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PubMed2004

Survival and recovery of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on lettuce and parsley as affected by method of inoculation, time between inoculation and analysis, and treatment with chlorinated water.

The effects of method for applying inoculum and of drying time after inoculation on survival and recovery of foodborne pathogens on iceberg lettuce and parsley were studied. Five-strain mixtures of Escherichia coli O157:H7, Salmonella, or Listeria monocytogenes were applied to lettuce and parsley by dip, spot, or spray inoculation methods. Inocula were dried for 2 h at 22 degrees C or for 2 h at 22 degrees C and then 22 h at 4 degrees C before being treated with water (control) or chlorine (200 microg/ml). Significantly higher populations (CFU per lettuce or parsley sample) of E. coli O157:H7 and Salmonella (alpha = 0.05) were recovered from dip-inoculated produce than from spot- or spray-inoculated produce. This difference was attributed to larger numbers of cells adhering to lettuce and parsley subjected to dip inoculation. Populations of E. coli O157:H7 and Salmonella recovered from lettuce inoculated by spot and spray methods were not significantly different, but populations recovered from spot-inoculated parsley were significantly higher than those recovered from spray-inoculated parsley, even though the number of cells applied was the same. Significantly different numbers of L. monocytogenes were recovered from inoculated lettuce (dip > spray > spot); populations recovered from dip-inoculated parsley were significantly higher than those recovered from spot- or spray-inoculated parsley, which were not significantly different from each other. Populations of pathogens recovered from lettuce and parsley after drying inoculum for 2 h at 22 degrees C were significantly higher than or equal to populations recovered after drying for 2 h at 22 degrees C and then for 22 h at 4 degrees C. Significant differences (water > chlorine) were observed in populations of all pathogens recovered from treated lettuce and parsley, regardless of inoculation method and drying time. It is recommended that spot inoculation with a drying time of 2 h at 22 degrees C followed by 22 h at 4 degrees C be used to determine the efficacy of chlorine and other sanitizers in killing foodborne pathogens on lettuce and parsley.

Bacterial Adhesion↗
PubMed2006

Effective disinfection of orthodontic pliers.

OBJECTIVE: Pathogenic microbes may be transmitted directly from the orthodontist to the patient or from the patient to the doctor, and indirectly from patient to patient. The latter may occur via contaminated instruments or surfaces, and is referred to as cross-contamination. The objective of this study was to evaluate the extent of bacterial contamination of orthodontic pliers and the efficacy of the disinfection techniques applied after clinical use. We also sought to examine under standardized conditions the virucidal, bactericidal and fungicidal effects of disinfection techniques used in practice. MATERIALS AND METHODS: The efficacy of various disinfection methods was determined after clinical use in-vivo on 10 test subjects and in-vitro with deliberate contamination. The following disinfection methods were tested: 1. Iso-Septol spray 2. Incidur spray 3. Trough disinfection in combination with 5% Sekusept Plus solution 4. Ultrasound bath in combination with 5% Sekusept Plus solution 5. Thermal disinfection For in-vitro contamination we used the test organisms Staphylococcus aureus, Escherichia coli, Candida albicans, Coxsackie virus B4, HSV 1, and Adenovirus type 5. The tests were carried out six to eight times for each organism. The Weingart pliers and distalend cutters were tested. The criteria for effective disinfection were a reduction in infectiosity of five log steps (for bacteria and fungi) or four log steps (viruses). Statistical analysis was carried out using the Wilcoxon and Whitney U-test. RESULTS: The presence of contamination following clinical use was not adequately eliminated with all disinfection methods. The spray methods exhibited shortcomings in disinfection. For the type of contamination defined, trough disinfection with 5% Sekusept Plus and the Incidur and Iso-Septol spray disinfection methods provided insufficient disinfection. Conversely, the ultrasound bath with 5% Sekusept Plus solution and steam disinfection met the criteria for effective disinfection for all microbes. No statistically significant difference was found between the oiled and unoiled states. In some cases, there were slightly higher rates of contamination with the Weingart pliers as with the distalend cutters. However, these were not statistically significant. CONCLUSIONS: It should be possible to disinfect lipophilic viruses and the usual bacterial infections adequately with all methods, provided that the use of sprays and trough disinfection is preceded by cleaning with brush and water, followed by drying. With hydrophilic viruses, however, the spray and trough disinfection methods are limited in their efficacy and cannot be considered adequate. Exclusively chemical methods are therefore less effective than thermal or physical-chemical methods. Thermal disinfection and the ultrasound bath in combination with 5% Sekusept Plus are clearly superior to spray disinfection and trough disinfection alone. The ultrasound bath and thermal disinfection can therefore be recommended for the disinfection of orthodontic pliers. We recommend that the pliers be cleaned beforehand due to their uneven surfaces.

