Pharmacological properties of traditional medicine (XXX): effects of Gyokuheifusan ([Symbol: see text]) on murine antigen-specific antibody production

In the theory of traditional Chinese medicine (TCM), eqi ([Symbol: see text]) circulates at the superficial portion of the body to guard against exopathogen. Gyokuheifusan (GHS; [Symbol: see text]), containing Astragalus Root, Atractylodes Rhizome, and Saposhnikovia Root, is a TCM formula to treat the insufficiency of eqi by invigorating qi and consolidating the superficial resistance. In this study, we evaluated the effect of GHS on murine antibody production against ovalbumin (OVA) used as exopathogen. Balb/c mice were sensitized with OVA and alum via intraperitoneal (i.p.) injection or intranasal (i.n.) infusion daily for 7 d. GHS was orally administered daily at the dose of 10-times amount of human daily dosage from 3 d before the sensitization for 14 d. Fourteen d after the final sensitization, the blood was collected, and the concentrations of OVA-specific or non-specific immunoglobulins were measured. When OVA was sensitized i.p., the concentration of OVA-specific IgG, IgG1, IgG2a and IgA in the sera significantly increased by GHS-treatment. When OVA was sensitized i.n., GHS significantly reduce the concentration of OVA-specific IgG and IgG1 in the sera. Non-specific immunoglobulins were not changed by GHS-treatment. It is suggested that GHS could stimulate immune responses when antigen had already been invaded into the inside of the body, and that GHS might consolidate the resistance of nasal mucosa to protect from the invasion of OVA, then OVA-specific antibodies in sera might be hypocritically suppressed. The present study might provide the experimental evidence for TCM theory.     

Enhanced mucosal and systemic immune response with squalane oil-containing multiple emulsions upon intranasal and oral administration in mice

The objective of this study was to develop and evaluate squalane oil-containing water-in-oil-in-water (W/O/W) multiple emulsion for mucosal administration of ovalbumin (OVA) as a model candidate vaccine in BALB/c mice. Control and optimized OVA-containing W/O/W emulsion (OVA-Emul) and chitosan-modified W/O/W emulsion (OVA-Emul-Chi) formulations were administered intranasally and orally at an OVA dose of 100 mug. The mucosal and systemic immune responses were evaluated after the first and second immunization. The OVA-Emul formulations resulted in higher immunoglobulin-G (IgG) and immunoglobulin-A (IgA) responses as compared with aqueous solution. In addition, significant IgG and IgA responses were observed after the second immunization dose using the emulsions with both routes of administration. Intranasal vaccination was more effective in generating the systemic OVA-specific IgG response than the mucosal OVA-specific IgA response. Oral immunizations, on the other hand, showed a much higher systemic IgG and mucosal IgA responses as compared with the nasally treated groups. The results of this study show that squalane oil-containing W/O/W multiple emulsion formulations can significantly enhance the local and systemic immune responses, especially after oral administration, and may be adopted as a better alternative in mucosal delivery of prophylactic and therapeutic vaccines.     

Methylated N-(4-N,N-dimethylaminocinnamyl) chitosan-coated electrospray OVA-loaded microparticles for oral vaccination

The purpose of this study was to prepare microparticles entrapping ovalbumin (OVA) as a model antigen to induce immune responses in mice following oral vaccination. In this study, calcium-alginate and calcium-yam-alginate microparticles were prepared by crosslinking alginate with calcium chloride solution using an electrospraying technique. 0.1% (w/v) of methylated N-(4-N,N-dimethylaminocinnamyl) chitosan (TM₆₅CM₅₀CS) was used to coat microparticles entrapping an initial OVA of 20% w/w to polymer. The results indicated that the coated microparticles were spherical and had a smooth surface, with an average size of 1–3 μm, and were positively charged. In addition, the particles demonstrated a greater swelling and mucoadhesive properties than did uncoated microparticles. The in vitro release from the microparticles indicated that the coated microparticles resulted in more sustained release than uncoated microparticles. The cytotoxicity results showed that all of the formulations were safe. The in vivo oral administration demonstrated that at the same amount of 250 μg OVA, coated microparticles exhibited the highest in vivo adjuvant activity in both IgG and IgA immunogenicity.     

