Cannabinoid-Based Ocular Therapies and Formulations.

The interest in the pharmacological applications of cannabinoids is largely increasing in a wide range of medical areas. Recently, research on its potential role in eye conditions, many of which are chronic and/or disabling and in need of new alternative treatments, has intensified. However, due to cannabinoids' unfavorable physicochemical properties and adverse systemic effects, along with ocular biological barriers to local drug administration, drug delivery systems are needed. Hence, this review focused on the following: (i) identifying eye disease conditions potentially subject to treatment with cannabinoids and their pharmacological role, with emphasis on glaucoma, uveitis, diabetic retinopathy, keratitis and the prevention of Pseudomonas aeruginosa infections; (ii) reviewing the physicochemical properties of formulations that must be controlled and/or optimized for successful ocular administration; (iii) analyzing works evaluating cannabinoid-based formulations for ocular administration, with emphasis on results and limitations; and (iv) identifying alternative cannabinoid-based formulations that could potentially be useful for ocular administration strategies. Finally, an overview of the current advances and limitations in the field, the technological challenges to overcome and the prospective further developments, is provided.

Cannabinoids as Emergent Therapy Against COVID-19.

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory distress syndrome coronavirus 2 (SARS-Cov-2), was identified for the first time in late 2019 in China, resulting in a global pandemic of massive impact. Despite a fast development and implementation of vaccination strategies, and the scouting of several pharmacological treatments, alternative effective treatments are still needed. In this regard, cannabinoids represent a promising approach because they have been proven to exhibit several immunomodulatory, anti-inflammatory, and antiviral properties in COVID-19 disease models and related pathological conditions. This mini-review aims at providing a practical brief overview of the potential applications of cannabinoids so far identified for the treatment and prevention of COVID-19, finally considering key aspects related to their technological and clinical implementation.

Potential use for chronic pain: Poly(Ethylene Glycol)-Poly(Lactic-Co-Glycolic Acid) nanoparticles enhance the effects of Cannabis-Based terpenes on calcium influx in TRPV1-Expressing cells.

The objective of these in vitro studies was to investigate the impact of the encapsulation of three cannabis-based terpenes, namely ß-myrcene (MC), ß-caryophyllene (CPh), and nerolidol (NL), on their potential efficacy in pain management. Terpene-encapsulated poly(ethylene glycol)-poly(lactic-co-glycolic acid) nanoparticles (PEG-PLGA NPs) were prepared by an emulsion-solvent evaporation method. The terpene-loaded NPs were examined in HEK293 cells that express the nociceptive transient receptor potential vanilloid-1 (TRPV1), an ion channel involved in pain perception. TRPV1 activation was assessed by monitoring calcium influx kinetics over 1 h in cells pre-treated with the fluorescent indicator Fluo-4. In addition, the fluorescence intensity changes induced by the NPs in living cells were also explored by a fluorescence microscope. Furthermore, the cytotoxicity of the terpene-loaded NPs was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-3,5-diphenyl tetrazolium bromide (MTT) proliferation assay. The terpene-loaded NPs had a diameter in the range of 250-350 nm and a zeta potential of approximately -20 mV. The encapsulation efficiency was 18.5%, 51.3%, and 60.3% for MC, NL, and CPh NPs, respectively. The nano-formulations significantly increased the fluorescence intensity in comparison with free terpenes. Furthermore, combinations of terpene-loaded NPs produced significantly higher calcium responses when compared to combinations of free terpenes. Similar findings were shown by the fluorescence images. In conclusion, the terpene-PLGA NPs can be promising therapeutics for more effective pain management.

Receptor-targeted nanoparticles modulate cannabinoid anticancer activity through delayed cell internalization.

Δ9-tetrahydrocannabinol (Δ9-THC) is known for its antitumor activity and palliative effects. However, its unfavorable physicochemical and biopharmaceutical properties, including low bioavailability, psychotropic side effects and resistance mechanisms associated to dosing make mandatory the development of successful drug delivery systems. In this work, transferring (Tf) surface-modified Δ9-THC-loaded poly(lactide-co-glycolic) nanoparticles (Tf-THC-PLGA NPs) were proposed and evaluated as novel THC-based anticancer therapy. Furthermore, in order to assess the interaction of both the nanocarrier and the loaded drug with cancer cells, a double-fluorescent strategy was applied, including the chemical conjugation of a dye to the nanoparticle polymer along with the encapsulation of either a lipophilic or a hydrophilic dye. Tf-THC PLGA NPs exerted a cell viability decreased down to 17% vs. 88% of plain nanoparticles, while their internalization was significantly slower than plain nanoparticles. Uptake studies in the presence of inhibitors indicated that the nanoparticles were internalized through cholesterol-associated and clathrin-mediated mechanisms. Overall, Tf-modification of PLGA NPs showed to be a highly promising approach for Δ9-THC-based antitumor therapies, potentially maximizing the amount of drug released in a sustained manner at the surface of cells bearing cannabinoid receptors.