Dental Instruments↗
PubMed1991

Epidermal toxicity of disinfectants.

The purpose of the present study was to investigate the capacity of various disinfectant chemicals to cause epithelial toxicity with repeated exposure. The abdominal area of 3-month old, experimental ICR/CD-1 mice was initially shaved, denuded with a depilatory agent and allowed to rest for 24 hours. Commercial preparations of iodophors, bleach, synthetic phenols, phenolic/alcohols, and glutaraldehydes were then sprayed onto the exposed abdominal tissue 8 times/day (0.8 ml spray) for 2 consecutive days. The applied disinfectant was allowed to dry between procedures. In comparison to controls sprayed with distilled water, each disinfectant stimulated some degree of epidermal changes. Resultant multiple brownish lesions showed local thickening and hardening. Histologically, epidermal changes ranged from mild hypertrophy to extensive epithelial erosion. A few inflammatory cells were occasionally detected in the epithelium. When present, dermal reactions ranged from a mild inflammation to focal areas of collagen degeneration. The results indicated that iodophors stimulated the mildest reactions, followed by the synthetic phenol preparations, bleach, phenolic/alcohols, and glutaraldehyde sprays. Similar assays using glutaraldehyde immersion sterilants/disinfectants produced marked tissue destruction.

Animals↗
PubMed2004

[A new therapy concept for the treatment of dry eye--the usefulness of phospholipid liposomes].

BACKGROUND: Most of the eye drops currently used replace only the aqueous phase of the tear film. But, due to the fact that, with approximately 80 % of the patients with a dry eye, a disturbance of the lipid phase is present, an approach for new treatment methods needed to be found. We examined a new therapy concept with an eye spray containing liposomes for the therapy of the "dry eye" in a long-term study. GOAL: An examination of the effectiveness of a liposome eye spray (TEARS AGAIN, Optima Pharmaceutical GmbH, Germany) in patients with "dry eye" compared with a spray containing a balanced salt solution was carried out. METHODS: Between August 2003 and May 2004 a double-blind study with 382 patients was accomplished. The treatment group (V; n = 191) was compared with the control group (K; n = 191) for a period of 6 months regarding the following examination criteria: eyelid edge parallel conjunctival folds (LIPCOF), BREAK UP time (BUT), Schirmer I test, best corrected visual acuity, as well as slit lamp findings of the cornea and conjunctiva. Follow-up was after 4 weeks and 6 months. The statistical analysis was performed with the statistical program SPSS v.11.5. RESULTS: The examined parameters such as LIPCOF, BUT and Schirmer were significantly better in the treatment group than in the control group. We found likewise significant improvements of the inflammations of the edge of eyelid with a remarkable decrease of around 89.5 %. Questioning of the patients resulted in, among other things, the belief that the liposome eye spray led altogether to a clear subjective improvement of the symptoms in 72 % of the cases, although an initial burning sensation was mentioned after the application. All patients were of the opinion that application with a spray is more favourably and more pleasant than teardrops. CONCLUSION: The liposome tear substitute shows statistically significant advantages against a balanced salt solution. This new liposome eye spray represents a new, revolutionary and effective procedure in the therapy of the "dry eye". Considering the disturbance of the lipid phase in 80 % of the patients, TEARS AGAIN ought to be a first choice treatment.

