Supramolecular eutectogel as new oral paediatric delivery system to enhance benznidazole bioavailability.

Benznidazole (BNZ) serves as the primary drug for treating Chagas Disease and is listed in the WHO Model List of Essential Medicines for Children. Herein, a new child-friendly oral BNZ delivery platform is developed in the form of supramolecular eutectogels (EGs). EGs address BNZ's poor oral bioavailability and provide a flexible twice-daily dose in stick-pack format. This green and sustainable formulation strategy relies on the gelation of drug-loaded Natural Deep Eutectic Solvents (NaDES) with xanthan gum (XG) and water. Specifically, choline chloride-based NaDES form stable and biocompatible 5 mg/mL BNZ-loaded EGs. Rheological and Low-field NMR investigations indicate that EGs are viscoelastic materials comprised of two co-existing regions in the XG network generated by different crosslink distributions between the biopolymer, NaDES and water. Remarkably, the shear modulus and relaxation spectrum of EGs remain unaffected by temperature variations. Upon dilution with simulated gastrointestinal fluids, EGs results in BNZ supersaturation, serving as the primary driving force for its absorption. Interestingly, after oral administration of EGs to rats, drug bioavailability increases by 2.6-fold, with a similar increase detected in their cerebrospinal fluid. The noteworthy correlation between in vivo results and in vitro release profiles confirms the efficacy of EGs in enhancing both peripheral and central BNZ oral bioavailability.

Characterization and Hydrolysis Studies of a Prodrug Obtained as Ester Conjugate of Geraniol and Ferulic Acid by Enzymatic Way.

Ferulic acid (Fer) and geraniol (Ger) are natural compounds whose antioxidant and anti-inflammatory activity confer beneficial properties, such as antibacterial, anticancer, and neuroprotective effects. However, the short half-lives of these compounds impair their therapeutic activities after conventional administration. We propose, therefore, a new prodrug (Fer-Ger) obtained by a bio-catalyzed ester conjugation of Fer and Ger to enhance the loading of solid lipid microparticles (SLMs) designed as Fer-Ger delivery and targeting systems. SLMs were obtained by hot emulsion techniques without organic solvents. HPLC-UV analysis evidenced that Fer-Ger is hydrolyzed in human or rat whole blood and rat liver homogenates, with half-lives of 193.64 ± 20.93, 20.15 ± 0.75, and 3.94 ± 0.33 min, respectively, but not in rat brain homogenates. Studies on neuronal-differentiated mouse neuroblastoma N2a cells incubated with the reactive oxygen species (ROS) inductor H2O2 evidenced the Fer-Ger ability to prevent oxidative injury, despite the fact that it appears ROS-promoting. The amounts of Fer-Ger encapsulated in tristearin SLMs, obtained in the absence or presence of glucose, were 1.5 ± 0.1%, allowing the control of the prodrug release (glucose absence) or to sensibly enhance its water dissolution rate (glucose presence). These new "green" carriers can potentially prolong the beneficial effects of Fer and Ger or induce neuroprotection as nasal formulations.

Dimeric ferulic acid conjugate as a prodrug for brain targeting after nasal administration of loaded solid lipid microparticles.

OBJECTIVE: Ferulic acid (Fer) displays antioxidant/anti-inflammatory properties useful against neurodegenerative diseases. To increase Fer uptake and its central nervous system residence time, a dimeric prodrug, optimizing the Fer loading on nasally administrable solid lipid microparticles (SLMs), was developed. METHODS: The prodrug was synthesized as Fer dimeric conjugate methylated on the carboxylic moiety. Prodrug antioxidant/anti-inflammatory properties and ability to release Fer in physiologic environments were evaluated. Tristearin or stearic acid SLMs were obtained by hot emulsion technique. In vivo pharmacokinetics were quantified by HPLC. RESULTS: The prodrug was able to release Fer in physiologic environments (whole blood and brain homogenates) and induce in vitro antioxidant/anti-inflammatory effects. Its half-life in rats was 18.0 ± 1.9 min. Stearic acid SLMs, exhibiting the highest prodrug loading and dissolution rate, were selected for nasal administration to rats (1 mg/kg dose), allowing to obtain high prodrug bioavailability and prolonged residence in the cerebrospinal fluid, showing AUC (Area Under Concentration) values (108.5 ± 3.9 µg∙mL-1∙min) up to 30 times over those of Fer free drug, after its intravenous/nasal administration (3.3 ± 0.3/5.16 ± 0.20 µg∙mL-1∙min, respectively) at the same dose. Chitosan presence further improved the prodrug brain uptake. CONCLUSIONS: Nasal administration of prodrug-loaded SLMs can be proposed as a noninvasive approach for neurodegenerative disease therapy.

