Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine最新文献

This study used aerosol probes and lung function tests to investigate whether all trans retinoic acid (RA) can reverse experimental emphysema in dogs. Three dogs were evaluated with lung mechanics tests, including inspiratory capacity (IC), total lung capacity (TLC), and the ratio of forced expired volume in 0.5 sec to forced vital capacity (FEV0.5/FVC), an aerosol-derived measure of pulmonary airspace size (effective airspace diameter, EAD), and an aerosol-derived measure of nonuniform ventilation (aerosol dispersion, AD). Emphysema was induced by exposure to aerosolized papain. At 11 or 12 weeks post-papain exposure, dogs received oral RA (2 mg/kg/day) for 8 weeks, and were followed for an additional 4 weeks after stopping RA treatment. In all dogs, lung injury increased in the first 11-12 weeks following papain exposure, as evidenced by increasing trends of inspiratory capacity IC, TLC, EAD, and AD, and a decreasing trend of FEV0.5/FVC. These parameters of lung injury partially and transiently reversed their trends between 2 and 6 weeks following the initiation of RA treatment. A sham RA-treated group was not studied. However, similar reversals of lung injury were not seen in a previous study of dogs treated with papain but not RA, suggesting that RA altered emphysema progression in the current study. The limited reversal of lung injury in this study contrasts with more pronounced treatment effects seen in previous studies with rats. This paper discusses possible reasons for differences in these studies, as well as suggestions for improved experimental investigations of emphysema therapies.

We compared the peak inspiratory flows (PIF) generated through a novel dry powder inhaler device, the Novolizer (PIF-N), and the Turbuhaler (PIF-T). Forty-six pediatric patients with stable bronchial asthma were randomized in an open-label, multicenter, crossover trial. No drug was administered during the inhalation maneuvers that were spaced by 10 min. There was neither a carryover nor a sequence effect. The patients were characterized by mean age of 8.5 years, mean FEV(1) of 1.79 L, and mean PIF without any device (baseline, PIF-B) of 185 L/min. Through the devices mean PIF-N of 94 L/min and mean PIF-T of 69 L/min were achieved, calculated from the maxima of three inhalations. This resulted in p < 0.0001 for the difference. The median PIFN/PIF-T ratio was estimated as 1.39. Each child achieved a higher PIF-N than PIF-T and was able to release the feedback mechanisms of the Novolizer indicating sufficient inhalation performance. We conclude that the PIF through the Novolizer is higher than the PIF through the Turbuhaler in stable asthmatic children. The flow rates achieved through the Novolizer allow for sufficient lung deposition even in children as young as 6 years.

A facemask on a valved holding chamber (VHC) facilitates the inhalation of aerosols from metered dose inhalers (MDI) for young children. Only recently the facemask has been recognized as a vital part for efficient aerosol delivery. Several in vitro and in vivo studies show that a tight seal of the facemask is crucial for optimal aerosol deposition to the lungs. Even a small leak can reduce the dose delivered to the lungs considerably. However, a tight seal is difficult to obtain when a child is not cooperative. Depending on the design of the facemask, it is easier to obtain a good seal. Factors such as dead space, shape, and material should be considered when designing a facemask. However, when a child is upset and not cooperative during the administration, aerosol deposition will be minimal, even with the best-designed facemask.

Valved holding chambers (VHCs) are widely prescribed for use with pressurized metered dose inhalers (pMDIs) for the treatment of respiratory disease by aerosol therapy. The facemask is the preferred patient interface for use by infants and small children, as well as by geriatric patients, due primarily to poor coordination skills. However, care is required in the design of the facemask-VHC system to optimize the delivery of medication. In particular, it is essential to achieve an effective mask-to-face seal and to minimize the volume of dead space. It is also important to ensure that the fit of the facemask is comfortable to the patient when applied with sufficient force to create a seal. We review each of these design principles and their application in the evolution of a range of VHCs from the same family of devices during the past fifteen years. We also examine the various methods available for evaluating VHC-facemasks as a system, recommending where future work might be directed.