Adolescent↗
PubMed2004

Electrospray sample deposition for matrix-assisted laser desorption/ionization (MALDI) and atmospheric pressure MALDI mass spectrometry with attomole detection limits.

Electrospray sample deposition was explored for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). In this method, nanoliter volumes of matrix/analyte mixture were electrosprayed from a high voltage biased (1-2 kV) fused-silica capillary onto a grounded MALDI plate mounted 100-500 microm from the capillary outlet. Electrospray deposition with these conditions produced sample spots 200-300 microm in diameter thus matching the laser spot size. Varying spray voltage and distance resulted in different crystal sizes and volatilization rates for alpha-cyano-4-hydroxycinnamic acid matrix. Best results were obtained when the sample was deposited as wet droplets as opposed to deposition as dried solid. Under 'wet-spray' conditions, 2-4 microm diameter crystals were formed and detection limits for several neuropeptides were 0.7-25 amol. Samples could be pre-concentrated on the plate by spraying continuously and allowing sample to evaporate in a small spot. Sample volumes as large as 580 nL were deposited yielding a detection limit of 35 pM for neurotensin 1-11. Electrospray sample deposition yielded similar results when using atmospheric pressure-MALDI coupled with a quadrupole ion trap mass spectrometer, except that the sensitivity was approximately seven-fold worse.

Atmospheric Pressure↗
PubMed2002

Comparison of carbon dioxide versus refrigerant spray to determine pulpal responsiveness.

There is little evidence for which cold delivery method is most accurate in determining pulp responsiveness. This study compared carbon dioxide dry ice sticks (CO2) versus refrigerant spray (RS) to generate a patient response from different types of teeth restored to varying degrees. Fifteen human patients were selected. In each quadrant, three teeth were identified and the restoration type recorded. Blindfolded patients were randomly tested with either CO2 or RS in a crossover design at two different sessions. Responsiveness was recorded as yes/no and the interval (in seconds) from application to response was determined. Results showed that (a) CO2 and RS were equivalent in producing a pulpal response regardless of tooth and presence of restoration, and (b) CO2 took significantly (p < 0.05) longer to evoke a response than RS using paired t tests. In conclusion, RS and CO2 were equivalent in determining pulpal responsiveness, but the elicited response from RS was faster.

Adult↗
PubMed1997

Characterization of a commercial liposome spray.

The commercial liposome spray Heparin-pur-ratiopharm was physicochemically characterized. This preparation is said to result in a fine gel-film containing pure, concentrated liposomes (including drug) on the skin after application and evaporation of the water/ethanol-mixture of the system. As phospholipids tends to form lamellar structures at lower water concentrations the structural characteristics of Heparin-pur-ratiopharm were investigated in the original preparation and after a drying process, which should be comparable to application on skin. For the characterization several methods were used, e.g. photon correlation spectroscopy, electron and polarized light microscopy, small angle X-ray (SAX) scattering and SAX diffraction. The results of the present investigation indicate that there are no changes in the colloidal state of the phospholipids before and after drying and application of the spray. There seem to be only changes in the degree of dispersion of the liquid crystalline phase, i.e. from small uni- or oligolamellar liposomes in the original preparation via multilamellar vesicles to a lamellar mesophase during the drying process. Therefore, it seems that there are no differences for the application of heparin if a preparation containing small uni- or oligolamellar liposomes is used or if the phospholipids are structured differently. The major point of importance for drug application, therefore, seems to be the presence of phospholipids as they possibly work as enhancer for the uptake of the drug through the skin to achieve a quick effect.

Aerosols↗
PubMed1999

Monitoring the susceptibility of citrus rust mite (Acari: Eriophyidae) populations to abamectin.

