The Encapsulation of Citicoline within Solid Lipid Nanoparticles Enhances Its Capability to Counteract the 6-Hydroxydopamine-Induced Cytotoxicity in Human Neuroblastoma SH-SY5Y Cells

Citicoline eluting hydrogels for therapeutic contact lenses intended to treat neurodegenerative diabetic ocular diseases

Ophthalmic neurodegenerative diseases related to diabetes, such as glaucoma and retinopathy, are among the major causes of blindness in the world. Citicoline (CIT) in the form of eye drops is currently used for the treatment/prevention of these diseases, which affect the posterior segment of the eye. To ensure the drug penetration into the back of the eye, frequent instillations of highly concentrated drug solutions are required with potential side effects. Drug-loaded soft contact lenses (SCLs) may be an effective alternative to the conventional eye drop treatment, since they may enable a sustained drug release during daily wear, ensuring a higher drug bioavailability, and avoiding drug waste. In this work, one 2-hydroxyethyl methacrylate (HEMA) based hydrogel was functionalised with N-(3-aminopropyl) methacrylamide hydrochloride (APMA), molecularly imprinted with CIT and loaded with the same drug. The material was extensively characterised, in terms of morphology, optical, mechanical, and physical-chemical properties, namely, equilibrium water content, wettability, oxygen and ionic permeability, Young's modulus, shear deformation, transmittance and refractive index, before and after steam sterilisation. Additionally, the tendency of the material to adsorb proteins of the lachrymal fluid was evaluated and its biocompatibility was assessed by irritation and cytotoxicity assays. Comparison with the non-functionalised and non-imprinted hydrogel showed that the modified hydrogel led to a sustained in vitro release of a much higher amount of CIT than the original one, while keeping typical values for physical-chemical properties of SCLs. The drug-loaded material resisted steam sterilisation and proved to be biocompatible, demonstrating adequate properties to be used in therapeutic SCLs for the prophylaxis/treatment of neurodegenerative diabetic ocular diseases. The neuroprotective effect of the released drug was confirmed with tests using porcine retinal explants.

Dopamine and Citicoline-Co-Loaded Solid Lipid Nanoparticles as Multifunctional Nanomedicines for Parkinson's Disease Treatment by Intranasal Administration

This work aimed to evaluate the potential of the nanosystems constituted by dopamine (DA) and the antioxidant Citicoline (CIT) co-loaded in solid lipid nanoparticles (SLNs) for intranasal administration in the treatment of Parkinson disease (PD). Such nanosystems, denoted as DA-CIT-SLNs, were designed according to the concept of multifunctional nanomedicine where multiple biological roles are combined into a single nanocarrier and prepared by the melt emulsification method employing the self-emulsifying Gelucire® 50/13 as lipid matrix. The resulting DA-CIT-SLNs were characterized regarding particle size, surface charge, encapsulation efficiency, morphology, and physical stability. Differential scanning calorimetry, FT-IR, and X ray diffraction studies were carried out to gain information on solid-state features, and in vitro release tests in simulated nasal fluid (SNF) were performed. Monitoring the particle size at two temperatures (4 °C and 37 °C), the size enlargement observed over the time at 37 °C was lower than that observed at 4 °C, even though at higher temperature, color changes occurred, indicative of possible neurotransmitter decomposition. Solid-state studies indicated a reduction in the crystallinity when DA and CIT are co-encapsulated in DA-CIT-SLNs. Interestingly, in vitro release studies in SNF indicated a sustained release of DA. Furthermore, DA-CIT SLNs displayed high cytocompatibility with both human nasal RPMI 2650 and neuronal SH-SY5Y cells. Furthermore, OxyBlot assay demonstrated considerable potential to assess the protective effect of antioxidant agents against oxidative cellular damage. Thus, such protective effect was shown by DA-CIT-SLNs, which constitute a promising formulation for PD application.