Nivalenol inhibits total and antigen-specific IgE production in mice

Nivalenol (NIV) has been reported to induce hyperproduction of IgA, which is regulated by T-helper 2 cells (Th2); however, whether IgE production, which is under the regulation of Th2 cells, is induced by this compound remains largely unknown. We examined the effect of NIV on antigen-specific IgE production using ovalbumin (OVA)-specific T cell receptor alphabeta-transgenic mice. The mice produced significant amounts of total and antigen-specific IgE, IgG1, and IgA in serum when given OVA orally. Administration of NIV with OVA suppressed total IgE and OVA-specific IgE, IgG1, and IgA production significantly. Cytokine assay using splenocytes obtained from mice given the OVA plus NIV diet revealed that interleukin 4 (IL-4) production was suppressed and interleuin-2 (IL-2) production was enhanced. These results suggest that the inhibition of IL-4 production and enhancement of IL-2 production induced by NIV suppressed total and antigen-specific IgE production.     

The mechanism of PLA microparticle formation by water-in-oil-in-water solvent evaporation method

Microparticles containing ovalbumin as a model protein drug were prepared using poly(L-lactide; PLA) with a water-in-oil-in-water emulsion/solvent evaporation technique. The dispersed phase was PLA dissolved in dichloromethane (DCM), and the continuous phase was water-containing polyvinyl pyrolidone (PVP) as stabilizer with sodium chloride. Microparticle characteristics, loading efficiencies, protein distribution in microparticles, and in-vitro release properties were investigated. The OVA leaking into the continuous phase during the formation of microparticle by DCM evaporation was also evaluated. Results show that OVA was successfully entrapped in the microparticles with trapping efficiencies up to 72%, loading level 8.7% w/v, and particle size 14 microm. The semi-solid suspension changes to a solid particle happened during a 10-min period. Total protein-leaking amount was reduced after addition of NaCl in the continuous aqueous phase, which resulted from reducing the solidification time and protein-leaking rate. Using 5% w/v NaCl in the continuous phase resulted in higher loading content (87.2 +/- 1.0 microg/mg), and loading efficiency (72.2%), which resulted from more protein in the deeper layer (50.2 +/- 2.3 microg/mg) and higher microparticle yield (75.2%) than without NaCl (loading content: 74.0 +/- 1.0 microg/mg; loading efficiency 51.8%; deeper layer content: 18.3 +/- 3.5 microg/mg; yield: 63.6%). These results constitute a step forward in the improvement of existing technology in controlling protein encapsulation and delivery from microparticles prepared by the multiple emulsion solvent evaporation method.     

Optimizing formulation factors in preparing chitosan microparticles by spray-drying method

The chitosan only, chitosan/Pluronic F68, chitosan/gelatin, chitosan/Pluronic F68/gelatin microparticles and betamethasone-loaded chitosan/Pluronic F68/gelatin microparticles were successfully prepared by a spray-drying method. Microparticle characteristics (yield rate, zeta potential, particle size and tap density), loading efficiencies, microparticle morphology and in-vitro release properties were investigated. By properly choosing excipient type, concentration and varying the spray-drying parameters, a high degree of control was achieved over the physical properties of the dry chitosan powders. SEM micrograph shows that the particle sizes of the varied chitosan composed microparticles ranged from 2.12-5.67 microm and the external surfaces appear smooth. Using betamethasone as model drug, the spray-drying is a promising way to produce good spherical and smooth surface microparticles with a narrow particle size range for controlled delivery of betamethasone. The positively charged betamethasone-loaded microparticles entrapped in the chitosan/Pluronic F68/gelatin microparticles with trapping efficiencies up to 94.5%, yield rate 42.5% and mean particle size 5.64 microm varied between 4.32-6.20 microm and tap densities 0.128 g/cm(3). The pH of particle was increased with increasing betamethasone-loaded amount, but both zeta potential and tap density of the particles decreased with increasing betamethasone-loaded amount. The betamethasone release rates from chitosan/Pluronic F68/gelatin microparticles were influenced by the drug/polymer ratio in the manner that an increase in the release% and burst release% was observed when the drug loading was decreased. The in vitro release of betamethasone showed a dose-dependent burst followed by a slower release phase that was proportional to the drug concentration in the concentration range between 14-44%w/w.     