Conjugation, Prodrug, and Co-Administration Strategies in Support of Nanotechnologies to Improve the Therapeutic Efficacy of Phytochemicals in the Central Nervous System.

Phytochemicals, produced as secondary plant metabolites, have shown interesting potential therapeutic activities against neurodegenerative diseases and cancer. Unfortunately, poor bioavailability and rapid metabolic processes compromise their therapeutic use, and several strategies are currently proposed for overcoming these issues. The present review summarises strategies for enhancing the central nervous system's phytochemical efficacy. Particular attention has been paid to the use of phytochemicals in combination with other drugs (co-administrations) or administration of phytochemicals as prodrugs or conjugates, particularly when these approaches are supported by nanotechnologies exploiting conjugation strategies with appropriate targeting molecules. These aspects are described for polyphenols and essential oil components, which can improve their loading as prodrugs in nanocarriers, or be part of nanocarriers designed for targeted co-delivery to achieve synergistic anti-glioma or anti-neurodegenerative effects. The use of in vitro models, able to simulate the blood-brain barrier, neurodegeneration or glioma, and useful for optimizing innovative formulations before their in vivo administration via intravenous, oral, or nasal routes, is also summarised. Among the described compounds, quercetin, curcumin, resveratrol, ferulic acid, geraniol, and cinnamaldehyde can be efficaciously formulated to attain brain-targeting characteristics, and may therefore be therapeutically useful against glioma or neurodegenerative diseases.

Pharmacokinetic and Permeation Studies in Rat Brain of Natural Compounds Led to Investigate Eugenol as Direct Activator of Dopamine Release in PC12 Cells.

Eugenol, cinnamaldehyde and D-limonene, the main components of natural essential oils, are endowed with antioxidant and anti-inflammatory properties which allow them to induce beneficial effects on intestinal, cardiac and neuronal levels. In order to characterize their pharmacokinetic profiles and aptitude to permeate in the central nervous system after intravenous and oral administration to rats, new analytical procedures, easily achievable with HPLC-UV techniques, were developed. The terminal half-lives of these compounds range from 12.4 ± 0.9 (D-limonene) and 23.1 ± 1.6 min (cinnamaldehyde); their oral bioavailability appears relatively poor, ranging from 4.25 ± 0.11% (eugenol) to 7.33 ± 0.37% (cinnamaldehyde). Eugenol evidences a marked aptitude to permeate in the cerebrospinal fluid (CSF) of rats following both intravenous and oral administrations, whereas cinnamaldehyde appears able to reach the CSF only after intravenous administration; limonene is totally unable to permeate in the CSF. Eugenol was therefore recruited for in vitro studies of viability and time-/dose-dependent dopamine release in neuronal differentiated PC12 cells (a recognized cellular model mimicking dopaminergic neurons), evidencing its ability to increase cell viability and to induce dopamine release according to a U-shaped time-course curve. Moreover, concentration-response data suggest that eugenol may induce beneficial effects against Parkinson's disease after oral administration.

Improving in vivo oral bioavailability of a poorly soluble drug: a case study on polymeric versus lipid nanoparticles.

