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PubMed1989

Dose-effect relationship of terbutaline using a multi-dose powder inhalation system ('Turbuhaler') and salbutamol administered by powder inhalation ('Rotahaler') in asthmatics.

A study was carried out in 8 patients with chronic stable bronchial asthma to compare the bronchodilator response with terbutaline, administered by a recently developed powder inhalation system ('Turbuhaler') and equipotent doses of salbutamol administered by a widely used powder inhaler ('Rotahaler'). Dose-effect relationships with usually applied clinical doses of the bronchodilators were estimated by maximal expiratory flow-volume analysis and airway resistance estimates from body plethysmography. There was no significant difference in clinical response using either inhaler. The equal and opposite changes in forced vital capacity and residual volume with increasing dose indicate an improvement in peripheral airway resistance and, therefore, adequate peripheral powder deposition of the bronchodilators. Only at the highest dose was a mild increase noted in pulse frequency and tremor score with both systems. It is suggested that, because of the multi-dose character, absence of additives, easy handling (no capsule loading) and low inspiratory flow needed for actuation, the 'Turbuhaler' system may be considered preferable for the application of a bronchodilator in children and severely obstructed adults.

Administration, Inhalation↗
PubMedDate not supplied

Development of milk powder reference materials certified for aflatoxin M1 content (Part II): Certification of milk powder RM 283.

The development of a full cream milk powder reference material, certified for its aflatoxin M1 content (target concentration: 0.1 microgram/kg), is described. The material (RM 283) was prepared and certified within the Reference Material Programme of the Community Bureau of Reference, along with other members of a series of milk powder reference materials. Homogeneity, evaluated by determining the aflatoxin M1 content of 30 units, was found to be acceptable (coefficient of variation of analysis results: 9.1%); stability has been demonstrated in a long-term study. The certification exercise involved 7 laboratories. Calibration, control of recoveries, blank values, and independence of the replicate measurements were emphasized. All sets of results of the certification exercise were accepted for statistical evaluation. A certified value for the aflatoxin M1 content: 0.09(+0.04)(-0.02) micrograms/kg was derived. The certification of RM 283 completes the series of 4 milk powder reference materials having certified aflatoxin M1 contents.

Aflatoxin M1↗
PubMed2004

Use of a cognitive ergonomics approach to compare usability of a multidose dry powder inhaler and a capsule dry powder inhaler: an open-label, randomized, controlled study.

BACKGROUND: Usability (ease of use) is an important feature of inhalers to ensure optimal dose delivery OBJECTIVE: The aim of this study was to compare the usability of a multidose dry powder inhaler (mDPI) and a capsule dry powder inhaler (cDPI) in older individuals, using a range of qualitative and quantitative techniques from the field of cognitive ergonomics. METHODS: Participants aged >50 years were enrolled in this 2-visit, open-label, randomized, controlled, parallel-group study conducted at Northumbria University, Newcastle upon Tyne, United Kingdom. Participants who had used an inhaler or were inhaler naive were randomized to use the mDPI or cDPI. At visit 1, the inhaler procedure was demonstrated twice by the investigator. Participants then repeated the procedure (although they were not expected to inhale because no drug was to be administered) until they made 3 consecutive correct attempts. They also undertook a range of tests to assess their confidence in using the device, manual dexterity, and self-efficacy At visit 2 (2 days later), participants made a single inhaler attempt before receiving any demonstrations from the investigator; this was intended to simulate clinical practice, in which the patient may not use an inhaler for a few days after it is prescribed. Participants then completed the inhaler procedure 10 times while undertaking a concurrent distracter task. The number of critical errors (ie, those having a high impact on dose delivery) was recorded for all attempts. To facilitate subsequent correlation analyses, an overall performance measure was derived from a combination of the results of the single inhaler trial and the 10 trials with a distracter. RESULTS: Eighty individuals (51 women, 29 men; mean [SD] age, 74.1 [7.5] years) participated in the study(40 participants per device). Forty of the participants (50%) had used an inhaler previously; 40 (50%) were inhaler naive. Based on the overall performance measure, participants testing the mDPI made significantly fewer critical errors than participants testing the cDPI (P < 0.001). Participants rated both inhalers as easy to use but were overconfident concerning their ability to use the 2 devices. CONCLUSIONS: In this study of usability of an mDPI and a cDPI in older participants, participants found both inhalers easy to use, but fewer critical errors were made with the mDPI compared with the cDPI. However, the results suggest a degree of overconfidence and the need for continual monitoring of patients' inhalation technique, especially with the cDPI.

