Pharmacokinetics of calcium absorption from two commercial calcium supplements.
This study was conducted to compare pharmacokinetic indices of calcium absorption after a single oral (500 mg calcium) load of Citracal (calcium citrate) and Os-Cal (calcium carbonate). In 18 postmenopausal normal women, venous blood samples were obtained for the measurement of calcium before and hourly for 6 hours after an oral ingestion of Citracal, Os-Cal, or placebo with a breakfast meal. The change in area under the curve (delta AUC) in serum calcium from preload was 2.5-fold greater for Citracal than Os-Cal, and the peak-basal variation in serum calcium was 76% higher for Citracal than Os-Cal. The increment in serum calcium from preload after Citracal administration was significantly higher than that obtained after placebo load during most time periods and significantly higher than that of Os-Cal at 1, 4, and 5 hours after load. In contrast, delta AUC and peak basal variation of Os-Cal did not differ significantly from placebo and increment in serum calcium was significantly increased from placebo only at 6 hours. In conclusion, Citracal is much more bioavailable than Os-Cal.
Heller
H J
HJ
Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas 75235-8885, USA.
Stewart
A
A
Haynes
S
S
Pak
C Y
CY
D000042:Absorption; D000368:Aged; D019540:Area Under Curve; D002118:Calcium / Q000097:blood / Q000493:pharmacokinetics*; D002119:Calcium Carbonate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019355:Calcium Citrate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000378:metabolism; D013997:Time Factors
D002119:Calcium Carbonate; D019355:Calcium Citrate; D002118:Calcium