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，给全球医疗体系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道问题的常见药物输送方式。许多吸入器使用雾化器将溶液类药物转化为由患者吸入的雾化液滴。为了成功到达患者的肺部，气雾剂液滴的大小应小于5微米。大于5微米的水滴被收集在嘴里和上呼吸道树上。目前可用的雾化器产生的液滴大小范围很大，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。由于大多数药物都很昂贵，人们希望有一种雾化器，可以使用它的每一滴药物。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。目前拟议研究的目标是开发一种雾化器/吸入器，其所有液滴都小于5微米。这种雾化器将有效地将液体药物转移到患者的肺部，确保以最小的浪费获得适当剂量的药物。拟议的吸入器将基于超声雾化一个小的固着液滴。在压电式换能器的表面上放置一个固着液滴形式的小液体质量，并在兆赫的频率范围内振动。我们的初步结果表明，当固着液滴的尺寸小于约500微米时，2-5微米的小液滴从其表面喷射出来。我们将其称为总消耗量雾化器，因为产生的所有药物都被吸入并用于患者的治疗。在这个概念付诸实践之前，我们需要了解它为什么有效，它的局限性是什么。因此，我们提出了一项关于超声雾化微小(0.3-1 mm)固着液滴的基础研究，该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)上，并以不同的频率(1-100 MHz)振动。此外，还将测试液体性质的影响，包括使用吸入器中使用的那种流变液，以及含有颗粒(浆液)的溶液。雾化过程也将从理论上(计算上)进行研究，以揭示这一过程中涉及的物理现象，并验证形成这种小液滴的假说。我们计划在这个项目上有两个学生。一个在做实验，一个在理论上。该项目的拟议预算为每年7.3万美元，其中将包括两名博士生的费用和实验测试。

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.