Novel preparation of enteric-coated chitosan-prednisolone conjugate microspheres and in vitro evaluation of their potential as a colonic delivery system.

After chitosan-succinyl-prednisolone conjugate (Ch-SP) was synthesized, conjugate microspheres (Ch-SP-MS), Eudragit L100-coated Ch-SP-MS and Eudragit S100-coated Ch-SP-MS, were prepared under novel preparative conditions. Namely, sonication was utilized to prepare finer Ch-SP-MS, and the addition ratio of Eudragit was reduced to yield Eudragit-coated Ch-SP-MS with higher drug content. Ch-SP-MS and Eudragit-coated Ch-SP-MS had mean sizes of 1.3microm and approximately 30microm, respectively, and showed prednisolone (PD) contents of 4.6% (w/w) and approximately 3% (w/w), respectively. Morphological changes of all the types of microparticles in different pH media were observed by scanning electron microscopy and confocal laser scanning microscopy. Both methods gave similar results. Both types of Eudragit-coated Ch-SP-MS protected Ch-SP-MS from morphological change at pH 1.2, and regenerated Ch-SP-MS fast at pH 6.8 and 7.4. For all types of microparticles, release of PD was suppressed at pH 1.2, but caused gradually at pH 6.8. These particle characteristics and in vitro behaviors demonstrated that the present Eudragit-coated Ch-SP-MS were considered potentially suitable for in vivo or practical application as a specific delivery system of PD to IBD sites.     

Adjuvant effects of inhaled mono-2-ethylhexyl phthalate in BALB/cJ mice

Phthalates, including di(2-ethylhexyl) phthalate (DEHP), are widely used and have been linked with the development of wheezing and asthma. The main metabolite of DEHP, mono-2-ethylhexyl phthalate (MEHP), was investigated for adjuvant effects in a mouse inhalation model. BALB/cJ mice were exposed to aerosols of 0.03 or 0.4 mg/m(3) MEHP 5 days/week for 2 weeks and thereafter weekly for 12 weeks together with a low dose of ovalbumin (OVA) as a model allergen. Mice exposed to OVA alone or OVA+Al(OH)(3) served as negative and positive controls, respectively. Finally, all groups were exposed to a nebulized 1% OVA solution on 3 consecutive days to investigate the development of an inflammatory response. Serum, bronchoalveolar lavage (BAL) fluid, and draining lymph nodes were collected 24h later. In the OVA+Al(OH)(3) group, significantly increased levels of OVA-specific IgE and IgG1 in serum as well as of eosinophils in BAL fluid were observed. OVA-specific IgG1 production in both MEHP groups was significantly increased. OVA-specific IgE and IgG2a were not increased significantly. A dose-dependent increase in inflammatory cells was observed in BAL fluid, leading to significantly higher lymphocyte and eosinophil numbers in the OVA+0.4 mg/m(3) MEHP group. Ex vivo cytokine secretion by cultures of draining lymph nodes suggested a T(H)2 profile of MEHP. In conclusion, MEHP acted as a T(H)2 adjuvant after inhalation. However, it is suggested that the inflammation in the MEHP groups was primarily mediated by an IgG1-dependent mechanism. To address implications for humans, a margin-of-exposure was estimated based on the lack of significant effects on IgE production and inflammation after exposures to 0.03 mg/m(3) MEHP observed in the present study and estimated human exposure levels.     

