Release Of Naproxen Research Articles

Insights and relative effect of aspirin, naproxen and ibuprofen containing hydrogels: From design to performance as a functional dual capacity restorative material and build in free radical defense: <i>In-vitro</i> studies

Restorative materials in the new era aim to be “bio-active” and long-lasting. It has been suggested that the anti-inflammatory activity of some non-steroidal anti-inflammatory drugs (NSAIDs) may be partly due to their ability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS), as well as to inhibit the respiratory burst of neutrophils triggered by various activating agents. As a part of our continuous interest of developing functional dual action restorative materials capable of being “bio-active” and long-lasting, we design and evaluate novel chitosan hydrogels containing krill oil (antioxidant containing material), naproxen, ibuprofen (non steroidal anti-inflammatory medication), aspirin (pain relieve medication and free radical scavengers) and combinations thereof (chitosan-H-krill oil, chitosan-H-krill oil-aspirin and chitosan-H-naproxen, chitosan-H-naproxen-krill oil, chitosan-H-krill oil-ibuprofen and chitosan-H-ibuprofen) as functional additive prototypes for further development of “dual function restorative materials”; secondly, determine their effect on the dentin bond strength of a composite and thirdly, evaluate the capability of newly designed hydrogels to play an integral role of “build in” free radical defense mechanism by using BSA solubility as a “molecular prototype” of the site of free radical attack in vitro. Materials and Methods: The above mentioned hydrogels were prepared by dispersion of the corresponding component in glycerol and acetic acid with the addition of chitosan gelling agent. The surface morphology (SEM), release behaviors (physiological pH and also in acidic conditions), stability of the therapeutic agent-antioxidant-chitosan and the effect of the hydrogels on the shear bond strength of dentin were also evaluated. Results: The release of aspirin, ibuprofen and naproxen confers the added benefit of synergistic action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to the commercially available products alone. Neither the release of aspirin, ibuprofen or naproxen nor the antioxidant stability was affected by storage over a 6- month period. The hydrogel formulations have a uniform distribution of drug content, homogenous texture and yellow color (SEM study). All chitosan dentin treated hydrogels gave significantly (P P in vitro conditions. Conclusion: The added benefits of the chitosan treated hydrogels involved positive influence on the aspirin, ibuprofen and naproxen release, increased dentin bond strength as well as demonstrated in vitro “build in” free radical defense mechanism, therefore acting as a “proof of concept” for the functional multi-dimentional restorative materials with the build in free radical defense mechanism.

Effects of Electrode Reversal on the Distribution of Naproxen in the Electrospun Cellulose Acetate Nanofibers

Naproxen (NAP)/cellulose acetate hybrid nanofibers were prepared by positive and reversed emitting electrodes electrospinning setups. The morphology and structure of the resultant nanofibers were characterized, and the NAP release behaviors were investigated. It was found that NAP dispersed in the CA matrix in molecular level, and no aggregation and dimers of NAP were found in the resultant NAP/CA hybrid nanofibers due to the formation of hydrogen bonds between NAP and CA. The nanofibers obtained by reversed emitting electrode electrospinning setup have a thicker diameter and a faster NAP release rate compared with those obtained by positive emitting electrode electrospinning setup. The faster drug release of NAP from nanofibers prepared by reversed emitting electrode electrospinning is due to the fact that the concentration of NAP molecules near the surface of the nanofibers is relatively higher than that of the nanofibers prepared by positive emitting electrode electrospinning setup. The effects of the electrode polarity on the distribution of drugs in nanofibers can be used to prepare hybrid electrospun fibers of different drug release rates, which may found applications in biomedical materials.

Chitosan:Vitamin C Containing Hydrogels as a Prototype Functional Prolonged Pain Management Restorative Material <i>In-Vitro</i> Studies

