title: Pharmacokinetics and relative bioavailability of absorbed testosterone after administration of a 1.62% testosterone gel to different application sites in men with hypogonadism.
abstract: OBJECTIVE
  To determine the pharmacokinetics, bioavailability, and safety of a new formulation (1.62%) of testosterone gel that produces eugonadal serum testosterone levels with use of a lower amount of gel than the currently available 1% gels.
  
  
  METHODS
  In an open-label, randomized, 3-way crossover study, 36 male patients with hypogonadism applied 5 g of 1.62% testosterone gel (81 mg of testosterone) once daily to the abdomen, to the upper arms/shoulders, or alternating between both sites per an established schedule for 7 days. Serum levels of testosterone, dihydrotestosterone, and estradiol were measured and used to compare the pharmacokinetics and bioavailability of the 3 treatments.
  
  
  RESULTS
  Each application method produced average serum testosterone concentrations within the eugonadal range (300 to 1,000 ng/dL), and steady-state testosterone concentrations were achieved after 2 days of gel application to either the abdomen or the upper arms/shoulders. When testosterone gel was applied to the abdomen, approximately 30% to 40% lower bioavailability (based on area under the serum concentration-time curve from 0 to 24 hours) was observed in comparison with application to the upper arms/shoulders. The 1.62% testosterone gel was found to be safe and well tolerated in men with hypogonadism.
  
  
  CONCLUSIONS
  Although lower testosterone bioavailability was observed after abdominal application of 1.62% testosterone gel in comparison with application to the upper arms/shoulders, application to either site yielded eugonadal levels of serum testosterone.
authors: Abbott, Abbott Park, Illinois 60064, USA.
authors: Jodi
authors: J
authors: Miller
authors: Margaret
authors: M
authors: Britto
authors: Sherahe
authors: S
authors: Fitzpatrick
authors: Cecilia
authors: C
authors: McWhirter
authors: Samuel A
authors: SA
authors: Testino
authors: John J
authors: JJ
authors: Brennan
authors: Troy L
authors: TL
authors: Zumbrunnen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004333:Drug Administration Routes; D006801:Humans; D007006:Hypogonadism / Q000097:blood* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D013739:Testosterone / Q000493:pharmacokinetics / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D013739:Testosterone