To compare the bioequivalence of calcium acetate oral solution vs. calcium acetate gelcaps in healthy volunteers with calcium citrate as a positive control.

Inclusion Criteria:

• Signed and dated informed consent form
• Ages: 18-75 years
• Serum Calcium level 8.6-10.2 mg/dL
• 25 vitamin D level 20-100 ng/mL
• 1, 25 dihydroxy vitamin D level 6-62 pg/mL
• Fasting glucose level of 65-99 mg/dL (min 8 hr fast)
• iPTH level of 10-65 pg/mL
• Serum phosphorous level of 2.5-4.5 mg/dL
• Albumin level of 3.6-5.1 g/dL
• Sodium level of 135-146 mEq/L
• Potassium level of 3.5-5.3 mEq/L
• Negative pregnancy test (at screening and prior to dosing) for women of childbearing potential and subjects must agree to use adequate contraception (hormonal or double barrier method) during the study
• No clinically significant abnormalities on electrocardiogram (ECG) reading as determined by the INVESTIGATOR
• No clinically significant abnormalities on liver function tests
• No clinically significant abnormalities on CBC and coagulation studies
• No clinically significant abnormalities on kidney function (eGFR using serum creatinine)
• BMI between 18.5-30
• Subjects must agree not to consume alcohol while in the treatment phase of the study

Exclusion Criteria:

• Women who are pregnant or breast feeding
• Malignancy except squamous cell carcinoma of the skin
• Documented current acute or chronic disease
• Positive for human immunodeficiency virus (HIV), hepatitis B or hepatitis C
• Myocardial infarction within 6 months of study Day 0
• Parathyroidectomy within 6 months of study Day 0
• Gastrointestinal disorder associated with impaired absorption of oral medications
• Inability to swallow tablets or tolerate calcium acetate oral solution
• Hormonal therapy (except for contraceptives), immunotherapy or corticoid therapy
• Concurrent antibiotic treatment
• Any concurrent investigational treatment within 30 days of screening
• Unable or unwilling to comply fully with the protocol
• Diuretic therapy such as Thiazides, Furosemide (INN) or frusemide (former BAN) within one month before screening
• Subjects taking over-the-counter (OTC) or prescribed phosphorous or calcium containing supplements
• Subjects testing positive for drugs of abuse