acid doses were increased stepwise in a standardised protocol.

FINDINGS

The procedure and implantation were well-tolerated by all subjects. Four subjects responded with > 50% seizure reduction at the highest tested dose of 160 mg/day. Two subjects experienced extended periods of complete seizure freedom. All five subjects reported significant quality of life improvement. No clinical dose limiting side effects were encountered and there was no evidence of local periventricular toxicity in three subjects who were evaluated with imaging (T2 MRI). Side effects included nausea and appetite loss but were not dose-limiting. Mean CSF valproic acid levels were 45 μg per ml (range 20-120 μg per ml), with corresponding serum levels of 4-14 μg per ml.  Subjects have received therapy for up to 2.5 years in total . The efficacy analysis presented focuses on the period of time with the current pump with a mean 12.5 months, range 11.5-15 months. Pump failure requiring reimplantation was a significant initial issue in all subjects but resolved with use of pumps suitably compatible with long-term exposure to valproic acid.

INTERPRETATION

The study demonstrated that chronic intraventricular administration of valproic acid is safe and effective in subjects with medically refractory epilepsy over many months. The procedure for implanting the infusion system is safe and well-tolerated. High CSF levels are achieved with corresponding low serum levels and this therapy is shown to be effective despite unsuccessful earlier use of oral valproate preparations. Drug side effects were minimal.

FUNDING

The study was funded by Cerebral Therapeutics Inc., Suite 137 12635 East Montview Blvd Aurora CO 80045.

Electrochemically Controlled Drug Release from a Conducting Polymer Hydrogel (PDMAAp/PEDOT) for Local Therapy and Bioelectronics

In this study, the release of fluorescein from a photo-crosslinked conducting polymer hydrogel made from a hydrogel precursor poly(dimethylacrylamide-co-4-methacryloyloxy benzophenone (5%)-co-4-styrenesulfonate (2.5%)) (PDMAAp) and the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is investigated. Fluorescein, here used as a model for a drug, is actively released through application of an electrical trigger signal. The detected quantity is more than six times higher in comparison to that released from a conventional PEDOT/polysterene sulfonate (PSS) system. Release profiles, drug dose, and timing can be tailored by the application of different trigger signals and pretreatments. To demonstrate that the novel drug release system can be used for a drug relevant for local delivery to a neural interface, experiments are furthermore performed with the anti-inflammatory drug dexamethasone (Dex). The conducting polymer hydrogel facilitates the active release of Dex, in comparison to the previously used PEDOT/Dex. It is suggested that PEDOT/PDMAAp is an interesting alternative for conducting polymer based drug release systems, with the potential to offer more volume for storage, yet retaining the excellent electrochemical properties known for PEDOT electrodes.

Advanced fabrication approaches to controlled delivery systems for epilepsy treatment

INTRODUCTION

Epilepsy is a chronic brain disease characterized by unprovoked seizures, which can have severe consequences including loss of awareness and death. Currently, 30% of epileptic patients do not receive adequate seizure alleviation from oral routes of medication. Over the last decade, local drug delivery to the focal area of the brain where the seizure originates has emerged as a potential alternative and may be achieved through the fabrication of drug-loaded polymeric implants for controlled on-site delivery.

AREAS COVERED

This review presents an overview of the latest advanced fabrication techniques for controlled drug delivery systems for refractory epilepsy treatment. Recent advances in the different techniques are highlighted and the limitations of the respective techniques are discussed.

EXPERT OPINION

Advances in biofabrication technologies are expected to enable a new paradigm of local drug delivery systems through offering high versatility in controlling drug release profiles, personalized customization and multi-drug incorporation. Tackling some of the current issues with advanced fabrication methods, including adhering to GMP-standards and industrial scale-up, together with innovative solutions for complex designs will see to the maturation of these techniques and result in increased clinical research into implant-based epilepsy treatment.

