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PubMed2003

Drug nano- and microparticles processed into solid dosage forms: physical properties.

The use of nanoparticles of relatively insoluble drugs has enormously widened the window of achievable pharmacokinetic performance. For the successful development of this technology, it is essential to understand the characteristics of nanoparticles. In this study, the processability and solid dosage performance of nanoparticulates are compared with those of microparticulates. Nanoparticle suspensions are first prepared by wet comminution in the presence of stabilizers. Spray drying converts them into dried particles from which compacts are prepared. Nanoparticles easily form aggregates during spray drying. These aggregates can be slowly redispersed into nanoparticles in water. Compacts show differences in their internal structure and micromechanical deformations, according to the size of their primary particles. Stress to break and indentation hardness are found to be only slightly higher in nanoparticulate systems.

Administration, Oral↗

PubMed1981

Aluminum chlorohydrate II: Physicochemical properties.

Determination of the chloride content of aluminum chlorohydrate by a chloride-selective indicated that gamma Cl leads to 1. IR analysis demonstrated that chloride was exchanged readily by nitrate and that the IR bands of the anion were not perturbed significantly. Thus, chloride is believed to act as a counterion. A high positive charge is predicted based o the critical coagulation concentration of aluminum chlorohydrate and the stability of aluminum chlorohydrate to attack by protons, as demonstrated by pH-stat titration Potentiometric titration with sodium hydroxide showed adsorption of hydroxyl anions initially, but a higher pH than expected was observed at the end-point. This behavior is consistent with the Al13O4(OH)24(H2O)7+12 complex, which would adsorb hydroxyl anions initially and in which the central tetrahedral aluminum is shielded from the added hydroxyl anions. The reaction rate with ferron (8-hydroxy-7-iodo-5-quinolinesulfonic acid) suggests that the major species in aluminum chlorohydrate is a large aluminum poly-cation. A platey morphology for lyophilized, air-dried, and spray-dried aluminum chlorohydrate was observed by scanning electron microscopy. The platey appearance is consistent with the structure of Al13O4(OH)24(H2O)7+12 since the spherical nature and high uneven charge of the complex make stacking difficult.

Aluminum Hydroxide↗

PubMed1998

Polyorganophosphazene microspheres for drug release: polymer synthesis, microsphere preparation, in vitro and in vivo naproxen release.

Microsphere preparation for naproxen slow release was investigated using two newly prepared biodegradable polyorganophosphazenes, derivatized at the phosphorus atoms with phenylalanine ethyl ester and imidazole at molar ratios of 71/29 and 80/20. The polymers were prepared by substitution of the chloride atoms of polydichlorophosphazene with a phenylalanine ethyl ester-imidazole mixture followed, after 7 or 48 h reaction, by the addition of excess imidazole. Three methods of microsphere preparation have been considered: spray-drying, emulsion/solvent evaporation and emulsion/solvent evaporation-extraction. Microparticles obtained by spray-drying were found to possess a narrow distribution size with a mean diameter of 2-5 microm. Their internal structure consisted of a porous or empty core depending upon the solvent used for the preparation. Furthermore the microspheres prepared with this technique rapidly released the entrapped naproxen independently of the used polymer, the drug loading or the preparation process. On the other hand microspheres prepared by solvent evaporation or solvent evaporation-extraction showed a distribution size ranging between 10 and 100 microm. By the appropriate choice of pH and solvent composition of the external phase, naproxen could be entrapped, in these microspheres, with a yield higher of 80%. The polymer composition dictates the in vitro release rate of naproxen from the particles, which was faster when the microspheres were prepared with the polymer at higher imidazole content. In vivo experiments, carried out by subcutaneous implantation in rats of microspheres prepared by solvent evaporation, demonstrated that a constant level of naproxen in plasma could be maintained up to 400 h at a suitable concentration for antinflammatory activity.

Animals↗

PubMed2004

Stabilization of proteins in dry powder formulations using supercritical fluid technology.