The mechanism of PLA microparticle formation by waterin-oil-in-water solvent evaporation method

Microparticles containing ovalbumin as a model protein drug were prepared using poly(L-lactide; PLA) with a water-in-oil-in-water emulsion/solvent evaporation technique. The dispersed phase was PLA dissolved in dichloromethane (DCM), and the continuous phase was water-containing polyvinyl pyrolidone (PVP) as stabilizer with sodium chloride. Microparticle characteristics, loading efficiencies, protein distribution in microparticles, and in-vitro release properties were investigated. The OVA leaking into the continuous phase during the formation of microparticle by DCM evaporation was also evaluated. Results show that OVA was successfully entrapped in the microparticles with trapping efficiencies up to 72%, loading level 8.7% w/v, and particle size 14 #181;m. The semi-solid suspension changes to a solid particle happened during a 10-min period. Total protein-leaking amount was reduced after addition of NaCl in the continuous aqueous phase, which resulted from reducing the solidification time and protein-leaking rate. Using 5% w/v NaCl in the continuous phase resulted in higher loading content (87.2 1.0 #181;g/mg), and loading efficiency (72.2%), which resulted from more protein in the deeper layer (50.2 2.3 #181;g/mg) and higher microparticle yield (75.2%) than without NaCl (loading content: 74.0 1.0 #181;g/mg; loading efficiency 51.8%; deeper layer content: 18.3 3.5 #181;g/mg; yield: 63.6%). These results constitute a step forward in the improvement of existing technology in controlling protein encapsulation and delivery from microparticles prepared by the multiple emulsion solvent evaporation method.     

The preparation of sustained release erythropoietin microparticle

PURPOSE: Protein microencapsulation in biodegradable polymers is a promising route to provide for sustained release. The erythropoietin (EPO) microparticles are using human serum albumin (HSA) and poly-L-lysine (PK) as the protection complex to increased EPO integrity, entrapped efficiency and active EPO release by w/o/w solvent evaporation techniques. The optimum formulation development process was also reported by using FITC-OVA as a model protein. METHODS: The model protein FITC-ovalbumin and EPO are protected by human serum albumin and poly-L-lysine complex and encapsulated in 50:50 poly(DL-lactide-co-glycolide) by a w/o/w solvent evaporation method. Protein active integrity and degradation compound is measured by size-exclusion chromatography. Protein-loaded microparticle physical properties and in vitro active and degradation compounds release profile are characterized. RESULTS: High active integrity protein loading efficiency and particle yield of EPO or OVA-HSA/PK-loaded PLG microparticles are successfully produced by a w/o/w solvent evaporation method. Varied protection protein complex formulations and encapsulation processes are investigated. The high OVA model protein loading efficiency (80.2%), FITC-OVA content (0.24 microg mg(-1)) and yield (72.4%) are obtained by adding 100 microg mL(-1) FITC-OVA complex with 10% HSA/0.05% PK (Mw 1.5-3 kD) in the initial solution to protect the model protein. In vitro release profiles show more active OVA release from HSA/PK OVA-loaded than OVA-loaded only microparticles and also the amount of degraded protein that comes out after 3 weeks incubated in the PBS medium for OVA-loaded only microparticles is observed. The same formulation and preparation process resulted in EPO loading efficiency (68.4%), EPO content (0.23 microg mg(-1)) and yield (76.1%) for HSA/PK EPO-loaded microparticles. In vitro release profiles show active EPO sustained release over 7 days. Using HSA/PK as carried in the primary emulsion of EPO-loaded microparticles resulted in less burst release% than EPO-loaded only microparticles.     

Preparation of double liposomes and their efficiency as an oral vaccine carrier

The usefulness of double liposomes (DL), liposomes containing liposomes inside, as an oral vaccine carrier was examined. Ovalbumin (OVA) encapsulating liposomes sized to 230 nm (small liposomes, SL) were prepared by the glass-beads (GB) method and sequential sonication and extrusion. For the purpose of stabilizing the model antigen, DL containing SL were prepared by the GB method and the reverse-phase evaporation (REV) method. They were named GB-DL and REV-DL, respectively. The morphological structure of DL was confirmed using confocal laser scanning microscopy and scanning electron microscopy by the freeze-fracture method. DL showed suppressed release of OVA and stabilized OVA in pepsin solution as compared with SL. BALB/c mice were immunized with OVA solution, SL and DL suspension by oral administration. Significantly higher levels of IgA in feces were observed in mice immunized with SL and REV-DL as compared with OVA solution, and REV-DL tended to show the higher level of IgA than SL. REV-DL elicited significantly higher anti-OVA IgG responses as compared with OVA solution. Furthermore, GB-DL tended to raise the IgG level as compared with SL. The results suggest that DL have the potential to be an effective carrier for oral immunization.     