ABBREVIATIONS

GMP: Good manufacturing process; DDS(s): Drug delivery system(s); 3D: Three-dimensional; AEDs: Anti-epileptic drugs; BBB: Blood brain barrier; PLA: Polylactic acid; PLGA: Poly(lactic-co-glycolic acid); PCL: poly(ɛ-caprolactone); ESE: Emulsification solvent evaporation; O/W: Oil-in-water; W/O/W: Water-in-oil-in-water; DZP: Diazepam; PHT: Phenytoin; PHBV: Poly(hydroxybutyrate-hydroxyvalerate); PEG: Polyethylene glycol; SWD: Spike-and-wave discharges; CAD: Computer aided design; FDM: Fused deposition modeling; ABS: Acrylonitrile butadiene styren; eEVA: Ethylene-vinyl acetate; GelMA: Gelatin methacrylate; PVA: Poly-vinyl alcohol; PDMS: Polydimethylsiloxane; SLA: Stereolithography; SLS: Selective laser sintering.

Egg Component-Composited Inverse Opal Particles for Synergistic Drug Delivery

Microparticles have a demonstrated value in drug delivery systems. The attempts to develop this technology focus on the generation of functional microparticles by using innovative but accessible materials. Here, we present egg component-composited microparticles with a hybrid inverse opal structure for synergistic drug delivery. The egg component inverse opal particles were produced by using egg yolk to negatively replicate colloid crystal bead templates. Because of their huge specific surface areas, abundant nanopores, and complex nanochannels of the inverse opal structure, the resultant egg yolk particles could be loaded with different kinds of drugs, such as hydrophobic camptothecin (CPT), by simply immersing them into the corresponding drug solutions. Attractively, additional drugs, such as the hydrophilic doxorubicin (DOX), could also be encapsulated into the particles through the secondary filling of the drug-doped egg white hydrogel into the egg yolk inverse opal scaffolds, which realized the synergistic drug delivery for the particles. It was demonstrated that the egg-derived inverse opal particles were with large quantity and lasting releasing for the CPT and DOX codelivery, and thus could significantly reduce cell viability, and enhance therapeutic efficacy in treating cancer cells. These features of the egg component-composited inverse opal microparticles indicated that they are ideal microcarriers for drug delivery.

Application of mobile phones in epilepsy care

Objectives To evaluate the applications of mobile phones in the day to day care of epileptic patients as a diagnostic, prognostic and therapeutic tool.

Methods Detailed search of various mobile applications in the field of epileptology was made in MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, CINAHL, LILACS and corresponding developer websites of mobile applications were also looked into regarding their technical specifications and user friendliness.

Results A plethora of apps are available across various mobile platforms especially Android, iOS and Windows. Careful selection and application of such apps by both the healthcare providers, the epileptic patients and their caregivers with proper understanding of their potential benefits as well as limitations will result in better diagnosis, prognosis and treatment of epilepsy.

Conclusion The field of medicine is rapidly inculcating advanced cutting edge technologies for better diagnosis of diseases and better targeted therapy to such diseases. Hi tech electronic gadgets, in particular, are now becoming part and parcel of patient care in many specialties. The advent of the modern portable computers has revolutionised almost every specialty. The field of mobile technology is advancing with a break neck pace, with increase in mobile subscribers, advanced handsets practically like digital personal assistants with advanced capabilities. The possibilities of using such rapidly evolving mobile technology in the field of medicine are endless. This article explores such possibilities in the field of epileptology after analysing the current and existing applications of mobile phones in care of the epileptic patients worldwide.

Microfluidic generation of egg-derived protein microcarriers for 3D cell culture and drug delivery

Microcarriers have a demonstrated value for biomedical applications, in particular for drug delivery and three-dimensional cell culture. Attempts to develop this technique tend to focus on the fabrication of functional microparticles by using convenient methods with innovative but accessible materials. Inspired by the process of boiling eggs in everyday life, which causes the solidification of egg proteins, we present a new microfluidic "cooking" approach for the generation of egg-derived microcarriers for cell culture and drug delivery. As the egg emulsion droplets are formed with exquisite precision during the microfluidic emulsification, the resultant egg microcarriers present highly monodisperse and uniform morphologies at the size range of hundred microns to one millimeter. Benefiting from the excellent biocompatibility of the egg protein components, the obtained microcarriers showed good performances of cell adherence and growth. In addition, after a freezing treatment, the egg microcarriers were shown to have interconnected porous structures throughout their whole sphere, could absorb and load different kinds of drugs or other active molecules, and work as microcarrier-based delivery systems. These features point to the potential value of the microfluidic egg microcarriers in biomedicine.

