Piribedil loaded thermo-responsive nasal in situ gelling system for enhanced delivery to the brain: formulation optimization, physical characterization, and in vitro and in vivo evaluation

Refinement of intranasal delivery in rats: A cadaveric study

The intranasal route enables direct delivery of multiple substances from the nose to the brain, through olfactory and trigeminal pathways, bypassing the blood-brain barrier and avoiding systemic absorption. Despite the potential of this route, the various administration approaches make data reproducibility and interpretation challenging, emphasizing the necessity to establish a consistent methodology. Considering this, the aim of our study was to assess and compare the distribution of two dye volumes (30 µl and 50 µl) in the nasal cavity of rat cadavers. We employed three distinct methods of intranasal delivery: nose drops, by pipette tip, or cannula inserted into the nasal cavity. The results indicated that for both volumes, using the nose drops and the pipette tip methods, the dye dispersion occurred mainly in the vestibule, respiratory and olfactory regions, without reaching the olfactory bulbs. Using the cannula method, the deposition predominantly occurred in the respiratory and olfactory regions, with the dye reaching 66.7% and 100% of the olfactory bulbs, respectively, to low and high volume. Furthermore, the results demonstrated differences between the two volumes, in the pharynx, larynx, trachea, septal window, and incisive papilla, where an increased dye presence was observed with the 50 µl instillation across all three methods. According to our results, the intranasal delivery with a cannula was the most effective method for dye deposition in the olfactory region. However, further studies in live animals will be necessary to determine and refine the administration method that consistently allows specific deposition in the olfactory system.

Slightly viscous dispersions of mucoadhesive polymers as vehicles for nasal administration of dopamine and grape seed extract-loaded solid lipid nanoparticles

With the aim to find an alternative vehicle to the most used thermosensitive hydrogels for efficient nanotechnology-based nose-to-brain delivery approach for Parkinson's disease (PD) treatment, in this work we evaluated the Dopamine (DA) and the antioxidant grape seed-derived pro-anthocyanidins (Grape Seed Extract, GSE) co-loaded solid lipid nanoparticles (SLNs) put in slight viscous dispersions (SVDs). These SVDs were prepared by dispersion in water at low concentrations of mucoadhesive polymers to which SLN pellets were added. For the purpose, we investigated two polymeric blends, namely Poloxamer/Carbopol (PF-127/Carb) and oxidized alginate/Hydroxypropylmethyl cellulose (AlgOX/HPMC). Rheological studies showed that the two fluids possess Newtonian behaviour with a viscosity slightly higher that water. The pH values of the SVDs were mainly within the normal range of nasal fluid as well as almost no osmotic effect was associated to both SVDs. All the SVDs were capable to provide DA permeation through nasal porcine mucosa. Moreover, it was found that PF-127/Carb blend possesses penetration enhancer capability better than the Alg OX/HPMC combination. Flow cytometry studies demonstrated the uptake of viscous liquids incorporating fluorescent SLNs by human nasal RPMI 2650 cell in time-dependent manner. In conclusion, the SVD formulations may be considered promising alternatives to thermosensitive hydrogels strategy. Moreover, in a broader perspective, such SVD formulations may be also hopeful for treating various neurological diseases beyond PD treatment.

Chitosan-coated nanostructured lipid carriers for effective brain delivery of Tanshinone IIA in Parkinson's disease: interplay between nuclear factor-kappa β and cathepsin B

