Development and characterization of lipid nanocapsules loaded with iron oxide nanoparticles for magnetic targeting to the blood-brain barrier.

Brain drug delivery is severely hindered by the presence of the blood-brain barrier (BBB). Its functionality relies on the interactions of the brain endothelial cells with additional cellular constituents, including pericytes, astrocytes, neurons, or microglia. To boost brain drug delivery, nanomedicines have been designed to exploit distinct delivery strategies, including magnetically driven nanocarriers as a form of external physical targeting to the BBB. Herein, a lipid-based magnetic nanocarrier prepared by a low-energy method is first described. Magnetic nanocapsules with a hydrodynamic diameter of 256.7 ± 8.5 nm (polydispersity index: 0.089 ± 0.034) and a ξ-potential of -30.4 ± 0.3 mV were obtained. Transmission electron microscopy-energy dispersive X-ray spectroscopy analysis revealed efficient encapsulation of iron oxide nanoparticles within the oily core of the nanocapsules. Both thermogravimetric analysis and phenanthroline-based colorimetric assay showed that the iron oxide percentage in the final formulation was 12 wt.%, in agreement with vibrating sample magnetometry analysis, as the specific saturation magnetization of the magnetic nanocapsules was 12% that of the bare iron oxide nanoparticles. Magnetic nanocapsules were non-toxic in the range of 50-300 µg/mL over 72 h against both the human cerebral endothelial hCMEC/D3 and Human Brain Vascular Pericytes cell lines. Interestingly, higher uptake of magnetic nanocapsules in both cell types was evidenced in the presence of an external magnetic field than in the absence of it after 24 h. This increase in nanocapsules uptake was also evidenced in pericytes after only 3 h. Altogether, these results highlight the potential for magnetic targeting to the BBB of our formulation.

Cyclosporin A-loaded dissolving microneedles for dermatitis therapy: Development, characterisation and efficacy in a delayed-type hypersensitivity in vivo model.

Several drugs can be used for treating inflammatory skin pathologies like dermatitis and psoriasis. However, for the management of chronic and long-term cases, topical administration is preferred over oral delivery since it prevents certain issues due to systemic side effects from occurring. Cyclosporin A (CsA) has been used for this purpose; however, its high molecular weight (1202 Da) restricts the diffusion through the skin structure. Here, we developed a nano-in-micro device combining lipid vesicles (LVs) and dissolving microneedle array patches (DMAPs) for targeted skin delivery. CsA-LVs allowed the effective incorporation of CsA in the hydrophilic DMAP matrix despite the hydrophobicity of the drug. Polymeric matrix composed of poly (vinyl alcohol) (5% w/v), poly (vinyl pyrrolidine) (15% w/v) and CsA-LV dispersion (10% v/v) led to the formation of CsA-LVs@DMAPs with adequate mechanical properties to penetrate the stratum corneum barrier. The safety and biocompatibility were ensured in an in vitro viability test using HaCaT keratinocytes and L929 fibroblast cell lines. Ex vivo permeability studies in a Franz-diffusion cell setup showed effective drug retention in the skin structure. Finally, CsA-LVs@DMAPs were challenged in an in vivo murine model of delayed-type hypersensitivity to corroborate their potential to ameliorate skin inflammatory conditions. Different findings like photon emission reduction in bioluminescence study, normalisation of histological damage and decrease of inflammatory cytokines point out the effectivity of CsA-LVs@DMAPs to treat these conditions. Overall, our study demonstrates that CsA-LVs@DMAPs can downregulate the skin inflammatory environment which paves the way for their clinical translation and their use as an alternative to corticosteroid-based therapies.

Antibiotic resistance and tolerance: What can drug delivery do against this global threat?