Pressurized metered dose inhalers (pMDIs) are the most widely prescribed and economical respiratory drug delivery systems. Conventional pMDI actuators-those based on "two-orifice-and-sump" designs-produce an aerosol with a reasonable respirable fraction, but with high aerosol velocity. The latter is responsible for high oropharyngeal deposition, and consequently low drug delivery efficiency. Kos' pMDI technology is based on a proprietary vortex nozzle actuator (VNA), an innovative actuator configuration that seeks to reduce aerosol plume velocity, thereby promoting deep lung deposition. Using VNA development as a case study, this paper presents a systematic design optimization process to improve the actuator performance through use of advanced optical characterization tools. The optimization effort mainly relied on laser-based optical diagnostics to provide an improved understanding of the fundamentals of aerosol formation and interplay of various geometrical factors. The performance of the optimized VNA design thus evolved was characterized using phase Doppler anemometry and cascade impaction. The aerosol velocities for both standard and optimized VNA designs were found to be comparable, with both notably less than conventional actuators. The optimized VNA design also significantly reduces drug deposition in the actuator as well as USP throat adapter, which in turn, leads to a significantly higher fine particle fraction than the standard design (78 +/- 3% vs. 63 +/- 2% on an ex valve basis). This improved drug delivery efficiency makes VNA technology a practical proposition as a systemic drug delivery platform. Thus, this paper demonstrates how advanced optical diagnostic and characterization tools can be used in the development of high efficiency aerosol drug delivery devices.

In this (CAMOXI) study, three carbon monoxide (CO) monitors and salivary cotinine are assessed regarding their ability to distinguish smokers from nonsmokers, both in chronic obstructive pulmonary disease (COPD) and healthy people. Twenty-six healthy smokers, 25 healthy nonsmokers, 25 smoking, and 25 former smoking stable COPD patients (age 40-72 years) were included based on self-report (N = 101). All volunteers were measured following a 12-h abstinence period. Sensitivity, specificity, and predictive values of a positive and negative test result were assessed for a range of cutoff points for both CO and salivary cotinine. The prescribed 9-ppm cutoff point of the Breath CO generates a sensitivity of 68% and 42% for COPD patients and healthy people, respectively. Using the prescribed cutoff point (10 ppm) the Smokelyzer produces 56% sensitivity for COPD patients and 23% for healthy people. Both monitors generate 100% specificity in both groups. The cutoff point for the Micro CO meter (5 ppm) generates 88% sensitivity and 92% specificity for COPD patients, and for healthy people 92% and 88%, respectively. The optimal cutoff points depend upon the goal of the test. Salivary cotinine has a 100% sensitivity, specificity, positive predictive value, and negative predictive value over the range of 15 ng/mL through 40 ng/mL for healthy participants and at 10 ng/mL for COPD patients. The prescribed cutoff points for all three CO monitors generate misleading results concerning the determination of the smoking status in both populations. Salivary cotinine measurement outperforms CO measurements and a combination of the two tools is recommended.

The penetration, translocation, and distribution of ultrafine and nanoparticles in tissues and cells are challenging issues in aerosol research. This article describes a set of novel quantitative microscopic methods for evaluating particle distributions within sectional images of tissues and cells by addressing the following questions: (1) is the observed distribution of particles between spatial compartments random? (2) Which compartments are preferentially targeted by particles? and (3) Does the observed particle distribution shift between different experimental groups? Each of these questions can be addressed by testing an appropriate null hypothesis. The methods all require observed particle distributions to be estimated by counting the number of particles associated with each defined compartment. For studying preferential labeling of compartments, the size of each of the compartments must also be estimated by counting the number of points of a randomly superimposed test grid that hit the different compartments. The latter provides information about the particle distribution that would be expected if the particles were randomly distributed, that is, the expected number of particles. From these data, we can calculate a relative deposition index (RDI) by dividing the observed number of particles by the expected number of particles. The RDI indicates whether the observed number of particles corresponds to that predicted solely by compartment size (for which RDI = 1). Within one group, the observed and expected particle distributions are compared by chi-squared analysis. The total chi-squared value indicates whether an observed distribution is random. If not, the partial chi-squared values help to identify those compartments that are preferential targets of the particles (RDI > 1). Particle distributions between different groups can be compared in a similar way by contingency table analysis. We first describe the preconditions and the way to implement these methods, then provide three worked examples, and finally discuss the advantages, pitfalls, and limitations of this method.