Development of drug-loaded polymer microcapsules for treatment of epilepsy

Fibre- and sphere-based microcapsules have been developed, exhibiting controllable uniform morphologies, predictable drug release profiles, and neuro-cytocompatibility.

Dimensional evaluation of patient-specific 3D printing using calcium phosphate cement for craniofacial bone reconstruction

The 3D printing process is highlighted nowadays as a possibility to generate individual parts with complex geometries. Moreover, the development of 3D printing hardware, software and parameters permits the manufacture of parts that can be not only used as prototypes, but are also made from materials that are suitable for implantation. In this way, this study investigates the process involved in the production of patient-specific craniofacial implants using calcium phosphate cement, and its dimensional accuracy. The implants were previously generated in a computer-aided design environment based on the patient's tomographic data. The fabrication of the implants was carried out in a commercial 3D powder printing system using alfa-tricalcium phosphate powder and an aqueous solution of Na₂HPO₄ as a binder. The fit of the 3D printed implants was measured by three-dimensional laser scanning and by checking the right adjustment to the patient's anatomical biomodel. The printed parts presented a good degree of fitting and accuracy.

Evaluation of the Biocompatibility of Polypyrrole Implanted Subdurally in GAERS

This blinded controlled prospective randomized study investigates the biocompatibility of polypyrrole (PPy) polymer that will be used for intracranial triggered release of anti-epileptic drugs (AEDs). Three by three millimeters PPy are implanted subdurally in six adult female genetic absence epilepsy rats from Strasbourg. Each rat has a polymer implanted on one side of the cortex and a sham craniotomy performed on the other side. After a period of seven weeks, rats are euthanized and parallel series of coronal sections are cut throughout the implant site. Four series of 15 sections are histological (hematoxylin and eosin) and immunohistochemically (neuron-specific nuclear protein, glial fibrillary acidic protein, and anti-CD68 antibody) stained and evaluated by three investigators. The results show that implanted PPy mats do not induce obvious inflammation, trauma, gliosis, and neuronal toxicity. Therefore the authors conclude the PPy used offer good histocompatibility with central nervous system cells and that PPy sheets can be used as intracranial, AED delivery implant.

Injectable phenytoin loaded polymeric microspheres for the control of temporal lobe epilepsy in rats

PURPOSE

Epilepsy is a prevalent neurological disorder with a high frequency of drug resistance. While significant advancements have been made in drug delivery systems to overcome anti-epileptic drug resistance, efficacies of materials in biological systems have been poorly studied. The purpose of the study was to evaluate the anti-epileptic effects of injectable poly(epsilon-caprolactone) (PCL) microspheres for controlled release of an anticonvulsant, phenytoin (PHT), in an animal model of epilepsy.

METHODS

PHT-PCL and Blank-PCL microspheres formulated using an oil-in-water (O/W) emulsion solvent evaporation method were evaluated for particle size, encapsulation efficiency, surface morphology and in-vitro drug release profile. Microspheres with the most suitable morphology and release characteristics weresubsequently injected into the hippocampus of a rat tetanus toxin model of temporal lobe epilepsy. Electrocorticography (ECoG)from the cerebral cortex were recorded for all animals. The number of seizure events, severity of seizures, and seizure duration were then compared between the two treatment groups.

RESULTS

We have shown that small injections of drug-loaded microspheres are biologically tolerated and released PHT can control seizures for the expected period of time that is in accord with in-vitro release data.

CONCLUSION

The study demonstrated the feasibility of polymer-based delivery systems incontrolling focal seizures.

Nanoporous capsules of block co-polymers of [(MeO-PEG-NH)-b-(L-GluA)]-PCL for the controlled release of anticancer drugs for therapeutic applications