Antimicrobial resistance and tolerance (AMR&T) are urgent global health concerns, with alarmingly increasing numbers of antimicrobial drugs failing and a corresponding rise in related deaths. Several reasons for this situation can be cited, such as the misuse of traditional antibiotics, the massive use of sanitizing measures, and the overuse of antibiotics in agriculture, fisheries, and cattle. AMR&T management requires a multifaceted approach involving various strategies at different levels, such as increasing the patient's awareness of the situation and measures to reduce new resistances, reduction of current misuse or abuse, and improvement of selectivity of treatments. Also, the identification of new antibiotics, including small molecules and more complex approaches, is a key factor. Among these, novel DNA- or RNA-based approaches, the use of phages, or CRISPR technologies are some potent strategies under development. In this perspective article, emerging and experienced leaders in drug delivery discuss the most important biological barriers for drugs to reach infectious bacteria (bacterial bioavailability). They explore how overcoming these barriers is crucial for producing the desired effects and discuss the ways in which drug delivery systems can facilitate this process.

Latest advances in glucose-responsive microneedle-based systems for transdermal insulin delivery.

The development of a self-regulated minimally invasive system for insulin delivery can be considered as the holy grail in the field of diabetes mellitus. A delivery system capable of releasing insulin in response to blood glucose levels would significantly improve the quality of life of diabetic patients, eliminating the need for frequent finger-prick tests and providing better glycaemic control with lower risk of hypoglycaemia. In this context, the latest advances in glucose-responsive microneedle-based transdermal insulin delivery are here compiled with a thorough analysis of the delivery mechanisms and challenges lying ahead in their clinical translation. Two main groups of microneedle-based systems have been developed so far: glucose oxidase-containing and phenylboronic acid-containing systems. Both strategies in combination have also been tested and two other novel strategies are under development, namely electronic closed-loop and glucose transporter-based systems. Results from preclinical studies conducted using these different types of glucose-triggered release systems are comprehensively discussed. Altogether, this analysis from both a mechanistic and translational perspective will provide rationale and/or guidance for future trends in the research hotspot of glucose-responsive microneedle-based insulin delivery systems.

Assessment of In Vitro Release Testing Methods for Colloidal Drug Carriers: The Lack of Standardized Protocols.

Although colloidal carriers have been in the pipeline for nearly four decades, standardized methods for testing their drug-release properties remain to be established in pharmacopeias. The in vitro assessment of drug release from these colloidal carriers is one of the most important parameters in the development and quality control of drug-loaded nano- and microcarriers. This lack of standardized protocols occurs due to the difficulties encountered in separating the released drug from the encapsulated one. This review aims to compare the most frequent types of release testing methods (i.e., membrane diffusion techniques, sample and separate methods and in situ detection techniques) in terms of the advantages and disadvantages of each one and of the key parameters that influence drug release in each case.

An overview of in vitro 3D models of the blood-brain barrier as a tool to predict the in vivo permeability of nanomedicines.

The blood-brain barrier (BBB) prevents efficient drug delivery to the central nervous system. As a result, brain diseases remain one of the greatest unmet medical needs. Understanding the tridimensional structure of the BBB helps gain insight into the pathology of the BBB and contributes to the development of novel therapies for brain diseases. Therefore, 3D models with an ever-growing sophisticated complexity are being developed to closely mimic the human neurovascular unit. Among these 3D models, hydrogel-, spheroid- and organoid-based static BBB models have been developed, and so have microfluidic-based BBB-on-a-chip models. The different 3D preclinical models of the BBB, both in health and disease, are here reviewed, from their development to their application for permeability testing of nanomedicines across the BBB, discussing the advantages and disadvantages of each model. The validation with data from in vivo preclinical data is also discussed in those cases where provided.