Administration, Inhalation↗
PubMed2006

Air classifier technology (ACT) in dry powder inhalation Part 3. Design and development of an air classifier family for the Novolizer multi-dose dry powder inhaler.

In this study, the design of a multifarious classifier family for different applications is described. The main design and development steps are presented as well as some special techniques that have been applied to achieve preset objectives. It is shown by increasing the number of air supply channels to the classifier chamber (from 2 to 8), that the fine particle losses from adhesion onto the classifier walls can be reduced from 75% to less than 5% of the real dose for soft (spherical) agglomerates. By applying a bypass flow that is arranged as a co-axial sheath of clean air around the aerosol cloud from the classifier, the airflow resistance of the classifier can be controlled over a relatively wide range of values (0.023-0.041 kPa(0.5) min l(-1)). This, without affecting the fine particle dose or increasing the fine particle losses in the inhaler. Moreover, the sheath flow can be modelled to reduce the depositions in the induction port to the cascade impactor or in the patient's mouth, which are the result of back flows in these regions. The principle of powder induced pressure drop reduction across a classifier enables assessment of the amount of powder in the classifier at any moment during inhalation, from which classifier loading (from the dose system) and discharge rates can be derived. This principle has been applied to study the residence time of a dose in the classifier as function of the carrier size fraction and the flow rate. It has been found that this residence time can be controlled in order to obtain an optimal balance between the generated fine particle fraction and the inhalation manoeuvre of the patient. A residence time between 0.5 and 2 s at 60 l/min is considered favourable, as this yields a high fine particle dose (depending on the type of formulation used) and leaves sufficient inhaled volume for particle transport into the deep lung.

Adhesiveness↗
PubMed2002

In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.

Apatites↗
PubMed2003

Investigating the effects of excipients on the powder flow characteristics of theophylline anhydrous powder formulations.

Pharmaceutical excipients may have a great effect on properties affecting tablet production. To determine if formulations containing theophylline anhydrous would have properties allowing them to be easily tableted, functional parameters affecting powder flow were evaluated. The Carr Flowability Indices were used for this evaluation. Formulations to be studied include theophylline anhydrous as the active ingredient, hydrous lactose and dicalcium phosphate dihydrate as diluents, polyvinylpyrrolidone as a binder, and fumed silica as a flow promoter. The effect of each component on powder flow is discussed.

Calcium Phosphates↗
PubMed2005

Formoterol delivered via a new multi-dose dry powder inhaler (Certihaler) is as effective and well tolerated as the formoterol dry powder inhaler (Aerolizer) in children with persistent asthma.

The Certihaler is a new multi-dose dry powder inhaler for the delivery of formoterol (Foradil), a long-acting beta(2)-agonist. This dose-ranging study compared the efficacy and safety of formoterol 5, 10, 15 and 30 microg and placebo administered via the Certihaler or formoterol 12 microg via a single-dose dry powder inhaler (Aerolizer) in children with persistent asthma. This was a randomized, placebo-controlled, double-blind, double-dummy, incomplete block crossover, dose-finding and pharmacokinetic study. Children (5-12 years, n = 77) received four of the active treatments twice weekly (BID) for 1 week separated by 1-week single-blind washouts. The primary efficacy variable was 12-h AUC of FEV(1) after 1 week's treatment. Secondary variables included serial 12-h FEV(1). A subset of patients (n = 37) participated in a pharmacokinetic analysis. All formoterol doses resulted in significant increases in 12-h AUC of FEV(1) compared with placebo, and there was no difference between active treatments. The onset of action of formoterol was <3 min for all active treatments. Doses of formoterol > or =10 microg via the Certihaler increased FEV(1) significantly for up to 12 h compared with placebo. The 5 microcg dose via the Certihaler and 12 microg dose via the Aerolizer had a significant effect up to 8 and 7 h post-dose, respectively. Urinary excretion of formoterol via the Certihaler increased in a dose-proportional manner. All formoterol doses were well tolerated, but some patients experienced tremor at the 15 and 30 microg doses. Despite the lack of significant differences between the active doses in the overall bronchodilation, formoterol 10 microg BID via the Certihaler was the dose that provided the best balance between efficacy and tolerability: its duration of action was sustained over 12 h, contrary to that the lower dose (5 microg BID), whereas its tolerability, especially with regard to tremor, was better than the higher doses (15 and 30 microg BID). Overall, Certihaler 10 microg BID was not significantly different from formoterol 12 microg BID via Aerolizer.

Adrenergic beta-Agonists↗
PubMed2002

Powder properties and their influence on dry powder inhaler delivery of an antitubercular drug.

