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1.
BACKGROUND: Pulmonary delivery of gene therapy offers the potential for the treatment of a range of lung conditions, including cystic fibrosis, asthma and lung cancer. Spray-drying may be used to prepare dry powders for inhalation; however, aerosolisation of such powders is limited, resulting in poor lung deposition and biological functionality. In this study, we examine the use of amino acids (arginine, aspartic acid, threonine, phenylalanine) to enhance the aerosolisation of spray-dried powders containing model non-viral gene vectors. METHODS: Lipid/polycation/pDNA (LPD) vectors, in the presence or absence of amino acids, were dispersed in lactose solutions, and spray-dried to produce appropriately sized dry powders. Scanning electron microscopy and laser diffraction were used to determine particle morphology and diameter, respectively. Gel electrophoresis was used to examine the influence of amino acids on the structural integrity of the LPD complex. In vitro cell (A549) transfection was used to determine the biological functionality of the dry powders, and the in vitro aerosolisation performance was assessed using a multistage liquid impinger (MSLI). RESULTS: Both gel electrophoresis and in vitro cell transfection indicated that certain amino acids (aspartic acid, threonine) can adversely affect the integrity and biological functionality of the LPD complex. All amino acids significantly increased the aerosolisation of the powder, with the arginine and phenylalanine powders showing optimal deposition in the lower stages of the MSLI. CONCLUSIONS: Amino acids can be used to enhance the aerosolisation of spray-dried powders for respiratory gene delivery, allowing the development of stable and viable formulations for pulmonary gene therapy.  相似文献   

2.
The purpose of this research was to evaluate the influence of dry granulation parameters on granule and tablet properties of spray-dried extract (SDE) fromMaytenus ilicifolia, which is widely used in Brazil in the treatment of gastric disorders. The compressional behavior of the SDE and granules of the SDE was characterized by Heckel plots. The tablet properties of powders, granules, and formulations containing a high extract dose were compared. The SDE was blended with 2% magnesium stearate and 1% colloidal silicon dioxide and compacted to produce granules after slugging or roll compaction. The influences of the granulation process and the roll compaction force on the technological properties of the granules were studied. The flowability and density of spray-dried particles were improved after granulation. Tablets produced by direct compression of granules showed lower crushing strength than the ones obtained from nongranulated material. The compressional analysis by Heckel plots revealed that the SDE undergoes plastic deformation with a very low tendency to rearrangement at an early stage of compression. On the other hand, the granules showed an intensive rearrangement as a consequence of fragmentation and rebounding. However, when the compaction pressure was increased, the granules showed plastic deformation. The mean yield pressure values showed that both granulation techniques and the roll compaction force were able to reduce the material's ability to undergo plastic deformation. Finally, the tablet containing a high dose of granules showed a close dependence between crushing strength and the densification degree of the granules (ie, roll compaction force). Published: October 14, 2005  相似文献   

3.
Crystallization of spray-dried and freeze-dried amorphous lactose over different relative vapor pressures (RVP) and storage times was studied. Crystallization was observed from increasing peak intensities in X-ray diffraction patterns. Lactose was crystallized in the samples stored at RVP of 44.1% and above in both types of dehydrated powders. The rate of crystallization increased with increasing RVP and storage time. Similar crystallization behavior of both spray-dried and freeze-dried lactose was observed. Lactose crystallized as alpha-lactose monohydrate, anhydrous beta-lactose, and the anhydrous form of alpha- and beta-lactose in a molar ratio of 5:3 and 4:1 in both spray-dried and freeze-dried forms. Peak intensities of X-ray diffraction patterns for anhydrous beta-lactose were decreased, and for alpha-lactose monohydrate increased with increasing storage RVP and time. The crystallization data were successfully modeled using Avrami equation at RVP of 54.5% and above. The crystallization data obtained is helpful in understanding and predicting storage stability of lactose-containing food and pharmaceutical products.  相似文献   