La frontera con los productos sanitarios en el actual marco legislativo español / The borderline with medical devices in the current Spanish legal framework

Los productos sanitarios abarcan un amplio rango de artículos imprescindibles en la asistencia sanitaria y cuidados de salud. En 2017 se aprobó un nuevo reglamento que los regula en la Unión Europea, y cuya entrada en vigor fue en 2021. En él se especifican su definición legal, su clasificación, sus procedimientos de evaluación de la conformidad, los requerimientos de las investigaciones clínicas que evalúan su seguridad y/o funcionamiento y su base de datos europea.Pese a los intentos por sistematizar la definición legal de producto sanitario en el nuevo reglamento, la determinación de la situación reglamentaria de los artículos conocidos como ‘productos frontera’, para los que diferentes normativas podrían ser de aplicación (como en la frontera con los complementos alimenticios, los cosméticos, los productos de cuidado personal, los biocidas, los equipos de protección individual y los productos de consumo), no está exenta de dificultades. Debido a su relevancia terapéutica, esta revisión profundiza en la frontera entre los medicamentos y los productos sanitarios, y se diferencia de aquellas presentaciones en que medicamentos y productos sanitarios se usan de manera conjunta, sin constituir frontera.Establecer unas definiciones actualizadas, fomentar la transparencia en el sector y prevenir los conflictos de interés, debe motivar a los agentes implicados a la revisión periódica de una normativa en un campo sometido a constante evolución y desarrollo tecnológico. (AU)

Medical devices cover a wide range of products essential for healthcare. In 2017 a new European regulation covering them was approved that fully applies from 2021 onwards. In it, their legal definition, classification, conformity assessment procedures, requirements for the clinical investigations that asses their safety and/or performance, and European database are specified.Despite the efforts for systematizing the legal definition of medical device in the new regulation, the determination of the legal status of devices known as ‘borderline products’, for which different regulations may apply (like in the borderline with food supplements, cosmetics, personal care products, biocides, personal protective equipment and consumer products), is not without difficulties. On account of their therapeutic significance, this review delves into the borderline between medicinal products and medical devices, and differentiates them from presentations where medicinal products and medical devices are used in combination, without constituting a borderline.Establishing updated definitions, promoting transparency in the sector and preventing conflicts of interest should motivate all stakeholders to the periodic review of the regulation in a field in continuous technological evolution and development. (AU)

Sistemas de liberación prolongada de opioides: Analgesia y dependencia / Extended-release delivery systems of opioids: Analgesia and dependence

El consumo de analgésicos opioides ha experimentado un vertiginoso ascenso en las últimas décadas a nivel mundial. Este elevado consumo está relacionado con el aumento del número de prescripciones de opioides para el tratamiento del dolor crónico y por el aumento de la dependencia a opioides. Los analgésicos opioides tienen una corta duración de acción, siendo necesarias múltiples administraciones para obtener analgesia prolongada. El empleo de formulaciones de liberación prolongada permite espaciar los intervalos posológicos y estabilizar las concentraciones máximas de fármaco en sangre, favoreciendo el cumplimiento terapéutico y reduciendo el riesgo de desarrollar adicción. Sin embargo, estas formulaciones llevan dosis más altas de analgésicos opioides que las hacen más susceptibles de ser alteradas. Así, los avances en tecnología farmacéutica más recientes se han orientado hacia la aplicación de recursos tecnológicos disuasorios de su utilización por vías de administración alternativas con fines no terapéuticos. A su vez, los sistemas de liberación modificada también juegan un papel esencial en el tratamiento de la adicción a opioides: con el desarrollo de sistemas de administración parenteral capaces de prolongar la liberación de opioides durante meses se consigue superar una de las mayores dificultades para alcanzar el éxito del tratamiento en este tipo de pacientes como es el cumplimiento terapéutico. En este artículo se realiza una revisión bibliográfica de los diferentes sistemas de liberación prolongada de opioides que se encuentran actualmente autorizados en Europa y/o en Estados Unidos para el tratamiento del dolor y de la dependencia a opioides. (AU)

The consumption of opioid analgesics has increased drastically in the last decades worldwide. This high consumption is linked with a surge in the number of opioid prescriptions for the treatment of chronic pain and a surge in opioid misuse and addiction. Opioid analgesics have a short duration of action, making necessary frequent administrations to provide extended analgesia. The use of prolonged-release formulations enables dosing intervals to be spaced out and drug blood levels to be stabilized, improving therapeutic compliance, and reducing the likelihood of developing addiction. However, these formulations contain higher doses of opioid analgesics which make them more susceptible to be manipulated. Hence, the most recent advances in pharmaceutical technology have been oriented towards the application of abuse deterrent technologies aiming to prevent their administration through alternative routes. Moreover, prolonged- release systems also play an essential role in the treatment of opioid addictions with the development of parenteral dosage forms capable of prolonging opioid release for months that help overcome one of the most important drawbacks in achieving treatment success, namely, patient compliance. We review herein the different prolonged-release opioid dosage forms currently approved in Europe and/or the United States for the treatment of pain and opioid dependence. (AU)