Restorative materials in the new era aim to be “bio-active” and long-lasting. As a part of our continuous interest of developing functional dual action restorative materials capable of being “bio-active” and wound healing, we design and evaluate several novel chitosan-vitamin C (5:1) containing hydrogels as a prototype of host:guest molecular free radical defense material containing hydroethanoic propolis extract (antioxidant containing material), naproxen, ibuprofen (non steroidal anti-inflammatory medication), or aspirin (pain relieve medication and free radical scavengers) as functional restorative materials. We will evaluate the physical properties, bonding to dentin as well as test the bioadhesion of the newly designed materials in order to access the suitability of these prototype materials as suitable restorative materials. Materials and Methods: The hydrogels were prepared by previously reported by us protocol. The physico-chemical features including surface morphology (SEM), release behaviors, stability of the therapeutic agent-anti-oxidant-chitosan and the effect of the hydrogels on the shear bond strength of dentin were measured and compared to the earlier reported chitosan-antioxidant containing hydrogels. Structural investigations of the reactive surface of the hydrogel were reported. Bio-adhesive studies were performed in order to assess the suitability of these designed materials. Results: Release of aspirin, ibuprofen and naproxen conferred the added benefit of synergistic action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to the commercially available products alone. Either the release of therapeutic agents or the antioxidant stability was affected by storage over a 12-month period. All chitosan:vitamin C hydrogels showed gave significantly higher shear bond values than dentin treated or not treated with phosphoric acid, which highlighted the feasibility. The bio-adhesive capacity of the materials in the 2 separate “in vitro” systems were tested and quantified. Additional action of chitosan:vitamin C pre-complex was investigated and it was found that favourable synergistic effect of free radical build-in defense mechanism of the new functional materials. Conclusion: Additional action of chitosan:vitamin C pre-complex was investigated and it was found that favorable synergistic effect of free radical build-in defense mechanism of the new functional materials, increased dentin bond strength, sustainable bio-adhesion, and acted as a “proof of concept” for the functional multi-dimensional restorative materials with potential application in wound healing in vitro.

Preparation and study of naproxen in silica and lipid/polymer hybrid composites

Three different powdered hybrid inorganic–organic composites for pharmaceutical use have been successfully obtained using CO2 as an antisolvent in a batch mode process. Naproxen was chosen as the hydrophobic Class II model drug, for which its dissolution rate in water must be enhanced. As excipients, two kind of commercial lipids (G44/14 and G50/13) and a mixture of Eudragit RS100 and Eudragit RL100 polymers were used. Silica microparticles have also been incorporated into the formulation to restrict the naproxen crystals growth and to obtain a powdered material with appropriate micromeritic properties. The morpho-chemical characteristics of these microcomposites and their different release profiles are reported. Importantly, the components have not suffered structural or chemical modifications during the processing and no specific chemical bonds were detected between them. High drug loading has been achieved in the three cases. Water dissolution of the drug formulations is controlled mainly by the wetting properties and nature of the excipients and by the size of the crystals. Among the materials prepared, samples made with Gelucires (hydrophilic species) result in the fastest release of naproxen. We thus conclude that lipid-based ternary formulations display a synergetically accelerated release compared to binary mixtures.

Cyclodextrin Mediated Controlled Release of Naproxen from pH-Sensitive Chitosan/Poly(Vinyl Alcohol) Hydrogels for Colon Targeted Delivery

pH-Responsive hydrogels are the current need of the hour in controlled drug delivery applications. pH-sensitive interpolymeric hydrogels based on chitosan and polyvinyl alcohol cross-linked with glutaraldehyde were synthesized. Preformed inclusion complex of naproxen with β-cyclodextrin (1:1) was directly loaded into the hydrogel. The hydrogels exhibited maximum swelling at neutral pH. They showed negligible drug release in the simulated gastric fluid and sustained release in the intestinal fluid. The preliminary kinetic analysis revealed that cyclodextrin influences the relaxation rate of the polymer chains, leading to slower release of the drug. It can be proposed that the deleterious effects of naproxen on the epithelium of the gastro-intestinal tract could be minimized by using the cyclodextrin containing hydrogels as drug delivery systems because they provide a controlled release resulting in a reduced concentration of free naproxen. Further, the pH-specific release behavior of these hydrogels can be utilized for colon-targeted drug delivery.

Plasmon Excitation of Supported Gold Nanoparticles Can Control Molecular Release from Supramolecular Systems

Hybrid mesoporous silica materials containing gold nanoparticles (AuNPs) have been investigated as potential molecular delivery systems. The photophysical properties of AuNPs, particularly their plasmon band transitions, have been used to control the rate of the release of naproxen from the pores of mesoporous silica matrices. Two different approaches were employed to incorporate AuNPs into the silica network: that is, grafting (using 3-aminopropyltriethoxisilane) and direct absorption. In this research, the anti-inflamatory drug naproxen serves as a test molecule, showing how localized plasmon heating could be used to modify diffusion kinetics within mesoporous materials. Beyond naproxen release, the methodology developed could be employed to release other drugs, sensors, or active molecules, not just in medicine, but in many other fields where nanotechnology is leading to many innovative applications. The hybrid materials developed show a new simple system to efficiently control the release of active cargo from mesoporous silica matrices.