Poorly soluble drugs must be appropriately formulated for clinical use to increase the solubility, dissolution rate, and permeation across the intestinal epithelium. Polymeric and lipid nanocarriers have been successfully investigated for this aim, and their physicochemical properties, and in particular, the surface chemistry, significantly affect the pharmacokinetics of the drugs after oral administration. In the present study, PLGA nanoparticles (SS13NP) and solid lipid nanoparticles (SS13SLN) loaded with SS13, a BCS IV model drug, were prepared. SS13 bioavailability following the oral administration of SS13 (free drug), SS13NP, or SS13SLN was compared. SS13NP had a suitable size for oral administration (less than 300 nm), a spherical shape and negative zeta potential, similarly to SS13SLN. On the contrary, SS13NP showed higher physical stability but lower encapsulation efficiency (54.31 ± 6.66%) than SS13SLN (100.00 ± 3.11%). When orally administered (0.6 mg of drug), SS13NP showed higher drug AUC values with respect to SS13SLN (227 ± 14 versus 147 ± 8 µg/mL min), with higher Cmax (2.47 ± 0.14 µg/mL versus 1.30 ± 0.15 µg/mL) reached in a shorter time (20 min versus 60 min). Both formulations induced, therefore, the oral bioavailability of SS13 (12.67 ± 1.43% and 4.38 ± 0.39% for SS13NP and SS12SLN, respectively) differently from the free drug. These in vivo results confirm that the chemical composition of nanoparticles significantly affects the in vivo fate of a BCS IV drug. Moreover, PLGA nanoparticles appear more efficient and rapid than SLN in allowing drug absorption and transport to systemic circulation.

Effects of Microencapsulated Ferulic Acid or Its Prodrug Methyl Ferulate on Neuroinflammation Induced by Muramyl Dipeptide.

Ferulic acid (Fer) is known for its antioxidant and anti-inflammatory activities, which are possibly useful against neurodegenerative diseases. Despite the ability of Fer to permeate the brain, its fast elimination from the body does not allow its therapeutic use to be optimized. The present study proposes the preparation and characterization of tristearin- or stearic acid-based solid lipid microparticles (SLMs) as sustained delivery and targeting systems for Fer. The microparticles were produced by conventional hot emulsion techniques. The synthesis of the methyl ester of Fer (Fer-Me) allowed its encapsulation in the SLMs to increase. Fer-Me was hydrolyzed to Fer in rat whole blood and liver homogenate, evidencing its prodrug behavior. Furthermore, Fer-Me displayed antioxidant and anti-inflammatory properties. The amount of encapsulated Fer-Me was 0.719 ± 0.005% or 1.507 ± 0.014% in tristearin or stearic acid SLMs, respectively. The tristearin SLMs were able to control the prodrug release, while the stearic acid SLMs induced a significant increase of its dissolution rate in water. Jointly, the present results suggest that the tristearin SLMs loaded with Fer-Me could be a potential formulation against peripheral neuropathic pain; conversely, the stearic acid SLMs could be useful for Fer-Me uptake in the brain after nasal administration of the formulation.

Effect of a Fiber D-Limonene-Enriched Food Supplement on Intestinal Microbiota and Metabolic Parameters of Mice on a High-Fat Diet.

Several studies showed that D-Limonene can improve metabolic parameters of obese mice via various mechanisms, including intestinal microbiota modulation. Nevertheless, its effective doses often overcome the acceptable daily intake, rising concerns about toxicity. In this study we administered to C57BL/6 mice for 84 days a food supplement based on D-Limonene, adsorbed on dietary fibers (FLS), not able to reach the bloodstream, to counteract the metabolic effects of a high-fat diet (HFD). Results showed that daily administration of D-Limonene (30 and 60 mg/kg body weight) for 84 days decreased the weight gain of HFD mice. After 84 days we observed a statistically significant difference in weight gain in the group of mice receiving the higher dose of FLS compared to HFD mice (35.24 ± 4.56 g vs. 40.79 ± 3.28 g, p < 0.05). Moreover, FLS at both doses tested was capable of lowering triglyceridemia and also fasting glycemia at the higher dose. Some insights on the relevant fatty acid changes in hepatic tissues were obtained, highlighting the increased polyunsaturated fatty acid (PUFA) levels even at the lowest dose. FLS was also able to positively modulate the gut microbiota and prevent HFD-associated liver steatosis in a dose-dependent manner. These results demonstrate that FLS at these doses can be considered non-toxic and could be an effective tool to counteract diet-induced obesity and ameliorate metabolic profile in mice.

