Novel radioiodinated desvenlafaxine-loaded lipid nanocapsule for brain delivery.

Lipid nanocapsules (LNCs) are lipid nanocarriers developed for drug delivery enhancement. The antidepressant drug desvenlafaxine (DSV) was entrapped in LNC to improve its brain delivery. Different DSV-loaded LNCs formulae using different oils and surfactants were studied to obtain the optimum formula for further studies. In vivo biodistribution studies were done using Swiss albino mice by intravenous injection of DSV-loaded LNCs by radioiodination technique. The optimum DSV-loaded LNC formula was obtained by using Labrafil® M1944CS as the oil and Solutol® HS15 as the surfactant in the ratio of 1:1, with a particle size of 34.28 ± 0.41 nm, a polydispersity index of 0.032 ± 0.05, a zeta potential of -25.77 ± 1.41, and good stability for up to 6 months. The in vivo biodistribution and pharmacokinetics data ensure the bioavailability improvement for DSV brain delivery as Cmax and AUC(1-t) increased more than double for intravenously DSV-loaded LNCs compared with the DSV solution. In conclusion, the results obtained from this study give an insight into the great potential of using DSV-loaded LNC for the enhancement of brain delivery.

Engineering a novel water-in-oil biocompatible microemulsion system for the ocular delivery of dexamethasone sodium phosphate in the treatment of acute uveitis.

Due to their unique characteristics, microemulsions (ME) represent one of the most promising delivery systems which can conquer poor ocular drug bioavailability providing long residence time. Development of a ME system, relying on the use of a safe and non-irritant surfactant combination derived from sustainable resources and which can consolidate the small ME droplets, is the goal of this work. Herein, we report the design and characterization of a novel biocompatible, eco-friendly ME system loaded with the hydrophilic dexamethasone sodium phosphate (DEXP) using a novel surfactant mixture composed of D-α-tocopherol polyethylene glycol succinate (TPGS) and Plantacare® (coco-Glycosides). Capryol™ PGMC and double-distilled water were used as the respective oil and aqueous phases and the MEs were prepared by the water titration method, suitable for scaling up. Optimization of ME formulae was conducted by varying Plantacare® grades, TPGS to Plantacare® mass ratios and drug loading. The formulae were characterized in terms of physical appearance, droplet size (PS), size distribution (PDI), zeta potential (ZP), and stability. The optimized DEXP-loaded ME formula attained acceptable PS, PDI, and ZP values of 43 ± 5 nm, 0.35 ± 0.07, -12 ± 4 mV, respectively. TEM images confirmed a small PS ≤ 100 nm. The in vivo safety of ME was proved by the Draize test. The ME formula prompted excellent mucoadhesion and transcorneal permeation. The confocal studies showed deep penetration into the rabbits' corneas. In vivo studies using endotoxin-induced uveitis showed high ocular efficacy and a significant reduction in inflammatory cells, including interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The obtained results elect the novel engineered ME system as a promising tool for the ocular delivery of hydrophilic moieties in the management of various ophthalmic diseases.

Boosting the In Vivo Transdermal Bioavailability of Asenapine Maleate Using Novel Lavender Oil-Based Lipid Nanocapsules for Management of Schizophrenia.

Lipid nanocapsules (LNCs) are promising for transdermal drug delivery due to their higher permeability-enhancing effects compared to polymeric nanoparticles. Lavender oil is an essential oil consisting of several terpenes (primarily linalool and linalyl acetate) known for their profound permeation-enhancing action. In the present work, we successfully encapsulated asenapine maleate (a second-generation antipsychotic that is highly metabolized by the liver, reducing its oral bioavailability) into biocompatible LNCs for transdermal application using a novel oily phase, i.e., lavender oil (LO-LNCs). A comparative study was conducted to determine the effects of different oily phases (i.e., Miglyol® 812, Labrafil® M1944CS, and Labrafac™ PG) on the LNCs. Surfactant types (Kolliphor® HS15, Kolliphor® EL and Tween80) and oil:surfactant ratios were studied. Blank and asenapine-loaded LNCs were optimized for particle size, polydispersity index, zeta potential, drug content and ex vivo skin permeation. Lavender oil and Labrafil® showed smaller vesicular sizes, while LO-LNCs increased the permeation of ASP across rat skin. In vivo pharmacokinetics revealed that LO-LNCs could increase the ASP Cmax via transdermal application by fourfold compared to oral suspension. They increased the bioavailability of ASP by up to 52% and provided sustained release for three days. The pharmacokinetic profile of the LO-LNCs was compared to ASP-loaded invasomes (discussed in a previous study) to emphasize LNCs' transdermal delivery behavior.