A Thermal Controlled Release of Naproxen from Sodium Phosphorylated Chitosan Nanoemulsion

The aim of this research was to control the delivery of naproxen from emulsion-based sodium phosphorylated chitosan (PCTS) nanoparticles (PCTS nanoemulsion) by thermal stimulus. The dynamic light scattering and optical microscope results demonstrated that the droplet size of emulsion-based nanoparticles was sensitive to temperature. The PCTS nanoemulsion exhibited the droplet size around 230 nm at 30°C. Emulsion droplets were increased in their size over critical temperature of around 60°C. Besides, the droplet size was reversible to 270 nm when the temperature decreased to 30°C. This indicated that the droplet size of PCTS nanoemulsion was sensitive to thermal stimulus. It might owe to molecular chain extension and rearrangement of PCTS at the interface of emulsion droplets. Therefore, the control release of naproxen from PCTS nanoemulsion via thermal stimulus was investigated.In vitrorelease study showed that the naproxen was released from PCTS nanoemulsion in high amount over critical temperature. These results indicated that the PCTS nanoemulsion exhibited a potential application as intelligent thermal sensitive drug carrier.

Insights into chitosan based gels as functional restorative biomaterials prototypes: <i>In vitro</i> approach

Restorative materials in the new era aim to be “bioactive” and long-lasting. The purpose of the study was to design and evaluate novel chitosan hydrogels containing melatonin and/or propolis (antioxidant containing material), nystatin (antifungal), naproxen (pain relieve medication) and combinations thereof (chitosan-H-melatonin, chitosan-H-melatonin-naproxen, chitosan-H-propolis, chitosan-H-propolisnaproxen, chitosan-H-naproxen-propolis-melatonin, Chitosan/Propolis/Nystatin, Chitosan/Melatonin/Propolis/Nystatin, Chitosan/Propolis/BSA/Nystatin, Chitosan/Melatonin/BSA/Nystatin) as functional additive prototypes for further development of “dual function restorative materials”, to determine their effect on the dentin bond strength of a composite, to evaluate stability of the encapsulated antioxidants as well as evaluate antimicrobial properties of the selected group of “designer” functional materials. Materials and Methods: The above mentioned hydrogels were prepared by dispersion of the corresponding component in glycerol and acetic acid with the addition of chitosan gelling agent. The surface morphology (SEM), drug-polymer solid state interaction (FT-IR spectroscopy), released behaviours (physiological pH and also in acidic conditions), stability of the therapeutic agent-antioxidant-chitosan and the effect of the hydrogels on the shear bond strength of dentin were also evaluated. Results: The release of naproxen confers the added benefit of synergistic action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to the commercially available products alone. Neither the release of naproxen or the antioxidant stability was affected by storage over a 6-month period. The hydrogel formulations have a uniform distribution of drug content, homogenous texture and yellow colour (SEM study). All chitosan dentin treated hydrogels gave significantly (P

Sustained release of naproxen in a new kind delivery system of carbon nanotubes hydrogel.

In this paper, carbon nanotubes (CNTs) were added into chitosan (CS) hydrogels in the form of chitosan modified CNTs (CS-CNTs) composites to prepare carbon nanotubes hydrogels (CNTs-GEL). The products, named CS-MWCNTs, were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Swelling properties and effect of pH on controlled release performance of the two kinds of hydrogels, CNTs- GEL and pure chitosan hydrogels without CNTs (GEL), were investigated respectively. The results showed that CNTs-GEL possess better controlled release performance than GEL. The releasing equilibrium time of CNTs-GEL was longer than that of GEL in both pH = w7.4 and pH=1.2 conditions, although the release ratios of the model drug are similar in the same pH buffer solutions. It is found that release kinetics is better fitted Ritger-Peppas empirical model indicating a fick-diffusion process in pH = 1.2, while in pH = 7.4 it was non-fick diffusion involving surface diffusion and corrosion diffusion processes.