Targeting Systems to the Brain Obtained by Merging Prodrugs, Nanoparticles, and Nasal Administration.

About 40 years ago the lipidization of hydrophilic drugs was proposed to induce their brain targeting by transforming them into lipophilic prodrugs. Unfortunately, lipidization often transforms a hydrophilic neuroactive agent into an active efflux transporter (AET) substrate, with consequent rejection from the brain after permeation across the blood brain barrier (BBB). Currently, the prodrug approach has greatly evolved in comparison to lipidization. This review describes the evolution of the prodrug approach for brain targeting considering the design of prodrugs as active influx substrates or molecules able to inhibit or elude AETs. Moreover, the prodrug approach appears strategic in optimization of the encapsulation of neuroactive drugs in nanoparticulate systems that can be designed to induce their receptor-mediated transport (RMT) across the BBB by appropriate decorations on their surface. Nasal administration is described as a valuable alternative to obtain the brain targeting of drugs, evidencing that the prodrug approach can allow the optimization of micro or nanoparticulate nasal formulations of neuroactive agents in order to obtain this goal. Furthermore, nasal administration is also proposed for prodrugs characterized by peripheral instability but potentially able to induce their targeting inside cells of the brain.

Versatile Nasal Application of Cyclodextrins: Excipients and/or Actives?

Cyclodextrins (CDs) are oligosaccharides widely used in the pharmaceutical field. In this review, a detailed examination of the literature of the last two decades has been made to understand the role of CDs in nasal drug delivery systems. In nasal formulations, CDs are used as pharmaceutical excipients, as solubilizers and absorption promoters, and as active ingredients due to their several biological activities (antiviral, antiparasitic, anti-atherosclerotic, and neuroprotective). The use of CDs in nasal formulations allowed obtaining versatile drug delivery systems intended for local and systemic effects, as well as for nose-to-brain transport of drugs. In vitro and in vivo models currently employed are suitable to analyze the effects of CDs in nasal formulations. Therefore, CDs are versatile pharmaceutical materials, and due to the continual synthesis of new CDs derivatives, the research on the new nasal applications is an interesting field evolving in the coming years, to which Italian research will still contribute.

Nasal biocompatible powder of Geraniol oil complexed with cyclodextrins for neurodegenerative diseases: physicochemical characterization and in vivo evidences of nose to brain delivery.

Recently, many studies have shown that plant metabolites, such as geraniol (GER), may exert anti-inflammatory effects in neurodegenerative diseases and, in particular, Parkinson's disease (PD) models. Unfortunately, delivering GER to the CNS via nose-to-brain is not feasible due to its irritant effects on the mucosae. Therefore, in the present study ß-cyclodextrin (ßCD) and its hydrophilic derivative hydroxypropyl-beta-cyclodextrin (HPßCD) were selected as potential carriers for GER nose-to-brain delivery. Inclusion complexes were formulated and the biocompatibility with nasal mucosae and drug bioavailability into cerebrospinal fluid (CSF) were studied in rats. It has been demonstrated by DTA, FT-IR and NMR analyses that both the CDs were able to form 1:1 GER-CD complexes, arising long-term stable powders after the freeze-drying process. GER-HPßCD-5 and GER-ßCD-2 complexes exhibited comparable results, except for morphology and solubility, as demonstrated by SEM analysis and phase solubility study, respectively. Even though both complexes were able to directly and safely deliver GER to CNS, GER-ßCD-2 displayed higher ability in releasing GER in the CSF. In conclusion, ßCD complexes can be considered a very promising tool in delivering GER into the CNS via nose-to-brain route, preventing GER release into the bloodstream and ensuring the integrity of the nasal mucosa.

