Development of Atomoxetine-Loaded NLC In Situ Gel for Nose-to-Brain Delivery: Optimization, In Vitro, and Preclinical Evaluation

Development of in vitro and in vivo evaluation of mucoadhesive in-situ gel for intranasal delivery of vinpocetine

Alzheimer's disease (AD), which is marked by gradual neuronal decline and subsequent loss of cognitive functions and memory, poses significant treatment challenges. The present study involved the development, in vitro, and in vivo evaluation of a novel intranasal mucoadhesive in-situ gel of vinpocetine (VIN) with the aim to target the brain. An innovative gel formulation composed of poloxamer 407, HPMC E15 LV, and citric acid as a solubilizer was developed by 23 Factorial Design. The developed optimal formulation exhibited favorable rheological properties as it displayed ideal gelation time (31.6 ± 1.52 sec), optimum gelling temperature (32 ± 1.0 °C), enhanced mucoadhesive strength (6622 ± 2.64 dynes/cm2), prolonged adhesion (7.22 ± 0.57 hrs) compared with the baseline formulation (F18), and improved drug release in 12 hrs (39.59 ± 1.6%). In vivo, pharmacokinetics revealed a significant increase in Cmax (∼2-fold) and AUC0-t (∼2-fold) in the brain with the in-situ intranasal gel compared to the oral route. In the rat model of AD, in-situ intranasal gel demonstrated significantly greater efficacy (p < 0.001) than oral administration in alleviating AD symptoms as evidenced by behavioral and histological studies. Thus, VIN in-situ gel can be safe and noninvasive for nose-to-brain drug delivery.

Surface-modified liposomal in-situ nasal gel enhances brain targeting of berberine hydrochloride for Alzheimer's therapy: optimization and in vivo studies

This work aimed to formulate surface-modified berberine hydrochloride (BER)-loaded liposomes containing in-situ nasal gel for bran targeting. The liposomes were prepared by ethanol-injection method and optimized following a 32 full-factorial design. Size, morphology, zeta potential, ex-vivo permeation, and in-vitro release were estimated. The surface of optimized liposome was modified with ascorbic acid. The size of surface-modified liposomes was bigger (191.4 nm) than the unmodified liposomes (171 nm). Surface-modified liposomes were embedded in in-situ gel using poloxamer and Carbopol 934P. Liposomal in-situ gel showed higher permeation (71.94%) in contrast to the plain gel (46.64%). In-vivo pharmacokinetic examination of payload from liposomal in-situ gel displayed higher concentration in brain (Cmax of 93.50 ng/mL). The liposomal in-situ nasal gel had a higher drug targeting efficiency (138.43%) and a higher drug targeting potential (27.77%) confirming improved brain targeting. In male Wistar rats, the pharmacodynamic parameters (path length and escape latency) were evaluated with trimethyl tin-induced neurodegeneration. Animals treated with BER-loaded in-situ gel significantly decreased escape latency and path length in comparison to the control group. Histopathological assessment showed that the formulated gel was safe for intranasal administration. The developed formulation has the potential to effectively enhance the efficacy of BER in Alzheimer's disease management.

Nose to Brain: Exploring the Progress of Intranasal Delivery of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers

The intranasal (IN) route of drug delivery can effectively penetrate the blood-brain barrier and deliver drugs directly to the brain for the treatment of central nervous system (CNS) disorders via intra-neuronal or extra-neuronal pathways. This approach has several advantages, including avoidance of first-pass metabolism, high bioavailability, ease of administration, and improved patient compliance. In recent years, an increasing number of studies have been conducted using drugs encapsulated in solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), and delivering them to the brain via the IN pathway. SLNs are the first-generation solid lipid nanocarriers, known for their excellent biocompatibility, high drug-loading capacity, and remarkable stability. NLCs, regarded as the second-generation SLNs, not only retain the advantages of SLNs but also exhibit enhanced stability, effectively preventing drug leakage during storage. In this review, we examined in vivo studies conducted between 2019 and 2024 that used SLNs and NLCs to address CNS disorders via the IN route. By using statistical methods to evaluate pharmacokinetic parameters, we found that IN delivery of SLNs and NLCs markedly enhanced drug accumulation and targeting within the brain. Additionally, pharmacodynamic evaluations indicated that this delivery method substantially improved the therapeutic effectiveness of the drugs in alleviating symptoms in rat models of CNS diseases. In addition, methods for enhancing the efficacy of nose-to-brain delivery of SLNs and NLCs are discussed, as well as advances in clinical trials regarding SLNs and NLCs.