Evaluation of poly (lactic-co-glycolic acid) nanoparticles to improve the therapeutic efficacy of paclitaxel in breast cancer.

Introduction: Paclitaxel (PTX) is a cornerstone in the treatment of breast cancer, the most common type of cancer in women. However, this drug has serious limitations, including lack of tissue-specificity, poor water solubility, and the development of drug resistance. The transport of PTX in a polymeric nanoformulation could overcome these limitations. Methods: In this study, PLGA-PTX nanoparticles (NPs) were assayed in breast cancer cell lines, breast cancer stem cells (CSCs) and multicellular tumor spheroids (MTSs) analyzing cell cycle, cell uptake (Nile Red-NR-) and α-tubulin expression. In addition, PLGA-PTX NPs were tested in vivo using C57BL/6 mice, including a biodistribution assay. Results: PTX-PLGA NPs induced a significant decrease in the PTX IC50 of cancer cell lines (1.31 and 3.03-fold reduction in MDA-MB-231 and E0771 cells, respectively) and CSCs. In addition, MTSs treated with PTX-PLGA exhibited a more disorganized surface and significantly higher cell death rates compared to free PTX (27.9% and 16.3% less in MTSs from MCF-7 and E0771, respectively). PTX-PLGA nanoformulation preserved PTX's mechanism of action and increased its cell internalization. Interestingly, PTX-PLGA NPs not only reduced the tumor volume of treated mice but also increased the antineoplastic drug accumulation in their lungs, liver, and spleen. In addition, mice treated with PTX-loaded NPs showed blood parameters similar to the control mice, in contrast with free PTX. Conclusion: These results suggest that our PTX-PLGA NPs could be a suitable strategy for breast cancer therapy, improving antitumor drug efficiency and reducing systemic toxicity without altering its mechanism of action.

A novel nanoformulation of PLGA with high non-ionic surfactant content improves in vitro and in vivo PTX activity against lung cancer.

Paclitaxel (PTX), a chemotherapy agent widely used to treat lung cancer, is characterised by high toxicity, low bioavailability and the need to use of excipients with serious side effects that limit its use. Paclitaxel encapsulation into nanoparticles (NPs) generates drug pharmacokinetic and pharmacodynamic advantages compared to free PTX. In this context, a NP carrier formed from a copolymer of lactic acid and glycolic acid (PLGA) has demonstrated high biocompatibility and low toxicity and therefore being approved by FDA to be used in humans. We synthesised a new PLGA NP and loaded it with PTX to improve drug efficacy and reduce side effects. This nanoformulation showed biocompatibility and no toxicity to human immune system. These NPs favor the intracellular uptake of PTX and enhance its antitumor effect in human and murine lung cancer cells, with up to 3.6-fold reductions in the PTX's IC50. Although PLGA NPs did not show any inhibitory capacity against P-glycoprotein, they increased the antitumor activity of PTX in cancer stem cells. Treatment with PLGA-PTX NPs increased apoptosis and significantly reduced the volume of the tumorspheres derived from A549 and LL2 cells by up to 36% and 46.5%, respectively. Biodistribution studies with PLGA-PTX NPs revealed an increase in drug circulation time, as well as a greater accumulation in lung and brain tissues compared to free PTX. Low levels of PTX were detected in the dorsal root ganglion with PLGA-PTX NPs, which could exert a protective effect against peripheral neuropathy. In vivo treatment with PLGA-PTX NPs showed a greater decrease in tumor volume (44.6%) in immunocompetent mice compared to free PTX (24.4%) and without increasing the toxicity of the drug. These promising results suggest that developed nanosystem provide a potential strategy for improving the chemotherapeutic effect and reducing the side effects of PTX.

Potential Use of Nanomedicine for the Anti-inflammatory Treatment of Neurodegenerative Diseases.

