The spatula is used to “work” powders, ointments, and creams in the process of levitation and trituration. It is also used to transfer quantities of drugs from their containers to the prescription balance. Spatulas are not to be used to pry open cans, as screwdrivers, or as knives for opening boxes. Once the surface is scratched or the edges bent, the spatula’s precision surface is ruined and it becomes useless.
Mortar and Pestle
These two items always go together, one being useless without the other. The mortar is basically a heavy bowl, with one distinct property: the inside concavity is geometrically hemispheric. The accompanying pestle is primarily a handtool, whose tip is of identical material as the mortar, and its convexity forms a perfect hemisphere. The reason for the two opposing hemispheres is to provide an even grinding surface when in use. Mortars and pestles are made of glass, metal, or unglazed pottery called wedgewood. Glass is always used when triturating very pure products, such as eye ointments, and when the preparations contain stains. Metal ones should never by used when the drugs are likely to react with the metals.
Graduates
These are conical or cylindrical clear glass containers, graduated to specified quantities, used to measure liquids volumetrically. Measuring should always be done at eye level.
Wire Gauze
A wire gauze is placed under a container in order that the heating flame will distribute uniformly about the bottom of the container. The wire is a good conductor of heat, and the heat penetrates rapidly.
Pipettes
Pipettes are narrow, graduated tubes for measuring small quantities of liquids volumetrically.
Suction Flask
The suction flask is an Erlenmeyer flask with a tube extending from the neck at a right angle. The tube provides a connection site for attaching a means of suction. When a filtering apparatus is attached to the neck of the flask and suction applied, the filtering process is speeded up by the vacuum created in the flask by the suction.
Ribbed Funnel
The ribbed funnel is a utensil used in filtering and is most commonly made of glass, but other substances (tin, copper, rubber) are occasionally used. The funnel is shaped so that the inside surface tapers at a 600 angle, ending in a tapered delivery spout. The inside surface is “ribbed” to allow air to escape from between the glass and the filtering medium, thus improving the filtration process.
Pharmaceutical Baths
Baths are vessels in which any substance in a container can be heated uniformly by immersion into the conductive matter of the bath. Baths are commonly used when a substance cannot be heated above a certain temperature. For example, cocoa butter cannot be heated above 100°F during the manufacture of suppositories.
The most common type of bath is a circular bowl made of tinned copper. The bowl contains water and as this water is heated, the heat is transmitted to the container that is placed in the bath. Using this method, you can maintain a constant temperature of 100°C over long periods.
PHARMACEUTICAL BALANCES
There are two types of pharmaceutical balances in common use in the Navy: The single beam, equal arm balance, and the torsion balance. These balances are classified as either “Class A” or “Class B.” The Class A balance is used for weighing loads from 120 mg to 120 g. All dispensing pharmacies are required to have at least one Class A balance on hand at all times. The Class B balance is optional equipment in the pharmacy, which is used to weigh loads of more than 648 mg, and must be conspicuously marked “Class B.”
Operation of the Torsion Balance
1. Place precut protective paper over each of the pans.
2. Adjust the balance so that the indicator reads zero.
3. Always place the weight on the right pan and the substance to be weighed on the left pan (facing the balance).