Design of long acting invasomal nanovesicles for improved transdermal permeation and bioavailability of asenapine maleate for the chronic treatment of schizophrenia.

Asenapine Maleate (ASPM) is a second generation antipsychotic used for the management of schizophrenia but with very limited oral bioavailability due to its extensive first pass metabolism. Transdermal administration of ASPM using nanocarriers like invasomes might offer an excellent alternative to its oral administration with enhanced bioavailability and a sustained action. ASPM-loaded invasomes were successfully prepared by thin film hydration technique; meanwhile the penetration enhancing effect of terpenes (cineole and limonene) was compared to hydromiscible cosolvent (Transcutol®). Soft nanovesicles containing Transcutol® displayed smaller particle sizes than invasomes containing limonene and cineole while invasomes showed higher efficiency to encapsulate asenapine. Ex- vivo skin permeation revealed that invasomes with limonene are more efficient than those with cineole for the transdermal delivery of asenapine. The optimum nano-invasomes formulation contained 1% Limonene and showed particle size of 82 ± 0.6 nm, entrapment efficiency of 56.6 ± 1.5 % and transdermal flux of 3401.6 ± 604.2 (µg/h.cm2). Transmission electron microscopy of the selected formulation showed uniform spherical vesicles with intense outline and lighter core and FTIR study emphasized that ASPM was completely incorporated within the vesicles. The in- vivo pharmacokinetic study revealed that transdermal invasomes achieved 2 folds higher Cmax compared to oral suspension and delayed the Tmax from 1.5 h to around 4 h. The bioavailability of asenapine loaded invasomes after transdermal application was significantly improved to 54.5% compared to the 3.6 % achieved with the oral administration and exceeding the bioavailability of sublingual tablets currently available in the market and exhibited sustained release kinetics over 72 h which permits reduction of dosing frequency to increase patient adherence to medication.

Microparticles-in-Thermoresponsive/Bioadhesive Hydrogels as a Novel Integrated Platform for Effective Intra-articular Delivery of Triamcinolone Acetonide.

Intra-articular (IA) injection of thermoresponsive hydrogels coupled with microparticles (MPs) possess the benefit of sustaining the anti-inflammatory drug effect within the joint cavity for rheumatoid arthritis treatment. Star-shaped thermoresponsive poly(polyethylene glycol) methacrylate [Poly(PEGMA)] copolymers were synthesized using free radical polymerization technique and fully characterized. Triamcinolone acetonide (TA)-loaded PLA/mPEG-PDL MPs, previously optimized, were integrated into the synthesized copolymer solutions at various concentrations and tested for their gelation temperatures. The MPs-in-hydrogel formulations were characterized using scanning electron microscope (SEM), viscosity measurements, ex vivo bioadhesion, and in vitro release studies. The anti-inflammatory effect of integrated systems was assessed in adjuvant-induced monoarthritic rat knee joints and compared to Kenacort and TA-loaded MPs. Two copolymers were successfully synthesized; G-1 = poly(PEGMA188-ME-co-PEGMA475-ME) and G-2 = poly(PEGMA246-EE-co-PEGMA475-ME). Using the tube inversion technique, the gel formation was found dependent on copolymer concentration. An irreversible aggregation was obtained at copolymer concentrations ≤10% (w/v), while a gel was formed at 20 and 30% (w/v) of both copolymers upon increasing temperature. The MP-hydrogel formulations were optimized at 20 and 30% (w/v) of G-1 and G-2 with gelation temperatures of 33 and 37 °C, respectively. SEM images revealed the porous microstructures of hydrogels and their adsorption on MP surfaces. The integrated formulas showed pseudoplastic behaviors, while the bioadhesion study confirmed their bioadhesiveness on excised cartilage. The in vitro release study confirmed drug sustainment from MPs-hydrogels compared to MPs. In vivo studies proved the superiority of MP-in-hydrogels in treatment of induced arthritis, relative to Kenacort and MPs alone, suggesting the applicability of this integrated platform in IA drug delivery.