4.
The effect of the size of oil droplets on the oxidative stability of flaxseed oil in spray-dried powders was investigated. Maltodextrin with a dextrose equivalent of 25 was used as a wall material, and sodium caseinate and transglutaminase-polymerized sodium caseinate were used as emulsifiers. The oxidative stability of flaxseed oil encapsulated in the spray-dried powders was evaluated using lipid oxidation and conductometric determination tests at 105 °C. The powders containing larger oil droplets exhibited higher surface oil content after spray drying, and higher peroxide value and conductivity after storage at 105 °C. Removal of the surface oil from the powders by washing with hexane significantly decreased the conductivity. The results indicated that the surface oil of the spray-dried flaxseed oil powders affected the oxidation stability.  相似文献   

5.
The interaction of cellulose layers with colloidal silica particles was investigated by direct force measurements with the atomic force microscope (AFM). Upon approach, repulsive forces were found between the negatively charged silica particles and the cellulose surface. The forces were interpreted quantitatively in terms of electrostatic interactions due to overlap of diffuse layers originating from negatively charged carboxylic groups on the cellulose surface. The diffuse layer charge density of cellulose was estimated to be 0.80 mC/m2 at pH 9.5 and 0.21 mC/m2 at pH 4. The forces upon retraction are characterized by molecular adhesion events, whereby individual cellulose chains desorb from the probe surface. The retraction profiles are dominated by well-defined force plateaus, which correspond to single-chain desorption forces of 35-42 pN. We surmise that adsorption of cellulose to probe surfaces is dominated by nonelectrostatic forces, probably originating from hydrogen bonding. Electrostatic contributions to desorption force could be detected only at high pH, where the silica surface is highly charged.  相似文献   

6.
The purpose of this research was to develop a new method to predict the flow behavior of pharmaceutical powders using a multichamber microscale fluid bed. Different amounts of poorly flowing paracetamol were added to various grades of microcrystalline celluloses and silicified microcrystalline cellulose powders. Magnesium stearate was used as a lubricant. Experimental minimum fluidization velocities (u mf) were defined using 2 to 4 g (equal to 10 mL) of material (Video 1). The reference flowability of the powders was determined using a specific flow meter. Also, the weight variation of the compressed powders, using a single-punch press, was measured. When the amount of paracetamol in the excipients was increased, the experimentalu mf increased and the fluidization behavior grew worse (Video 2). Principal component analysis (PCA) established that the pressure difference over the bed as a function of fluidization velocity could be used to characterize the behavior of powders. The increase in poor fluidization behavior of the powders was in accordance with the increasing amount of paracetamol and with the increasing weight variation of the tablets. Furthermore, the angle of repose and the flow rate of silicified microcrystalline cellulose powders were predicted using a partial least squares (PLS) model. The developed method to predict flowability is a promising approach for use in the preformulation and formulation stages of new drug candidates, for example.  相似文献   

7.
Leaves of the pantropical genus Bauhinia (Fabaceae) are known popularly as cow's foot, due to their unique characteristic bilobed aspect. The species Bauhinia forficata (Brazilian Orchid-tree) is widely used in folk medicine as an antidiabetic. The present work investigates the hypoglycemic activity of the dried extracts of Bauhinia forficata leaves in vivo, as well as the influence of the drying and granulation processes on this activity. The fluid extract was dried to generate oven-dried (ODE), spray-dried (SDE) and wet granulation (WGE) extracts, with the aid of colloidal silicon dioxide and/or cellulose:lactose mixture. The dried extracts were characterized by spectrophotometric, chromatographic and photo microscopy image analysis. 200 mg/kg body wt., p.o. of each dried product were administered orally to male Wistar rats over 7 days old, for biomonitoring of the hypoglycemic activity profile. The effect of the extracts was studied in STZ-induced diabetic rats. After 7 days of treatment, fasting glucose was determined, and the livers were removed, dried on tissue paper, weighed, and stored at -20 °C to estimate hepatic glycogen. Our results show that spray-drying or oven-drying processes applied to B. forficata extracts did not significantly alter its flavonoid profile or its hypoglycemic activity. Indeed, the dried extracts of B. forficata act differently from glibenclamide. Despite the lower active content in WGE, because of the higher concentration of adjuvants, the use of the granulation process improved the manufacturing properties of the ODE, making this material more appropriate for use in tablets or capsules.  相似文献   