Therapeutic proteins have become essential in the treatment of many diseases. Their formulation in dry form is often required to improve their stability. Traditional freeze-drying or spray-drying processes are often harmful to labile proteins and could be replaced by supercritical fluid (SCF) drying to produce particles with defined physicochemical characteristics in a mild single step. A survey of the current SCF drying processes for proteins is presented to give insight into the effect of SCF drying on protein stability and to identify issues that need further investigation. Methods used for drying aqueous and organic protein solutions are described. In particular, effects of process and formulation parameters on particle formation and protein stability are discussed. Although SCF methodology for drying proteins is still in its infancy, it can provide a serious alternative to existing drying methods for stabilizing proteins.

Carbon Dioxide↗

PubMed2001

Influence of the preparation method on the physicochemical properties of tolbutamide/cyclodextrin binary systems.

Tolbutamide (TBM) was found to form an inclusion complex with beta cyclodextrin (beta-CD) in solution and in solid state. Inclusion complex formation between tolbutamide and beta-cyclodextrin in aqueous solution was studied by phase solubility and spectral shift methods. The apparent stability constant Ks calculated by these techniques, in water, were estimated as 195.7 and 236.5 M(-1), respectively. The phase solubility studies revealed a B(S)-type diagram with an inclusion complex of 1:2 molar ratio. The solid inclusion complexes of TBM and beta-CD were prepared at a molar ratio of 1:2 by kneading, coprecipitation, freeze-drying, and spray-drying methods. In addition, the physical mixture was prepared. Characterization of TBM: beta-CD inclusion was performed using differential scanning calorimetry (DSC), Raman spectroscopy, and X-ray diffractometry and by application of a so-called ether wash method. All the inclusion systems investigated led to a significant improvement in the dissolution over free TBM, and the dissolution rate of the active material was observed to be independent of the preparation method.

Calorimetry, Differential Scanning↗

PubMed1988

Coprecipitation of enzymes with water soluble starch--an alternative to freeze-drying.

Krill proteases were prepared in solid form from a partially purified extract by coprecipitation of the enzymes with water-soluble starch in an organic solvent at 22 degrees C. The precipitation did not affect the activity of the enzymes. The recovery of proteolytic activity was 100%. The thermostability of the krill proteases increased when incorporated in the starch precipitate. No reduction in enzymatic activity could be seen after storage at +50 degrees C for 99 days. After milling the coprecipitate could be dispensed. The enzyme preparation consisted of irregular needle-shaped particles. This simple precipitation technique offers an alternative to freeze-drying or spray-drying.

Animals↗

PubMed1984

[Enzymatic modification of proteins of commercial sesame meals (Sesamum indicum, L.)].

Sesame (Sesamum indicum, L.) is one of the most important oilseed crops in Venezuela. However, the low solubility of the flour made of commercial meals does not allow its use in the preparation of fluid foods. To solve this situation, the alternative of solubilizing the sesame proteins by an enzymatic method, using commercial proteases, was studied. Hydrolysis was carried out with two types of bacterial proteases: neutrasa 0.5L, and alcalase 0.6L. Basically, the process consisted of milling and sieving the sesame cake (60 mesh), concentrating the proteins by solubilizing them at a pH of 9.5, and then precipitating at a pH of 4.5. Proteins were hydrolyzed by an enzymatic method, and the hydrolysates freeze-dried and spray-dried. Optimal conditions of hydrolysis using neutrase 0.5L at a pH of 7 were: 6% substrate concentration, 3% enzyme:substrate ratio, temperature 50 degrees +/- 1 degree C, and hydrolysis degree of 8%. When alcalase 0.6L was used at a pH of 8, optimal conditions were: 8% substrate concentration, 2.3% enzyme:substrate ratio, temperature 58 degrees +/- 1 degree C, and hydrolysis degree of 10%. The enzyme affinity (Km) was best at temperatures near the optimal temperature for the hydrolysates. Dried hydrolysates had protein values which ranged between 66.3% and 66.9% and a nitrogen solubility in water, of approximately 85%. Hydrolysis yields referred to the concentrate dried mass were 42% for the atomized hydrolysate, and 56% for the freeze-dried one. In conclusion, the enzymatic hydrolysis process improved the nitrogen solubility in water of the sesame proteins.

Animal Feed↗

PubMed1984

[Functional and nutritional properties of modified proteins of sesame (Sesamum indicum, L.)].