Sorption and desorption of carbamazepine, naproxen and triclosan in a soil irrigated with raw wastewater: Estimation of the sorption parameters by considering the initial mass of the compounds in the soil

In conventional sorption studies, the prior presence of contaminants in the soil is not considered when estimating the sorption parameters because this is only a transient state. However, this parameter should be considered in order to avoid the under/overestimation of the soil sorption capacity. In this study, the sorption of naproxen, carbamazepine and triclosan was determined in a wastewater irrigated soil, considering the initial mass of the compounds. Batch sorption–desorption tests were carried out at two soil depths (0–10cm and 30–40cm), using either 10mM CaCl2 solution or untreated wastewater as the liquid phase. Data were satisfactorily fitted to the initial mass model. For the two soils, release of naproxen and carbamazepine was observed when the CaCl2 solution was used, but not in the soil/wastewater system. The compounds’ release was higher in the topsoil than in the 30–40cm soil. Sorption coefficients (Kd) for CaCl2 solution tests showed that in the topsoil, triclosan (64.9Lkg−1) is sorbed to a higher extent than carbamazepine and naproxen (5.81 and 2.39Lkg−1, respectively). In the 30–40cm soil, carbamazepine and naproxen Kd values (11.4 and 4.41Lkg−1, respectively) were higher than those obtained for the topsoil, while the triclosan Kd value was significantly lower than in the topsoil (19.2Lkg−1). Differences in Kd values were found when comparing the results obtained for the two liquid phases. Sorption of naproxen and carbamazepine was reversible for both soils, while sorption of triclosan was found to be irreversible. This study shows the sorption behavior of three pharmaceuticals in a wastewater irrigated soil, as well as the importance of considering the initial mass of target pollutants in the estimation of their sorption parameters.

Novel Brain Targeting Prodrugs of Naproxen Based on Dimethylamino Group with Various Linkages

As a preventive and treatment drug for Alzheimer's disease (AD), naproxen's clinical application is hampered by its limited distribution in the brain. To increase the delivery of naproxen across the blood-brain barrier (BBB), 3 prodrugs (P1, P2 and P3) of naproxen were synthesized through either ester bond or amido bond using the dimethylamino moiety as a brain-targeting ligand. The in vitro release of naproxen from the 3 prodrugs was studied in PBS, rat plasma and brain homogenate. P3 with an amido bond appeared to be highly stable in all incubation media, whereas P1 and P2 with ester bonds were partially hydrolyzed in alkaline environment and brain homogenate to yield the parent drug. After i. v. administration to rats, the brain concentration of total naproxen (summation of released and bound naproxen, TN) of P1, P2 and P3 groups were 28.81, 24.51 and 15.54 times greater than that of the control naproxen group at 5 min, respectively, and the brain AUC0-t were 6.94, 10.06 and 6.70 times greater than that of the control naproxen group. In addition, the Cmax of TN in the brain after the administration of prodrugs with ester bonds (P1 and P2) was higher than that of the amide prodrug (P3). The results highlighted the possibility of brain delivery of naproxen using prodrug strategies based on the brain-targeting ligand with dimethylamino moiety, in which the linkage between drug and targeting group might play an important role in modulating the in vivo behaviors of these prodrugs.

Electrolyte-Stimulated Biphasic Dissolution Profile and Stability Enhancement for Tablets Containing Drug-Polyelectrolyte Complexes

Recently introduced drug-polyelectrolyte complexes prepared by hot-melt extrusion should be processed to solid dosage forms with tailor-made release properties. Their potential of stability enhancement should be investigated. Milled hot-melt extruded naproxen-EUDRAGIT® E PO polyelectrolyte complexes were subsequently processed to double-layer tablets with varying complex loadings on a rotary-die press. Physicochemical interactions were studied under ICH guideline conditions and using the Gordon-Taylor equation. Sorption and desorption were determined to investigate the influence of moisture and temperature on the complex and related to stability tests under accelerated conditions. Naproxen release from the drug-polyelectrolyte complex is triggered by electrolyte concentration. Depending on the complex loading, phosphate buffer pH 6.8 stimulated a biphasic dissolution profile of the produced double-layer tablets: immediate release from the first layer with 65% loading and prolonged release from the second layer within 24h (98.5% loading). XRPD patterns proved pseudopolymorphism for tablets containing the pure drug under common storage conditions whereas the drug-complex was stable in the amorphous state. Drug-polyelectrolyte complexes enable tailor-made dissolution profiles of solid dosage forms by electrolyte stimulation and increase stability under common storage conditions.