Airway inflammation and adjuvant effect after repeated airborne exposures to di-(2-ethylhexyl)phthalate and ovalbumin in BALB/c mice

BACKGROUND: Epidemiological studies have suggested an association between exposure to phthalate plasticizers, including di-(2-ethylhexyl)phthalate (DEHP), and increased prevalence of asthma, rhinitis or wheezing. Furthermore, studies in mice have demonstrated an adjuvant effect from DEHP after parenteral administration with the model allergen ovalbumin (OVA). OBJECTIVE: Exposures to DEHP were investigated for adjuvant effects and airway inflammation in a mouse inhalation model. METHODS: BALB/cJ mice were exposed to aerosols of 0.022-13 mg/m(3) DEHP and 0.14 mg/m(3) OVA 5 days/week for 2 weeks and thereafter weekly for 12 weeks. Mice exposed to OVA alone or OVA+Al(OH)(3) served as control groups. Finally, all groups were exposed to a nebulized 1% OVA solution on three consecutive days. Serum, bronchoalveolar lavage (BAL) fluid, and draining lymph nodes were collected 24h later. RESULTS: In the OVA+Al(OH)(3) group, significantly increased levels of OVA-specific IgE and IgG1 in serum as well as of eosinophils in BAL fluid were observed. DEHP affected OVA-specific IgG1 production in a concentration-dependent manner, whereas little effect was seen on IgE and IgG2a. Dose-dependent increases in inflammatory cells were observed in BAL fluids, leading to significantly higher lymphocyte, neutrophil and eosinophil numbers in the OVA+13 mg/m(3) DEHP group. Ex vivo cytokine secretion by cultures of draining lymph nodes suggested that DEHP has a mixed Th1/Th2 cytokine profile. CONCLUSION: Airborne DEHP is able to increase serum IgG1 and lung inflammatory cell levels, but only at very high concentrations. Realistic DEHP levels do not have an adjuvant effect or induce allergic lung inflammation in the present mouse model.     

Prolonged intestinal absorption of cephradine with chitosan-coated ethylcellulose microparticles in rats

Cephradine-containing ethylcellulose microparticles (MPC) were prepared by the solvent evaporation method. Chitosan-coated MPC (Chi-MPC) were prepared by doping MPC with viscous chitosan solution and subsequently drying. When fluorescein isothiocyanate (FITC)-labeled chitosan-coated ethylcellulose microparticles without drug were administered intraduodenally, they moved slowly in the intestine, that is, most of them were retained at the upper and middle parts of the small intestine for more than 8 h, which is considered due to mucoadhesive properties of coated chitosan. When MPC and Chi-MPC was incubated at 37 degrees C in the JP 14 second fluid, pH 6.8, both released the drug slowly with similar release rates. Cephradine solution and suspension, MPC and Chi-MPC were administered intraduodenally to investigate intestinal drug absorption. Only Chi-MPC suppressed the initial plasma level and maintained the plasma concentration for a long time up to 24 h, suggesting Chi-MPC would be useful for prolonged intestinal absorption of cephradine.     

Novel Chitosan Particles and Chitosan-Coated Emulsions Inducing Immune Response via Intranasal Vaccine Delivery

PURPOSE: The aim of this study was to prepare a novel vaccine carrier particulate system (nanoparticles and emulsions) with chitosan and to evaluate the effect of this system on the immune response for intranasal delivery. METHODS: Chitosan nanoparticles (NP) and chitosan-coated emulsions (CC-Emul) were prepared by improvement of the method previously reported and by modified ethanol injection methods, respectively. The rats were immunized with the particles adsorbed with ovalbumin (OVA) and cholera toxin (CT) by intranasal (i.n.) and intraperitoneal (i.p.) administration. RESULTS: NP and CC-Emul could be prepared with particle diameter from about 0.4 microm to 3 microm. IgG induced by i.n. of NP was comparable with that by i.p., and IgA induced by i.n. of 0.4-microm- and 1-microm-size NP was significantly higher than control (OVA and CT). IgG and IgA induced by i.n. of 2-microm-size CC-Emul were significantly higher than those with control. CONCLUSIONS: The novel chitosan particles used simple preparation methods showed high OVA adsorption. When administered intranasally, NP and CC-Emul induced systemic immune response in rats. These findings suggested that CC-Emul and the smaller-size (0.4 microm) NP are effective for targeting to nasal-associated lymphoid tissues (NALTs) in nasal vaccine delivery.     