Nanocannabinoides como terapia frente a glioma / Nannocannabinoids for brain tumor drug delivery

Las patologías cerebrales representan un desafío terapéutico por la restricción al paso de fármacos a través de la barrera hematoencefálica. Por ello, actualmente se persigue diseñar transportadores de fármacos capaces de atravesar de manera eficiente el endotelio cerebral tras su administración intravenosa. Sin embargo, el impacto traslacional de la nanomedicina es aún discreto. Sin duda, la transición de un desarrollo empírico hacia un diseño racional adecuado a las necesidades terapéuticas concretas en cada caso aumentará las posibilidades de éxito.Bajo esta premisa y aprovechando tanto el tropismo cerebral como la actividad antiproliferativa del cannabidiol, y a fin de contribuir al diseño racional de nanocápsulas dirigidas para el tratamiento de gliomas, hemos evaluado la influencia de distintos parámetros en su comportamiento in vitro e in vivo. Efectivamente, hemos demostrado que tanto el paso a través de barrera hematoencefálica como la captación por células de glioma, así como la velocidad de liberación de fármacos pueden modularse variando su tamaño de partícula. El método térmico de inversión de fases posibilita la obtención de nanocápsulas bajo demanda en términos de tamaño gracias al modelo matemático lineal en una variable aquí descrito.Además, hemos desarrollado una novedosa estrategia de vectorización con cannabidiol (que incluso supera a otras que ya se encuentran en ensayos clínicos). Asimismo, las nanocápsulas sirven como transportadores de liberación prolongada del cannabidiol, superando así sus problemas de formulación que venían limitando su potencial terapéutico.En conjunto, las nanocápsulas lipídicas, cargadas y funcionalizadas con cannabidiol, constituyen prometedores candidatos para el tratamiento de gliomas. (AU)

Brain diseases are a major health challenge as brain drug delivery is truly hindered by the blood-brain barrier. Therefore, targeted drug nanocarriers arise as an alternative to achieve efficient transport across the brain endothelium following minimally-invasive intravenous injection. However, the global translational impact of nanomedicine remains modest. Certainly, the transition from empirical development towards a rational design tailored to the specific disease needs is likely to improve the chances of success.Under this assumption and taking advantage of both the natural brain tropism and the antiproliferative activity of cannabidiol, to contribute to the rational design of targeted nanocapsules for glioma therapy, we have thoroughly screened the influence of distinct parameters on their in vitro and in vivo behaviour. Effectively, we have demonstrated that both the brain and glioma targeting ability and the drug release rate can be tailored by varying the particle size of the nanocapsules. This fine size-tailoring can be achieved by the phase inversion temperature method thanks to the hereindescribed linear univariate mathematical model as a function of the oily phase/surfactant mass ratio.Moreover, we have introduced, on the one hand, a pioneering brain tumor targeting strategy with cannabidiol (with better targeting properties than other strategies that have already reached the clinical trials stage) and, on the other hand, nanocapsules as extendedrelease carriers of cannabidiol to overcome the formulation problems that have traditionally constrained its therapeutic potential.Altogether, small lipid nanocapsules loaded and functionalized with cannabidiol arise as promising dually-targeted candidates for intravenous treatment of glioma. (AU)

Embolization therapy with microspheres for the treatment of liver cancer: State-of-the-art of clinical translation.