Neurodegenerative diseases, like Alzheimer´s and Parkinson´s disease, are a group of disorders that have in common their increasingly high prevalence along with the shortage of effective treatments. In addition, the scientific community faces the challenge of getting the drugs used in these treatments to cross the blood-brain barrier (BBB) and reach the brain in sufficient concentration to be able to exert its effect. Hence, researchers across multiple disciplines are working together in order to improve the ability of therapeutics to penetrate the BBB. In this sense, the use of nanomedicine, nanoscale structures for drug delivery, exhibits a really high therapeutic potential in the field of neurodegenerative diseases therapy. Since there is new evidence that neuroinflammation produced by reactive microglia contributes to the activation and pathogenesis of neurological disorders, many investigations focus on the identification of new targets whose inhibition can reduce, totally or partially, microglial activation. This review analyzes a wide variety of compounds as possible candidates to achieve this target, from compounds with a natural origin to anti-diabetics, antidepressants, antibiotics and hormones. We also discuss the different strategies to enhance the capacity of these compounds to cross the BBB. Although this review focuses on PLGA nanoparticles as one of the most versatile drug delivery nanosystems, we also describe other strategies, such as direct intranasal administration (nose-tobrain), novel viral vectors and novel implanted catheters.

Single oral dose of cannabinoid derivate loaded PLGA nanocarriers relieves neuropathic pain for eleven days.

Neuropathic pain, resistant to opiates and other drugs, is a chronic/persistent state with a complex treatment and often poor efficacy. In this scenario, cannabinoids are increasingly regarded as a genuine alternative. In this paper, and in an experimental animal model of neuropathic pain, we studied the efficacy of three kinds of PLGA nanoparticles containing synthetic cannabinoid CB13: (i) plain nanoparticles (PLGA); (ii) particles coated with PEG chains (PLGA+PEG) and (iii) particles possessing hydrophilic surfaces obtained by covalently binding PEG chains (PLGA-PEG). The optimized formulation, CB13-PLGA-PEG, showed high drug loading (13%) and small size (<300nm) with a narrow distribution and controlled surface properties (near-neutral zeta potential and stable PEG corona). Animal nociceptive behavioral studies were conducted by paw pressure and acetone tests. Versus the free CB13, CB13-PLGA-PEG nanoparticles showed a very noticeable analgesic efficacy with the longest sustained pain-relieving effect, lasting up to eleven days after one oral dose.

Engineering of Δ9-tetrahydrocannabinol delivery systems based on surface modified-PLGA nanoplatforms.

The objective of this work is to develop a nanoplatform that can potentiate the oral administration of Δ9-tetrahidrocannabinol, a highly lipophilic active agent with very promising antiproliferative and antiemetic activities. To that aim, colloidal carriers based on the biodegradable and biocompatible poly(D,L-lactide-co-glycolide) were investigated. Such delivery systems were prepared by nanoprecipitation, and nanoparticle engineering further involved surface modification with a poly(ethylene glycol), chitosan, or poly(ethylene glycol)-chitosan shells to assure the greatest uptake by intestinal cells and to minimize protein adsorption. Characterization of the nanoplatforms included particle geometry (size and shape), electrophoretic properties (surface charge). Δ9-tetrahydrocannabinol vehiculization capabilities (loading and release), blood compatibility, and cellular uptake and cytotoxicity. Results were satisfactorily used to define the optimum engineering conditions to formulate surface modified nanoparticles for the efficient oral administration of Δ9-tetrahydrocannabinol. To the best of our knowledge, this is the first time that biocompatible polymeric nanoparticles have been formulated for Δ9-tetrahydrocannabinoldelivery.

Enhanced cellular uptake and biodistribution of a synthetic cannabinoid loaded in surface-modified poly(lactic-co-glycolic acid) nanoparticles.

This article aimed to produce, characterize and evaluate different surface-modified naphthalen-1-yl-(4-pentyloxynaphthalen-1-yl)methanone (CB13) loaded poly(lactic-co-glycolic acid) nanoparticles in order to improve their oral absorption and in vivo biodistribution. Plain and surface-modified PLGA nanoparticles were successfully prepared using a nanoprecipitation method. Chitosan, Eudragit RS, lecithin and vitamin E were used as surface modifying agents. The NPs were evaluated in terms of mean diameter and size distribution, zeta potential, morphology, drug loading, drug release profiles, mucoadhesive properties, in vitro cell viability and uptake and in vivo biodistribution. Mean particle size distributions in the range of 253-344 nm, spherical shape and controlled zeta potential values were observed depending on the additive employed. High values of entrapment efficiency were obtained for all the formulations. Lecithin and vitamin E modified particles showed higher release rates when compared to the rest of formulations. A clear improvement in ex vivo mucoadhesion properties was observed in the case of chitosan- and Eudragit RS-modified nanoparticles. Chitosan-poly(lactic-co-glycolic acid) nanoparticles showed the highest uptake values on Caco-2 cells. Biodistribution assays proved that most of the particles were accumulated in liver and spleen. An important goal has been achieved in this investigation: CB13, a highly lipophilic drug with low water solubility, can reach the interior of cells more efficiently when it is included in these surface-modified polymeric carriers.

