28 PHARMACY 



Collodium Collodion 



CoUodium Cantharidatum Cantharidal Collodion 



Collodium Flexile Flexible Collodion 



OLEATA — OLEATES 



These were formerly defined as solutions of oxides or alkaloids 

 in oleic acid but in the revision of the Pharmacopoeia of 1910 bxit one 

 is official, " Oleatum Hydrargyri " — so that oleate would be defined 

 as a solution of an oxide in oleic acid. Oleates are applied by inunc- 

 tion and depend upon absorption from the skin for their physiological 

 action. As stated above they are prepared by dissolving an oxide or 

 an alkaloid in oleic acid. An excess of heat should be avoided in 

 making metallic oleates, as the acid easily reduces the metals, espe- 

 cially when heated. 



INFUSA — INFUSIONS 



These are preparations of vegetable drugs made by maceration or 

 percolation. In the one official infusion, Infusum Digitalis, and the 

 general formula for making infusions, the water is poured on while 

 boiling hot. Cold water should be used for those drugs whose active 

 principle would be driven off or its formation prevented by boiling 

 water. 



DECOCTA — DECOCTIONS 



Decoctions are liquids made by boiling the drug in closed vessels 

 for fifteen minutes. They are then allowed to cool, strained and 

 water added to make up the required amount. There are no official 

 decoctions but the Pharmacopoeia includes a general formula for their 

 preparation. Decoctions and infusions do not keep well and should 

 be freshly prepared for use. 



TINCTUR.ffi — TINCTURES 



Tinctures are alcoholic solutions of non-volatile substances ob- 

 tained by the extraction of drugs. Tincture of iodine is an exception 

 to the rule of non-volatile substances, while both tincture of iodine and 

 tincture of the chloride of iron are made by solution. They differ 

 from spirits in that, with the exception of tincture of iodine, the sub- 

 stances from which they are prepared are non-volatile. They differ 

 from fluidextracts in respect to strength. They are weaker than 

 fluidextracts and not uniform in strength, except that the potent tinc- 

 tures are ten per cent, strength of the drug. Tinctures may be pre- 

 pared by maceration, percolation, and solution or dilution. 



The Pharmacopoeia states that unless otherwise directed in the 

 text, tinctures shall be made by one of two processes — Type P, Per- 

 colation, and Type M, Maceration. 