Triamcinolone acetonide-loaded PLA/PEG-PDL microparticles for effective intra-articular delivery: synthesis, optimization, in vitro and in vivo evaluation.

Nowadays the use of sustainable polymers as poly-lactic acid (PLA) and poly-δ-decalactone (PDL) in drug delivery is advantageous compared to polymers derived from fossil fuels. The present work aimed to produce microparticles (MPs) derived from novel sustainable polymers, loaded with triamcinolone acetonide (TA) for treatment of rheumatoid arthritis via intra-articular (IA) delivery. PDL was synthesized from green δ-decalactone monomers and co-polymerized with methoxy-polyethylene glycol (mPEG) forming PEG-PDL with different molecular weights. The Hansen's solubility parameters were applied to select the most compatible polymer with the drug. An o/w emulsion/solvent evaporation technique was used for MPs fabrication, using 3 [3] full factorial design. Selection of the optimized MPs was performed using Expert Design® software's desirability function. The optimized formulations were characterized using scanning electron microscope, powder X-ray diffraction, differential scanning calorimetry, infrared spectroscopy and in vitro release studies. The inhibition percents of inflammation and histopathological studies were assessed in complete Freund's adjuvant-induced rats' knee joints evaluating the effect of IA injections of selected MPs compared to the free drug suspension. Solubility studies revealed high compatibility and miscibility between TA and PEG-PDL1700, which was blended with PLA for convenient MPs formation. The in vitro characterization studies confirmed the formation of drug-copolymer co-crystals. The in vivo studies ensured the superiority of the newly designed composite MPs in inflammation suppression, compared to the free drug suspension and PLA MPs as well. The present study proved the advantage of using sustainable polymers in a novel combination for effective drug delivery and suggesting its usefulness in designing versatile platforms for therapeutic applications.

Tailoring novel soft nano-vesicles 'Flexosomes' for enhanced transdermal drug delivery: Optimization, characterization and comprehensive ex vivo - in vivo evaluation.

The transdermal route is a convenient non-invasive way for drug delivery, however, the hydrophobic compact nature of stratum corneum (SC) forms an obstacle hindering the diffusion of drugs particularly hydrophilic ones. Hence, the purpose of this study was to develop novel soft nano-vesicles, entitled Flexosomes, amalgamating two penetration enhancers, ethanol and one edge activator (EA) from various types and different hydrophilic-lipophilic balances. The tailored vesicles were loaded with tropisetron hydrochloride (TRO), a potent highly-soluble anti-emetic, and compared with ethosomes. Aiming to preclude the formation of rigid non-deformable mixed micelles, all critical parameters; EA type, phosphatidylcholine-to-EA molar ratio, and cholesterol concentration, were optimized proving their influences on vesicle-to-micelle transitions. The prepared formulations were characterized in terms of visual inspection, particle size, polydispersity, zeta potential, turbidity measurements, entrapment efficiency, and vesicle morphology. The permeation mechanisms were assessed by differential scanning calorimetry on isolated SC. The modified vesicles, based on ethanol and either vitamin E or PEGylated castor oil derivatives exhibited the highest transdermal fluxes confirmed by a deeply tracking to dermis using confocal laser microscopy. Both vesicles demonstrated higher bioavailability relative to ethosomes, topical and oral aqueous solutions. The findings endorsed the effectiveness of tailored nano-vesicles in boosting TRO skin transport suggesting their applicability with various drug entities for enhanced transdermal delivery.

Clinical cosmeceutical repurposing of melatonin in androgenic alopecia using nanostructured lipid carriers prepared with antioxidant oils.