Design of experiment (DoE) of mucoadhesive valproic acid-loaded nanostructured lipid carriers (NLC) for potential nose-to-brain application

Epilepsy is a highly prevalent neurological disease and valproic acid (VPA) is used as a first-line chronic treatment. However, this drug has poor oral bioavailability, which requires the administration of high doses, resulting in adverse effects. Alternative routes of VPA administration have therefore been investigated, such as the nose-to-brain route, which allows the drug to be transported directly from the nasal cavity to the brain. Here, the use of nanostructured lipid carriers (NLC) to encapsulate drugs administered in the nasal cavity has proved advantageous. The aim of this work was to optimise a mucoadhesive formulation of VPA-loaded NLC for intranasal administration to improve the treatment of epilepsy. The Design of Experiment (DoE) was used to optimise the formulation, starting with component optimisation using Mixture Design (MD), followed by optimisation of the manufacturing process parameters using Central Composite Design (CCD). The optimised VPA-loaded NLC had a particle size of 76.1 ± 2.8 nm, a polydispersity index of 0.190 ± 0.027, a zeta potential of 28.1 ± 2.0 mV and an encapsulation efficiency of 85.4 ± 0.8%. The in vitro release study showed VPA release from the NLC of 50 % after 6 h and 100 % after 24 h. The in vitro biocompatibility experiments in various cell lines have shown that the optimised VPA-loaded NLC formulation is safe up to 75 µg/mL, in neuronal (SH-SY5Y), nasal (RPMI 2650) and hepatic (HepG2) cells. Finally, the interaction of the optimised VPA-loaded NLC formulation with nasal mucus was investigated and mucoadhesive properties were observed. The results of this study suggest that the use of intranasal VPA-loaded NLC may be a promising alternative to promote VPA targeting to the brain, thereby improving bioavailability and minimising adverse effects.

Development, Statistical Optimization, and Characterization of Resveratrol-Containing Solid Lipid Nanoparticles (SLNs) and Determination of the Efficacy in Reducing Neurodegenerative Symptoms Related to Alzheimer's Disease: In Vitro and In Vivo Study

Resveratrol (RSV), as a natural polyphenol exhibiting antioxidative properties, is studied in the treatment of neurodegenerative diseases. However, RSV has low oral bioavailability. In this study and in order to overcome the issue, RSV was encapsulated into the solid lipid nanoparticles (SLNs). In this study, RSV-loaded solid lipid nanoparticles (RSV-SLNs) were prepared by the solvent emulsification-evaporation technique, and their physicochemical properties were optimized using Box-Behnken response surface methodology. The morphology of the particles was evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The neuroprotective effects of the nanoparticles were investigated in animal models using the Morris water maze (MWM). Then after, the rats were sacrificed, their brains were collected, and the extent of lipid peroxidase (LPO) as well as the level of reduced glutathione (GSH) were determined in the hippocampus section samples. Finally, the collected brain tissues were histologically studied. The particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE%), and drug loading (DL%) of the optimized nanoparticles were 104.5 ± 12.3 nm, 0.322 ± 0.11, -3.1 ± 0.15 mV, 72.9 ± 5.31% and 14.6 ± 0.53%, respectively. The microscopic images revealed spherically shaped and nonaggregated nanoparticles. The in vivo studies demonstrated higher efficiency of RSV-SLN in the reduction of escape latency time and improvement in the time spent in the target quadrant compared to free RSV. Moreover, it was demonstrated that RSV-SLN posed a higher potency in the reduction of LPO as well as elevation of the GSH levels in the brain samples. The histological studies revealed a decline in neural degeneration and an improvement in the CA1 pyramidal cell morphology. The obtained data revealed that RSV-SLNs caused more reduction in Alzheimer-related symptoms rather than free RSV.