A citrus leaf disk bioassay was developed to monitor the susceptibility of citrus rust mite, Phyllocoptruta oleivora (Ashmead), populations to abamectin. Disks from leaves of several citrus cultivars were equally suitable bioassay substrates, and there was no difference in mortality when mites were sprayed directly or exposed to dry abamectin residue. The concentration-response relationship was determined at intervals over 2 yr for a reference population of citrus rust mites that had been maintained in culture and never exposed to acaricides. Three diagnostic concentrations of abamectin were selected based on the response of the reference population and were used to test the susceptibility of 15 populations of mites from commercial citrus groves. Comparisons with the reference population showed reduced levels of susceptibility in some populations. Populations of citrus rust mites from 6 commercial groves were sprayed twice in 1997 with combinations of acaricides designed to exert different intensities of selection pressure from abamectin. None of these populations showed a change in their response to abamectin in pre- and postspray bioassays, although their susceptibility was usually less than that of mites from the susceptible reference population. Biweekly counts of rust mites on fruit in these 6 groves suggested that, relative to groves which received no abamectin or 1 abamectin spray, mite control was not adversely affected in the groves sprayed twice with abamectin. The bioassay method is discussed in relation to factors that affect the interpretation of results from its use, and factors that may affect the development of resistance to abamectin in citrus rust mite populations are presented. This study has provided baseline data with which the results of ongoing tests of the response of citrus rust mite populations to abamectin can be compared.

Animals↗
PubMed2001

Consumption of residue containing cucurbitacin feeding stimulant and reduced rates of carbaryl insecticide by western corn rootworm (Coleoptera: Chrysomelidae).

Application of insecticide at a reduced rate with a cucurbitacin-based feeding stimulant is a viable alternative to a broadcast insecticide application for control of adult western corn rootworms, Diabrotica virgifera virgifera, LeConte. Because of the small amount of material applied, it is conceivable that a high density of beetles could consume all of the spray residue before economic control is achieved. A laboratory experiment was conducted to determine the amount of cucurbitacin-based spray residue consumed by beetles. Dried residue of four treatments were exposed to three groups of 10 rootworm beetles for 1 h each. Treatments consisted of a cucurbitacin-based adjuvant (Cidetrak CRW, Trécé, Salinas, CA) with carbaryl insecticide (Sevin XLR Plus, Rhone Poulenc, Research Triangle Park, NC) mixed at 0, 0.12, 1.2, and 12 g (AI)/liter. For the treatment with cucurbitacin adjuvant only (no insecticide), beetles consumed 0.029 mg beetle(-1) h(-1) of exposure. Approximately 54% of the beetles were recorded as feeding at any given time during the 60-min feeding period. However, when the spray residue contained carbaryl, no weight loss of treatment residue was measured, though the beetles were observed to feed from the residue during the first few minutes of exposure. When residue included insecticide, beetles quickly ceased feeding (within 20 min), and toxicity behavior was observed 30 min after initial exposure for up to 75% of the beetles, which were classified as moribund (unable to stand upright). Beetle mortality was recorded 24 h after exposure and demonstrated that male beetles (53% dead for three insecticide treatments) were more susceptible to carbaryl toxicity than female beetles (28% dead for three insecticide treatments). Regression analysis showed a significant positive relationship between mortality of female beetles and ovarian development. Based on the measurements of this experiment, it is unlikely that realistic beetle densities would consume enough spray residue to prevent economic control of the beetle population.

Animals↗
PubMedDate not supplied

An in vitro investigation of the efficacy of CPC for use in toothbrush decontamination.