The purpose of this study was to characterize the toxicity, pharmacokinetics, and pharmacodynamics of human insulin inhalation powder (HIIP) in beagle dogs when administered daily as an aerosolized dry powder formulation for 26 weeks via head-only inhalation. Conscious beagle dogs were exposed for 15 mins/day to an air control, placebo, maximal placebo (approximately three-fold the placebo dose), or one of three doses of HIIP (mean inhaled doses of 80, 240, or 701 microg/kg/day for the HIIP-low, HIIP-mid, and HIIP-high dose, respectively), The mass median aerodynamic diameters (MMAD) were between 2 and 3 microm and geometric standard deviation (GSD) values were approximately 2 across the groups, which is the ideal size range for favorable lung deposition. All groups were comprised of four dogs/sex, with the air control, HIIP-high, and maximal placebo groups having an additional two dogs/sex as recovery subgroups. Concentrations of serum insulin and glucose were determined from blood samples obtained following the first and last exposure for evaluation of the pharmacokinetics and pharmacodynamics of HIIP. Dose-related exposure (C(max), AUC) to inhaled insulin was observed with rapid absorption and no apparent gender differences or accumulation after repeated inhalation exposures for 26 weeks. The expected pharmacological effect of insulin was observed with dose-related decreases in serum glucose levels following HIIP administration. There were no toxic effects observed including no HIIP or placebo treatment-related effects on mean body weights, absolute body weight changes, clinical observations, food consumption, respiratory function parameters, ophthalmic examinations, electrocardiograms, heart rates, clinical pathology, or urinalysis. Similarly, there were no HIIP or placebo treatment-related effects on pulmonary assessments that included respiratory function parameters, bronchial alveolar lavage assessments, organ weights, or macroscopic and microscopic evaluations, including lung cell proliferation indices. HIIP was considered to have either low or no immunogenic potential in dogs. The no-observed-adverse-effect level (NOAEL) and maximum tolerated dose were the average inhaled dose of 701 microg insulin/kg/day.

The popular pressurized metered dose inhaler (pMDI), especially for asthma treatment, has undergone various changes in terms of propellant use and valve design. Most significant are the choice of hydrofluoroalkane-134a (HFA-134a) as a new propellant (rather than chlorofluorocarbon, CFC), a smaller exit nozzle diameter and attachment of a spacer in order to reduce ultimately droplet size and spray inhalation speed, both contributing to higher deposition efficiencies and hence better asthma therapy. Although asthma medicine is rather inexpensive, the specter of systemic side effects triggered by inefficient pMDI performance and the increasing use of such devices as well as new targeted drug-aerosol delivery for various lung and other diseases make detailed performance analyses imperative. For the first time, experimentally validated computational fluid-particle dynamics technique has been applied to simulate airflow, droplet spray transport and aerosol deposition in a pMDI attached to a human upper airway model, considering different device propellants, nozzle diameters, and spacer use. The results indicate that the use of HFA (replacing CFC), smaller valve orifices (0.25 mm instead of 0.5 mm) and spacers (ID = 4.2 cm) leads to best performance mainly because of smaller droplets generated, which penetrate more readily into the bronchial airways. Experimentally validated computer simulations predict that 46.6% of the inhaled droplets may reach the lung for an HFA-pMDI and 23.2% for a CFC-pMDI, both with a nozzle-exit diameter of 0.25 mm. Commonly used inhalers are nondirectional, and at best only regional drug-aerosol deposition can be achieved. However, when inhaling expensive and aggressive medicine, or critical lung areas have to be reached, locally targeted drug-aerosol delivery is imperative. For that reason the underlying principle of a future line of "smart inhalers" is introduced. Specifically, by generating a controlled air-particle stream, most of the inhaled drug aerosols reach predetermined lung sites, which are associated with specific diseases and/or treatments. Using the same human upper airway model, experimentally confirmed computer predictions of controlled particle transport from mouth to generation 3 are provided.