The purpose of this study was to determine if aerosol delivery of drug loaded microparticles to lungs infected with Mycobacterium tuberculosis may be achieved by predicting dispersion of dry powders through knowledge of particle surface properties. Particle sizes of rifampicin-loaded poly(lactide-co-glycolide) microparticles (R-PLGA), rifampicin alone, and lactose and maltodextrin carrier particles (bulk and 75-125- microm sieved fractions) were determined by electron microscopy for the projected area diameter (D(p)) and laser diffraction for the volume diameter (D(v)). Surface energies (gamma) of R-PLGA, rifampicin alone, lactose, and maltodextrin were obtained by inverse phase gas chromatography, surface areas (S(a)) by N2 adsorption, and cohesive energy densities by calculation. Particle dispersion was evaluated (Andersen nonviable impactor) for 10% blends of R-PLGA and rifampicin alone with bulk and sieved fractions of the carriers. D(p) for R-PLGA and rifampicin alone was 3.02 and 2.83 microm, respectively. D(v) was 13 +/- 1 and 2 +/- 1 microm for R-PLGA and rifampicin alone, respectively, indicating that R-PLGA was more aggregated. This was evident in gamma of 35 +/- 1 and 19 +/- 6 mJ/m2 for R-PLGA and rifampicin alone. D(p) for lactose and maltodextrin (sieved and bulk) was approximately 40 mm. Bulk maltodextrin (D(v) = 119 +/- 6 microm) was more aggregated than bulk lactose (D(v) = 54 +/- 2 microm). This was a result of the higher S(a) for maltodextrin (0.54 m2/g) than for lactose (0.21 m2/g). The gamma of bulk lactose and maltodextrin was 40 +/- 4 and 60 +/- 6 mJ/m2 and of sieved lactose and maltodextrin was 39 +/- 1 and 50 +/- 1 mJ/m2. Impaction studies yielded higher fine particle fractions of R-PLGA from sieved lactose, 13% +/- 3%, than from sieved maltodextrin, 7% +/- 1%, at 90 L/min. An expression, based on these data, is proposed as a predictor of drug dispersion from carrier particles. Delivery of dry powder formulations can be achieved by characterizing particle surfaces and predicting impact on dispersion.

Administration, Inhalation↗
PubMed1998

Measurement of electrostatic charge decay in pharmaceutical powders and polymer materials used in dry powder inhaler devices.

The electrostatic charge generated on drug/excipient particles during the formulation, manufacture, and use of pharmaceutical dry powder inhaler (DPI) devices may significantly affect the performance of such devices. An experimental investigation has been undertaken of charge accumulation and decay on compacts of selected powders (lactose and salbutamol sulfate) and a device material (polyvinyl chloride, PVC) used during the formulation, manufacture, and use of DPIs. Significant differences in charge acquisition and decay for the three materials have been demonstrated after charging using a corona electrode. PVC acquired the highest charge, which decayed rapidly in 30 min toward the value prior to exposure to corona. Lactose and salbutamol acquired similar charge values, which decayed to zero after 30 min for lactose, whereas salbutamol retained a significant charge after 120 min. The significant differences in charging propensity among drug, excipient, and device materials may have relevance in DPI formulation, manufacture, and use.

Albuterol↗
PubMedDate not supplied

[The treatment of bronchial asthma with powdered salbutamol and powdered beclomethasone dipropionate].

The active bronchodilators and anti-inflammatory drugs used as dry powder in inhalatory treatment of bronchial asthma represent an important advance during last years. In this way the inconveniences of pressurized aerosols treatment where the drugs are only partially inhaled as well as severe side-effects of systemic corticotherapy are avoided. The bronchodilator drug Ventodisk and the antiinflammatory Becodisks as dry powder are given by inhalation with a special device (Diskhaler). The study deals with a group of 60 subjects with moderate and severe forms of bronchial asthma out of which 20 were treated by Ventodisk associated to Becodisks and other two groups of 20 subjects each treated during the same interval time with only Becodisks and Ventodisk respectively. The clinical results after two months treatment were much better in the first group of subjects (85% good results) in comparison to Becodisks (75%) and Ventodisk (60%) treated cases. One can state in conclusion that the association of Ventodisk to Becodisks leads to very good results in basic treatment of bronchial asthma.

Administration, Inhalation↗
PubMed1978

[Microflora in milk powder and baby food in powder form (author's transl)].

