Inhalers metered-dose

Pharmaceutical powder aerosols have more stringent requirements placed upon the formulation regarding moisture, particle size, and the valve. For metered-dose inhalers, the dispensed product must be deflvered as a spray having a relatively small (3—6 -lm) particle size so that the particles can be deposited at the proper site in the respiratory system. On the other hand, topical powders must be formulated to minimize the number of particles in the 3—6-p.m range because of the adverse effects on the body if these materials are accidently inhaled. 

In the United States, use of CEC propeUants, designated as PropeUants 11, 12, and 114, is strictly limited to specialized medicinal aerosol products such as metered-dose inhalers. The physical properties and chemical names of these propeUents are given in Table 2. 

To properly instruct the patient in administration of drug via a metered-dose inhaler, the nurse must be aware of general instructions for use for all metered-dose inhalers and three common methods of rise holding the lips around the mouthpiece, holding the inhaler away from the mouth, and rising a spacer or extender. 

To monitor the amount of drug in a metered-dose inhaler, you can periodically place the canister in a container of water. The figure shows the positioning of the canister with various amounts of medication remaining in the canister. (Adapted from the American Uung Assoaation. [1993]. Understanding lung medications How they work—how to use them, p. 4)... 

Do not puncture metered dose inhalers or store them near heat or open flame the contents of such inhalers are under pressure Never throw the container into a fire or incinerator. If an unusual smell or taste is noted with use of the inhaler, discontinue use and contact the primary care provider. 

Ms. Smith, age 68 years, returned to the clinic for a follow-up visit after receiving a diagnosis of COPD. She is taking theophylline daily and using a metered-dose inhaler 4 times a day. Determine what assessments would be most important for you to make at this time. 

Fomulationis) nasal spray 25 mg/metered dose inhaler with 0.25 mg/spray... 

Some physicians recommend epinephrine metered-dose inhalers as an alternative to epinephrine autoinjectors. While a few inhalations might relieve mild or moderate respiratory symptoms, for relief of life-threatening airway obstruction or shock, adults need to inhale 20-30 puffs and children need to inhale 10-20 puffs, which is hard to do [35]. Epinephrine metered-dose inhalers contain chlorofluorocarbon propellants. For environmental reasons, they might not be manufactured in the future. 

A metered dose inhaler with spacer is equivalent to nebulized therapy, may have a more rapid onset, and fewer adverse effects ° 4-8 puff doses... 

Albuterol (salbutamol) metered-dose inhaler as needed Ortho-Tri-Cyclen Lo by mouth daily Echinacea 1 to 2 tablets by mouth daily as needed Multivitamin 1 tablet by mouth daily... 

FEV, forced expiratory volume in 1 second PEF, peak expiratory flow MDI, metered-dose inhaler DPI, dry powder inhaler. 

CFC, chlorofluorocarbon propellant HFA, hydrofluoroalkane propellant MDI, metered-dose inhaler. 

Ipratropium is the most commonly used anticholinergic for treating bronchoconstriction in asthma. It is available as an MDI and solution for nebulization. Ipratropium has an onset of action of approximately 30 minutes and a duration of action of 4 to 8 hours. Care should be taken not to spray the metered-dose inhaler into or allow the nebulized solution to get in the patient s eyes, as it can cause mydriasis and blurred vision. 

The most common adverse effects from inhaled corticosteroids include oropharyngeal candidiasis and hoarse voice. These can be minimized by rinsing the mouth after use and by using a spacer device with metered-dose inhalers. Increased bruising and decreased bone density have also been reported the clinical importance of these effects remains uncertain.1,2,19... 

Albuterol is the preferred bronchodilator for treatment of acute exacerbations because of its rapid onset of action. Ipratropium can be added to allow for lower doses of albuterol, thus reducing dose-dependent adverse effects such as tachycardia and tremor. Delivery can be through metered-dose inhaler (MDI) and spacer or nebulizer. The nebulizer route is preferred in patients with severe dyspnea and/or cough that would limit delivery of medication through an MDI with spacer. If response is inadequate, theophylline can be considered however, clinical evidence supporting its use is lacking. 

Airway clearance therapy is usually accompanied by bron-chodilator treatment [albuterol (also known as salbutamol outside the United States) by nebulizer or metered-dose inhaler] to stimulate mucociliary clearance and prevent bronchospasm associated with other inhaled agents. A mucolytic agent may be administered to reduce sputum viscosity and enhance clearance. 

Ipratropium metered dose inhaler (MDI) 2 puffs every 6 hours Albuterol MDI 2 puffs every 4 hours as needed Prednisone 10 mg daily Diclofenac 75 mg two times a day Aspirin 81 mg daily... 

A number of other peptide molecules are currently being explored for delivery via inhalation (6). Very recently, a much smaller peptide (leuprolide, about 9 amino acid residues) has been delivered by metered dose inhaler (MDI) in a characterized fashion to humans (7). This work revealed that about 50% of a dose deposited in the lung could be bioavailable. This value is much greater than those reported for nasal bioavailabilities of this and similar molecules (8). These results, and ours in the rat lung (9), imply that inhalation administration of some peptide and polypeptide molecules is perfectly feasible. 

Fig. 4 (A) Propellant-driven metered dose inhaler. (B) Metering valve.

T. S. Purewal and D. J. W. Grant, Metered Dose Inhaler Technology, Interpharm Press, Inc., Buffalo Grove, IL, 1998. 

USP24. <601 > Aerosols, Metered Dose Inhalers, and Dry Powder Inhalers. The United States Pharmacopoeia and National Formulary 1895-1912, 2000. 

Draft Guidance for Industry-Metered Dose Inhaler (MDI) and Dry Powder Inhaler (DPI) Drug Products Chemistry, Manufacturing, and Controls Documentation, Nov. 13, 1998. 

AJ Hickey, RM Evans. Aerosol generation from propellent-driven metered dose inhalers. In AJ Hickey, ed. Inhalation Aerosols. New York Marcel Dekker, Inc., 1996, pp. 417-439. 

M Vidgren, J Arppe, P Vidgren, P Vainio, M Silvasti, H Tukiainen. Pulmonary deposition of 99mTc-labelled salbutamol particles in healthy volunteers after inhalation from a metered-dose inhaler and from a novel multiple-dose powder inhaler. S.T.P. Pharm Sci 4 29-32, 1994. 

The development pharmaceutics section should also include consideration of possible overdosing of the active ingredient that might arise from normal use of the dosage form—e.g., deposition of drug substance from a metered dose inhalation product in the mouth. 

FIGURE 80-2. Home management of acute asthma exacerbation. Patients at risk of asthma-related death should receive immediate clinical attention after initial treatment. Additional therapy may be required. (MDI, metered-dose inhaler PEF, peak expiratory flow.) (Adapted from NHLBI, National Asthma Education and Prevention Program, Expert Panel Report 2. Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 97-4051. Bethesda, MD U.S. Department of Health and Human Services, 1997.)... 

CFC, chlorofluorocarbon DPI, dry-powder inhaler HFA, hydrofluoroalkane MDI, metered-dose inhaler UK, unknown. °Lung delivery from in vivo radiolabel scintigraphy or pharmacokinetic studies. 

These agents are effective only by inhalation and are available as metered-dose inhalers cromolyn also comes as a nebulizer solution. 

---