the other. When circumstances produce a feeling of doubt on the part of the pharmacy technician, the prescribing physician should be consulted.
Physical incompatibilities are often called pharmaceutical incompatibilities and are evidenced by the failure of the drugs to combine properly. It is virtually impossible for uniform dosages of medicine to be given from such solutions or mixtures. Ingredients such as oil and water, which are physically repellant to each other, and substances that are insoluble in the prescribed vehicle are primary examples of physical incompatibilities.
This type of incompatibility exists when agents are prescribed that react chemically when mixed, altering the composition of one or more of the constituents.
MANIFESTATIONS OF INCOMPATIBILITY
Insolubility of prescribed agent in vehicle (physical)
Immiscibility of two or more liquids (physical)
Precipitation due to change in menstrum that results in decreased volubility is called salting out (physical)
Eutexiathe liquefaction of solids mixed in dry state (physical)
Cementation of insoluble ingredients in liquid mixtures (physical)
Evolution in color (chemical)
Oxidation-reduction or explosive reaction (chemical)
Precipitation due to chemical reaction (chemical)
Inactivation of sulfa drugs by procaine HCl (therapeutic)
Addition of an ingredient that does not alter the therapeutic value, such as the addition of an ingredient to alter volubility of an agent
Omission of an agent that has no therapeutic value, or that maybe dispensed separately
Change of an ingredient. Minor changes such as a soluble form of an ingredient for an insoluble form are included.
Change of a solvent
The utilization of special techniques in compounding
PRACTICAL PHARMACY PROCEDURES
Read the prescription, formula, or recipe carefully. Be sure you understand its contents.
Make sure that all ingredients required are on hand, in the quantities required.
Any substitutions or changes must be approved by the prescriber and initialed.
As you weigh or measure each ingredient, check it off the prescription. If any doubt exists as to what or how much has been used, discard and begin again. It is better to waste some material than to chance a faulty medication.
Be neat, precise, and methodical when compounding drugs. Haste not only makes waste hereit also endangers the patient.
Adhere to the sequences of compounding the ingredients and the techniques prescribed by the formula or recipethere is a reason, otherwise they would not be specified.
Strive for pharmaceutically elegant results, such as smooth ointments and creams, devoid of lumps and grit; clear solution; etc.