8.
The aim of the study was to analyze hydroxypropylcellulose (HPC) in pure form and in excipient mixtures and to relate its physical and chemical properties to tablet binder functionality. The materials used were Klucel hydroxypropylcellulose grades ranging from low to high molecular weight (80-1000 kDa) of regular particle size (250 microm mean size) and fine particle size (80 microm mean size). These were compared with microcrystalline cellulose, spray-dried lactose, and dicalcium phosphate dihydrate. Thermal behavior of HPC was analyzed by modulated temperature differential scanning calorimetry (MTDSC). Tablets of the pure materials and of dry blends with 4% low viscosity, fine particle HPC and 30% high viscosity, fine particle HPC were produced on an instrumented eccentric tableting machine at 3 relative humidities. The 3-dimensional (3-D) model with the parameters time plasticity d, pressure plasticity e, and the twisting angle omega, the inverse of fast elastic decompression was compared with the Heckel method for characterization of compaction. Elastic recovery and compactibility were also studied. The results show that HPC tablet formation is characterized by high plastic deformation. The d, e, and omega values were markedly higher as compared with the reference materials. Plasticity was highest for the fine particle size HPC types. Maximum compactibility was observed for low molecular weight, fine particle size HPC. Tableting of the mixtures showed deformation, which was strongly influenced by HPC. Plasticity and crushing force of formed tablets was increased. In conclusion, HPC is characterized by strong plastic deformation properties, which are molecular weight and particle size dependent.  相似文献   

9.
The purpose of this study was to produce spray-dried Pluronic-colloidal silicon dioxide (Aerosil) composite particles as a liquid crystal precursor that would form a liquid crystalline phase upon hydration. A Pluronic-colloidal silicon dioxide dispersion in isopropyl alcohol was spray-dried to obtain composite particles using different concentrations of Aerosil. Polarizing microscopy, gelation, gel melting, and rheological studies were employed to characterize the composite particles. The composite particles obtained were irregular, with concave depression. Gelation was found to decrease with the addition of Aerosil, while gel melting was found to increase with the concentration of Aerosil. Rheological studies showed an increase in elasticity as well as viscosity with an increase in the concentration of Aerosil. Composite particles showed improved gelation and rheological properties. These composite particles and the process by which they were obtained may be useful for designing various drug delivery systems.  相似文献   

10.
Novel self-microemulsifying floating tablets were developed to enhance the dissolution and oral absorption of the poorly water-soluble tetrahydrocurcumin (THC). Their physicochemical properties and THC permeability across Caco-2 cell monolayers were assessed. The self-microemulsifying liquid containing THC was adsorbed onto colloidal silicon dioxide, mixed with HPMC, gas-generating agents (sodium bicarbonate and tartaric acid), lactose and silicified-microcrystalline cellulose and transformed into tablets by direct compression. The use of different types/concentrations of HPMC and sodium bicarbonate in tablet formulations had different effects on the floating characteristics and in vitro THC release. The optimum tablet formulation (F2) provided a short floating lag time (∼23 s) together with a prolonged buoyancy (>12 h). About 72% of THC was released in 12 h with an emulsion droplet size in aqueous media of 33.9 ± 1.0 nm while that of a self-microemulsifying liquid was 29.9 ± 0.3 nm. The tablet formulation was stable under intermediate and accelerated storage conditions for up to 6 months. The THC released from the self-microemulsifying liquid and tablet formulations provided an approximately three- to fivefold greater permeability across the Caco-2 cell monolayers than the unformulated THC and indicated an enhanced absorption of THC by the formulations. The self-microemulsifying floating tablet could provide a dosage form with the potential to improve the oral bioavailability of THC and other hydrophobic compounds.KEY WORDS: Caco-2 cells, controlled release, permeability, self-microemulsifying floating tablets, tetrahydrocurcumin  相似文献   

11.
The addition of positively charged colloidal materials to the growth medium markedly increased the concentration of cellulase enzymes produced by Trichoderma reesei Rut-C30. Filter paper activities of up to 4 and 13 IU/ml have been achieved by the addition of colloidal materials, using 3% lactose and 3% cellulose, respectively, as a substrate. The particles exert their effect by binding soluble sugars and slowing their uptake by the organism.  相似文献   

