Bovine Serum Albumin Encapsulation Efficiency Research Articles

Gelatin/alginate-based microspheres with sphere-in-capsule structure for spatiotemporal manipulative drug release in gastrointestinal tract

Microsphere with sphere-in-capsule structure is a multi-drugs delivery system to achieve the purpose of combination therapy. In this paper, we have prepared gelatin/alginate-based microspheres with sphere-in-capsule structure by a relatively fast, simple, and easily large-scale industrialized emulsification method for spatiotemporal manipulative drug release in gastrointestinal tract. Calcium alginate microspheres encapsulated with bovine serum albumin (BSA) were first prepared as inner microspheres, and then inner microspheres and ranitidine hydrochloride (RH) were co-encapsulated by gelatin microspheres to form double-layer microspheres with sphere-in-capsule structure. The size and distribution of microspheres can be easily controlled by emulsifying conditions. The microspheres with sphere-in-capsule structure displayed desirable encapsulation efficiency of BSA (61.52 %) and RH (56.07 %). The in vitro simulated drug release showed the spatiotemporal release feature of microspheres with sphere-in-capsule structure. In the specific simulated fluid, the release behavior and cumulative release of RH (sustainedly released 95 % in simulated gastric fluid) and BSA (rapidly released 73 % in simulated intestinal fluid) were different. The drug release mechanisms were analyzed to determine RH and BSA's release behavior. Overall, the microspheres with sphere-in-capsule structure have the potential application of spatiotemporal manipulative drug delivery in the gastrointestinal tract.

Preparation and Characterization of PLG Microparticles by the Multiple Emulsion Method for the Sustained Release of Proteins.

Rapid release and diminished stability are two of the limitations associated with the growth factors that are essentially used in dental applications. These growth factors are employed to enhance the quality and quantity of tissue or bone matter during regeneration. Therefore, drug delivery devices and systems have been developed to address these limitations. In this study, bovine serum albumin (BSA), as a representative growth factor, was successfully sustained by encapsulation with the medium-absorbable copolymer, poly(L-lactide-co-glycolide) (PLG) 70:30% mol, via the multiple emulsion method. Different PLG, PVA, and BSA concentrations were used to investigate their effects on the BSA encapsulation efficiency. The suitable ratios leading to a better characterization of microparticles and a higher encapsulation efficiency in producing encapsulated PLG microparticles were 8% (w/v) of PLG, 0.25% (w/v) of PVA, and 8% (w/v) of BSA. Furthermore, an in vitro release study revealed a bursting release of BSA from the encapsulated PLG microsphere in the early phase of development. Subsequently, a gradual release was observed over a period of eight weeks. Furthermore, to encapsulate LL-37, different proteins were used in conjunction with PLG under identical conditions with regard to the loading efficiency and morphology, thereby indicating high variations and poor reproducibility. In conclusion, the encapsulated PLG microparticles could effectively protect the protein during encapsulation and could facilitate sustainable protein release over a period of 60 days. Importantly, an optimal method must be employed in order to achieve a high degree of encapsulation efficiency for all of the protein or growth factors. Accordingly, the outcomes of this study will be useful in the manufacture of drug delivery devices that require medium-sustained release growth factors, particularly in dental treatments.

Formulation and Characterization of Alginate Coated Chitosan Nanoparticles as Therapeutic Protein for Oral Delivery System