NSAID naproxen in mesoporous matrix MCM-41: drug uptake and release properties

Hexagonally ordered mesoporous silica material MCM-41 (SBET = 1090 m2/g, pore size = 31.2 A) was synthesized and modified by 3-aminopropyl ligands. The differences in an uptake and subsequent release of anti-inflammatory drug naproxen from unmodified and amino modified MCM-41 samples were studied. The prepared materials were characterized by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM), nitrogen adsorption/desorption, Fourier-Transform Infrared Spectroscopy (FT-IR), Small-angle X-ray scattering (SAXS), thermoanalytical methods (TG/DTA) and elemental analysis. The amount of the drug released was monitored with thin layer chromatography (TLC) with densitometric detection in defined time intervals. The amounts of the released naproxen from mesoporous silica MCM-41/napro and amine-modified silica sample A-MCM-41/napro were 95 and 90% of naproxen after 72 h. In this study we compare the differences of release profiles from mesoporous silica MCM-41 and mesoporous silica SBA-15.

An investigation of formulation factors affecting feasibility of alginate-chitosan microparticles for oral delivery of naproxen

In the present work we investigated the feasibility of chitosan treated Ca-alginate microparticles for delivery of naproxen in lower parts of GIT and evaluated influence of formulation factors on their physicochemical characteristics and drug release profiles. Investigated factors were drug/polymer ratio, chitosan molecular weight, chitosan concentration in hardening medium, and hardening time. Sixteen microparticle formulations were prepared utilizing 24 full factorial design (each factor was varied at two levels). Microparticles size varied between 262.3 ± 14.9 and 358.4 ± 21.7 μm with slightly deformed spherical shape. Low naproxen solubility and rapid reaction of ionotropic gelation resulted in high encapsulation efficiency (> 75.19%). Under conditions mimicking those in the stomach, after two hours, less than 6.18% of naproxen was released. Significant influence of all investigated factors on drug release rate was observed in simulated small intestinal fluid. Furthermore, experimental design analysis revealed that chitosan molecular weight and its concentration had the most pronounced effect on naproxen release. Release data kinetics indicated predominant influence of a pH-dependent relaxation mechanism on drug release from microparticles.

Encapsulation of Naproxen in Lipid-Based Matrix Microspheres: Characterization and Release Kinetics

The objective of this study was to microencapsulate the anti-inflammatory drug (naproxen) to provide controlled release and minimizing or eliminating local side effect by avoiding the drug release in the upper gastrointestinal track. Naproxen was microencapsulated with lipid-like carnauba wax, hydrogenated castor oil using modified melt dispersion (modified congealable disperse phase encapsulation) technique. Effect of various formulation and process variables such as drug-lipid ratio, concentration of modifier, concentration of dispersant, stirring speed, stirring time, temperature of external phase, on evaluatory parameters such as size, entrapment efficiency, and in vitro release of naproxen were studied. The microspheres were characterized for particle size, scanning electron microscopy (SEM), FT-IR spectroscopy, drug entrapment efficiency, in vitro release studies, for in vitro release kinetics. The shape of microspheres was found to be spherical by SEM. The drug entrapment efficiency of various batches of microspheres was found to be ranging from 60 to 90 %w/w. In vitro drug release studies were carried out up to 24 h in pH 7.4 phosphate buffer showing 50-65% drug release. In vitro drug release from all the batches showed better fitting with the Korsmeyer-Peppas model, indicating the possible mechanism of drug release to be by diffusion and erosion of the lipid matrix.

Encapsulation of naproxen in nanostructured system: structural characterization and in vitro release studies

Nanoparticles were produced by solvent emulsification evaporation method with the following characteristics: nanometric size (238 ± 3 nm), narrow polydispersity index (0.11), negative zeta potential (-15.1 mV), good yield of the process (73 ± 1.5%), excellent encapsulation efficiency (81.3 ± 4.2%) and spherical shape. X-rays diffraction demonstrated the loss of drug crystallinity after encapsulation; however, the profile of the diffractograms of the poly-e-caprolactone (PCL) nanoparticles was kept. Differential scanning calorimetry thermograms, correspondingly, exhibited the loss of drug melting peak and the increasing of the melting point of the PCL nanoparticles, evidencing an interaction drug-polymer. Naproxen release was low and sustained obeying the Higuchi´s kinetic. The results show that nanoparticles are promising sustained release system to the naproxen.