BACKGROUND: The present work aims to formulate nanostructured lipid carriers (NLCs) exhibiting high skin deposition and high inherent antioxidant potential to repurpose the use of melatonin hormone and some antioxidant oils in the treatment of androgenic alopecia (AGA). RESEARCH DESIGN AND METHODS: NLCs were characterized for their size, charge, drug entrapment, anti-oxidant potential, physical stability, in vitro release, surface morphology, and ex-vivo skin deposition. Their merits were clinically tested on patients suffering from AGA by calculating the degree of improvement, conduction of hair pull test, histometric assessment, and dermoscopic evaluation. RESULTS: Results revealed that melatonin NLCs showed nanometer size, negatively charged surface, high entrapment efficiency, and high anti-oxidant potential, in addition to sustained release for 6 h. Furthermore, NLCs displayed good storage stability and they were able to increase the skin deposition of melatonin 4.5-folds in stratum corneum, 7-folds in epidermis, and 6.8-folds in the dermis compared to melatonin solution. Melatonin NLCs displayed more clinically desirable results compared to the melatonin solution in AGA patients, manifested by increased hair density and thickness and decreased hair loss. CONCLUSIONS: The aforementioned system was shown to be a very promising treatment modality for AGA, which is worthy of futuristic experimentation.

Melatonin vitamin C-based nanovesicles for treatment of androgenic alopecia: Design, characterization and clinical appraisal.

The present study aimed to develop vitamin C based nanovesicles (aspasomes) loaded with the antioxidant melatonin, as a novel cosmeceutical to be used for clinical treatment of androgenic alopecia (AGA). Aspasomes were assessed regarding their particle size, charge, drug entrapment, anti-oxidant potential, physical stability, in vitro release, surface morphology, and ex-vivo skin deposition. Clinically, melatonin aspasomes were tested on AGA patients, and assessed by evaluating the degree of improvement through conduction of hair pull test, histometric analysis and dermoscopic evaluation. Results revealed that melatonin aspasomes showed favorable pharmaceutical properties in addition to clinically promising results compared to melatonin solution, manifested by increased hair thickness, density and decreased hair loss, with photographic improvement in most patients. Therefore, melatonin vitamin C-based aspasomes were clinically auspicious in the treatment of AGA, hence, paving the way for their further exploration in other oxidative-dependent dermatological diseases.

Recent Advances in Antioxidant Cosmeceutical Topical Delivery.

Antioxidants are among the most important cosmeceuticals, with proven ability of inhibiting cellular damage. The topical skin administration of antioxidants is essential for minimizing skin aging and achieving better skin protection against harmful free radicals. However, their unfavorable physiochemical properties such as chemical instability, excessive hydrophilicity or lipophilicity and others could be a great obstacle against their skin promising effects as well as their delivery to deeper skin layers. These problems could all be remedied through the use of delivery carriers. The present review discusses the various delivery carriers which were proven successful in improving the beneficial effects of antioxidants against skin aging, namely different vesicular systems, lipidic systems, polymeric systems and carbon nanotubes, and their applications in topical antioxidant delivery.

Enhancing the Intestinal Permeation of the Chondroprotective Nutraceuticals Glucosamine Sulphate and Chondroitin Sulphate Using Conventional and Modified Liposomes.

BACKGROUND: Liposomes are promising systems for the delivery of macromolecules and poorly absorbed drugs, owing to their ability to compartmentalize drugs, their biodegradability and biocompatibility. OBJECTIVE: The aim of the present study was to formulate and evaluate conventional and modified glucosamine sulphate (GluS) and chondroitin sulphate (CS) liposomal formulations, to enhance their oral permeation for the treatment of osteoarthritis (OA). METHOD: Liposomal formulations were prepared by the thin-film hydration method using two types of phospholipids; Epikuron 200© and Epikuron 200© SH, and three permeation enhancers; poloxamer 407, cetylpyridinium chloride, and sodium deoxycholate. In-vitro characterization of liposomal formulations was conducted in terms of entrapment efficiency, particle size, zeta potential, viscosity, physical stability and mucoadhesive strength. Surface morphology and vesicle shape, ex-vivo intestinal permeation, and histopathological studies were further carried out on the selected formulation. RESULTS: Results showed that the liposomal formulation containing sodium deoxycholate was the most optimum formula, showing high entrapment efficiency (60.11% for GluS and 64.10% for CS) with a particle size of 4.40 µm, zeta potential of -17.2 mV and viscosity of 2.50 cP. CONCLUSION: The aforementioned formula displayed the highest cumulative % permeated of GluS and CS through rabbit intestinal mucosa compared to the solution of drugs and other liposomal formulations (64.20% for GluS and 78.21% for CS) after 2 hours. There were no histopathological alterations in the intestinal tissue, suggesting the safety of the utilized liposomal formulation. In light of the above, liposomes can be considered promising oral permeation-enhancer system for GluS and CS, which is worthy of future bioavailability experimentation.

