Title
Dibasic Calcium Phosphate (Hydrous) – Merck & Co., Inc.
Author
Manufacturer: Merck & Co., Inc., Rahway, New Jersey
Image
Description
This vintage amber-glass jar contains Dibasic Calcium Phosphate (CaHPO₄·2H₂O), a common pharmaceutical excipient and calcium source. Manufactured by Merck & Co., Inc., this compound was used in the production of tablets, supplements, and compounded prescriptions. The U.S.P. designation indicates it met the purity and quality standards of the United States Pharmacopeia.
Still widely used today, dibasic calcium phosphate acts as a binder, tablet diluent, and nutritional additive. In its hydrous form, it contains two water molecules and appears as a pale, slightly granular powder—still visible inside the bottle.
Condition
Glass: Amber bottle intact, no visible cracks
Contents: Still contains original orange-tinted powder
Label: Some light wrinkling; Merck cross and text clearly visible
Cap: Metal screw cap shows oxidation but remains tight
Gallery
Historical context
During the mid-20th century, Merck was one of the most prominent suppliers of bulk pharmaceuticals, reagents, and fine chemicals for pharmacies, laboratories, and manufacturers. Compounds like this were measured and mixed by hand, often in back-room labs or university dispensaries. This jar preserves a snapshot of that era—before barcoding, child safety caps, or digital labeling.
The packaging, typography, and labeling style suggest a manufacture date between the 1950s and early 1970s, placing it firmly in the postwar golden age of industrial pharmacy.
Curious Facts, Ephemera, and Trivia
The hydrous form contains two molecules of water per unit and was preferred in some formulations due to its greater stability and flow properties.
Despite its medicinal origins, dibasic calcium phosphate is still used in modern toothpaste, dietary supplements, and even animal feed.
Merck’s Rahway plant, listed on the label, was their headquarters and primary production site throughout the 20th century.
Excerpt
“Dibasic Calcium Phosphate, Hydrous – CaHPO₄·2H₂O – 170.08 – U.S.P. – 1753 – Net weight: 1 lb – Merck & Co., Inc., Rahway, N.J., U.S.A.”
Why it is in the Cabinet
This preserved jar of dibasic calcium phosphate reflects the backbone of mid-century compounding pharmacy, where pharmacists still blended powders, measured excipients, and pressed tablets by hand. It’s a direct link to the raw, tactile side of pharmaceutical production, when Merck labels were trusted emblems of scientific precision and pharmacy shelves were lined with jars just like this one.
Support Dr. Bebout’s Cabinet of Medical Curiosities
If you enjoy the history, the oddities, and the effort, help keep this cabinet open. Every little bit helps preserve and share the strange wonders of medicine's past.
Buy Me a Ko-fi ☕ Buy Me a Coffee ☕ Tip via PayPal 💵