Herein, new nanoporous capsules of the block co-polymers of MeO-PEG-NH-(L-GluA)10 and polycaprolactone (PCL) have been synthesized through a surfactant-free cost-effective self-assembled soft-templating approach for the controlled release of drugs and for therapeutic applications. The nanoporous polymer capsules are designed to be biocompatible and are capable of encapsulating anticancer drugs (e.g., doxorubicin hydrochloride (DOX) and imatinib mesylate (ITM)) with a high extent (∼279 and ∼480 ng μg(-1), respectively). We have developed a nanoformulation of porous MeO-PEG-NH-(L-GluA)10-PCL capsules with DOX and ITM. The porous polymer nanoformulations have been programmed in terms of the release of anticancer drugs with a desired dose to treat the leukemia (K562) and human carcinoma cells (HepG2) in vitro and show promising IC50 values with a very high mortality of cancer cells (up to ∼96.6%). Our nanoformulation arrests the cell divisions due to 'cellular scenescence' and kills the cancer cells specifically. The present findings could enrich the effectiveness of idiosyncratic nanoporous polymer capsules for use in various other nanomedicinal and biomedical applications, such as for killing cancer cells, immune therapy, and gene delivery.

Antiepileptic Effects of Lacosamide Loaded Polymers Implanted Subdurally in GAERS

The current experiment investigated the ability of coaxial electrospun poly(D,L-lactide-co-glycolide) (PLGA) biodegradable polymer implants loaded with the antiepileptic drugs (AED) lacosamide to reduce seizures following implantation above the motor cortex in the Genetic Absence Epilepsy Rat from Strasbourg (GAERS). In this prospective, randomized, masked experiments, GAERS underwent surgery for implantation of skull electrodes (n=6), skull electrodes and blank polymers (n=6), or skull electrodes and lacosamide loaded polymers (n=6). Thirty-minute electroencephalogram (EEG) recordings were started at day 7 after surgery and continued for eight weeks. The number of SWDs and mean duration of one SWD were compared week-by-week between the three groups. There was no difference in the number of SWDs between any of the groups. However, the mean duration of one SWD was significantly lower in the lacosamide polymer group for up to 7 weeks when compared to the control group (0.004<p<0.038). The mean duration of one seizure was also lower at weeks 3, 5, 6, and 7 when compared to the blank polymer group (p= 0.016, 0.037, 0.025, and 0.025, resp.). We have demonstrated that AED loaded PLGA polymer sheets implanted on the surface of the cortex could affect seizure activity in GAERS for a sustained period.

Effects of NaCl Replacement with Gamma-Aminobutyric acid (GABA) on the Quality Characteristics and Sensorial Properties of Model Meat Products

This study investigated the effects of γ-aminobutylic acid (GABA) on the quality and sensorial properties of both the GABA/NaCl complex and model meat products. GABA/NaCl complex was prepared by spray-drying, and the surface dimensions, morphology, rheology, and saltiness were characterized. For model meat products, pork patties were prepared by replacing NaCl with GABA. For characteristics of the complex, increasing GABA concentration increased the surface dimensions of the complex. However, GABA did not affect the rheological properties of solutions containing the complex. The addition of 2% GABA exhibited significantly higher saltiness than the control (no GABA treatment). In the case of pork patties, sensory testing indicated that the addition of GABA decreased the saltiness intensity. Both the intensity of juiciness and tenderness of patties containing GABA also scored lower than the control, based on the NaCl reduction. These results were consistent with the quality characteristics (cooking loss and texture profile analysis). Nevertheless, overall acceptability of the pork patties showed that up to 1.5%, patties containing GABA did not significantly differ from the control. Consequently, the results indicated that GABA has a potential application in meat products, but also manifested a deterioration of quality by the NaCl reduction, which warrants further exploration.

Neuronal networks and energy bursts in epilepsy

Epilepsy can be defined as the abnormal activities of neurons. The occurrence, propagation and termination of epileptic seizures rely on the networks of neuronal cells that are connected through both synaptic- and non-synaptic interactions. These complicated interactions contain the modified functions of normal neurons and glias as well as the mediation of excitatory and inhibitory mechanisms with feedback homeostasis. Numerous spread patterns are detected in disparate networks of ictal activities. The cortical-thalamic-cortical loop is present during a general spike wave seizure. The thalamic reticular nucleus (nRT) is the major inhibitory input traversing the region, and the dentate gyrus (DG) controls CA3 excitability. The imbalance between γ-aminobutyric acid (GABA)-ergic inhibition and glutamatergic excitation is the main disorder in epilepsy. Adjustable negative feedback that mediates both inhibitory and excitatory components affects neuronal networks through neurotransmission fluctuation, receptor and transmitter signaling, and through concomitant influences on ion concentrations and field effects. Within a limited dynamic range, neurons slowly adapt to input levels and have a high sensitivity to synaptic changes. The stability of the adapting network depends on the ratio of the adaptation rates of both the excitatory and inhibitory populations. Thus, therapeutic strategies with multiple effects on seizures are required for the treatment of epilepsy, and the therapeutic functions on networks are reviewed here. Based on the high-energy burst theory of epileptic activity, we propose a potential antiepileptic therapeutic strategy to transfer the high energy and extra electricity out of the foci.