Examining Insulin Adsorption onto Mesoporous Silica Microparticles for Oral Delivery.

BACKGROUND: Microencapsulation is one of the most common techniques for the delivery of macromolecules; however, it can cause various stability problems, such as degradation or loss of bioactivity of the loaded molecules. For this reason, several techniques were investigated to load insulin into pre-formed porous microparticles (MPs). OBJECTIVE: The high loading of insulin is a prerequisite of its delivery in sufficient concentration; hence we examined insulin loading in mesoporous silica (SBA15-NH2) as a model for uniformly porous microparticles using different loading methods and factors. METHOD: The MPs were characterized with respect to their morphology, porosity and pore diameter while insulin adsorption into the porous substrates was investigated using immersion and freeze-drying at different pH and initial peptide concentrations. MPs were further coated with Chitosan as a technique for pore blocking. RESULTS: The results showed that the extent of insulin adsorption by freeze-drying varied depending on substrate affinity to insulin and pH where it could achieve the highest loading capacity at a pH near its isoelectric point. A significant increase in drug loading along with slower drug release was observed with Chitosan coated SBA15-NH2 MPs. In addition, the structural integrity of insulin was maintained after loading into the MPs, as confirmed by gel electrophoresis and fluorescent spectroscopy together with the in vivo study which in turn confirmed the preservation of insulin bioactivity in lowering blood glucose after oral administration. CONCLUSION: The present work displays the various factors that can control insulin loading in mesoporous silica MPs and their effects in enhancing the efficiency of insulin oral delivery using such substrates.

Geriatric-Oriented High Dose Nutraceutical ODTs: Formulation and Physicomechanical Characterization.

CONTEXT: Oral disintegrating tablets (ODTs) represent a better option than conventional tablets for geriatric population, owing to their fast onset of action and their better patient compliance. OBJECTIVE: Two principal therapeutic high-dose nutraceuticals; chondroitin sulphate and glucosamine were formulated into an oral disintegration tablet (ODT) intended for sublingual administration, and optimized to improve compliance and achieve rapid onset of action in osteoarthritis treatment. MATERIALS AND METHODS: Different formulations were prepared either by melt granulation or direct compression techniques. Excipients at different ratios such as superdisintegrants, pharmaburst™ C1, spray-dried mannitol, and polyethylene glycols were used to enhance the disintegration time for the ODT systems. RESULTS: Although the ODT systems weighed around 1.3 gm with 60% drug load, some systems disintegrated within 2-3 min with 100% drug release. Pharmaburst™ C1 turned out to be the key excipient responsible for the superdisintegration properties of the ODTs. Dissolution enhancement of the two nutraceuticals could be achieved compared to the marketed conventional tablets. CONCLUSION: The improved disintegration and dissolution properties of our prepared ODTs are expected to enhance the bioavailability of the high dose glucosamine and chondroitin sulphate in comparison with conventional tablets, which delineates them as a promising dosage form for the aforementioned nutraceuticals.

Self-assembled amphiphilic core-shell nanocarriers in line with the modern strategies for brain delivery.

Disorders of the central nervous system (CNS) represent increasing social and economic problems all over the world which makes the effective transport of drugs to the brain a crucial need. In the last decade, many strategies were introduced to deliver drugs to the brain trying to overcome the challenge of the blood brain barrier (BBB) using both invasive and non-invasive methods. Non-invasive strategy represented in the application of nanocarriers became very common. One of the most hopeful nanoscopic carriers for brain delivery is core-shell nanocarriers or polymeric micelles (PMs). They are more advantageous than other nanocarriers. They offer small size, ease of preparation, ease of sterilization and the possibility of surface modification with various ligands. Hence, the aim of this review is to discuss modern strategies for brain delivery, micelles as a successful delivery system for the brain and how micelles could be modified to act as "magic bullets" for brain delivery.