Dichotomous effect of a traditional Japanese medicine, bu-zhong-yi-qi-tang on allergic asthma in mice

To determine the potentiality of prophylactic and/or therapeutic approaches using a traditional herbal medicine, Bu-zhong-yi-qi-tang (Japanese name: Hochu-ekki-to, HOT), for the control of allergic disease, we examined the effects of oral administration of HOT on a murine model of asthma allergic responses. When oral administration of HOT was begun at the induction phase immediately after OVA sensitization, eosinophilia and Th2-type cytokine production in the airway were reduced in OVA-sensitized mice following OVA inhalation. The serum levels of OVA-specific immunoglobulin (Ig)E and IgG1 were significantly decreased, whereas the level of OVA-specific IgG2a was increased. Interleukin (IL)-4 production by spleen T cells in response to OVA was significantly suppressed, while Interferon (IFN)-gamma production was increased in mice treated with HOT in the induction phase. On the other hand, HOT given in the eliciting phase induced a predominant Th2 response with increased IgE production in OVA-sensitized mice following OVA inhalation. These results suggest that the oral administration of HOT dichotomously modulates allergic inflammation in a murine model for asthma, thus offering a different approach for the treatment of allergic disorders.     

Inhibitory effect of DA-9201, an extract of Oryza sativa L., on airway inflammation and bronchial hyperresponsiveness in mouse asthma model

Asthma is one of the major public health problems worldwide and the morbidity and mortality of asthma has increased in the past two decades. Accumulating data suggest that unnecessary immune responses and inflammation should be suppressed to treat asthma. The purpose of this study is to investigate the anti-asthmatic effects of DA-9201, an ethanolic extract of black rice (Oryza sativa L. var japonica), on an ovalbumin (OVA)-induced mouse model of asthma. Balb/c mice immunized with OVA were administered with DA-9201 (30, 100 or 300 mg/kg, p.o.) or dexamethasone (3 mg/kg, p.o.) and challenged with 1% aerosolized OVA for 30 min. The effects on airway inflammation, airway hyperresponsiveness (AHR), antibody profiles and cytokines were evaluated. DA-9201 treatment significantly reduced the number of eosinophils in bronchoalveolar lavage fluid (BALF) and ameliorated the AHR. Lung histological features also showed that DA-9201 reduced airway inflammation. Furthermore, DA-9201 treatment decreased IFN-gamma as well as IL-4, IL-5 and IL-13 levels in the supernatant of cultured splenocytes, and suppressed the level of OVA-specific IgG, IgG2a, IgG1 and total IgE in plasma. DA-9201 showed anti-asthmatic effects by suppressing unnecessary immune responses, airway inflammation, eosinophilia, AHR and IgE level. These results suggest DA-9201 might be beneficial for the treatment of asthma.     

Characterization of alginate/poly-L-lysine particles as antisense oligonucleotide carriers

The gel forming characteristics of alginate in the presence of calcium ions and further crosslinking with poly-L-lysine led to the formation of sponge-like nano- and microparticles. The particle size was varied by adjusting the final concentrations of and proportions between the components. The region for particle formation was from 0.04 to 0.08% (w/v) of alginate in the final formulation, the change from the nm to microm size range occurred at a concentration of approx. 0.055% (w/v). Oligonucleotide-loaded microparticles were prepared by two different methods, either by absorption of the drug into the crosslinked polymeric matrix or by incorporation of an oligonucleotide/poly-L-lysine complex into a calcium alginate pre-gel. The release of oligonucleotide from microparticles prepared by the first method was higher. The addition of increasing amounts of poly-L-lysine resulted in larger particles, higher oligonucleotide loading and slower drug release. An increase in the final solid content of the formulation led to larger particles, especially with high concentrated calcium alginate pre-gels. Microparticles based on alginate and poly-L-lysine are potential carriers for antisense oligonucleotides.     