A study on the functional and nutritional properties of sesame (Sesamum indicum, L.) flour, concentrate and enzymatic hydrolysates, demonstrated that nitrogen solubility of the hydrolysates is improved, in water (85%) and at different pHs (91-95%), by the action of neutrasa 0.5L and alcalasa 0.6L, yielding a product with good emulsifying and improved foaming properties. Hydrolysates produced by the pH-stat method, then freeze-dried and spray-dried presented a PER of 1.1 and 0.9, respectively. The flour and the concentrate had PER values of 1.2. Supplementation of one of the hydrolysates with soya hydrolysate (1:1), improved the PER to a value similar to that of casein. Use of neutrasa 0.5L and alcalasa 0.6L enzymes, enhances the sesame protein solubility without modifying extensively the PER. Besides, it yields a dehydrated product with improved emulsifying and foaming properties.

Flour↗

PubMed1982

Dietary cadmium, zinc and copper: effects on chick lung morphology and elastin cross-linking.

Day-old White Leghorn cockerels were divided into seven dietary groups and fed one of the following diets: 1) a casein-based basal diet; 2) a casein-based diet supplemented with 10 mg/kg cadmium, 3) 100 mg/kg cadmium, 4) or 800 mg/kg zinc; 5) a casein-based diet pair-fed to the 100 mg/kg Cd group; 6) a spray-dried nonfat milk-based diet with no added copper, or 7) a spray-dried nonfat milk-based diet supplemented with 5 mg/kg copper. At termination (5 weeks), the birds were killed, and the effects of the diets on selected features of lung composition and morphology were assessed. Body weights were reduced in the 100 mg/kg Cd, pair-fed, and Cu-deficient groups when compared to their controls (casein-based or milk-based copper-supplemented diets). There were no differences in lung weights (expressed relative to metabolic body size) among the groups, although copper deficiency did result in a slight decrease in the dry to wet weight ratio of lung. Lung elastin content and the desmosine content in elastin were significantly lower in the Cu-deficient group and tended to be lower in the group fed 800 ppm Zn. Significant alterations (enlargement of the tertiary bronchial lumen) in morphology were also observed in lungs from both the 100 mg/kg Cd and Cu-deficient groups. Alteration in lung morphology observed in the 100 mg/kg Cd group could not be explained by changes in the elastin content of lung.

Animals↗

PubMedDate not supplied

[The composition of amino acid-peptide mixtures obtained during hydrolysis of proteins].

The composition of the amino acid and peptide fraction of the protein hydrolyzate and its dependence upon the spray-drying process at elevated temperatures were investigated by GLC and GLC-MS. Spray-drying leads to decrease in the Glu and Met contents, to transformation of Cys into cystine and to formation of lactames (pyroglutamic acid and pyrrolidone) and diketopiperazines. Some dipeptides, acetylproline, paraffines, fatty acid pyridinecarboxylic and lactic acids, ethylene glycol were identified in the fraction. The incidental occurrence of these compounds should be taken into account when investigating the biological activity of protein hydrolyzates.

Amino Acids↗

PubMed2026

Lpb. plantarum inhalation powders for the reduction of lung inflammation and S. aureus growth control in non-CF bronchiectasis.

INTRODUCTION: The reduced diversity of the lung microbiome in respiratory conditions, including bronchiectasis, promotes bacterial infection and inflammation, contributing to worsening clinical outcomes. Traditional treatments often fail to address both infection and inflammation. Because of their potential dual-action, lactic acid bacteria (LAB) directly administered to the lungs could represent an innovative therapeutic approach for these diseases. RESEARCH DESIGN AND METHODS: Two powders for inhalation containing Lpb. plantarum, lactose, l-leucine with and without raffinose, a prebiotic, were produced by spray drying and in vitro tested. The focus was on investigating their potential in vitro anti-inflammatory and anti-microbial activities against S. aureus. RESULTS: The powders showed a fine particle fraction (<5 µm) of >40% and allowed the maintenance of anti -inflammatory activity in vitro for both treatment and prevention. Moreover, both powders led to a significant reduction in S. aureus growth. The stability study of the powders in capsules at different storage conditions showed the preservation of the LAB up to 90 days in refrigerated conditions (4°C/-20°C). CONCLUSIONS: This proof-of-concept study shows that inhalable spray-dried live LABs retain biological activity and are suitable for pulmonary delivery, supporting their potential as a microbiota-modulating therapy, which, however, requires further preclinical validation.