PURPOSE: A product designed as a toothbrush disinfectant containing cetylpyridinium chloride (CPC), a quaternary ammonium compound, recently was introduced. The purpose of this study was to provide additional evidence that CPC provides a practical solution for destroying residual microorganisms on air-dried toothbrushes and toothbrushes stored in a travel container. METHODS: Sterile synthetic toothbrushes were inoculated with optical density standardized laboratory cultures of Staphylococcus epidermidis or Candida albicans. Half were then disinfected with CPC and half were used as untreated controls. The toothbrushes were vortexed in sterile saline solution, diluted in a ten-fold series, and plated on 5% blood agar or Sabouraud dextrose agar. The plates were incubated at 37 degrees C in a normal atmosphere for 48 hours, and colonies were counted. RESULTS: CPC produced significant decreases in residual microorganisms. Using the CPC spray treatment on air-dried toothbrushes, Staphylococcus epidermidis essentially was reduced 100-fold, while Candida albicans had a 94% reduction of growth. Bacterial counts were higher in the samples stored in closed containers as compared to the air-dried samples. CONCLUSION: CPC appeared to be an effective toothbrush disinfectant for the organisms evaluated. It is practical and economical. CPC could easily fit into the recommendations of a practice committed to infection control.

Anti-Infective Agents, Local↗
PubMed1999

Fatigue behavior of calcium phosphate coatings with different stability under dry and wet conditions.

To obtain stable plasma sprayed calcium phosphate coatings, coatings with a high crystallinity and low solubility were developed. However, stability of ceramic coatings is also influenced by their fatigue resistance. Recently, fatigue failure was proposed to explain coating detachment from implants under loaded conditions. Therefore, plasma-sprayed calcium phosphate coatings with different crystallinity were investigated in vitro for fatigue failure. An amorphous and a crystalline hydroxylapatite coating (AHA and CHA) and a highly crystalline fluorapatite coating (FA) were subjected to cyclic load tests, both in dry conditions and in simulated body fluid (SBF). The results in SBF revealed that the crystalline CHA and FA coating detached completely at the highest stressed middle section of the bar. The FA coating delaminated earlier than the CHA coating. The amorphous AHA coating showed only partial coating loss at the completion of the test. Tests in dry conditions did not reveal any change in the coatings tested. These results suggest a relation between crystallinity of apatite coatings and their failure due to fatigue: high crystallinity coatings demonstrate earlier and more complete fatigue failure than the amorphous apatite coatings. It can be concluded that coating stability is not determined solely by static dissolution, but by fatigue failure as well.

Biocompatible Materials↗
PubMed2005

The production of protein-loaded microparticles by supercritical fluid enhanced mixing and spraying.

In this study, we use supercritical carbon dioxide as a processing medium for the fabrication of poly(DL-lactic acid) P(DLLA) microparticles that encapsulate a protein material. We have previously demonstrated that this polymer and a dry powder of a protein can be mixed under supercritical carbon dioxide conditions (above 31.1 degrees C and 73.8 bar) and that the protein component retains its biological activity. In this paper, we progress the work to demonstrate that the plasticized polymer and dry powder protein mixture can be sprayed to form solid polymer particles that encapsulate the protein. Particle size range is between 10 and 300 microm after spraying. Ribonuclease A and lysozyme were encapsulated in the polymer without significant loss of enzymatic activity. Biological assays of insulin and calcitonin confirm retention of activity after fabrication of the microparticles and release of the peptides/proteins.

Calcitonin↗
PubMed2005

Dipping versus spraying: exploring the deposition conditions for speeding up layer-by-layer assembly.

Polyelectrolyte film fabrication by successive spraying of polycation and polyanion solutions is described and compared to classic dipping. The poly(styrenesulfonate)/poly(allylamine) system is examined in detail. The influence of various parameters such as spraying time, polyelectrolyte concentration, and effect of film drying during multilayer construction is investigated. It is found that film deposition by spraying is easily controlled and very reliable. The thickness of the multilayers grows linearly with the number of deposition cycles similarly to what is observed when dipping substrates or when polyelectrolyte solutions flow over a surface. The assembly of films is very fast and leads to films with small surface roughness as estimated by atomic force microscopy and X-ray reflectometry. Spray deposition allows achieving regular multilayer growth even under conditions for which dipping fails to produce homogeneous films (e.g., extremely short contact times). Moreover, because drainage constantly removes a certain quantity of the excess material arriving at the surface, one can even skip the rinsing step and, thus, speed up even further the whole buildup process.