Embolization with microspheres is a therapeutic strategy based on the selective occlusion of the blood vessels feeding a tumor. This procedure is intraarterially performed in the clinical setting for the treatment of liver cancer. The practice has evolved over the last decade through the incorporation of drug loading ability, biodegradability and imageability with the subsequent added functionality for the physicians and improved clinical outcomes for the patients. This review highlights the evolution of the embolization systems developed through the analysis of the marketed embolic microspheres for the treatment of malignant hepatocellular carcinoma, namely the most predominant form of liver cancer. Embolic microspheres for the distinct modalities of embolization (i.e., bland embolization, chemoembolization and radioembolization) are here comprehensively compiled with emphasis on material characteristics and their impact on microsphere performance. Moreover, the future application of the embolics under clinical investigation is discussed along with the scientific and regulatory challenges ahead in the field. STATEMENT OF SIGNIFICANCE: Embolization therapy with microspheres is currently used in the clinical setting for the treatment of most liver cancer conditions. The progressive development of added functionalities on embolic microspheres (such as biodegradability, imageability or drug and radiopharmaceutical loading capability) provides further benefit to patients and widens the therapeutic armamentarium for physicians towards truly personalized therapies. Therefore, it is important to analyze the possibilities that advanced biomaterials offer in the field from a clinical translational perspective to outline the future trends in therapeutic embolization.

La frontera con los productos sanitarios en el actual marco legislativo español / The borderline with medical devices in the current Spanish legal framework

Los productos sanitarios abarcan un amplio rango de artículos imprescindibles en la asistencia sanitaria y cuidados de salud. En 2017 se aprobó un nuevo reglamento que los regula en la Unión Europea, y cuya entrada en vigor fue en 2021. En él se especifican su definición legal, su clasificación, sus procedimientos de evaluación de la conformidad, los requerimientos de las investigaciones clínicas que evalúan su seguridad y/o funcionamiento y su base de datos europea. Pese a los intentos por sistematizar la definición legal de producto sanitario en el nuevo reglamento, la determinación de la situación reglamentaria de los artículos conocidos como ‘productos frontera’, para los que diferentes normativas podrían ser de aplicación (como en la frontera con los complementos alimenticios, los cosméticos, los productos de cuidado personal, los biocidas, los equipos de protección individual y los productos de consumo), no está exenta de dificultades. Debido a su relevancia terapéutica, esta revisión profundiza en la frontera entre los medicamentos y los productos sanitarios, y se diferencia de aquellas presentaciones en que medicamentos y productos sanitarios se usan de manera conjunta, sin constituir frontera. Establecer unas definiciones actualizadas, fomentar la transparencia en el sector y prevenir los conflictos de interés, debe motivar a los agentes implicados a la revisión periódica de una normativa en un campo sometido a constante evolución y desarrollo tecnológico.(AU)

Medical devices cover a wide range of products essential for healthcare. In 2017 a new European regulation covering them was approved that fully applies from 2021 onwards. In it, their legal definition, classification, conformity assessment procedures, requirements for the clinical investigations that asses their safety and/or performance, and European database are specified. Despite the efforts for systematizing the legal definition of medical device in the new regulation, the determination of the legal status of devices known as ‘borderline products’, for which different regulations may apply (like in the borderline with food supplements, cosmetics, personal care products, biocides, personal protective equipment and consumer products), is not without difficulties. On account of their therapeutic significance, this review delves into the borderline between medicinal products and medical devices, and differentiates them from presentations where medicinal products and medical devices are used in combination, without constituting a borderline. Establishing updated definitions, promoting transparency in the sector and preventing conflicts of interest should motivate all stakeholders to the periodic review of the regulation in a field in continuous technological evolution and development.(AU)

The combination of medical devices and medicinal products revisited from the new European legal framework.