Nanoparticles have been promptly studied and developed for oral protein delivery. Selection of excipients and formulation method depends on the physicochemical characteristics of the protein carried. Therefore, this study aims to design a formulation and characterize the alginate coated chitosan nanoparticles which carried different protein. Alginate coated chitosan nanoparticles were formed using an ionic gelation method. Optimization was done by varying the parameter such as crosslinker concentration, agitation method, rate, and time. The results show that chitosan nanoparticles formed by sonication using sodium tripolyphosphate (STPP): chitosan (1:0.8) was the best method to form nanoparticles. The particle size and polydispersity index (PDI) of bovine serum albumin (BSA) and lysozyme nanoparticles were 812.2 nm and 0.412 for BSA while 793.3 nm and 0.438 for lysozyme. Encapsulation efficiency (EE) of BSA is 52 % and lysozyme is 68 %. In vitro tests on acidic/gastric conditions showed that lysozyme (±32 %) was released faster than BSA (±10 %) during the 24 h incubation. Under neutral/terminal intestine conditions, percentage of BSA (±17 %) release is slightly higher than lysozyme (±13 %) for 8 h incubation period. It was concluded that the formulation of alginate coated chitosan nanoparticles in this study appears to be more effective for BSA delivery than lysozyme.
 HIGHLIGHTS
 
 Nanoparticle vesicular system is an effective approach for protein drug delivery system
 Factors affecting the formation of chitosan nanoparticle are crosslinker concentration, agitation method, rate, and time
 Alginate coated chitosan nanoparticle was more effective for oral delivery of BSA compared to lysozyme
 
 GRAPHICAL ABSTRACT

Synthesis and characterizations of sugar-glass nanoparticles mediated protein delivery system for tissue engineering application

The present work focuses on the synthesis and characterization of a sugar-glass nanoparticle (SGnP) based reservoir type protein delivery system pertinent to tissue engineering applications. The SGnP nanocarriers were prepared via inverse micelle of sodium bis(2-ethylhexyl) sulfosuccinate based on an anionic surfactant and subsequent flash-freezing technique. Initially, a total of five different grades of protein-free SGnPs have been prepared to examine the effects of systematic changes in starting concentrations of the aqueous phase, organic solvent, the molar ratio of water, and surfactant in controlling the size, shape, and uniformity of micelles. Evidently, the Fourier transform infrared (FTIR) and scanning electron microscope (SEM) results confirmed that the SGnP can be successfully prepared. Subsequently, SGnP based protein depot has been validated using bovine serum albumin (BSA), horseradish peroxidase (HRP) and growth and differentiation factor-5 (GDF-5). The particle size, morphology, protein encapsulation efficiency and in vitro release kinetics were assessed using SEM, FTIR, UV–visible spectroscopy and Bradford protein assays. Excellent encapsulation efficiency (93%–94%) and sustained release behaviour of BSA (∼22% protein release after 14 d) and GDF-5 proteins (∼29% protein release after 30 d) were exhibited by the optimal grades of SGnP constructs with an average particle size of 266 nm and 93 nm, respectively. Furthermore, FTIR, differential scanning calorimeter (DSC), polyacrylamide gel electrophoresis (PAGE) and NATIVE-PAGE studies results confirm successful encapsulation, stability and preserving the structural integrity of proteins placed into the core of the SGnP constructs. Evidently, a very high (93%) residual HRP enzyme activity signifies the capability of our SGnP system to protect the encapsulated proteins from process-related stresses. In vitro cytotoxicity and fluorescence cell morphology analyses using human adipose-derived mesenchymal stem cells affirmed good cytocompatibility of protein encapsulated SGnP. Overall, the study findings indicate SGnP nanocarrier-mediated protein delivery systems as a promising approach complementary to conventional techniques in tissue engineering and therapeutic applications.

Encapsulation of protein within alginate-inulin matrix for targeted drug delivery system

By using sodium alginate and inulin as the core matrix, targeted release hydrogels were produced through ionotropic gelation method. As for model protein, bovine serum albumin (BSA) was chosen for in-vitro assessments. It appeared that amount of inulin had major impact on the encapsulation of BSA and also stability of hydrogels in simulated gastro intestinal fluid. The encapsulation efficiency of BSA was enhanced as the amount of inulin incorporated into the hydrogels was increased. In addition, only a little amount of BSA was released throughout 2 hours in simulated gastric fluid, SGF exposure. However, after changing into simulated intestinal fluid, SIF 100% of protein was released within 1.5 hours. Lower swelling index has been observed from alginate-inulin hydrogels in acidic condition (pH 1.2) as compared to alkaline medium, phosphate buffer (pH 7.4). This phenomenon is an indicative of pH responsive swelling activities. These hydrogels were characterized by Fourier-Transform Infared spectroscopy and Scanning Electron Microscopy for protein-excipients and hydrogels surface morphology, respectively. These developed alginate-inulin hydrogel has demonstrated high stability in acidic medium and good release efficiency at the targeted area.