12.
The purpose of this research was to prepare spray-dried mucoadhesive microspheres for nasal delivery. Microspheres composed of hydroxypropyl methylcellulose (H), chitosan (CS), carbopol 934P (CP) and various combinations of these mucoadhesive polymers, and maltodextrin (M), colloidal silicon dioxide (A), and propylene glycol (P) as filler and shaper, were prepared by spray-drying technique. Using propranolol HCl as a model drug, microspheres were prepared at loadings exceedings 80% and yields between 24% and 74%. Bulky, free flowing microspheres that had median particle size between 15 and 23 μm were obtained. Their zeta potential was according to the charge of polymer. Adhesion time of mucoadhesive microspheres on isolated pig intestine was ranked, CS>CP: H>CP>H, while the rank order of swelling was CP>CS>H. Increasing the amount of CP in CP∶H formulations increased the percentage of swelling. Infrared (IR) spectra showed no interaction between excipients used except CS with acetic acid. The release of drug from CP and CP∶H microspheres was slower than the release from H and CS microspheres, correlated to their viscosity and swelling. Long lag time from the CP microspheres could be shortened when combined with H. The permeation of drug through nasal cell monolayer corresponded to their release profiles. These microspheres affected the integrity of tight junctions, relative to their swelling and charge of polymer. Cell viability was not affected except from CS microspheres, but recovery could be obtained. In conclusion, spray-dried microspheres of H, CS, CP, and CP∶H could be prepared to deliver drug through nasal cell monolayer via the opening of tight junction without cell damaging. Published: February 10, 2006  相似文献   

13.
Spray-dried whole bovine blood and a sodium polyacrylate polymer gel as a bulking and solidifying agent are among the constituents of the current larval diet for mass rearing screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae). Locally available, inexpensive dietary materials could reduce rearing cost and address an uncertain commercial supply of spray-dried blood. We compared efficacy of diet prepared from fresh bovine blood after decoagulation with sodium citrate or ethylenediaminetetraacetic acid (EDTA) or after mechanical defibrination, with the diet containing spray-dried blood using either gel or cellulose fiber as the bulking and solidifying agent. Several life-history parameters were compared among insects reared on each of the blood and bulking agent diets combination. Diets containing citrated blood yielded the lightest larval and pupal weights and fewest pupae. EDTA-treated blood with the gel also caused reductions. EDTA-treated blood with fiber yielded screwworms that were heavier and more numerous than those from the diet with citrated blood but lighter than those from the control diet using spray-dried blood. A reduction in percentage of adults emerging from pupae occurred from diets with both bulking agents using citrated blood and the diet using EDTA mixed with the gel bulking agent. As a group, the cellulose-fiber diets performed better than the gel diets. Larval diet did not affect adult longevity, weight of the eggs deposited by the females that emerged or subsequent egg hatch. Parameter measurements of insects from both defibrinated blood diets were similar to those from the spray-dried blood diets, indicating that fresh, defibrinated bovine blood can successfully replace the dry blood in the screwworm rearing medium.  相似文献   

14.
The aim of this study was to evaluate a non-steady-state needle sensor to determine the thermal conductivity (lambda) of powders and their blends. It was investigated how lambda of different powders was influenced by (1) bulk vs tapped density, (2) moisture content of the powders, and (3) blending time of the powders. Different powders were evaluated: 2 lactose powders with different properties, a microcrystalline cellulose powder, a cornstarch powder, and 3 herbal extracts. The results show that the values of lambda are highly dependent on the bulk and tapped density of the powders. Bulk density measurements were generally not sensitive enough to detect the moisture content within a powder. The tapped density measurements were reliable and highly reproducible and could differentiate between the nature of a powder and the powder moisture content. Measurements of lambda were able to be used to monitor the powder blending process. To be able to use thermal conductivity measurements to characterize powder properties in quality control, the powder density must be defined because changes in density affect lambda. Using thermal conductivity as a measure for process analytical technology seems to be feasible and can add valuable information to the process under investigation.  相似文献   