Medical devices and medicinal products have many similarities in their nature, scope or specific medical purposes, and despite the differences in their principal means of action, they are often used in combination. Indeed, many medicinal products depend on medical devices for their administration, and it is increasingly common for medical devices to contain medicinal substances to support their action. Therefore, the combination of medicinal products and medical devices provides additional benefits for patients. However, their higher technical complexity requires a strengthening of their authorisation and certification requirements. In this regard, more comprehensive requirements and classification rules are introduced by a new European regulation on medical devices that fully applies from May 26th 2021. On account of their therapeutic significance, this review aims at gaining insight into the borderline between medical devices and medicinal products in this new 2021 regulatory framework. For the first time, any item containing a medical device and a medicinal product will have both parts evaluated. Through exemplification of both marketed and investigational devices incorporating medicinal substances and drug-device combinations, the new European requirements and their implications are thoroughly illustrated herein.

Sistemas de liberación prolongada de opioides: Analgesia y dependencia / Extended-release delivery systems of opioids: Analgesia and dependence

El consumo de analgésicos opioides ha experimentado un vertiginoso ascenso en las últimas décadas a nivel mundial. Este elevado consumo está relacionado con el aumento del número de prescripciones de opioides para el tratamiento del dolor crónico y por el aumento de la dependencia a opioides. Los analgésicos opioides tienen una corta duración de acción, siendo necesarias múltiples administraciones para obtener analgesia prolongada. El empleo de formulaciones de liberación prolongada permite espaciar los intervalos posológicos y estabilizar las concentraciones máximas de fármaco en sangre, favoreciendo el cumplimiento terapéutico y reduciendo el riesgo de desarrollar adicción. Sin embargo, estas formulaciones llevan dosis más altas de analgésicos opioides que las hacen más susceptibles de ser alteradas. Así, los avances en tecnología farmacéutica más recientes se han orientado hacia la aplicación de recursos tecnológicos disuasorios de su utilización por vías de administración alternativas con fines no terapéuticos. A su vez, los sistemas de liberación modificada también juegan un papel esencial en el tratamiento de la adicción a opioides: con el desarrollo de sistemas de administración parenteral capaces de prolongar la liberación de opioides durante meses se consigue superar una de las mayores dificultades para alcanzar el éxito del tratamiento en este tipo de pacientes como es el cumplimiento terapéutico. En este artículo se realiza una revisión bibliográfica de los diferentes sistemas de liberación prolongada de opioides que se encuentran actualmente autorizados en Europa y/o en Estados Unidos para el tratamiento del dolor y de la dependencia a opioides

The consumption of opioid analgesics has increased drastically in the last decades worldwide. This high consumption is linked with a surge in the number of opioid prescriptions for the treatment of chronic pain and a surge in opioid misuse and addiction. Opioid analgesics have a short duration of action, making necessary frequent administrations to provide extended analgesia. The use of prolonged-release formulations enables dosing intervals to be spaced out and drug blood levels to be stabilized, improving therapeutic compliance, and reducing the likelihood of developing addiction. However, these formulations contain higher doses of opioid analgesics which make them more susceptible to be manipulated. Hence, the most recent advances in pharmaceutical technology have been oriented towards the application of abuse deterrent technologies aiming to prevent their administration through alternative routes. Moreover, prolonged- release systems also play an essential role in the treatment of opioid addictions with the development of parenteral dosage forms capable of prolonging opioid release for months that help overcome one of the most important drawbacks in achieving treatment success, namely, patient compliance. We review herein the different prolonged-release opioid dosage forms currently approved in Europe and/or the United States for the treatment of pain and opioid dependence

Limitations and Challenges in the Stability of Cysteamine Eye Drop Compounded Formulations.

Accumulation of cystine crystals in the cornea of patients suffering from cystinosis is considered pathognomonic and can lead to severe ocular complications. Cysteamine eye drop compounded formulations, commonly prepared by hospital pharmacy services, are meant to diminish the build-up of corneal cystine crystals. The objective of this work was to analyze whether the shelf life proposed for six formulations prepared following different protocols used in hospital pharmacies is adequate to guarantee the quality and efficacy of cysteamine eye drops. The long-term and in-use stabilities of these preparations were studied using different parameters: content of cysteamine and its main degradation product cystamine; appearance, color and odor; pH and viscosity; and microbiological analysis. The results obtained show that degradation of cysteamine was between 20% and 50% after one month of storage in the long-term stability study and between 35% and 60% in the in-use study. These data confirm that cysteamine is a very unstable molecule in aqueous solution, the presence of oxygen being the main degradation factor. Saturation with nitrogen gas of the solutions offers a means of reducing cysteamine degradation. Overall, all the formulae studied presented high instability at the end of their shelf life, suggesting that their clinical efficacy might be dramatically compromised.