Surfactant modified alginate composite gels for controlled release of protein drug

This study aims to modify alginate with sodium dodecyl sulfate (SDS) to reduce the release of oral protein in the acidic stomach environment and transport it to the colon medium. Bovine serum albumin (BSA), which was chosen as a model protein, was loaded into surfactant modified calcium alginate beads (SDS/Ca-Alg). The encapsulation efficiency of BSA in SDS/Ca-Alg beads was found significantly higher (96.3%) compared to that of beads without SDS. The most remarkable result is that protein release from the modified gel in the stomach environment was significantly reduced compared to protein release from the plain alginate gel. At the same time, the release time of the whole drug in the intestinal environment was significantly prolonged. The SDS-modified alginate beads are proposed as suitable carriers for the passage of orally taken protein-type drugs into the colon medium by preventing their degradation in acidic gastric fluid.

Fabrication of Quaternized Chitosan Nanoparticles Using Tripolyphosphate/Genipin Dual Cross-Linkers as a Protein Delivery System.

Various amounts of 2-((acryloyloxy)ethyl)trimethylammonium chloride were grafted onto chitosan (CS) via redox polymerization method to obtain water-soluble quaternized CS (QCS). The QCS nanoparticles loaded with bovine serum albumin (BSA) were then produced by ionic gelation with tripolyphosphate (TPP) and further covalently cross-linked with genipin. The formation of QCS nanoparticles was optimized as a function of monomer grafting yield, QCS/TPP weight ratio, and QCS/genipin weight ratio by Box-Behnken design and response surface methodology. The results showed that QCS nanoparticles prepared with a grafting yield of 50%, QCS/TPP weight ratio of 7.67, and QCS/genipin weight ratio of 60 had a particle size of 193.68 ± 44.92 nm, polydispersity of 0.232, zeta potential of +23.97 mV and BSA encapsulation efficiency of 46.37 ± 2.89%, which were close to the predicted values from mathematical models. In vitro drug release studies at pH 1.2 and pH 7.4 exhibited that the release rate of BSA was significantly decreased and the release period was significantly prolonged after QCS nanoparticles cross-linking with genipin. Therefore, QCS nanoparticles cross-linked with TPP/genipin dual cross-linkers may be a promising protein drug carrier for a prolonged and sustained delivery.

Immobilization of Bovine Serum Albumin on the Chitosan/PVA Film

Chitosan/polyvinyl alcohol (Chitosan/PVA) blended film was prepared by direct blend process and solution casting methods. In order to reduce the swelling ratio and enhance the chemical and mechanical stability, Chitosan/PVA film was cross-linked with glutaraldehyde in order to produce Chitosan-g-PVA. Bovine serum albumin (BSA) was used as a model protein to incorporate into the Chitosan-g-PVA. The chemical structure and morphological characteristics of films were studied by FT-IR and scanning electron microscopy (SEM). Mechanical and physical properties of blended films such as tensile properties in the dry and wet states, water uptake and water contact angle measurement were characterized. Blending PVA and chitosan improved strength and flexibility of the films. Crosslinking with glutaraldehyde further improves the tensile strength and decrease the hydrophilicity of films. BSA immobilized on the Chitosan-g-PVA film was calculated as BSA encapsulation efficiency.

Preparation and Characterization of Copolymeric Polymersomes for Protein Delivery.