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder associated with increased oxidative stress, the underlying vital process contributing to cell death. Tanshinone IIA (TAN) is a phytomedicine with a documented activity in treating many CNS disorders, particularly PD owing to its unique anti-inflammatory and antioxidant effect. However, its clinical utility is limited by its poor aqueous solubility, short half-life, and hence low concentration reaching targeted cells. This work aimed to develop a biocompatible chitosan-coated nanostructured lipid carriers (CS-NLCs) for effective brain delivery of TAN for PD management. The proposed nanosystem was successfully prepared using a simple melt-emulsification ultra-sonication method, optimized and characterized both in vitro and in vivo in a rotenone-induced PD rat model. The developed TAN-loaded CS-NLCs (CS-TAN-NLCs) showed good colloidal properties (size ≤ 200 nm, PDI ≤ 0.2, and ζ-potential + 20 mV) and high drug entrapment efficiency (> 97%) with sustained release profile for 24 h. Following intranasal administration, CS-TAN-NLCs succeeded to achieve a remarkable antiparkinsonian and antidepressant effect in diseased animals compared to both the uncoated TAN-NLCs and free TAN suspension as evidenced by the conducted behavioral tests and improved histopathological findings. Furthermore, biochemical evaluation of oxidative stress along with inflammatory markers, nuclear factor-kabba β (NF-Kβ) and cathepsin B further confirmed the potential of the CS-TAN-NLCs in enhancing brain delivery and hence the therapeutic effect of TAN of treatment of PD. Accordingly, CS-TAN-NLCs could be addressed as a promising nano-platform for the effective management of PD.

The prescription design and key properties of nasal gel for CNS drug delivery: A review

Central nervous system (CNS) diseases are among the major health problems. However, blood-brain barrier (BBB) makes traditional oral and intravenous delivery of CNS drugs inefficient. The unique direct connection between the nose and the brain makes nasal administration a great potential advantage in CNS drugs delivery. However, nasal mucociliary clearance (NMCC) limits the development of drug delivery systems. Appropriate nasal gel viscosity alleviates NMCC to a certain extent, gels based on gellan gum, chitosan, carbomer, cellulose and poloxamer have been widely reported. However, nasal gel formulation design and key properties for alleviating NMCC have not been clearly discussed. This article summarizes gel formulations of different polymers in existing nasal gel systems, and attempts to provide a basis for researchers to conduct in-depth research on the key characteristics of gel matrix against NMCC.

Optimization of In Situ Gel-Forming Chlorhexidine-Encapsulated Polymeric Nanoparticles Using Design of Experiment for Periodontitis

Periodontitis is a chronic inflammatory disease of the gums caused by pathogenic microorganisms damaging and destroying periodontal tissues. Chlorhexidine digluconate (CHX) is a commonly used antimicrobial agent for the treatment of periodontitis. However, it has many drawbacks, such as toxicity due to the high dosage required, low prolonged release, and low adhesion in the periodontal pocket. The objective of this study was to develop and optimize CHX-encapsulated polymeric nanoparticles (NPs) loaded into in situ gel-forming (ISGF) using design of experiment (DoE) to improve the treatment of periodontitis and overcome these limitations. CHX-NPs were optimized from 0.046%w/v chitosan, 0.05%w/w gelatin, and 0.25%w/w CHX. After that, the optimized of CHX-NPs was loaded into a thermosensitive ISGF, which was a mixture of 15%w/v Poloxamer 407 and 1% hydroxypropyl methylcellulose (HPMC). The optimized CHX-NPs, loaded into ISGF, was evaluated by measuring gelling temperature and time, pH, viscosity, compatibility, in vitro drug release, antibacterial activity, cytotoxicity, and stability. The results showed that the size, PDI, and zeta potential of optimized CHX-NPs were 53.07±10.17 nm, 0.36±0.02, and 27.63±4.16 mV, respectively. Moreover, the optimized ISGF loading CHX-NPs showed a gelling temperature at 34.3±1.2°C within 120.00±17.32 s with a pH value of 4.06. The viscosity of the formulations at 4°C was 54.33±0.99 cP. The DSC and FTIR showed no interaction between ingredients. The optimal formulations showed a prolonged release of up to 7 days while providing potential antibacterial activity and were safe for normal gingival fibroblast cells. Moreover, the formulations had high stability at 4°C and 25°C for 3 months. In conclusion, the study achieved the successful development of ISGF loading CHX-NPs formulations for effectiveness use in periodontal treatment.