Timeline of Translational Formulation Technologies for Cancer Therapy: Successes, Failures, and Lessons Learned Therefrom.

Over the past few decades, the field of cancer therapy has seen a significant change in the way in which formulations are designed and developed, resulting in more efficient products that allow us to ultimately achieve improved drug bioavailability, efficacy, and safety. However, although many formulations have entered the market, many others have fallen by the wayside leaving the scientific community with several lessons to learn. The successes (and failures) achieved with formulations that have been approved in Europe and/or by the FDA for the three major types of cancer therapy (peptide-based therapy, chemotherapy, and radiotherapy) are reviewed herein, covering the period from the approval of the first prolonged-release system for hormonal therapy to the appearance of the first biodegradable microspheres intended for chemoembolization in 2020. In addition, those products that have entered phase III clinical trials that have been active over the last five years are summarized in order to outline future research trends and possibilities that lie ahead to develop clinically translatable formulations for cancer treatment.

Glioblastoma chemotherapeutic agents used in the clinical setting and in clinical trials: Nanomedicine approaches to improve their efficacy.

Even though substantial advances in understanding glioma pathogenesis have prompted a more rational design of potential therapeutic strategies, glioblastoma multiforme remains an incurable disease with the lowest median overall survival among all malignant brain tumours. Therefore, there is a dire need to find novel drug delivery strategies to improve the current dismal survival outcomes. In this context, nanomedicine offers an appealing alternative as it shows potential to improve brain drug delivery. Accordingly, we here review nanomedicine-based drug delivery strategies tested in orthotopic animal models of glioblastoma intended to improve the efficacy of the drug candidates that are currently used in the clinical setting or that have entered clinical trials for the treatment of glioblastoma multiforme. We also outline the future perspectives of nanotechnology to provide emerging glioblastoma treatment with broad translational clinical potential based on the nanocarriers that have already entered the clinical trials stage for the treatment of malignant glioma.

Controlled Release of Highly Hydrophilic Drugs from Novel Poly(Magnesium Acrylate) Matrix Tablets.

The potential of a new poly(magnesium acrylate) hydrogel (PAMgA) as a pharmaceutical excipient for the elaboration of matrix tablets for the extended release of highly hydrophilic drugs was evaluated. The polymer was synthetized with two different crosslinking degrees that were characterized by FTIR and DSC. Their acute oral toxicity was determined in a mouse model, showing no toxicity at doses up to 10 g/kg. Matrix tablets were prepared using metformin hydrochloride as a model drug and the mechanisms involved in drug release (swelling and/or erosion) were investigated using biorrelevant media. This new hydrogel effectively controlled the release of small and highly hydrophilic molecules as metformin, when formulated in matrix tablets for oral administration. The rate of metformin release from PAMgA matrices was mainly controlled by its diffusion through the gel layer (Fickian diffusion). The swelling capacity and the erosion of the matrix tablets influenced the metformin release rate, that was slower at pH 6.8, where polymer swelling is more intensive, than in gastric medium, where matrix erosion is slightly more rapid. The crosslinking degree of the polymer significantly influenced its swelling capacity in acid pH, where swelling is moderate, but not in intestinal fluid, where swelling is more intense.

Size-Tailored Design of Highly Monodisperse Lipid Nanocapsules for Drug Delivery.