Biodegradable copolymeric polymersomes have been used for controlled drug delivery of proteins. These polymersomes important areas to overcome formulation associated problems of the proteins. The aim of this study was to develop polymersomes using biodegradable copolymers for delivery of bovine serum albumin (BSA) as a model protein. Encapsulated BSA by mPEG-PCL polymersomes led to formation of BSA-loaded mPEG-PCL polymersomes. The polymersomes synthesized with the protein-polymer ratio of 1:4 at 15 000 rpm gave maximum loading, minimum polydispersion with maximally sustained protein release pattern, among the prepared polymersomes. Investigation on FTIR and DSC results revealed that such a high encapsulation efficiency is due to strong interaction between BSA and the copolymer.The particles size and their morphology of polymersomes were determined by DLS and AFM.The encapsulation efficiency of BSA was 91.02%. The results of AFM showed that the polymersomes had spherical shapes with size of 49 nm.The sizes of BSA-loaded polymersomes ranged from 66.06 nm to 84.97 nm. The results showed that polymersomes exhibited a triphasic release, for BSA. Overall, the results indicated that mPEG-PCL polymersomes can be considered as a promising carrier for proteins.

Preparation of PLGA microspheres with different porous morphologies

Poly(D,L-lactide-co-glycolide) (PLGA) microspheres were prepared by emulsion solvent evaporation method. The influences of inner aqueous phase, organic solvent, PLGA concentration on the morphology of microspheres were studied. The results showed that addition of porogen or surfactants to the inner aqueous phase, types of organic solvents and polymer concentration affected greatly the microsphere morphology. When dichloromethane was adopted as organic solvent, microspheres with porous structure were produced. When ethyl acetate served as organic solvent, two different morphologies were obtained. One was hollow microspheres with thin porous shell under a lower PLGA concentration, another was erythrocyte-like microspheres under a higher PLGA concentration. Three types of microspheres including porous, hollow core with thin porous shell (denoted by hollow in brief) and solid structures were finally selected for in vitro drug release tests. Bovine serum albumin (BSA) was chosen as model drug and encapsulated within the microspheres. The BSA encapsulation efficiency of porous, hollow and solid microspheres was respectively 90.4%, 79.8% and 0. And the ultimate accumulative release was respectively 74.5%, 58.9% and 0. The release rate of porous microspheres was much slower than that of hollow microspheres. The experiment results indicated that microspheres with different porous structures showed great potentials in controlling drug release behavior.

Encapsulation of albumin in self-assembled layer-by-layer microcapsules: comparison of co-precipitation and adsorption techniques

Objective: The objective of this study is to prepare and characterize polymeric self-assembled layer-by-layer microcapsules (LbL-MC) to deliver a model protein, bovine serum albumin (BSA). The aim is to compare the BSA encapsulation in LbL-MC using co-precipitation and adsorption methods.Materials and methods: In co-precipitation method, BSA was co-precipitated with growing calcium carbonate particles to form a core template. Later, poly(styrene sulfonate) and poly(allylamine hydrochloride) were sequentially adsorbed onto the CaCO3 templates. In adsorption method, preformed LbL-MC were incubated with BSA and encapsulation efficiency is optimized for pH and salt concentration. Free and BSA-encapsulated LbL-MC were characterized using Zetasizer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and differential scanning calorimeter. Later, in vitro release studies were performed using dialysis membrane method at pH 4, 7.4 and 9.Results and discussion: Results from Zetasizer and SEM showed free LbL-MC with an average size and zeta-potential of 2.0 ± 0.6 μm and 8.1 ± 1.9 mV, respectively. Zeta-potential of BSA-loaded LbL-MC was (–)7.4 ± 0.7 mV and (–)5.7 ± 1.0 mV for co-precipitation and adsorption methods, respectively. In adsorption method, BSA encapsulation in LbL-MC was found to be greater at pH 6.0 and 0.2 M NaCl. Co-precipitation method provided four-fold greater encapsulation efficiency (%) of BSA in LbL-MC compared with adsorption method. At pH 4, the BSA release from LbL-MC was extended up to 120 h. Polyacrylamide gel electrophoresis showed that BSA encapsulated in LBL-MC through co-precipitation is stable toward trypsin treatment.Conclusion: In conclusion, co-precipitation method provided greater encapsulation of BSA in LbL-MC. Furthermore, LbL-MC can be developed as carriers for pH-controlled protein delivery.