Development and Evaluation of Docetaxel-Loaded Nanostructured Lipid Carriers for Skin Cancer Therapy

This study focuses on the design, characterization, and optimization of nanostructured lipid carriers (NLCs) loaded with docetaxel for the treatment of skin cancer. Employing a systematic formulation development process guided by Design of Experiments (DoE) principles, key parameters such as particle size, polydispersity index (PDI), zeta potential, and entrapment efficiency were optimized to ensure the stability and drug-loading efficacy of the NLCs. Combined XRD and cryo-TEM analysis were employed for NLC nanostructure evaluation, confirming the formation of well-defined nanostructures. In vitro kinetics studies demonstrated controlled and sustained docetaxel release over 48 h, emphasizing the potential for prolonged therapeutic effects. Cytotoxicity assays on human umbilical vein endothelial cells (HUVEC) and SK-MEL-24 melanoma cell line revealed enhanced efficacy against cancer cells, with significant selective cytotoxicity and minimal impact on normal cells. This multidimensional approach, encompassing formulation optimization and comprehensive characterization, positions the docetaxel-loaded NLCs as promising candidates for advanced skin cancer therapy. The findings underscore the potential translational impact of these nanocarriers, paving the way for future preclinical investigations and clinical applications in skin cancer treatment.

Syrupy herbal formulation of green bean pod extract of Phaseolus vulgaris L.: Formulation optimization by central composite design, and evaluation for anti-urolithiatic activity

The green bean pods of Phaseolus vulgaris L. are traditionally used as a folk remedy for treating calcium oxalate kidney stones. The current research aimed to develop a syrup formulation containing green bean pod extract for anti-urolithiatic activity. The syrup was prepared using a simple blending method and optimized through a central composite design (CCD) with two independent variables: the ratio of pod juice (PJ) to sugar solution (SS) ranging from 1:0.5 to 1:1.5, and the percentage of CMC from 0.2% to 0.4% w/v. These variables were analyzed for their impact on viscosity (CP) and sedimentation percentage, helping to identify the best formulation out of 13 variants. The finalized formulation (F-opt) underwent assessment for physicochemical characteristics such as organoleptic properties, viscosity, density, sedimentation rate, and stability. Additionally, a microbiological assessment was performed utilizing the spread plate method. Further, it was evaluated for in vitro, ex vivo, and in vivo anti-urolithiatic activity in rat models for 28 days and compared with that of the reference standard (Cystone syrup). Additionally, acute toxicity was assessed in albino Swiss mice. Histopathological evaluations were then conducted on the kidneys of the Wistar rats that had been used for the in vivo studies, providing insight into the treatment effects on kidney tissue structure. The optimized formulation (F-opt) was a green, viscous, clear syrup with a pH of 5.8, a viscosity of 256.38 CP, a density of 1.31 g/ml, and a sedimentation rate of 0.69%. The optimized formulation was found to be stable, showing no significant changes in physicochemical and microbiological properties. The results of the in vitro, ex vivo, and in vivo anti-urolithiatic studies indicated that the optimized formulation effectively inhibited the aggregation of calcium oxalate. The acute toxicity studies revealed no mortality or adverse effects for both the optimized formulation and pure bean pod juice at a dose of 2000 mg/kg body weight. Histopathological examination revealed that rats treated with the optimized formulation exhibited a significant reduction in both the number and size of calcium oxalate deposits within various parts of the renal tubules. It can be concluded that the syrupy formulation of Phaseolus vulgaris L. green bean pod extract demonstrated significant anti-urolithiatic activity. This activity could be due to its diuretic properties and its ability to inhibit the formation of calcium oxalate crystals. However, limitations of the study included a lack of elucidation of the mechanism and limited generalizability of the findings.