A BALB/c mouse model for assessing the potential allergenicity of proteins: Comparison of allergen dose,sensitization frequency,timepoint and sex

The present study was to investigate the possibility of using the BALB/c mouse as an animal model for assessing the potential allergenicity of proteins.Specific IgE and IgG1 against ovalbumin were induced by dosing BALB/c mice via intraperitoneal injection (absence of adjuvant). The effects of various allergen doses (5 mg, 0.5 mg or 0.05 mg OVA), sensitization times (twice or five times), timepoints (day 14 or day 28) and sex (male or female) were studied. IL-4, IFN-γ, OVA-specific IgE and IgG1 were measured by enzyme-linked immunosorbent assay (ELISA).A general finding was that mice treated with 0.05 mg OVA had the highest OVA-specific IgE and IgG1, statistically significant higher specific IgE and IgG1 were observed in groups sensitized five times than twice, OVA-specific IgE and IgG1 on day 28 were statistically higher than day 14, and higher IL-4 was observed in OVA-allergic mice than control mice.These results demonstrate that the BALB/c mouse model treated with 0.05 mg OVA intraperitoneally on days 0, 3, 6, 9, 12 might be used for further experiments. OVA-specific IgE and IgG1 should be detected on day 28. Further studies including reproducibility and other conditions were required before using the BALB/c mouse model for assessing the potential allergenicity of proteins.     

The Preparation and Characterization of Poly(lactide-co-glycolide) Microparticles. II. The Entrapment of a Model Protein Using a (Water-in-Oil)-in-Water Emulsion Solvent Evaporation Technique

Poly(lactide-co-glycolide) (PLG) microparticles with entrapped antigens have recently been investigated as controlled-release vaccines. This paper describes the preparation of PLG microparticles with an entrapped model antigen, ovalbumin (OVA), using a (water-in-oil)-in-water emulsion solvent evaporation technique. In a series of experiments, the effects of process parameters on particle size and OVA entrapment were investigated. It was found that smooth, spherical microparticles 1–2 µm in diameter containing up to 10% (w/w) OVA could be produced using a small volume of external aqueous phase containing a high concentration of emulsion stabilizer and a 1:5 antigen:polymer ratio. PAGE analysis, isoelectric focusing, and Western blotting of OVA released from the microparticles in vitro confirmed that the molecular weight and antigenicity of the protein remained largely unaltered by the entrapment procedure.     

The characteristics of betamethasone-loaded chitosan microparticles by spray-drying method

Betamethasone (BTM)-loaded microparticles prepared by a spray drying method using chitosan (CTS) as raw material, type-A gelatin and ethylene oxide-propylene oxide block copolymer (Pluronic F68) as modifiers. The BTM-loaded in varied chitosan/Pluronic F68/gelatin microparticle formulations was investigated. By properly choosing excipient type and concentration a high degree of control was achieved over the physical properties of the BTM-loaded microparticles. Microparticle characteristics (zeta potential, tap density, particle size and yield), loading efficiencies, microparticle morphology and in-vitro release properties were examined. Surface morphological characteristics and surface charges of prepared microparticles were observed by using scanning electron microscopy (SEM) and microelectrophoresis. A SEM micrograph shows that the particle sizes of the varied chitosan composed microparticles ranged from 1.1-4.7 microm and the external surfaces appear smooth. The BTM-loaded microparticles entrapped in the chitosan/Pluronic F68/gelatin microparticles with trapping efficiencies up to 93%, collected yield rate 44%, and mean particle size varied between 1-3 microm, positive surface charge (20-40 mv), and tap densities (0.04-0.40 g/cm3) were obtained. The collected BTM yield and size of particle was increased with increasing BTM-loaded amount but both zeta potential and tap density of the particles decreased with increasing BTM-loaded amount. The in vitro release of BTM showed a dose-dependent burst followed by a slower release phase that was proportional to the drug concentration in the concentration range between 5-30%w/w. The in vitro drug release from the chitosan/Pluronic F68/gelatin 1/0.1/0.4 microspheres had a prolong release pattern. These formulation factors were correlated to particulate characteristics for optimizing BTM microspheres in pulmonary delivery.