Protein encapsulated core–shell structured particles prepared by coaxial electrospraying: Investigation on material and processing variables

Biodegradable polymeric particles have been extensively investigated for controlled drug delivery of various therapeutic agents. ‘Coaxial’ electrospraying was successfully employed in this study, to fabricate core–shell PLGA particles containing bovine serum albumin (BSA) as the model protein, and the results were also compared to particles prepared by ‘emulsion’ electrospraying. Two different molecular weights of PLGA were employed to encapsulate the protein. Solution properties and processing parameters were found to influence the morphology of the core–shell particles. Depending on the type of solvent used to dissolve the polymer as well as the polymer concentration and molecular weight, the mean diameter of the particles varied between 3.0 to 5.5μm. Fluorescence microscopic analysis of the electrosprayed particles using FITC-conjugated BSA demonstrated the core–shell structure of the developed particles. The encapsulation efficiency and release behavior of BSA was influenced by shell:core feeding ratio, protein concentration, and the electrospraying method. The encapsulation efficiency of BSA within the core–shell particles of high and low molecular weight PLGA was found 15.7% and 25.1% higher than the emulsion electrosprayed particles, respectively. Moreover, the total amount of BSA released from low molecular weight PLGA particles was significantly higher than high molecular weight PLGA particles within 43 days of release studies, with negligible effect on encapsulation efficiency. The technique of coaxial electrospraying has high potential for encapsulation of susceptible protein-based therapeutic agents such as growth factors for multiple drug delivery applications.

Development and characterization of GRGDSPC-modified poly(lactide-co-glycolide acid) porous microspheres incorporated with protein-loaded chitosan microspheres for bone tissue engineering

Scaffolds that can achieve cell adhesion and controlled release of protein drugs are very promising in bone tissue engineering. Due to their biocompatibility and injectablity, poly(lactide-co-glycolide acid) (PLGA) porous microspheres (PLGA-pMS) present potential scaffolds in bone tissue engineering. However, their application is hampered by the burst release of protein drugs and hydrophobicity that leads to poor cell adhesion. To overcome these drawbacks, we developed novel PLGA-pMS by incorporating bovine serum albumin (BSA) loaded chitosan microspheres (CS-MS) in Gly-Arg-Gly-Asp-Ser-Pro-Cys (GRGDSPC) modified PLGA-pMS (CS-MS/PLGA-pMS). GRGDSPC was used to enhance the hydrophilicity and cell affinity of the porous microspheres. Results showed that PLGA-pMS had a size of 446.77±19.46μm, with an average surface pore size of 21.56±3.02μm, whereas CS-MS had a size of 15.98±0.96μm and 16.35±0.38μm (5% and 10% TPP-prepared CS-MS, respectively). A scanning electron microscope (SEM) and a confocal laser scanning microscope (CLSM) revealed that CS-MS were partly embedded in the PLGA matrices and the integrity of CS-MS was retained. Thermogravimetry analyzer (TGA) also demonstrated that CS-MS were incorporated into PLGA-pMS. The CS-MS/PLGA-pMS had a size of 454.02±16.09μm, with a BSA encapsulation efficiency of 53.19±1.67% and 62.16±3.44% (5% and 10% TPP-prepared CS-MS, respectively). CS-MS/PLGA-pMS exhibited a sustained FITC-BSA release for 28 days. Modification of GRGDSPC significantly improved adhesion of MG-63 cells on the porous microspheres. In conclusion, CS-MS/PLGA-pMS may act as potential bifunctional scaffolds for bone tissue engineering.