Natural-Origin Betaine Surfactants as Promising Components for the Stabilization of Lipid Carriers

In the present work, we demonstrate studies involving the influence of the formulation composition on the physicochemical properties of nanocarriers: solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). Novel lipid-origin platforms were prepared using two "green" betaine-based surfactants, cocamidopropyl betaine (ROKAmina K30) and coco betaine (ROKAmina K30B), in combination with three different solid lipids, cetyl palmitate (CRODAMOL CP), trimyristin (Dynasan 114), and tristearin (Dynasan 118). Extensive optimization studies included the selection of the most appropriate lipid and surfactant concentration for effective SLN and NLC stabilization. The control parameters involving the hydrodynamic diameters of the obtained nanocarriers along with the size distribution (polydispersity index) were determined by dynamic light scattering (DLS), while shape and morphology were evaluated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Electrophoretic light scattering (ELS) and turbidimetric method (backscattering profiles) were used to assess colloidal stability. The studied results revealed that both betaine-stabilized SLN and NLC formulations containing CRODAMOL CP as lipid matrix are the most monodisperse and colloidally stable regardless of the other components and their concentrations used, indicating them as the most promising candidates for drug delivery nanosystems with a diverse range of potential uses.

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.

Xanthan-Gum/Pluronic-F-127-Based-Drug-Loaded Polymeric Hydrogels Synthesized by Free Radical Polymerization Technique for Management of Attention-Deficit/Hyperactivity Disorder

Smart and intelligent xanthan gum/pluronic F-127 hydrogels were fabricated for the controlled delivery of atomoxetine HCl. Different parameters such as DSC, TGA, FTIR, XRD, SEM, drug loading, porosity, swelling index, drug release, and kinetics modeling were appraised for the prepared matrices of hydrogels. FTIR confirmed the successful synthesis of the hydrogel, while TGA and DSC analysis indicated that the thermal stability of the reagents was improved after the polymerization technique. SEM revealed the hard surface of the hydrogel, while XRD indicated a reduction in crystallinity of the reagents. High gel fraction was achieved with high incorporated contents of the polymers and the monomer. An increase in porosity, drug loading, swelling, and drug release was observed with the increase in the concentrations of xanthan gum and acrylic acid, whereas Pluronic F-127 showed the opposite effect. A negligible swelling index was shown at pH 1.2 and 4.6 while greater swelling was observed at pH 7.4, indicating a pH-responsive nature of the designed hydrogels. Furthermore, a higher drug release was found at pH 7.4 compared to pH 1.2 and 4.6, respectively. The first kinetics order was followed by the prepared hydrogel formulations. Thus, it is signified from the discussion that smart xanthan gum/pluronic F-127 hydrogels have the potential to control the release of the atomoxetine HCl in the colon for an extended period of time.

Design of experiment (DoE) as a quality by design (QbD) tool to optimise formulations of lipid nanoparticles for nose-to-brain drug delivery

INTRODUCTION

The nose-to-brain route has been widely investigated to improve drug targeting to the central nervous system (CNS), where lipid nanoparticles (solid lipid nanoparticles - SLN and nanostructured lipid carriers - NLC) seem promising, although they should meet specific criteria of particle size (PS) <200 nm, polydispersity index (PDI) <0.3, zeta potential (ZP) ~|20| mV and encapsulation efficiency (EE) >80%. To optimize SLN and NLC formulations, design of experiment (DoE) has been recommended as a quality by design (QbD) tool.

AREAS COVERED

This review presents recently published work on the optimization of SLN and NLC formulations for nose-to-brain drug delivery. The impact of different factors (or independent variables) on responses (or dependent variables) is critically analyzed.

EXPERT OPINION

Different DoEs have been used to optimize SLN and NLC formulations for nose-brain drug delivery, and the independent variables lipid and surfactant concentration and sonication time had the greatest impact on the dependent variables PS, EE, and PDI. Exploring different DoE approaches is important to gain a deeper understanding of the factors that affect successful optimization of SLN and NLC and to facilitate future work improving machine learning techniques.