Journal Article↗
PubMed2002

Toxicity of a formulation of the insecticide indoxacarb to the tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), and the big-eyed bug, Geocoris punctipes (Hemiptera: Lygaeidae).

Indoxacarb is a new oxadiazine insecticide that has shown outstanding field insecticidal activity. The toxicity of a 145 g litre-1 indoxacarb SC formulation (Steward) was studied on the tarnished plant bug Lygus lineolaris and the big-eyed bug Geocoris punctipes. Both insect species responded very similarly to indoxacarb in topical, tarsal contact and plant feeding toxicity studies. The topical LD50 of the formulation was c 35 ng AI per insect for both species. Prolonged tarsal contact with dry indoxacarb residues did not result in mortality for either insect species. However, both species were susceptible to feeding through dried residues of indoxacarb after spraying on young cotton plants. Feeding on water-washed plants resulted in lower mortality than that observed with unwashed plants, and toxicity declined even more dramatically after a, detergent rinse, indicating that much of the indoxacarb probably resides on the cotton leaf surface or in the waxy cuticle. These results were corroborated by HPLC-mass spectrometry measurements of indoxacarb residues on the plants. Greater mortality for both species was observed in a higher relative humidity environment. Higher levels of accumulated indoxacarb and its active metabolite were detected in dead G punctipes than in L lineolaris after feeding on sprayed, unwashed plants. When female G punctipes ate indoxacarb-treated Heliothis zea eggs, there was significant toxicity. However, only c 15% of the females consumed indoxacarb-treated eggs, and the rest of the females showed a significant diminution of feeding in response to the insecticide. Cotton field studies have shown that indoxacarb treatments at labelled rates lead to a dramatic decline in L lineolaris, with negligible declines in beneficial populations. A major route of intoxication of L lineolaris in indoxacarb-treated cotton fields thus appears to be via oral, and not cuticular, uptake of residues from treated cotton plants. The mechanisms for selectivity/safety for G punctipes are currently under investigation and may be a combination of differential feeding behavior and diminution of feeding by females exposed to indoxacarb-treated eggs.

Animals↗
PubMed1975

The standardisation of thin-layer chromatographic systems for the identification of basic drugs.

Three thin-layer chromatographic systems have been selected on the basis of their discriminating power on which to standardise for the identification of basic drugs. They are systems of silica gel sprayed with 0.1 N NaOH, dried and run using one of the following solvents: cyclohexane-toluene-diethylamine (75:15:10), chloroform-methanol (90:10) or acetone. They can be used in combination since their correlation coefficients are low. Four reference compounds should be used, equally spaced across the plate. The inter-laboratory variation of measurement of RF values has been ascertained and the use of a graphical RF correction method reduced the mean deviation of measurement to 0.02. The measurement of RF values was found to be less reproducible in the middle of the chromatogram than in regions of very low or very high RF values.

Amitriptyline↗
PubMed1996

Gender aspects and women's participation in the control and management of malaria in central Sudan.

This work was designed to study the contribution of women in central Sudan in the control and management of malaria with particular emphasis on gender-related aspects that define women's role and participation. The Blue Nile Health Project (BNHP 1980-1990) was launched in 1980 mainly for control of water associated diseases in central Sudan. The BNHP model was chosen to conduct this work. The study showed that women were actively involved in the implementation of the BNHP strategies as health instructors (murshidat) who constituted 75% of the staff of BNHP unit of health education, as members of village health committees (VHC) where they constituted 40% of the VHC members and also as recipients of the project services. All murshidat were interviewed whereas multistage random sampling for VHC members and recipient women in 40 villages was used to select a sample which was interviewed. The results showed that the murshidat and VHC women members played a major role in the motivation, organization and health education of local communities prior to campaigns of environmental sanitation and vector control. Household commitments and difficulties in communication with the public were the main gender-related factors that contributed negatively to women's activities. Cases of malaria have more considerable socio-economic impact than other common diseases, especially with regard to women's household commitments and work. Recipient women were more concerned with aspects of self protection, management of family cases of malaria and health education programmes. They were less involved in drying mosquito breeding sites and spraying activities of insecticides which had been reluctantly accepted because of allergy and bad odour. Although the majority of women considered antimalarials to be less harmful than effects of malaria itself on pregnancy, they did not realize the role of malaria chemoprophylaxis during pregnancy. This needs more health education. The study showed that the BNHP programme was very successful in recruiting women in control and management programmes. Therefore, health planners are urged to persuade the subordinated communities of women in many African countries like Sudan to play a more active role in the health programmes and welfare of their communities.