Biocompatible gemcitabine-based nanomedicine engineered by Flow Focusing for efficient antitumor activity.

We investigated the incorporation of gemcitabine into a colloidal carrier based on the biodegradable and biocompatible poly(d,l-lactide-co-glycolide) (PLGA) to optimize its anticancer activity. Two synthesis techniques (double emulsion/solvent evaporation, and Flow Focusing) were compared in terms of particle geometry, electrophoretic properties (surface charge), gemcitabine vehiculization capabilities (drug loading and release), blood compatibility, and in vitro antitumor activity. To the best of our knowledge, the second formulation methodology (Flow Focusing) has never been applied to the synthesis of gemcitabine-loaded PLGA particles. With the aim of achieving the finest (nano)formulation, experimental parameters associated to these preparation procedures were analyzed. The electrokinetics of the particles suggested that the chemotherapy agent was incorporated into the polymeric matrix. Blood compatibility was demonstrated in vitro. Flow Focusing led to a more appropriate geometry, higher gemcitabine loading and a sustained release profile. In addition, the cytotoxicity of gemcitabine-loaded particles prepared by Flow Focusing was tested in MCF-7 human breast adenocarcinoma cells, showing significantly greater antitumor activity compared to the free drug and to the gemcitabine-loaded particles synthesized by double emulsion/solvent evaporation. Thus, it has been identified the more adequate formulation conditions in the engineering of gemcitabine-loaded PLGA nanoparticles for the effective treatment of tumours.

Cannabinoid derivate-loaded PLGA nanocarriers for oral administration: formulation, characterization, and cytotoxicity studies.

CB13 (1-Naphthalenyl[4-(pentyloxy)-1-naphthalenyl]methanone)-loaded poly(lactic-co-glycolic acid) nanoparticles (NPs) were produced by nanoprecipitation and tested for their in vitro release behavior and in vitro cytotoxicity assays. The effects of several formulation parameters such as polymer type, surfactant concentration, and initial drug amount were studied. NPs had a particle size 90-300 nm in diameter. Results obtained show that the main influence on particle size was the type of polymer employed during the particle production: the greater the hydrophobicity, the smaller the particle size. In terms of encapsulation efficiency (%), high values were achieved (∼68%-90%) for all formulations prepared due to the poor solubility of CB13 in the external aqueous phase. Moreover, an inverse relationship between release rate and NP size was found. On the other hand, low molecular weight and low lactide content resulted in a less hydrophobic polymer with increased rates of water absorption, hydrolysis, and erosion. NPs showed no cytotoxicity and may be considered to be appropriate for drug-delivery purposes.

Use of Flow Focusing® technology to produce tobramycin-loaded PLGA microparticles for pulmonary drug delivery.

In the present work, a promising formulation of an inhaled powder based on tobramycin-loaded microparticles has been reported. Biodegradable microparticles with controlled diameters in the range of 1-5 µm and narrow size distribution were synthesized by Flow Focusing® technology. Particles production was planned and optimized with the aid of a well-established mathematic model. Close agreements between theoretical an experimental sizes were obtained. To deliver a high payload of tobramycin to the lungs, the influence of surfactant concentration, polymer-drug ratio and initial drug concentration were investigated. For chosen formulations, drug delivery profiles were also studied. In some cases, it was found a controlled drug delivery for more than ten days, which could represent an important advance in the treatment of chronic lung infections. Other particles factors affecting deposit of an aerosol in the lung were also studied, such as surface charge and density.

Flow Focusing: a versatile technology to produce size-controlled and specific-morphology microparticles.

The Flow Focusing platform is especially advantageous for micro- and nanoparticle production. This versatile technique is amenable to designing the size, surface treatment and internal topology of the particles; mechanical stresses are minimal-an optimal feature for the manipulation of delicate substances. Multiplexing and high-rate production are readily implemented. Adaptive operational design can lead, in one single step, to finely tuned microcapsules encasing different products within a targeted morphology. This achievement is of great significance for most microcapsule applications in the biosciences (for example, drug delivery, cell encapsulation, and the production of bead arrays).