Solid Lipid Nanoparticles as Formulative Strategy to Increase Oral Permeation of a Molecule Active in Multidrug-Resistant Tuberculosis Management.

The role of mycobacterial efflux pumps in drug-resistant tuberculosis has been widely reported. Recently, a new compound, named SS13, has been synthesized, and its activity as a potential efflux inhibitor has been demonstrated. In this work, the chemical-physical properties of the SS13 were investigated; furthermore, a formulative study aimed to develop a formulation suitable for oral administration was performed. SS13 shows nonintrinsic antitubercular activity, but it increases the antitubercular activity of all the tested drugs on several strains. SS13 is insoluble in different simulated gastrointestinal media; thus, its oral absorption could be limited. Solid lipid nanoparticles (SLNs) were, therefore, developed by using two different lipids, Witepsol and/or Gelucire. Nanoparticles, having a particle size (range of 200-450 nm with regards to the formulation composition) suitable for intestinal absorption, are able to load SS13 and to improve its permeation through the intestinal mucosa compared to the pure compound. The cytotoxicity is influenced by the concentration of nanoparticles administered. These promising results support the potential application of these nanocarriers for increasing the oral permeation of SS13 in multidrug-resistant tuberculosis management.

Cancer stem cells and nanomedicine: new opportunities to combat multidrug resistance?

'Multidrug resistance' (MDR) is a difficult challenge for cancer treatment. The combined role of cytochrome P450 enzymes (CYPs) and active efflux transporters (AETs) in cancer cells appears relevant in inducing MDR. Chemotherapeutic drugs can be substrates of both CYPs and AETs and CYP inducers or inhibitors can produce the same effects on AETs. In addition, a small subpopulation of cancer stem-like cells (CSCs) appears to survive conventional chemotherapy, leading to recurrent disease. Natural products appear efficacious against CSCs; their combinational treatments with standard chemotherapy are promising for cancer eradication, in particular when supported by nanotechnologies.

Nasal administration of nanoencapsulated geraniol/ursodeoxycholic acid conjugate: Towards a new approach for the management of Parkinson's disease.

The combined use of different therapeutic agents in the treatment of neurodegenerative disorders is a promising strategy to halt the disease progression. In this context, we aimed to combine the anti-inflammatory properties of geraniol (GER) with the mitochondrial rescue effects of ursodeoxycholic acid (UDCA) in a newly-synthesized prodrug, GER-UDCA, a potential candidate against Parkinson's disease (PD). GER-UDCA was successfully synthetized and characterized in vitro for its ability to release the active compounds in physiological environments. Because of its very poor solubility, GER-UDCA was entrapped into both lipid (SLNs) and polymeric (NPs) nanoparticles in order to explore nose-to-brain pathway towards brain targeting. Both GER-UDCA nanocarriers displayed size below 200 nm, negative zeta potential and the ability to increase the aqueous dissolution rate of the prodrug. As SLNs exhibited the higher GER-UDCA dissolution rate, this formulation was selected for the in vivo GER-UDCA brain targeting experiments. The nasal administration of GER-UDCA-SLNs (1 mg/kg of GER-UDCA) allowed to detect the prodrug in rat cerebrospinal fluid (concentration range = 1.1 to 4.65 µg/mL, 30-150 min after the administration), but not in the bloodstream, thus suggesting the direct nose to brain delivery of the prodrug. Finally, histopathological evaluation demonstrated that, in contrast to the pure GER, nasal administration of GER-UDCA-SLNs did not damage the structural integrity of the nasal mucosa. In conclusion, the present data suggest that GER-UDCA-SLNs could provide an effective and non-invasive approach to boost the access of GER and UDCA to the brain with low dosages.