Surface functionalization of methotrexate-loaded chitosan nanoparticles with hyaluronic acid/human serum albumin: Comparative characterization and in vitro cytotoxicity.

The active tumor targeting ligands, hyaluronic acid (HA) and human serum albumin (HSA), are considered promising targeting moieties of drug carriers for cancer therapy. The chitosan nanoparticles loaded with methotrexate (MTX-CsNPs) were employed as the core for subsequent coating process. HA and HSA coating solutions were used at different concentrations. The effect of different HA Mw (1000, 360, 10kDa) was also investigated. The coated MTX-CsNPs was characterized proving the success of surface functionalization. The antitumor activity of the prepared MTX-CsNPs was evaluated on MCF-7 breast cancer cell lines. Results showed that both 360 and 10kDa HA allowed for successful HA adsorption, while its Mw and concentration determined negative charge density. HSA coating was accompanied by a slight increase in nanoparticles (NPs) size and a final positive surface charge. The in vitro cytotoxicity proved that HA and HSA coated MTX-CsNPs improved the antitumor activity compared to uncoated NPs and free drug.

Studying the effect of physically-adsorbed coating polymers on the cytotoxic activity of optimized bisdemethoxycurcumin loaded-PLGA nanoparticles.

The aim of this work was to study the effect of different physically-adsorbed coating polymers on the cytotoxic activity of optimized bisdemethoxycurcumin (BDMC) loaded-PLGA nanoparticles. BDMC-loaded poly(DL-lactide-co-glycolide) (PLGA) nanoparticles were prepared adopting the nanoprecipitation technique according to a full factorial study design. The effects of three independent variables each at two levels, namely: the polymer type, polymer concentration, and poly vinyl alcohol concentration were studied. The particles were optimized regarding particle size and entrapment efficiency where sizes <200 nm and entrapment efficiencies reaching ∼98% were obtained. The particles were further characterized using x-ray diffraction, transmission electron microscopy, and in-vitro release studies. A selected formulation was subjected to physical coating using various coating moieties, namely: PEG 4000, Tween 80 and Pluronic F68, to impart a hydrophilic stealth character to the surface. The surface hydrophobicity was assessed using the Rose Bengal dye test where the hydrophilicity character followed the following order: Tween 80 > PEG 4000 > Pluronic F68. The particles coating rendered the particles suitable for cancer-targeting regarding particle size measurements, morphology, release kinetics, and stability studies. Moreover, cytotoxicity testing was performed using HepG-2 cells. Coated NPs showed the highest inhibition of malignant cells viability compared to the uncoated NPs and free BDMC where the IC50 of Pluronic-F68 coated NPs was 0.54 ± 0.01 µg/mL. The augmented effect against malignant cells poses these particles as a successful cancer remedy. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1433-1445, 2017.

Nanoethosomes for transdermal delivery of tropisetron HCl: multi-factorial predictive modeling, characterization, and ex vivo skin permeation.

OBJECTIVE: The aim of the present work is to exclusively optimize and model the effect of phospholipid type either egg phosphatidylcholine (EPC) or soybean phosphatidylcholine (SPC), together with other formulation variables, on the development of nano-ethosomal systems for transdermal delivery of a water-soluble antiemetic drug. Tropisetron HCl (TRO) is available as hard gelatin capsules and IV injections. The transdermal delivery of TRO is considered as a novel alternative route supposing to improve BAV as well as patient convenience. METHODS: TRO-loaded ethanolic vesicular systems were prepared by hot technique. The effect of formulation variables were optimized through a response surface methodology using 3 × 22-level full factorial design. The concentrations of both PC (A) and ethanol (B) and PC type (C) were the factors, while entrapment efficiency (Y1), vesicle size (Y2), polydispersity index (Y3), and zeta potential (Y4) were the responses. The drug permeation across rat skin from selected formulae was studied. Particle morphology, drug-excipient interactions, and vesicle stability were also investigated. RESULTS: The results proved the critical role of all formulation variables on ethosomal characteristics. The suggested models for all responses showed good predictability. Only the concentration of phospholipid, irrespective to PC type, had a significant effect on the transdermal flux (p < 0.01). The ethosomal vesicles were unilamellar with a nearly spherical shape. EPC-based ethosomes proved good stability. CONCLUSION: The study suggests the applicability of statistical modeling as a promising tool for prediction of ethosomal characteristics. The ethanolic vesicles were considered as novel potential nanocarriers for accentuated transdermal TRO delivery.

