Developing A Total Consumption Inhaler

哮喘和COPD（慢性阻塞性肺疾病）是最常见的呼吸系统疾病之一，给全球医疗保健系统带来了重大的公共卫生负担。大约11%的加拿大人患有呼吸系统疾病。吸入器是治疗所有呼吸系统疾病的常用药物输送方法。许多吸入器使用喷雾器将溶液型药物转化为液滴的气雾剂，其被患者吸入。为了成功地到达患者的肺部，气溶胶液滴尺寸应小于5微米。大于5微米的液滴被收集在口腔和上呼吸道树中。目前可用的雾化器产生广泛的液滴尺寸，通常在1-30微米之间，其中80-90%的药物质量属于大于5微米的液滴。因此，80-90%的药物被浪费。由于大多数药物是昂贵的，因此期望具有使用其每一个液滴的雾化器。此外，当大部分药物在口腔中丢失时，患者永远不知道是否使用了正确的剂量。 本研究的目的是开发一种雾化器/吸入器，其所有液滴均小于5微米。这种喷雾器将有效地将液体药物转移到病人的肺部，确保药物的适当剂量和最小的浪费。所提议的吸入器将基于小固着液滴的超声雾化来操作。在压电换能器的表面上设置呈固着液滴形式的小液体质量，并且使其在兆赫兹频率范围内振动。我们的初步结果表明，当固着液滴的尺寸低于约500微米时，2-5微米的小液滴从其表面喷射。我们将其称为全消耗雾化器，因为产生的所有药物都被吸入并用于患者的治疗。在将这个概念付诸实践之前，我们需要了解它为什么有效以及它的局限性。因此，我们提出了一个小的（0.3-1毫米）固着液滴，设置在不同类型的表面（不同的涂层，以改变表面接触角）和振动在不同的频率（1-100 MHz）的超声雾化的基础研究。此外，还将测试液体性质的影响，包括使用吸入器中使用的流变液以及含有颗粒的溶液（浆液）。雾化过程也将在理论上（计算上）进行研究，以揭示这一过程中涉及的物理学，并验证形成这种小液滴的假设。 我们计划在这个项目上有两个学生。一个做实验，一个做理论。该项目的拟议预算为每年7.3万美元，其中包括两名博士生和实验测试的费用。

Asthma and COPD (chronic obstructive pulmonary disease) are among the most occurring respiratory diseases, which present a significant public health burden to the global healthcare system. About 11% of Canadians suffer from respiratory diseases. Inhalers are a common drug delivery method for all respiratory problems. Many inhalers use a nebulizer to convert a solution type drug to an aerosol of droplets, which is inhaled by the patient. To successfully reach the patient's lungs, the aerosol droplet sizes should be less than 5 microns. Droplets larger than 5 microns are collected in the mouth and the upper respiratory tree. The currently available nebulizers generate a wide range of droplet sizes, usually between 1-30 microns, with 80-90% of the drug mass belonging to droplets with larger than 5 microns. Therefore, 80-90% of the drug is wasted. Since most medicines are costly, it is desired to have a nebulizer that every one of its droplets are used. In addition, when most of the medicine is lost in the mouth, the patient never knows if the right dosage is used. The objective of the present proposed research is to develop a nebulizer/inhaler that all of its droplets are less than 5 microns. This nebulizer would effectively transfer liquid medicine into a patient's lungs, ensuring proper dosage of medicine with minimal waste. The proposed inhaler would operate based on ultrasonic atomization of a small sessile droplet. A small liquid mass in the form of a sessile droplet is set on the surface of a piezoelectric transducer, and it is vibrated at Megahertz frequency ranges. Our preliminary results have shown that when the size of the sessile droplet goes below about 500 microns, small 2-5 micron droplets eject from its surface. We refer to this as a total consumption nebulizer since all the medicine that is generated is inhaled and used for the treatment of the patient. Before this concept is reduced to practice, we need to understand why it works and what are its limitations. Therefore, we propose a fundamental study of the ultrasonic atomization of a small (0.3-1 mm) sessile droplet, set on different types of surfaces (different coatings to change the surface contact angles) and vibrated at different frequencies (1-100 MHz). In addition, effect of liquid properties, including using rheological fluids of the type used in inhalers, as well as solutions containing particles (slurries) will be tested. The atomization process will also be studied theoretically (computationally) to reveal the physics involved in this process, and test out hypothesis for the formation of such small droplet. We plan to have two students on this project. One performing the experiments, and one on the theory. The proposed budget for this project is $73k a year, which will include the cost of two PhD students and the experimental tests.