Bile salt-coating modulates the macrophage uptake of nanocores constituted by a zidovudine prodrug and enhances its nose-to-brain delivery.

We have previously demonstrated that the ester conjugation of zidovudine (AZT) with ursodeoxycholic acid (UDCA) allows to obtain a prodrug (U-AZT) which eludes the active efflux transporters (AET). This allows the prodrug to more efficiently permeates and remains in murine macrophages than the parent compound. Here we demonstrate that U-AZT can be formulated, by a nanoprecipitation method, as nanoparticle cores coated by bile acid salt (taurocholate or ursodeoxycholate) corona, without any other excipients. The U-AZT nanoparticles appeared spherical with a mean diameter of ∼200 nm and a zeta potential of ∼-55 mV. During the incubation (5 h) in fetal bovine serum, the ursodeoxycholate-coated nanoparticle size did not change. Differently, taurocholate-coated particle size was firstly reduced and then increased up to 800 µm, thus suggesting the high aptitude of these nanoparticles to interact with serum proteins. The in vitro uptake of taurocholate coated particles by murine macrophages was strongly higher than that of ursodeoxycholate-coated particles or free U-AZT (∼500% and ∼7000%, respectively). AZT was also detected in macrophages following the prodrug uptake, with the greatest amounts observed after the taurocholate-coated nanoparticle incubation. As macrophages in the subarachnoid spaces of cerebrospinal fluid (CSF) constitute one of the most unreachable HIV sanctuaries in the body, we also tested the ability of taurocholate-coated nanoparticles (i.e., nanoparticles highly internalized by macrophages) to reach them after their nasal administration in the presence or absence of chitosan. The results indicate that chitosan allowed to obtain a relatively high uptake (up to 4 µg/ml) of U-AZT in CSF. Taking into account that chitosan may promote the direct brain nanoparticle uptake, these findings can be considered an initial step toward the in vivo targeting of the subarachnoid macrophages by U-AZT prodrug.

Uptake in the Central Nervous System of Geraniol Oil Encapsulated in Chitosan Oleate Following Nasal and Oral Administration.

The pharmacological activities of geraniol include anticancer and neuroprotective properties. However, its insolubility in water easily induces separation from aqueous formulations, causing administration difficulties. Here we propose new emulsified formulations of geraniol by using the amphiphilic polymer chitosan-oleate (CS-OA) as surfactant to combine mucoadhesive and absorption enhancer properties with stabilization effects on the oil dispersion. The formulation based on CS-OA 2% (w/w) (G-CS-OA-2.0%) showed viscosity values compatible with oral and nasal administration to rats, and mean diameter of the dispersed phase of 819 ± 104 nm. G-CS-OA-2.0% oral administration sensibly increases the geraniol bioavailability with respect to coarse emulsions obtained without CS-OA (AUC values in the bloodstream were 42,713 ± 1553 µg∙mL-1∙min and 2158 ± 82 µg∙mL-1∙min following administration of 50 mg/kg or 1 mg/kg, respectively), and enhances the aptitude of geraniol to reach the central nervous system from the bloodstream (AUC values in the cerebrospinal fluid were 7293 ± 408 µg∙mL-1∙min and 399 ± 25 µg∙mL-1∙min after oral administration of 50 mg/kg or 1 mg/kg, respectively). Moreover, relevant geraniol amounts were detected in the cerebrospinal fluid following the G-CS-OA-2% nasal administration (AUC values in the cerebrospinal fluid were 10,778 ± 477 µg∙mL-1∙min and 5571 ± 290 µg∙mL-1∙min after nasal administration of 4 mg/kg or 1 mg/kg, respectively).

Exploring the use of spray congealing to produce solid dispersions with enhanced indomethacin bioavailability: In vitro characterization and in vivo study.