The Improved Brain-Targeted Drug Delivery of Edaravone Temperature-Sensitive Gels by Ultrasound for γ-ray Radiation-Induced Brain Injury

Radiation-induced brain injury (RBI) is a common neurological disease caused by ionizing radiation (IR). Edaravone (EDA) is a free radical scavenger, has the potential to treat RBI. EDA loaded temperature-sensitive gels (TSGs) were prepared for subcutaneous injection to improve inconvenient administration of intravenous infusion. RBI mice model was established by irradiation of 60Co γ-ray on head. EDA TSGs could improve spontaneous behavior, learning and memory and anxiety of RBI mice by behavior tests, including the open field test, the novel object recognition test, the elevated plus maze test and the fear conditioning test. The therapeutic effects were enhanced with the assistance of ultrasound. Alleviative pathological changes, decreased the expression of Molondialdehyde (MDA) and Interleukin-6 (IL-6) in the hippocampus of brain, indicated reduced oxidative stress and inflammatory response with the treatment of EDA TSGs and ultrasound. Moreover, ultrasound was superior to the use of EDA TSGs. Safe and effective EDA TSGs were prepared for RBI, and the feasibility of brain-targeted drug delivery enhanced by ultrasound was preliminarily demonstrated in this study.

Design and evaluation of rufinamide nanocrystals loaded thermoresponsive nasal in situ gelling system for improved drug distribution to brain

Rufinamide (Rufi) is an antiepileptic drug used to manage Lennox-Gastaut Syndrome and partial seizures. The oral bioavailability of Rufi is less due to its poor solubility and low dissolution rate in the gastrointestinal fluids. This results in less amount of drug reaching the brain following the oral administration of drug. Oral formulations of Rufi are prescribed at a high dose and dosing frequency to increase its distribution to the brain. A Rufi loaded thermoresponsive nasal in situ gel which showed significantly high brain concentrations compared to aqueous suspension of Rufi administered through nasal route was developed by our research group and published. In the current work, we have formulated nanocrystals of Rufi and suspended them in a xyloglucan based thermoresponsive gel to improve the nose-to-brain distribution. The particle size, polydispersity index, and yield (%) of the optimized Rufi nanocrystals were 261.2 ± 2.1 nm, 0.28 ± 0.08, and 89.6 ± 2.0 respectively. The narrow PDI indicates that the manufacturing process is reproducible and reliable. Higher % yield suggested that the method of preparation is efficient. The sol-to-gel transition of in situ gel loaded with Rufi nanocrystals was at 32°C which suggested that the formulation transforms into gel at nasal epithelial temperatures. The nasal pharmacokinetic studies showed that Rufi nanocrystals loaded in situ gel produced higher concentration of the drug in brain (higher brain Cmax) and maintained the drug concentrations for longer duration (higher mean residence time) compared to aqueous suspension of Rufi nanocrystals as well aqueous suspension of Rufi and Rufi loaded in situ gel, reported previously. Nanometric size of the Rufi nanocrystals combined with the in situ gelling properties helped the optimized formulation achieve higher brain distribution and also sustain the drug concentrations in brain for longer duration compared to any of the formulations studied by our research group.

In situ gelling nanosuspension as an advanced platform for fluticasone propionate nasal delivery

In this work we present the development of in situ gelling nanosuspension as advanced form for fluticasone propionate nasal delivery. Drug nanocrystals were prepared by wet milling technique. Incorporation of drug nanocrystals into polymeric in situ gelling system with pectin and sodium hyaluronate as constitutive polymers was fine-tuned attaining appropriate formulation surface tension, viscosity and gelling ability. Drug nanonisation improved the release profile and enhanced formulation mucoadhesive properties. QbD approach combining formulation and administration parameters resulted in optimised nasal deposition profile, with 51.8% of the dose deposited in the middle meatus, the critical region in the treatment of rhinosinusitis and nasal polyposis. Results obtained in biocompatibility and physico-chemical stability studies confirmed the leading formulation potential for safe and efficient nasal corticosteroid delivery.