Betamethasone for lung maturation: testing dose and formulation in fetal sheep.
OBJECTIVE
We evaluated lung maturation responses to the mixture of betamethasone phosphate (Beta-PO4) + betamethasone acetate (Beta-Ac) in comparison to Beta-PO4 or Beta-Ac in fetal sheep.


METHODS
Ewes carrying singleton pregnancies at 122 days of gestation were randomized to single doses of 0.5 mg/kg Beta-PO4 + Beta-Ac, 0.25 mg/kg Beta-PO4, 0.5 mg/kg Beta-PO4, or 0.25 mg/kg Beta-Ac given 48 hours before delivery. These treatments were compared with saline placebo and 2 doses of 0.5 mg/kg Beta-PO4 + Beta-Ac that were given 48 and 24 hours before delivery. Fetal lung maturation was evaluated.


RESULTS
The 2 doses of the Beta-PO4 + Beta-Ac mixture gave the best lung maturation. Single doses of the Beta-PO4 + Beta-Ac mixture and Beta-Ac alone also induced lung maturation. There were no consistent responses to either dose of Beta-PO4.


CONCLUSIONS
Beta-PO4 alone is ineffective with the dosing schedule used; Beta-Ac can induce lung maturation. However, the best responses result from the mixture of Beta-PO4 + Beta-Ac.
Jobe
Alan H
AH
Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Moss
Timothy J M
TJ
Nitsos
Ilias
I
Ikegami
Machiko
M
Kallapur
Suhas G
SG
Newnham
John P
JP
D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects*; D005938:Glucocorticoids / Q000008:administration & dosage*; D008168:Lung / Q000196:embryology*; D008297:Male; D011247:Pregnancy; D037661:Pulmonary Surfactant-Associated Proteins / Q000032:analysis; D011663:Pulmonary Surfactants / Q000032:analysis; D011897:Random Allocation; D012121:Respiration, Artificial; D012756:Sheep
D005938:Glucocorticoids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C028994:betamethasone sodium phosphate; D001623:Betamethasone