Composite chitosan-transfersomal vesicles for improved transnasal permeation and bioavailability of verapamil.

The creation of composite systems has become an emerging field in drug delivery. Chitosan has demonstrated several pharmaceutical advantages, especially in intranasal delivery. In this manuscript, a comparative study was conducted between regular vesicles (transfersomes and penetration enhancer vesicles) and composite vesicles (chitosan containing transfersomes and penetration enhancer vesicles) loaded with a model antihypertensive drug; verapamil hydrochloride VRP. Composite vesicles displayed larger particle size than regular vesicles owing to the coating potential of chitosan on the vesicular bilayer as displayed by transmission electron microscopy, with an increased viscosity of composite vesicles and a shift in the zeta potential values from negative to positive. The entrapment efficiency of VRP in the vesicles ranged from 24 to 64%, with best physical stability displayed with transfersomal vesicles prepared using sodium deoxycholate. Chitosan slowed the in vitro release of VRP from the selected formulation but managed to achieve high penetrability across sheep nasal mucosa as displayed by confocal laser microscopy. The chitosan composite transfersomal formulation exhibited absolute bioavailability of 81.83% compared to the oral solution which displayed only 13.04%. Findings of this manuscript highly recommend chitosan as a promising functional additive in vesicular formulations to improve the intranasal delivery of drugs with low oral bioavailability.

Methotrexate loading in chitosan nanoparticles at a novel pH: Response surface modeling, optimization and characterization.

The aim of this study was to assess the feasibility of employing a novel but critical formulation pH (6.2) to encapsulate an anionic model drug (methotrexate, MTX) into chitosan(Cs)-tripolyphosphate nanoparticles(NPs). A response surface methodology using a three-level full factorial design was applied studying the effects of two independent variables namely; Cs concentration and MTX concentration. The responses investigated were the entrapment efficiency (EE%), mean hydrodynamic particle size (PS), polydispersity index (PDI) and zeta potential (ZP). In order to simultaneously optimize the series of models obtained, the desirability function approach was applied with a goal to produce high percent of MTX encapsulated into highly charged Cs-TPP NPs of homogenous optimum PS. MTX-loaded CsNPs were successfully prepared at the novel pH applied. The suggested significant models were found quadratic for EE, PS and ZP responses, while 2-factor interaction model for PDI. The optimization overlay graph showed that the maximum global desirability, D=0.856, was reached when the conditions were set at high Cs and MTX concentration. Thus, the use of such optimized conditions, at this novel pH, achieved a maximum drug EE% (73.38%) into NPs characterized by optimum PS (232.6nm), small PDI value (0.195) and highly surface charged (+18.4mV).

Chitosan-tripolyphosphate nanoparticles: Optimization of formulation parameters for improving process yield at a novel pH using artificial neural networks.

At a novel pH value of the polymeric solution (6.2), variable chitosan (Cs) and sodium tripolyphosphate (TPP) concentrations and mass ratios were optimized to improve the process yield without undesirable particle flocculation. Prepared formulations were characterized in terms of particle size (PS), zeta potential (ZP) and percentage yield (% yield). Artificial neural networks (ANN) were built up and used to identify the parameters that control nanoparticle (NP) size and yield, in addition to being tested for their ability to predict these two experimental outputs. Using these networks, it was found that TPP concentration has the greatest effect on PS and% yield. The most optimum formulation was characterized by a notable process yield reaching 91.5%, a mean hydrodynamic PS 227 nm, ZP+24.13 mv and spherical compact morphology. Successful Cs-TPP interaction in NP formation was confirmed by both Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). This study demonstrated the ability of ANN to predict not only PS of the formed particles but also NP% yield. This may have a great impact on Cs-TPP NPs preparation and can be used to customize the required target formulations.