Mussel-inspired protein-mediated surface functionalization of electrospun nanofibers for pH-responsive drug delivery

pH-responsive drug delivery systems could mediate drug releasing rate by changing the pH values at specific times as per the pathophysiological need of the disease. This paper demonstrates that a mussel-inspired protein polydopamine coating can tune the loading and releasing rate of charged molecules from electrospun poly(ε-caprolactone) (PCL) nanofibers in solutions with different pH values. In vitro release profiles show that the positive charged molecules release significantly faster in acidic than those in neutral and basic environments within the same incubation time. The results of fluorescein diacetate staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays show the viability of cancer cells after treatment with doxorubicin-released media at different pH values qualitatively and quantitatively, indicating that the media containing doxorubicin that were released in solutions at low pH values could kill a significantly higher number of cells than those released in solutions at high pH values. Together, the pH-responsive drug delivery systems based on polydopamine-coated PCL nanofibers could have potential application in the oral delivery of anticancer drugs for treating gastric cancer and in vaginal delivery of anti-viral drugs or anti-inflammatory drugs, which could raise their efficacy, deliver them to the specific target and minimize their toxic side effects.

Synthesis, characterization, and evaluation of a novel amphiphilic polymer RGD-PEG-Chol for target drug delivery system

An amphiphilic polymer RGD-PEG-Chol which can be produced in large scale at a very low cost has been synthesized successfully. The synthesized intermediates and final products were characterized and confirmed by ¹H nuclear magnetic resonance spectrum (¹H NMR) and Fourier transform infrared spectrum (FT-IR). The paclitaxel- (PTX-) loaded liposomes based on RGD-PEG-Chol were then prepared by film formation method. The liposomes had a size within 100 nm and significantly enhanced the cytotoxicity of paclitaxel to B16F10 cell as demonstrated by MTT test (IC₅₀ = 0.079  μg/mL of RGD-modified PTX-loaded liposomes compared to 9.57  μg/mL of free PTX). Flow cytometry analysis revealed that the cellular uptake of coumarin encapsulated in the RGD-PEG-Chol modified liposome was increased for HUVEC cells. This work provides a reasonable, facile, and economic approach to prepare peptide-modified liposome materials with controllable performances and the obtained linear RGD-modified PTX-loaded liposomes might be attractive as a drug delivery system.

Smart wearable systems: current status and future challenges

OBJECTIVE

Extensive efforts have been made in both academia and industry in the research and development of smart wearable systems (SWS) for health monitoring (HM). Primarily influenced by skyrocketing healthcare costs and supported by recent technological advances in micro- and nanotechnologies, miniaturisation of sensors, and smart fabrics, the continuous advances in SWS will progressively change the landscape of healthcare by allowing individual management and continuous monitoring of a patient's health status. Consisting of various components and devices, ranging from sensors and actuators to multimedia devices, these systems support complex healthcare applications and enable low-cost wearable, non-invasive alternatives for continuous 24-h monitoring of health, activity, mobility, and mental status, both indoors and outdoors. Our objective has been to examine the current research in wearable to serve as references for researchers and provide perspectives for future research.

METHODS

Herein, we review the current research and development of and the challenges facing SWS for HM, focusing on multi-parameter physiological sensor systems and activity and mobility measurement system designs that reliably measure mobility or vital signs and integrate real-time decision support processing for disease prevention, symptom detection, and diagnosis. For this literature review, we have chosen specific selection criteria to include papers in which wearable systems or devices are covered.

RESULTS

We describe the state of the art in SWS and provide a survey of recent implementations of wearable health-care systems. We describe current issues, challenges, and prospects of SWS.

CONCLUSION

We conclude by identifying the future challenges facing SWS for HM.