The current study proposes an original oral delivery system for the bioavailability enhancement of indomethacin (IND), a BCS class II drug, with the aim to overcome the common limitations of amorphous solid dispersion. In fact, the potential risk of drug re-crystallization is a serious concern for the stability of amorphous systems and represents, despite the great bioavailability, one of the primary causes of their limited clinical applications. IND-loaded microparticles (MPs) were prepared by spray congealing using oral-approved excipients (Gelucire 50/13 and the recently marketed Gelucire 48/16). MPs were characterized regarding particle size, morphology, drug content and IND solid state; moreover, they were tested in vitro for IND solubility and dissolution rate. Solid state characterization indicated that IND was present into the MPs in the amorphous form. The best formulation showed a considerable enhancement in drug dissolution rate and 31-fold higher drug solubility than pure γ-IND. The oral administration of MPs showed 2.5-times increased bioavailability in vivo compared to either pure γ-IND or its physical mixture with unloaded MPs. Notably, the formulation was stable after 18 months with no changes in IND solid state and dissolution performance. This study offers a valid approach to enhance IND oral bioavailability by conversion into the amorphous form by spray congealed MPs, which have great potential for industrial application due to their characteristics of high encapsulation efficiency, no-toxicity, low-cost, prolonged stability and the use of a simple and easily scaled-up manufacturing technology.

Oxcarbazepine free or loaded PLGA nanoparticles as effective intranasal approach to control epileptic seizures in rodents.

The brain as a target for drug delivery is a challenge in pharmaceutical research. Among the several proposed strategies, the intranasal route represents a good strategy to deliver drugs to the brain. The goal of this study was to investigate the potential use of oxcarbazepine (OXC) to enhance brain targeting efficiency after intranasal (IN) administration. As well as attempting to use as low a dose as possible to obtain therapeutic effect. Our results showed that, after IN administrations, the dose of OXC that was effective in controlling epileptic seizures was 0.5 mg/kg (1 dose, every 20 min for 1 h) in rodents, confirmed by Cerebral Spinal Fluid (CSF) bioavailability. With the aim of reducing the number of administrations, sustaining drug release and increasing brain targeting, OXC was loaded into poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs). The selected nanoformulation for in vivo studies was obtained re-suspending the freeze-dried and cryo-protected OXC loaded PLGA NPs. The translocation of 1-1'-Dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine Iodide loaded PLGA NPs, from nose to the brain, was confirmed by Fluorescence Molecular Tomography, which also evidenced an accumulation of NPs in the brain after repeated IN administrations. IN administrations of OXC loaded PLGA NPs reduced the number of administrations to 1 over 24 h compared to the free drug thus controlling seizures in rats. Immunohistochemical evaluations (anti-neurofilament, anti-beta tubulin, and anti-caspase3) demonstrated a neuroprotective effect of OXC PLGA NPs after 16 days of treatment. These encouraging results confirmed the possibility of developing a novel non-invasive nose to brain delivery system of OXC for the treatment of epilepsy.

The Role of Combined Penetration Enhancers in Nasal Microspheres on In Vivo Drug Bioavailability.

Microspheres based on both methyl-ß-cyclodextrins and chitosan were prepared by spray-drying as nasal formulations of a model polar drug to analyze, firstly, how the composition of the carrier affects drug permeation across synthetic membranes and, secondly, how it induces systemic or brain delivery of the drug. Microparticles with different weight ratios of the two penetration enhancers (10⁻90, 50⁻50, 90⁻10) were characterized with respect to morphology, size, structural composition, water uptake, and the in vitro drug permeation profile. The leader formulation (weight ratio of 50⁻50) was then nasally administered to rats; systemic and cerebrospinal fluid (CSF) drug concentrations were analyzed by high performance liquid chromatography (HPLC) over time. Microspheres obtained with a single enhancer, methyl-ß-cyclodextrins or chitosan, were administered in vivo as a comparison. The in vitro properties of combined microspheres appeared modified with regard to the polymeric matrix ratio. In vivo results suggest that the optimal drug distribution between CSF and bloodstream can be easily obtained by varying the amount of these two penetration enhancers studied in the matrix of nasal microspheres.