Calcium Hydroxide Topical Solution
»Calcium Hydroxide Topical Solution is a solution containing,in each 100mL,not less than 140mg of calcium hydroxide [Ca(OH)2].
Prepare Calcium Hydroxide Topical Solution as follows (see Pharmaceutical Compounding—Nonsterile Preparations á795ñ):
Calcium Hydroxide 3g
Purified Water 1000mL
Add the Calcium Hydroxide to 1000mLof cool Purified Water,and agitate the mixture vigorously and repeatedly during 1hour.Allow the excess calcium hydroxide to settle.Dispense only the clear supernatant.
NOTE—The solubility of calcium hydroxide,which varies with the temperature at which the solution is stored,is about 170mg per 100mLat 15and less at a higher temperature.The official concentration is based upon a temperature of 25.
The undissolved portion of the mixture is not suitable for preparing additional quantities of Calcium Hydroxide Topical Solution.
Packaging and storage— Preserve in well-filled,tight containers,at a temperature not exceeding 25.
Identification—
A: It absorbs carbon dioxide from the air,a film of calcium carbonate forming on the surface of the liquid.
B: When heated,it becomes turbid,owing to the separation of calcium hydroxide.
C: It responds to the tests for Calcium á191ñ.
Alkalies and their carbonates— Aportion of it,saturated with carbon dioxide and subsequently boiled,is neutral in reaction.
Assay— Pipet 100mLof Topical Solution into a suitable container,add 50mLof water,15mLof 1Nsodium hydroxide,and 300mg of hydroxy naphthol blue,and titrate with 0.05Medetate disodium VSto a blue endpoint.Each mLof 0.05Medetate disodium is equivalent to 3.705mg of calcium hydroxide [Ca(OH)2].
Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 329
Pharmacopeial Forum:Volume No.27(6)Page 3259
Phone Number:1-301-816-8389