Author: Stephen Newman- Ph.D student affiliated with Pharmaceuticals Ltd. Nottingham, United Kingdom.
Abstract:
Pressurized metered-dose inhalers (pMDI's) have many different components that can be altered to enhance the overall efficiency of an inhaler for patient individualization. These components include the container, the propellants, the drug formulation, the metering valve, and the actuator. These that can be changes are adjusting the formulation, the size of the metering valve, what spacer devices are being used.
Container- The containers main function is provide as a housing for the other components but it is not the outermost shell. In order to correctly do its job, the material must be robust. Also, the internal coating must provide an adhesive preventative surface in order to resist chemical degradation and drug particles of the drug. Aluminum is the standard material being used to manufacture the container. Internal coatings vary.
Propellants- liquefied compressed gases that, when inside the inhaler canister, are in the gaseous phase. When these gases are compressed, they turn into liquids which are what the patient inhales. Chlorofluorocarbons (CFC) were once used as the primary component of propellants in inhalers. They were banned under an international agreement because they caused damage to the ozone layer. Now, hydrofluroalkanes are used; however, they are considered greenhouse gases which could trigger future restrictions on the product. (design cannot be changed)
Drug Formulation (design cannot be changed)
Metering Valve- the metering valve is what controls the dosage levels of the propellant. There are currently many different designs of metering valves. The most important part about metering valve design is the consistency of the amount of medicine that is expelled from the inhaler each time.
Actuator- The actuator houses all of the components. It is composed of plastic and there are different designs based on the aerosol particle size. The nozzle diameter is based on the particle size.(explain why this is important-didn't understand from article)
***week 3 annotation was about the cost benefits of a meter-dose inhaler combined with a spacer compared to nebulizers. Are there health benefits?
A double blind study was conducted on 168 wheezing children whose ages ranged from 2 months to 2 years. Approximately half of the children were given nebulizers to treat their wheezing and half were given meter-dose inhalers combined with spacers to treat their wheezing.They measured the effects of the devices on each child with a Pulmonary Index score (a clinical assessment tool derived from wheezing, respiratory rate, use of accessory muscles, and inspiratory-expiratory ratio. The study revealed that meter-dose inhalers accompanied with spacers could be used instead of nebulizers for treatment in the emergency department for children 2 months to 2 years experience wheezing.
Next step: look at the design of spacers in particular
Author: Stephen Newman- Ph.D student affiliated with Pharmaceuticals Ltd. Nottingham, United Kingdom.
Abstract:
Pressurized metered-dose inhalers (pMDI's) have many different components that can be altered to enhance the overall efficiency of an inhaler for patient individualization. These components include the container, the propellants, the drug formulation, the metering valve, and the actuator. These that can be changes are adjusting the formulation, the size of the metering valve, what spacer devices are being used.
Container- The containers main function is provide as a housing for the other components but it is not the outermost shell. In order to correctly do its job, the material must be robust. Also, the internal coating must provide an adhesive preventative surface in order to resist chemical degradation and drug particles of the drug. Aluminum is the standard material being used to manufacture the container. Internal coatings vary.
Propellants- liquefied compressed gases that, when inside the inhaler canister, are in the gaseous phase. When these gases are compressed, they turn into liquids which are what the patient inhales. Chlorofluorocarbons (CFC) were once used as the primary component of propellants in inhalers. They were banned under an international agreement because they caused damage to the ozone layer. Now, hydrofluroalkanes are used; however, they are considered greenhouse gases which could trigger future restrictions on the product. (design cannot be changed)
Drug Formulation (design cannot be changed)
Metering Valve- the metering valve is what controls the dosage levels of the propellant. There are currently many different designs of metering valves. The most important part about metering valve design is the consistency of the amount of medicine that is expelled from the inhaler each time.
Actuator- The actuator houses all of the components. It is composed of plastic and there are different designs based on the aerosol particle size. The nozzle diameter is based on the particle size.(explain why this is important-didn't understand from article)
***week 3 annotation was about the cost benefits of a meter-dose inhaler combined with a spacer compared to nebulizers. Are there health benefits?
Delgado, A., KJ Chou, EJ Silver, and EF Crain. "Nebulizers vs Metered-dose Inhalers with Spacers for Bronchodilator Therapy to Treat Wheezing in Children Aged 2 to 24 Months in a Pediatric Emergency Department." Arch Pediatr Adolesc Med 157, no. 1 (2003): 76-80.
Abstract
A double blind study was conducted on 168 wheezing children whose ages ranged from 2 months to 2 years. Approximately half of the children were given nebulizers to treat their wheezing and half were given meter-dose inhalers combined with spacers to treat their wheezing.They measured the effects of the devices on each child with a Pulmonary Index score (a clinical assessment tool derived from wheezing, respiratory rate, use of accessory muscles, and inspiratory-expiratory ratio. The study revealed that meter-dose inhalers accompanied with spacers could be used instead of nebulizers for treatment in the emergency department for children 2 months to 2 years experience wheezing.
Next step: look at the design of spacers in particular