Inhalation↗

PubMed2004

Determination of amorphous content of lactose samples by solution calorimetry.

Earlies studies suggest that solution calorimetry can be used to determine the extent of amorphous content of drug and excipient, when the solubility and dissolution rate of the compound in the chosen solvent are reasonably high. In the present study, the use of solution calorimetry for assessment of amorphous content of a sample that is not completely dissolved in a solvent was evaluated. Physical mixtures of lactose and spray-dried lactose samples were analysed. The amorphous content of the physical mixtures and the spray-dried samples varied from 0% to 100% determined by isothermal microcalorimetry. The enthalpy of solution (delta(sol)H) was determined in water. The lactose samples were dissolved quickly in water. In addition, the enthalpy accompanied with an addition of a lactose sample in an over saturated aqueous solution (delta(sat)H) (prepared from the corresponding lactose sample) was determined. The lactose sample did not completely dissolve in the over saturated aqueous solution. An excellent correlation was observed between delta(sol)H and the amorphous content of the samples. Interestingly, there was a linear correlation also between delta(sat)H and the amorphous content of the samples. Further, a linear relationship was observed between the delta(sat)H and the delta(sol)H of the samples. Therefore, solution calorimetry may represent a rapid and simple method for determining the amorphous content also in samples that are not completely dissolved in the solvent.

Calorimetry↗

PubMed2003

Effect of chitosan on progesterone release from hydroxypropyl-beta-cyclodextrin complexes.

An inclusion complex composed of progesterone (Prog) and hydroxypropyl-beta-cyclodextrin (HPbetaCD) was prepared by the spray-drying and freeze-drying methods. Prog alone and its inclusion complex with HPbetaCD were incorporated into chitosan by spray-drying and freeze-drying. The inclusion complex was characterized by IR and DSC. The inclusion complex was investigated in solution by phase solubility diagrams and stability constant was determined at pH 7.4 and at different temperatures (10, 25 and 37 degrees C) to obtain the thermodynamic parameters of inclusion. The results indicate that the Prog-HPbetaCD inclusion complex is more water soluble than Prog alone. Release data from all samples showed significant improvement of the dissolution rate of Prog and a controlled release is obtained in the presence of chitosan.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed2005

Use of a turbidity sensor to characterize micellar casein powder rehydration: influence of some technological effects.

A simplified method to study rehydration of dairy powders was developed for native phosphocaseinate powder. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor under standardized conditions. The changes of turbidity occurring during powder rehydration highlighted several stages. These stages include particles wetting, and then swelling as the water penetrates into the powder bed, followed by a slow dispersion of the particles. With this tool, some technological effects on powder rehydration were analyzed. Ultrafiltrate incorporation to the casein concentrate before spray drying was found to greatly improve the rehydration, whereas mixing ultrafiltrate powder with casein powder after spray drying did not change the rehydration properties. The effect of granulation on powder rehydration stages was also investigated.

Caseins↗

PubMed1977

Microencapsulation of phenobarbital by spray polycondensation.

A new method for the microencapsulation of solids is described. It is based on the polycondensation of amphiphilic and, thus, tensioactive precondensates on a melamine-formaldehyde base on the surface of suspended particles during spray drying. A film-forming agent, preferably one that reacts chemically with the resin, is indispensable for spray drying and also for the formation of an efficient membrane around the drug particles. The resulting microcapsules are essentially spherical and have, after appropriate curing, a sustained-release effect in vitro. The factors that most influence the formation and properties of the microcapsules are the composition (qualitative and quantitative), pH, and viscosity of the suspension.

Capsules↗

PubMed2006

Antioxidative activities of soymilk fermented with lactic acid bacteria and bifidobacteria.

