Pharmacology: Pharmacodynamics: Mechanism of Action and Pharmacodynamic Effects: Flutiform inhaler contains both fluticasone propionate and formoterol fumarate. The mechanism of action described as follows for the individual components. These drugs represent two classes of medications (a synthetic corticosteroid and a long-acting selective beta2-adrenoceptor agonist).
Fluticasone propionate: Fluticasone propionate is an anti-inflammatory corticosteroid that exhibits potent glucocorticoid activity and weak mineralocorticoid activity. Inflammation is an important component in the pathogenesis of asthma. Corticosteroids have been shown to inhibit multiple cell types (e.g., mast cells, eosinophils, basophils, lymphocytes, macrophages, neutrophils) and mediator production or secretion (e.g., histamine, eicosanoids, leukotrienes, and cytokines) involved in the asthmatic response. These anti-inflammatory actions of corticosteroids contribute to their efficacy in asthma.
Formoterol fumarate: Formoterol fumarate is a long-acting selective beta2-adrenoceptor agonist with a rapid onset of action. Inhaled formoterol fumarate acts locally in the lung as a bronchodilator. The onset of bronchodilating effect is rapid, within 1-3 minutes, and the duration of effect is at least 12 hours after a single dose.
Pharmacokinetics: Absorption: Fluticasone propionate: Following inhalation of a single 250 microgram dose of fluticasone propionate from 2 actuations of Flutiform 125 microgram/5 micrograms inhaler by healthy volunteers, fluticasone propionate was rapidly absorbed into the plasma, reaching a mean maximum plasma fluticasone concentration of 32.8 pg/mL within 45 minutes of inhalation. In asthma patients who received single doses of fluticasone propionate from Flutiform inhaler, mean maximum plasma concentrations of 15.4 pg/mL and 27.4 pg/mL were achieved within 20 minutes and 30 minutes for 100 microgram/ 10 microgram (2 actuations of Flutiform 50 microgram/5 microgram inhaler) and 250 microgram/10 microgram (2 actuations of Flutiform 125 microgram/5 microgram inhaler) doses respectively.
In multiple dose studies in healthy volunteers, Flutiform inhaler doses of 100 microgram/10 micrograms, 250 microgram/10 micrograms and 500 microgram/10 micrograms resulted in mean maximum plasma fluticasone concentrations of 21.4, 25.9 to 32.4 and 178 pg/mL respectively. The data for the 100 microgram/10 microgram and 250 microgram/ 10 microgram doses were generated by use of a device without a spacer and the data of the 500 microgram/20 microgram dose were generated by use of a device with a spacer. Use of an AeroChamber Plus spacer increases mean systemic (which equates to pulmonary absorption) bioavailability of fluticasone by 35% in healthy volunteers compared to administration of Flutiform inhaler via a pMDI alone.
Use of an AeroChamber Plus spacer decrease mean systemic bioavailability of formoterol by 25% in healthy volunteers compared to administration of Flutiform inhaler via a pMDI alone. This is likely to be due to a reduction in absorption from the gastrointestinal tract when the spacer is used, offsetting the expected corresponding increase in pulmonary absorption.
Formoterol fumarate: Following a single dose of Flutiform inhaler in healthy volunteers, a dose of 20 micrograms of formoterol fumarate from 2 actuations of Flutiform 250 microgram/10 microgram inhaler resulted in a mean maximum plasma formoterol concentration of 9.92 pg/mL within 6 minutes of inhalation. Following multiple doses, 20 micrograms of formoterol fumarate from 2 actuations of Flutiform 250 microgram/10 microgram inhaler resulted in a mean maximum of plasma formoterol concentration of 34.4 pg/mL.
Distribution: There is currently no plasma protein binding information specific to fluticasone propionate or formoterol fumarate from Flutiform inhaler.
Metabolism: There are currently no data relating to the metabolism of fluticasone propionate or formoterol fumarate specifically from the inhalation of Flutiform inhaler.
Elimination: Fluticasone propionate: Following inhalation of fluticasone propionate from 2 actuations of Flutiform 250 microgram/10 microgram inhaler, fluticasone propionate has a terminal elimination half-life of approximately 14.2 h.
Formoterol fumarate: Following inhalation of formoterol fumarate from 2 actuations of Flutiform 250 microgram/10 microgram inhaler, formoterol fumarate has a terminal elimination half-life of approximately 6.5 h. Less than 2% of a single dose of formoterol fumarate from Flutiform inhaler is excreted in the urine.