title: Modified-release hydrocortisone for circadian therapy: a proof-of-principle study in dexamethasone-suppressed normal volunteers.
abstract: BACKGROUND
  All existing long-term glucocorticoid replacement therapy is suboptimal as the normal nocturnal rise and waking morning peak of serum cortisol is not reproduced.
  
  
  OBJECTIVE
  To test whether it is possible to reproduce the normal overnight rise and morning peak in serum cortisol using an oral delayed and sustained release preparation of hydrocortisone (Cortisol(ds)).
  
  
  METHODS
  Six healthy normal male volunteers attended on two occasions, in a single-dose, open-label, nonrandomized study. Endogenous cortisol secretion was suppressed by administration of dexamethasone. Cortisol(ds) (formulation A or B) was administered at 2200 h on day 1. Blood samples for measurement of cortisol were taken from 2200 h every 30 min until 0700 h, then hourly until 2200 h on day 2. Fifteen body mass index (BMI)-matched control subjects had serum cortisol levels measured at 20-min intervals for 24 h. Serum cortisol profiles and pharmacokinetics after Cortisol(ds) were compared with those in controls.
  
  
  RESULTS
  Formulations A and B were associated with delayed drug release (by 2 h and 4 h, respectively), with median peak cortisol concentrations at 4.5 h (0245 h) and 10 h (0800 h), respectively, thereby reproducing the normal early morning rise in serum cortisol. Total cortisol exposure was not different from controls.
  
  
  CONCLUSIONS
  For the first time we have shown that it is possible to mimic the normal circadian rhythm of circulating cortisol with an oral modified-release formulation of hydrocortisone, providing the basis for development of physiological circadian replacement therapy in patients with adrenal insufficiency.
authors.affiliation: Academic Unit of Diabetes, Endocrinology and Metabolism, The University of Sheffield, Sheffield, UK. j.newellprice@sheffield.ac.uk
authors.forename: J
authors.initials: J
authors.lastname: Newell-Price
authors.forename: M
authors.initials: M
authors.lastname: Whiteman
authors.forename: A
authors.initials: A
authors.lastname: Rostami-Hodjegan
authors.forename: K
authors.initials: K
authors.lastname: Darzy
authors.forename: S
authors.initials: S
authors.lastname: Shalet
authors.forename: G T
authors.initials: GT
authors.lastname: Tucker
authors.forename: R J M
authors.initials: RJ
authors.lastname: Ross
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000187:drug effects; D003907:Dexamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D006854:Hydrocortisone / Q000008:administration & dosage* / Q000627:therapeutic use*; D008297:Male