15.
The purpose of this study was to evaluate the nature of film formation on tablets with different compositions, using confocal laser scanning microscopy (CLSM), and to measure film adhesion via the application of a novel “magnet probe test”. Three excipients, microcrystalline cellulose (MCC), spray-dried lactose monohydrate, and dibasic calcium phosphate dihydrate, were individually blended with 0.5% magnesium stearate, as a lubricant, and 2.5% tetracycline HCl, as a fluorescent marker, and were compressed using a Carver press. Tablets were coated with a solution consisting of 7% hydroxypropyl methylcellulose (HPMC) phthalate (HP-55), and 0.5% cetyl alcohl in acetone and isopropanol (11:9). The nature of polymer interaction with the tablets and coating was evaluated using CLSM and a designed magnet probe test. CLSM images clearly showed coating efficiency, thickness, and uniformity of film formation, and the extent of drug migration into the film at the coating interfaces of tablets. Among the excipients, MCC demonstrated the best interface for both film formation and uniformity in thickness relative to lactose monohydrate and dibasic calcium phosphate dihydrate. The detachment force of the coating layers from the tablet surfaces, as measured with the developed magnet probe test, was in the order of MCC>lactose monohydrate>dibasic calcium phosphate dihydrate. It was also shown that the designed magnet probe test provides reliable and reproducible results when used for measurement of film adhesion and bonding strength.  相似文献   

16.
Pantoprazole-loaded microparticles were prepared using a blend of Eudragit® S100 and Methocel® F4M. The accelerated stability was carried out during 6 months at 40°C and 75% relative humidity. In order to improve technological characteristics of the pantoprazole-loaded microparticles, soft agglomerates were prepared viewing an oral delayed release and gastro-resistant solid dosage form. The agglomeration was performed by mixing the pantoprazole microparticles with spray-dried mannitol/lecithin powders. The effects of factors such as the amount of lecithin in the spray-dried mannitol/lecithin powders and the ratio between pantoprazole microparticles and spray-dried mannitol/lecithin powders were evaluated. The pantoprazole-loaded microparticles present no significant degradation in 6 months. The agglomerates presented spherical shape, with smooth surface and very small quantity of non-agglomerated particles. The agglomerates presented different yields (35.5–79.0%), drug loading (58–101%), and mechanical properties (tensile strength varied from 44 to 69 mN mm−2), when the spray-dried mannitol/lecithin powders with different lecithin amounts were used. The biopharmaceutical characteristics of pantoprazole microparticles, i.e., their delayed-release properties, were not affected by the agglomeration process. The gastro-resistance of the agglomerates was affected by the amount of spray-dried mannitol/lecithin powders. The ratio of lecithin in the spray-dried mannitol/lecithin powders was the key factor in the agglomerate formation and in the drug release profiles. The agglomerates presenting better mechanical and biopharmaceutical characteristics were prepared with 1:2 (w/w) ratio of pantoprazole-loaded microparticles and mannitol/lecithin (80:20) powder.Key words: agglomerates, delayed release, gastro-resistance, microparticles  相似文献   

17.
The flavonoids quercetin, 3-O-methylquercetin and luteolin play an important role in the anti-inflammatory activity of Achyrocline satureioides ethanol extracts when administered intraperitoneally. The present work describes the oral anti-inflammatory effect of quercetin and A. satureioides extracts and the role played by the solvent concentration, adjuvant and drying processes of freeze-drying (FD) or spray-drying (SD) on the effect. The best anti-edema effect was observed with 250 mg/kg body wt of the freeze-dried powder (FDP), prepared with 40% (v/v) ethanol (FDP40). In contrast, 250 mg/kg body wt of FDP80, prepared with ethanol 80% (ES80), did not significantly inhibit the carrageenan-induced rat paw edema. However, when ES80 was freeze-dried in the presence of polysorbate 80 (FDP80-P80) or spray-dried in the presence of colloidal silicon dioxide (CSD) and P80 (SDP80), both dried extracts became more active. Quercetin suspension in saline did not inhibit paw edema, but the mixture of quercetin with polysorbate 80 was effective in edema inhibition by the oral route. Aqueous extract (ESAQ), freeze-dried (FDPAQ, FDPAQ-P80) or spray-dried (SDPAQ) did not exhibit the edema-inhibition effect. Taken together, the results point to the following order of efficacy (at 4 h, for example): FDP40 > indomethacin > SDP40 > SDP80 = FDP80-80 > Quercetin-P80. Additionally, the FDP40, SDP40 (prepared from 40% v/v ethanol added of CSD) and SDP80 reduced the total leukocyte and polymorphonuclear cell migration in the pleural cavity.  相似文献   