Novel PEG-graft-PLA nanoparticles with the potential for encapsulation and controlled release of hydrophobic and hydrophilic medications in aqueous medium

This study concerns the encapsulation and controlled release of both hydrophobic and hydrophilic medications with one polymer, which are delivered together as a combined therapy to treat diseased tissue. To test our hypothesis that the novel PEG-graft-PLA (PEG, polyethylene glycol; PLA, polylactic acid) can deliver both the hydrophobic and hydrophilic medications on account of its amphiphility, charge, and graft structure, PEG-graft-PLA (molecular weight of PEG = 1900) with very low critical micelle concentration was synthesized. One hydrophilic (insulin) and one hydrophobic (naproxen) model medication were loaded in separately during its self-assembly in aqueous solution. The resulting nanoparticles (NPs) were narrowly distributed and spherical, with average particle size around 200 nm, zeta potential >−10 mV, and encapsulation efficiency >50%. The NPs realized controlled release of insulin and naproxen for over 24 and 160 hours, respectively. Specifically, the bioactivity of the insulin released from the NPs was maintained. Owing to encapsulation, both for hydrophobic and hydrophilic medicines, and NPs obtained with similar size and zeta potential, as well as maintenance of bioactivity of loaded protein, we expect the applications of PEG-graft-PLA NPs in combination therapy.

Biocompatible and pH‐responsive triblock copolymer mPEG‐b‐PCL‐b‐PDMAEMA: Synthesis, self‐assembly, and application

AbstractA series of well‐defined amphiphilic triblock copolymers [polyethylene glycol monomethyl ether]‐block‐poly(ε‐caprolactone)‐block‐poly[2‐(dimethylamino)ethyl methacrylate] (mPEG‐b‐PCL‐b‐PDMAEMA or abbreviated as mPEG‐b‐PCL‐b‐PDMA) were prepared by a combination of ring‐opening polymerization and atom transfer radical polymerization. The chemical structures and compositions of these copolymers have been characterized by Fourier transform infrared spectroscopy, 1H NMR, and thermogravimetric analysis. The molecular weights of the triblock copolymers were obtained by calculating from 1H NMR spectra and gel permeation chromatography measurements. Subsequently, the self‐assembly behavior of these copolymers was investigated by fluorescence probe method and transmission electron microscopy, which indicated that these amphiphilic triblock copolymers possess distinct pH‐dependent critical aggregation concentrations and can self‐assemble into micelles or vesicles in PBS buffer solution, depending on the length of PDMA in the copolymer. Agarose gel retardation assays demonstrated that these cationic nanoparticles can effectively condense plasmid DNA. Cell toxicity tests indicated that these triblock copolymers displayed lower cytotoxicity than that of branched polyethylenimine with molecular weight of 25 kDa. In addition, in vitro release of Naproxen from these nanoparticles in pH buffer solutions was conducted, demonstrating that higher PCL content would result in the higher drug loading content and lower release rate. These biodegradable and biocompatible cationic copolymers have potential applications in drug and gene delivery. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1079–1091, 2010

Influence of the inorganic matrix nature on the sustained release of naproxen

Naproxen, a non-steroidal anti-inflammatory drug, has been immobilised in different inorganic matrices, namely Mg, Al layered double hydroxide (LDH), MCM-41 mesoporous silica and mesoporous alumina. The synthesised systems were characterised using several physicochemical techniques and their delivery rates tested through in vitro experiments. It was found that the amounts of drugs incorporated in the mesoporous matrices are quite similar, ranging between ca. 15 and 20% in wt, mainly depending on their pore size, while the LDH can host up to ca. 41% wt. In all cases the release rate of naproxen for the mesoporous systems is lower than that detected measured for the LDH system and all of them can be well fitted to the Fick’s law.

Preparation, in vitro characterization and in vivo release of naproxen loaded in poly-caprolactone nanoparticles

Naproxen was loaded in poly-caprolactone (PCL) nanoparticles as an implantable sustained release system to prolong its anti-inflammatory activity. Naproxen-loaded nanoparticles were produced with the following characteristics: Nanometric size (< 300 nm), negative zeta potential, low polydispersity index (< 0.1), satisfactory encapsulation efficiency, low water content (< 1%), and spherical shape. In vitro naproxen release profile was sustained and the kinetic followed the Higuchi model. The PCL nanoparticles containing about 12.5% (w/w) of the naproxen (sample A3) was chosen for complementary studies of stability and in vivo release in rats. Nanoparticles did not suffer alteration during stability studies. In vivo release was sustained by one month. Thus, nanoparticles showed potential to act as an implantable sustained release system for chronic inflammatory diseases use.