After a discussion of the microbiological standards for milk powder and powdered baby food in various countries, the results of the microbiological analyses of some 1500 samples of these foodstuffs were presented. It emerged that the microflora of these products consists mainly of lactobacteria (they are not demonstrable with all culture methods), micrococci and bacilli: the latter are those with the greatest importance with respect to food hygiene. In addition to these Clostridia and moulds are also found in the samples; very occasionally enterobacteria are also found. No pathogenic germs were detected. With respect to the proposals for standards it was found that the latest Hungarian standards proposals are acceptable provided that the methods of analysis (culturing after Polonyi) are retained also for the proposals discussed.

Animals↗
PubMed2006

A Process Analytical Technology approach to near-infrared process control of pharmaceutical powder blending. Part III: Quantitative near-infrared calibration for prediction of blend homogeneity and characterization of powder mixing kinetics.

The Process Analytical Technology (PAT) initiative, undertaken by the Food and Drug Administration (FDA), paves the way for improvement of drug manufacturing through real-time measurements that allow better process understanding. This study is the third and final Part in a series of studies that represent an integrated approach for real-time blend uniformity assessment using near-infrared (NIR) technology. In this study, the development of a quantitative NIR model for prediction of blending end point is presented. Process signature was built into NIR calibration models by using blend samples that were collected from actual blend experiments under different processing conditions. Evaluation of various calibration algorithms including principal component regression (PCR), partial least squares (PLS), and multi-term linear regression (MLR) was performed. It was found that linear regression, using a single wavelength, yielded optimum calibration and prediction results. The blending profiles predicted by the NIR quantitative model correlated well to those determined by the UV reference analytical method. Characterization of intra-shell versus inter-shell powder mixing kinetics and its implication in sensor positioning was also performed and will be discussed.

Calibration↗
PubMed2006

Air classifier technology (ACT) in dry powder inhalation Part 4. Performance of air classifier technology in the Novolizer multi-dose dry powder inhaler.

In this study, the in vitro fine particle deposition from a multi dose dry powder inhaler (Novolizer) with air classifier technology has been investigated. It is shown that different target values for the fine particle fraction (fpf<5 microm) of the same drug can be achieved in a well-controlled way. This is particularly relevant to the application of generic formulations in the inhaler. The well-controlled and predictable fpf is achieved through dispersion of different types of formulations in exactly the same classifier concept. On the other hand, it is shown that air classifier-based inhalers are less sensitive to the carrier surface and bulk properties than competitive inhalers like the Diskus. For 10 randomly selected lactose carriers for inhalation from four different suppliers, the budesonide fpf (at 4 kPa) from the Novolizer varied between 30 and 46% (of the measured dose; R.S.D.=14.2%), whereas the extremes in fpf from the Diskus dpi were 7 and 44% (R.S.D.=56.2%) for the same formulations. The fpf from a classifier-based inhaler appears to be less dependent of the amount of lactose (carrier) fines (<15 microm) in the mixture too. Classifier-based inhalers perform best with coarse carriers that have relatively wide size distributions (e.g. 50-350 microm) and surface discontinuities inside which drug particles can find shelter from press-on forces during mixing. Coarse carrier fractions have good flow properties, which increases the dose measuring accuracy and reproducibility. The fpf from the Novolizer increases with increasing pressure drop across the device. On theoretical grounds, it can be argued that this yields a more reproducible therapy, because it compensates for a shift in deposition to larger airways when the flow rate is increased. Support for this reasoning based on lung deposition modelling studies has been found in a scintigraphic study with the Novolizer. Finally, it is shown that this inhaler produces a finer aerosol than competitor devices, within the fpf<5 microm, subfractions of particles (e.g. <1, 1-2, 2-3, 3-4 and 4-5 microm) are higher.

Adhesiveness↗
PubMed2002

Microstructures and mechanical properties of powder injection molded Ti-6Al-4V/HA powder.

Taguchi method with an L9 orthogonal array was employed to investigate the sintered properties of Ti-6Al-4V/HA tensile bars produced by powder injection molding. The effects of sintering factors at the 90% significance level: sintering temperature (1050 degrees C, 1100 degrees C and 1150 degrees C), heating rate (5 degrees C/min, 7.5 degrees C/min and 10 degrees C/min), holding time (30, 45 and 60 min) and cooling rate (5 degrees C/min, 20 degrees C/min and 40 degrees C/min) were investigated. Results showed that sintering temperature, heating rate and cooling rate have significant effects on sintered properties, whereas the influence of holding time was insignificant. It was found that a sintering temperature of 1100 degrees C, a heating rate of 7.5 degrees C/min and a cooling rate of 5 degrees C/min increased the relative density, Vicker's microhardness, flexural strength and flexural modulus. However, a further increment of sintering temperature to 1150 degrees C did not show any discernable improvement in the relative density and Vicker's microhardness, but there was a slight increase of 0.6% and 0.9% in the flexural strength and flexural modulus, respectively. Mechanically strong Ti-6Al-4V/HA parts with an open porosity of around 50% were developed.