18.
The atomic force microscope (AFM) is sensitive to electric double layer interactions in electrolyte solutions, but provides only a qualitative view of interfacial electrostatics. We have fully characterized silicon nitride probe tips and other experimental parameters to allow a quantitative electrostatic analysis by AFM, and we have tested the validity of a simple analytical force expression through numerical simulations. As a test sample, we have measured the effective surface charge density of supported zwitterionic dioleoylphosphatidylcholine membranes with a variable fraction of anionic dioleoylphosphatidylserine. The resulting surface charge density and surface potential values are in quantitative agreement with those predicted by the Gouy-Chapman-Stern model of membrane charge regulation, but only when the numerical analysis is employed. In addition, we demonstrate that the AFM can detect double layer forces at a separation of several screening lengths, and that the probe only perturbs the membrane surface potential by <2%. Finally, we demonstrate 50-nm resolution electrostatic mapping on heterogeneous model membranes with the AFM. This novel combination of capabilities demonstrates that the AFM is a unique and powerful probe of membrane electrostatics.  相似文献   

19.
The effect of milled and micronized lactose fines on the fluidization and in vitro aerosolization properties of dry powder inhaler (DPI) formulations was investigated, and the suitability of static and dynamic methods for characterizing general powder flow properties of these blends was assessed. Lactose carrier pre-blends were prepared by adding different lactose fines (Lactohale® (LH) 300, 230 and 210) with coarse carrier lactose (Lactohale100) at 2.5, 5, 10 and 20 wt% concentrations. Powder flow properties of lactose pre-blends were characterized using the Freeman Technology FT4 and Schulze RST-XS ring shear tester. A strong correlation was found between the basic flow energy (BFENorm) measured using the Freeman FT4 Rheometer and the flowability number (ffc) measured on Schulze RST-XS. These data indicate that both static and dynamic methods are suitable for characterizing general powder flow properties of lactose carriers. Increasing concentration of fines corresponded with an increase in the normalized fluidization energy (FENorm). The inclusion of fine particles of lactose resulted in a significant (p < 0.05) increase in fine particle delivery of budesonide and correlated with FENorm. This trend was strongest for lactose containing up to 10 wt% LH300. A similar trend was found for the milled lactose grades LH230 and LH210. However, the increase in FENorm upon addition of milled fines only corresponded to a very slight improvement in the performance. These data suggest that whilst the fluidization energy correlated with fine particle delivery, this relationship is specific to lactose grades of similar particle size.KEY WORDS: dry powder inhaler, fluidisation, lactose, powder flow  相似文献   

20.
The aim of this work was to develop self-nanoemulsifying liquisolid tablets (SNELT) to enhance the dissolution profile of poorly water-soluble simvastatin. SNELT present a unique technique of incorporating self-nanoemulsifying drug delivery systems (SNEDDS) into tablets. Optimized SNEDDS containing different oils, Cremophor® RH 40 (surfactant) and Transcutol® HP (co-surfactant), at different ratios, were used as liquid vehicles and loaded on carrier material, microcrystalline cellulose (MCC), and coating material, Cab-o-sil® H-5 (nanosize colloidal silicon dioxide) powders at different loading factors (L f ) and fixed excipient ratio (R?=?20). The effect of using different carrier materials, granulated mannitol, crystalline mannitol, and maltodextrin with MCC at different ratios, and different coating materials, Aeroperl® 300 (granulated silicon dioxide) at different excipient ratios (R), was also emphasized. Liquisolid powders with acceptable flowability, compressibility, and tablet weight were compressed into tablets. Results revealed that powders with L f ?=?0.2 possessed the most preferable properties to be tableted. SNELT with MCC and Cab-o-sil® H-5 were able to generate nanoemulsions and to enhance the cumulative percent of drug dissolved at 60 min significantly to reach up to 90%. Furthermore, using carrier material (granulated mannitol/MCC at ratio 3:1) enabled SNELT to disperse into nanoemulsion (Z-average?=?25.7 nm) and improved the dissolution profile significantly to reach 99% at 60 min. Cab-o-sil® H-5 proved to be a better coating material compared to Aeroperl® 300. In conclusion, developed SNELT were promising in enhancing in vitro dissolution of simvastatin and excipients highly affect SNELT’s performance.  相似文献   

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