The empirical development of nanocarriers has unfortunately led to high attrition rates in clinical trials. This underpins the importance of the rational design of nanomedicines to achieve efficient disease-driven therapies. Since particle size certainly influences in vivo behaviour, rational disease-driven colloid design can only be achieved by determining the parameters that accurately control their size distribution. To this end, we have thoroughly revisited the parameters that drive the phase-inversion temperature nanoemulsification method to obtain kinetically stable and monodisperse lipid nanocapsules. Notably, we have evidenced that the major parameter driving nanocapsule formation is the oily phase/surfactant ratio and consequently, we have established a linear univariate mathematical model that predicts the particle size distribution for various oily phase-surfactant combinations (R² > 0 99). Furthermore, we have observed that the difference between the HLB values of the surfactants and the triglycerides utilized as oily phase correlates with the steepness of the slope of the linear mathematical model. This model will bring the implementation of size-tailored lipid drug carriers determined by pathophysiological features a step closer. Importantly, this model pioneeringly fits all data available in the literature on size distribution of colloids prepared by low-energy methods and that were originally evaluated following other parameters. Moreover, the nanocapsules have been obtained following a single-step process, with the ensuing potential for a future scale-up in an energetically-efficient manner. These findings will eventually enable nanomedicines to be obtained "on-demand" to meet disease-driven criteria in terms of particle size and will also increase their chances of success.

Cannabidiol Enhances the Passage of Lipid Nanocapsules across the Blood-Brain Barrier Both in Vitro and in Vivo.

Diseases affecting the central nervous system (CNS) should be regarded as a major health challenge due to the current lack of effective treatments given the hindrance to brain drug delivery imposed by the blood-brain barrier (BBB). Since efficient brain drug delivery should not solely rely on passive targeting, active targeting of nanomedicines into the CNS is being explored. The present study is devoted to the development of lipid nanocapsules (LNCs) decorated with nonpsychotropic cannabinoids as pioneering nonimmunogenic brain-targeting molecules and to the evaluation of their brain-targeting ability both in vitro and in vivo. Noticeably, both the permeability experiments across the hCMEC/D3 cell-based in vitro BBB model and the biodistribution experiments in mice consistently demonstrated that the highest brain-targeting ability was achieved with the smallest-sized cannabinoid-decorated LNCs. Importantly, the enhancement in brain targeting achieved with the conjugation of cannabidiol to LNCs outperformed by 6-fold the enhancement observed for the G-Technology (the main brain active strategy that has already entered clinical trials for the treatment of CNS diseases). As the transport efficiency across the BBB certainly determines the efficacy of the treatments for brain disorders, small cannabinoid-decorated LNCs represent auspicious platforms for the design and development of novel therapies for CNS diseases.

Lipid nanocapsules decorated and loaded with cannabidiol as targeted prolonged release carriers for glioma therapy: In vitro screening of critical parameters.

The therapeutic potential of cannabinoids has been truly constrained heretofore due to their strong psychoactive effects and their high lipophilicity. In this context, precisely due to the lack of psychoactive properties, cannabidiol (CBD), the second major component of Cannabis sativa, arises as the phytocannabinoid with the most auspicious therapeutic potential. Hence, the incorporation of CBD in lipid nanocapsules (LNCs) will contribute to overcome the dosing problems associated with cannabinoids. Herein, we have prepared LNCs decorated and loaded with CBD for glioma therapy and screened in vitro their critical parameters. On the one hand, we have encapsulated CBD into the oily core of LNCs to test their in vitro efficacy as extended-release carriers against the human glioblastoma cell line U373MG. The in vitro antitumor effect was highly dependent on the size of LNCs due to its pivotal role in the extent of CBD release. Effectively, a comparison between two differently-sized LNCs (namely, 20-nm and 50-nm sized carriers) showed that the smaller LNCs reduced by 3.0-fold the IC50 value of their 50-nm sized counterparts. On the other hand, to explore the potential of this phytocannabinoid to target any of the cannabinoid receptors overexpressed in glioma cells, we decorated the LNCs with CBD. This functionalization strategy enhanced the in vitro glioma targeting by 3.4-fold in comparison with their equally-sized undecorated counterparts. Lastly, the combination of CBD-loading with CBD-functionalization further reduced the IC50 values. Hence, the potential of these two strategies of CBD incorporation into LNCs deserves subsequent in vivo evaluation.