To further the goal of developing a probiotic dietary adjunct using soymilk, soymilk is fermented with lactic acid bacteria (Lactobacillus acidophilus CCRC 14079 or Streptococcus thermophilus CCRC 14085) and bifidobacteria (Bifidobacterium infantis CCRC 14633 or Bifidobacterium longum B6) individually, and in conjunction. We investigate several antioxidative activities including the inhibition of ascorbate autoxidation, the scavenging effect of superoxide anion radicals and hydrogen peroxide, and the reducing activity exerted by different varieties of fermented soymilks. In addition, the effect of spray-drying and freeze-drying on changes in antioxidative activity is examined. We find that in fermented soymilk both the inhibition of ascorbate autoxidation, and the reducing activity and scavenging effect of superoxide anion radicals varied with the starters used, but nevertheless are significantly higher than those found in unfermented soymilk. In general, antioxidative activity in soymilk fermented with lactic acid bacteria and bifidobacteria simultaneously is significantly higher (P < 0.05) than that fermented with either individually. Moreover, antioxidative activity increases as the fermentation period is extended. However, unfermented soymilk shows an H2O2-scavenging effect, while there is no scavenging effect except for the accumulation of H2O2 in fermented soymilk. Finally, we find that freeze-drying causes a significantly lesser (P < 0.05) reduction in the antioxidative activity of soymilk than does spray-drying. Irrespective of the drying method and the starters used for fermentation. The antioxidative activity of fermented soymilk reduces after drying yet remains higher than that of dried unfermented soymilk.

Antioxidants↗

PubMedDate not supplied

New method for the effective production of ultrafine drug nanocrystals.

Particle size reduction, particularly nanonization, is a non-specific, universal approach to improve the bioavailability of poorly soluble drugs. The decreased particle size of drug nanocrystals leads to a distinct increase in surface area. Due to the increased surface area the rate of dissolution will be proportionally raised, leading to a better absorption of the poorly soluble drug. Various technologies for the production of drug nanocrystals are known, e.g., pearl milling (Nanocrystal technology, elan/Nanosystems), high pressure homogenization in water (DissoCubes, SkyePharma) or alternatively in non-aqueous media or water-reduced media (Nanopure, PharmaSol Berlin). A first combinative technology (precipitation followed by high pressure homogenization) is known as NANOEDGETM technology (Baxter). Relatively long milling times, high numbers of homogenization cycles or solvent residues are typical drawbacks of the existing technologies. In order to overcome the limitations of the existing technologies a new combination method was developed for the production of ultra-fine submicron suspensions. The method involves an evaporation step to provide a solvent-free modified starting material followed by high pressure homogenization to produce ultrafine drug nanocrystals. In this study it could be shown that modified hydrocortisone acetate was particularly suitable to be further processed by high pressure homogenization. In comparison to jet-milled hydrocortisone acetate powder the high pressure homogenization of spray-dried hydrocortisone acetate powder resulted in much more homogeneously dispersed nanosuspensions. By using co-processed, spray-dried material (9:1 drug/poloxamer 188 ratio) the required number of homogenization cycles to obtain nanosuspensions was distinctly reduced. In case of the modified material only 1 homogenization cycle at 1500 bar was sufficient to obtain a particle size smaller than that after 20 homogenization cycles using the jet-milled drug powder. The obtained nanosuspensions have shown excellent long-term storage stability.

Anti-Inflammatory Agents↗

PubMed1999

Enhancement of the foaming properties of protein dried in the presence of trehalose.

Surface tension, foamability, and foam stability kinetics have been measured for the pure proteins bovine serum albumin (BSA) and beta-lactoglobulin, before and after aqueous solutions of the proteins had been subjected to different drying conditions, and also for whey protein concentrate (WPC). Pure proteins were air-dried, at 78 or 88 degrees C, in the presence and absence of sucrose or trehalose, at a mass ratio of 5:1 sugar/protein. WPC was spray-dried in the presence of various sugars: trehalose, sucrose, lactose, and lactitol. Spray-drying WPC without sugars resulted in a dramatic decrease in the foam stability, whereas drying in the presence of sugars gave better retention of the original foaming properties. Trehalose in particular resulted in almost complete retention of the foam stability observed for the nondried WPC. Pure beta-lactoglobulin showed similar behavior, but trehalose did not seem to afford the same protection to BSA.

Animals↗