Alloys↗
PubMed1998

Powder densification. 2. Viscoelastic material properties in modeling the uniaxial compaction of powders.

A micromechanical model for predicting the densification of particulate matter under hydrostatic loading was developed to account for the time-dependent response of materials to applied loads. Viscoelastic material response used in the analysis was based upon a standard three-parameter rheological model. Compaction data under closed die conditions were collected using an Instron analyzer for different rates of applied load. Densification during the loading phase of PMMA/coMMA powder, a pharmaceutical polymeric coating material, was well predicted by the proposed algorithm, which contrasts with the prediction implied through a static indentation model. Secondary factors which affect compaction such as die-wall friction are also briefly discussed.

Algorithms↗
PubMed2006

Powder and other divided solids mixing. Scale-up and parametric study of a ribbon blender used in pharmaceutical powders mixing.

This work is aimed at evaluating the effect of ribbon blender operational parameters on mixture quality. Mix quality parameters and blend uniformity limits are enforced by regulatory bodies. These limits have served in this present work as targets for blending end-points. In a laboratory-scale model ribbon blender, built by scaling down a real industrial unit, powder mixtures composed of white and blue microcrystalline cellulose (MCC) were blended. Blend uniformity was evaluated using a statistical analysis method under various operating conditions such as loading patterns, blender filling percentage, impeller rotational speeds, and mixing times. It was shown that the filling percentage is the most influential mixing parameter. At high impeller rotational speed, the blending end-point was never reached during experimentation.

Algorithms↗
PubMedDate not supplied

Comparable efficacy and tolerability of formoterol (Foradil) administered via a novel multi-dose dry powder inhaler (Certihaler) or the Aerolizer dry powder inhaler in patients with persistent asthma.

BACKGROUND: For maximum treatment compliance there is a need to provide asthma patients with devices that suit their particular preferences. The Foradil Certihaler is a novel multi-dose dry powder inhaler developed to increase the choice of devices available. OBJECTIVES: To evaluate the safety and efficacy of formoterol administered via the Foradil Certihaler, or via the single-dose inhaler Foradil Aerolizer. METHODS: This was a randomized, placebo-controlled, double-dummy, incomplete block crossover, dose-ranging and pharmacokinetic study in patients with persistent asthma. Sixty-seven patients (mean 48.0 years) were randomized to formoterol 5, 10, 15 and 30 microg twice daily via the Certihaler, 12 microg formoterol b.i.d. via the Aerolizer, or placebo in four 1-week double-blind treatment periods separated by 1-week single-blind washouts. RESULTS All formoterol doses delivered via the Certihaler or the Aerolizer significantly increased FEV(1) compared with placebo (p < 0.0001). Formoterol demonstrated an onset of action of <3 min. All active treatments were well tolerated. Tremor was the most common adverse event and was more pronounced at high doses. At lower doses the incidence of tremor with the Certihaler was similar to that observed with placebo or the Aerolizer. The pharmacokinetic evaluation comprised 41 patients (mean 45.9 years). Urinary excretion of unchanged formoterol and total formoterol increased with dose delivered via the Certihaler. The optimum dose of formoterol via the Certihaler was 10 microg. CONCLUSION: Delivery of formoterol via the Certihaler or Aerolizer combines rapid relief with enduring control and provides convenient bronchodilation in patients with persistent asthma.

Administration, Inhalation↗
PubMed2006

Wet powder processing of sol-gel derived mesoporous silica-hydroxyapatite hybrid powders.

This paper describes a method by which a porous silica coating layer can be obtained on different apatite particles through a simple sol-gel synthesis route. Sol-gel derived powders of hydroxyapatite (HAP) and beta tricalciumphosphate (beta-TCP) were coated with a mesoporous silica using C16TAB (hexadecyltrimethylammonium bromide) as a template in order to induce mesophase formation. Further calcination of the material removes the template from the mesophase and leaves a highly ordered hexagonal arranged mesoporous silica structure with a core of HAP/beta-TCP. The phase purity of the SiO2/apatite composites has been thoroughly investigated by the means of FT-IR, XRD, and solid state 31P MAS NMR. The phase purity of these materials is shown to be dependent on the solubility properties of the used apatites. The hybrid materials are suitable as a multifunctional biomaterial where osteoconductive properties can be combined with drug delivery.

Apatites↗