Microfluidics-assisted engineering of polymeric microcapsules with high encapsulation efficiency for protein drug delivery

In this study, microfluidic technology was employed to develop protein formulations. The microcapsules were produced with a biphasic flow to create water–oil–water (W/O/W) double emulsion droplets with ultrathin shells. Optimized microcapsule formulations containing 1% (w/w) bovine serum albumin (BSA) in the inner phase were prepared with poly(vinyl alcohol), polycaprolactone and polyethylene glycol. All the particles were found to be intact and with a particle size of 23–47μm. Furthermore, the particles were monodisperse, non-porous and stable up to 4 weeks. The encapsulation efficiency of BSA in the microcapsules was 84%. The microcapsules released 30% of their content within 168h. This study demonstrates that microfluidics is a powerful technique for engineering formulations for therapeutic proteins.

Pulsatile protein release from monodisperse liquid-core microcapsules of controllable shell thickness.

Pulsatile delivery of proteins, in which release occurs over a short time after a period of little or no release, is desirable for many applications. This paper investigates the effect of biodegradable polymer shell thickness on pulsatile protein release from biodegradable polymer microcapsules. Using precision particle fabrication (PPF) technology, monodisperse microcapsules were fabricated encapsulating bovine serum albumin (BSA) in a liquid core surrounded by a drug-free poly(lactide-co-glycolide) (PLG) shell of uniform, controlled thickness from 14 to 19 μm. When using high molecular weight PLG (Mw 88 kDa), microparticles exhibited the desired core-shell structure with high BSA loading and encapsulation efficiency (55-65%). These particles exhibited very slow release of BSA for several weeks followed by rapid release of 80-90% of the encapsulated BSA within 7 days. Importantly, with increasing shell thickness the starting time of the pulsatile release could be controlled from 25 to 35 days. Biodegradable polymer microcapsules with precisely controlled shell thickness provide pulsatile release with enhanced control of release profiles.

Protein Encapsulation in and Release from Monodisperse Double-Wall Polymer Microspheres

Biodegradable polymer double-wall microspheres (DWMS) are promising vehicles for macromolecular therapeutics such as proteins and peptides. Using precision particle fabrication (PPF) technology, uniform DWMS with outer diameter approximately 55 μm were fabricated comprising poly(lactide-co-glycolide) cores encapsulating bovine serum albumin (BSA) and approximately 10 μm thick, drug-free, poly(lactic acid) (PLA) shells of varying PLA molecular weight. Also, monolithic single-wall microspheres (SWMS) were fabricated to mimic the BSA-loaded core. The use of relatively fast-extracting ethyl acetate and slowly extracting dichloromethane as shell- and core-phase solvents, respectively, was found to produce DWMS with well-defined core-shell structure, high BSA encapsulation efficiency, and the desired localization of protein in the particle core. Initial protein distribution, particle erosion, and in vitro protein release from DWMS and SWMS were examined. The presence of a BSA-free shell in DWMS decreased the protein release rate and extended the duration of release from approximately 50 days to 70-80 days, demonstrating the capacity of such DWMS to provide enhanced control of protein delivery rates.

Preparation and Protein Immobilization of Magnetic Dialdehyde Starch Nanoparticles

Superparamagnetic Fe3O4 nanoparticles were obtained using a hydrolysis product of starch, i.e., α-d-glucose, as the reducing agent and without any additional stabilizer and dispersant by a facile and green method at mild temperature. Magnetic dialdehyde starch nanoparticles (MDASN) were successfully synthesized with dialdehyde starch (DAS) as wrapper and epichlorohydrin as cross-linker by coembedding method. Bovine serum albumin (BSA) as a model drug was immobilized on the suface of MDASN. The particle size distribution of MDASN was 50-150 nm, and the average size was about 100 nm. The content of aldehyde group in DAS was 59.5%, and the package rate of DAS in MDASN was 33.2%. The loading amount and encapsulation efficiency of MDASN loading BSA were 5.0% and 54.4%, respectively. The saturation magnetization of MDASN at 300 K was 29.5 emu/g without coercivity and remanence. The as-prepared MDASN have not only lots of aldehyde functional groups but also stronger magnetic response, which might have potential applications such as drug carriers and targeted drug release.

