Erythrocyte-mediated delivery of dexamethasone in patients with chronic obstructive pulmonary disease.

Human erythrocytes from ten patients with chronic obstructive pulmonary disease (COPD) were loaded with increasing amounts of dexamethasone 21-phosphate and were re-infused into the original donors. Drug-loaded erythrocytes acted as circulating bioreactors, converting the non-diffusible dexamethasone 21-phosphate into the diffusible dexamethasone. Pharmacokinetic analyses on these patients showed that a single administration of drug-loaded erythrocytes was able to maintain detectable dexamethasone concentrations in blood for up to seven days. This continuous release of dexamethasone was paralleled by the suspension of beta2-agonist and oral corticosteroid treatments by all of the patients. Thus dexamethasone 21-phosphate-loaded erythrocytes are safe carriers for corticosteroid analogues and are a useful alternative to frequent oral or inhaled drugs in elderly patients with COPD.