Adolescent↗
PubMed2003

Coupling of HDPE/hydroxyapatite composites by silane-based methodologies.

Several coupling treatments based on silane chemicals were investigated for the development of high density (HDPE)/hydroxyapatite (HA) composites. Two HA powders, sintered HA (HAs) and non sintered HA (HAns), were studied in combination with five silanes, namely y-methacryloxy propyltrimethoxy silane (MEMO), 3-(2-aminoethyl)aminopropyltrimethoxy silane (DAMO), vinyltrimethoxy silane (VTMO), 3-aminopropyltriethoxy silane (AMEO) and trimethoxypropyl silane (PTMO). The HA particles were treated by a dipping in method or by spraying with silane solutions. After drying, the treated powders were compounded with HDPE or HDPE with acrylic acid and/or organic peroxide and subsequently compression molded. The tensile test specimens obtained from the molded plates were tensile tested and their fracture surfaces were observed by scanning electron microscopy (SEM). For the sintered HA (HAs) composites, the most effective coupling treatments concerning stiffness are those based on MEMO and AMEO. The low influence of these coupling procedures on strength is believed to be associated to the low volume fraction and the relatively smooth surface of the used HA particles. For the non-sintered HA (HAns) composites, it was possible to improve significantly both the stiffness and the strength. Amino silanes demonstrated to be highly efficient concerning strength enhancement. The higher effectiveness of the coupling treatments for HAns filled composites is attributed to their higher particle surface area, smaller particle size distribution and expected higher chemical reactivity. For both cases, the improvement in mechanical performance after the coupling treatment is consistent with the enhancement in interfacial adhesion observed by SEM.

Journal Article↗
PubMed2004

Spray-coating for biopharmaceutical powder formulations: beyond the conventional scale and its application.

PURPOSE: Fluid-bed spray-coating process is widely used to prepare non-protein pharmaceutical solid dosage forms using macro-size seed particles (200-1000 microm) at kilogram batch sizes. In this study we developed a small-scale fluid-bed spray-coating process (20 g) to produce micro-sized vaccine powder formulations (40-60 microm) for epidermal powder immunization (EPI) METHODS: A bench-top spray coater was used to spray two vaccines, diphtheria toxoid (dT) and alum-adsorbed hepatitis-B surface antigen (Alum-HBsAg), onto crystalline lactose particles of 40-60 microm in diameter. Particle properties such as particle size, surface morphology, and degree of particle agglomeration were determined. Protein stability was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The immunogenicity of the vaccine was evaluated in vivo by needle injection and epidermal powder immunization (EPI) of mice or guinea pigs. RESULTS: Coating feasibility was demonstrated for both vaccine formulations containing different excipients. However, the nature of the vaccine antigen appeared to affect coating feasibility in terms of particle agglomeration considerably. Delivery of spray-coated dT and alum-HBsAg through EPI to mice and guinea pigs, respectively, generated significant antibody responses, at a level comparable to liquid formulation delivered subcutaneously through needle/syringe injection. CONCLUSIONS: The new spray-coating process represents an important technical advance and may provide a useful tool for developing high-valued biopharmaceutical powder formulations for novel applications. The strong in vivo performance of the coated dT and alum-HBsAg powders by EPI further demonstrated that spray-coating is a viable dry powder formulation process and the skin's epidermal layer presents an efficient vaccine delivery route.

Animals↗