Chitosan nanoparticles as therapeutic protein nanocarriers: The effect of ph on particle formation and encapsulation efficiency

In the past, tripolyphosphate (TPP)‐crosslinked chitosan (CS) nanoparticles (CSNPs) have been widely applied for the delivery of biomacromolecules, because of their mild preparation conditions. However, poor uniformity and burst release limit their application to some extent. In this study, we investigated the effect of pH on the formation and on protein encapsulation efficiency (EE) of CSNPs. Results revealed that smaller particles are formed at lower pH and that the size distribution is conjointly influenced by pH and CS/TPP mass ratio. EE of bovine serum albumin (BSA) increased significantly with pH value. The influence of the pH of the crosslinker (TPP) solution was also studied, showing that CSNPs prepared with basic TPP solution (pH 9.5) had larger size, higher yield, and BSA EE compared with those obtained with acidic TPP solution (pH 5.5). Characterization by Fourier transform infrared‐attenuated total Reflectance (FTIR‐ATR) spectroscopy and SEM as well as the in vitro BSA release analysis revealed that the pH of the TPP solution might influence CSNPs' properties, by changing the conformation of polymer chains. This study analyzes the formation of CSNPs and protein encapsulation mechanisms at different pH values of both the polymer and the crosslinker solutions, suggesting strategies to overcome some of the major drawbacks of CSNPs as protein nanocarriers for therapeutic applications. POLYM. COMPOS., 34:1538–1545, 2013. © 2013 Society of Plastics Engineers

Quaternized chitosan–organic rectorite intercalated composites based nanoparticles for protein controlled release

Organic rectorite (OREC) was added in the quaternized chitosan (QC)/alginate (ALG) nanoparticles using an ionic gelation method to fabricate a controllable release system for proteins for the first time. The morphology of nanoparticles, the intercalated structure of OREC, bovine serum albumin encapsulation efficiency and in vitro release properties were investigated. Fourier transform infrared spectra, energy dispersive X-ray, X-ray photoelectron spectroscopy, small angle X-ray diffraction and size distribution analysis were performed to characterize the composite nanoparticles. With the addition of OREC, the encapsulation efficiency and the loading capacity of nanoparticles had increased from 21.2% to 44.9% and from 13.7% to 25.0%, respectively. In addition, the rapid initial release was inhibited successfully from 20.15% to 11.07% in stimulated gastric fluid and from 14.69% to 4.52% in stimulated intestinal fluid. The results verified that the addition of OREC could make these nanoparticles effective carriers to encapsulate drug and slow the drug controlled release of nanoparticles.

Polysaccharides-based spray-dried microspheres for maintained stability and controlled release of protein

Spray-dried microspheres based on polysaccharides were developed and the conformational stability and controlled release of incorporated protein were evaluated using bovine serum albumin (BSA) as a model protein. Microspheres composed of water soluble chitosan (WCS), hydroxypropyl-β-cyclodextrin (HP-β-CD) and polyethylene glycol (PEG) were prepared by spray dying. WCS was used as a mucoadhesive and biocompatible polymer. HP-β-CD and PEG were used as protein stabilizer during the spray drying process. Microspheres with 6–7 μm of mean diameter were successfully developed. Encapsulation efficiency of BSA in microsphere was over 70 %. Primary, secondary and tertiary structure of incorporated BSA in microsphere was analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, circular dichroism, and fluorescence intensity measurement, respectively. Conformational stability of BSA was maintained during the spray drying process. BSA release from microspheres was evaluated in in vitro model using the Transwell® insert, and showed a sustained release profile compared to naive BSA. Thus, these microspheres could possibly serve as an optimized delivery system for preserved stability and sustained release of protein.