Dopamine-loaded chitosan-coated solid lipid nanoparticles as a promise nanocarriers to the CNS

Dopamine is unable to access the central nervous system through the bloodstream. Only its precursor can do so, and with an effectiveness below 100% of the dose administered, as it is metabolized before crossing the blood-brain barrier. In this study, we describe a new solid lipid nanocarrier system designed and developed for dopamine. The nanoparticles were prepared by the melt-emulsification method and then coated with chitosan. The nanocarriers developed had a droplet size of about 250 nm, a polydispersity index of 0.2, a positive surface charge (+30 mV), and a percentage encapsulation efficiency of 36.3 ± 5.4. Transmission and scanning electron microscopy verified uniformity of particle size with spherical morphology. Various types of tests were performed to confirm that the nanoparticles designed are suitable for carrying dopamine through the blood-brain barrier. In vitro tests demonstrated the ability of these nanocarriers to pass through endothelial cell monolayers without affecting their integrity. This study shows that the formulation of dopamine in chitosan-coated solid lipid nanoparticles is a potentially viable formulation strategy to achieve the bioavailability of the drug for the treatment of Parkinson's disease in the central nervous system.

Tackling myelin deficits in neurodevelopmental disorders using drug delivery systems

Interest in myelin and its roles in almost all brain functions has been greatly increasing in recent years, leading to countless new studies on myelination, as a dominant process in the development of cognitive functions. Here, we explore the unique role myelin plays in the central nervous system and specifically discuss the results of altered myelination in neurodevelopmental disorders. We present parallel developmental trajectories involving myelination that correlate with the onset of cognitive impairment in neurodevelopmental disorders and discuss the key challenges in the treatment of these chronic disorders. Recent developments in drug repurposing and nano/micro particle-based therapies are reviewed as a possible pathway to circumvent some of the main hurdles associated with early intervention, including patient's adherence and compliance, side effects, relapse, and faster route to possible treatment of these disorders. The strategy of drug encapsulation overcomes drug solubility and metabolism, with the possibility of drug targeting to a specific compartment, reducing side effects upon systemic administration.

Lipid-based nanoparticles for drug delivery in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder that predominantly affects dopaminergic neurons in the substantia nigra and ventral tegmental area, resulting in symptoms such as tremors, muscle rigidity, bradykinesia, and potential cognitive and affective disturbances. The effective delivery of pharmacological agents to the central nervous system is hindered by various factors, including the restrictive properties of the blood‒brain barrier and blood‒spinal cord barrier, as well as the physicochemical characteristics of the drugs. Traditional drug delivery methods may not provide the therapeutic concentrations necessary for functional restoration in PD patients. However, lipid-based nanoparticles (NPs) offer new possibilities for enhancing the bioavailability of established treatment regimens and developing innovative therapies that can modify the course of the disease. This review provides a concise overview of recent advances in lipid-based NP strategies aimed at mitigating specific pathological mechanisms relevant to PD progression. This study also explores the potential applications of nanotechnological innovations in the development of advanced treatment modalities for individuals with PD.

Preparation of Solid Lipid Nanoparticles of Cinnamaldehyde and Determination of Sustained Release Capacity

Natural plant essential oils cannot be applied on a large scale due to their high volatility, easy deactivation, etc. This study provides a new method to prepare a long-lasting, slow-release essential oil product by taking advantage of solid lipid nanoparticles, which will provide a scientific guideline for the future essential oil industry. In this article, solid lipid cinnamaldehyde nanoparticles were prepared using an ultrahigh-pressure homogenization method. SLN-CA with a particle size of 74 ± 5 nm, PDI of 0.153 ± 0.032, and zeta potential of -44.36 ± 2.2 mV was screened using an additional amount of cinnamaldehyde, the ratio of oil phase components, and the homogenization pressure and number of times as factors. Differential thermal analysis and spectroscopy demonstrated that cinnamaldehyde was successfully encapsulated inside the nanoparticles. The change in particle size of nanoparticles under different conditions and times was used as an indicator of stability. The stability of the finished nanoparticles was evaluated. The retention and slow-release ability of cinnamaldehyde were investigated using the concentration of cinnamaldehyde in nanoparticles as an indicator. The results showed that after 15 days, SLN-CA retained 52.36% of the concentration from 15 days prior. The bacterial inhibition test shows that SLN-CA can inhibit bacteria.