Page 28 - Course Guide 2019

7.2 PREPARATION OF FORMULATION

7.2.1 Active ingredients (poison and non-poison)
Poison are actives that are regulated by the Poison Act 1952 (and Regulation) and Dangerous
Drug Act 1952 (and Regulations). Thus, it is important that if a poison is required in a
preparation, the amount of the poison taken be recorded. A form will be available in the lab
next to the poison.
You are also required to obtain a counter-signature from a pharmacist. The signature should
be on the prescription next to the amount of poison that you weighed. REMEMBER that the
pharmacist need to see the amount of powder that you weighed on the weighing balance, so
that he/she can be sure that you weigh the accurate amount.
Hence the process:

Go to the poison area  Fill in the form  Take the poison bottle  Weigh the exact amount
on your weighing balance (5% tolerance permitted)  Leave the weighed powder on the
weighing balance  Find a pharmacist to counter sign  The pharmacist will check the
weighed amount  Counter signed  Return the poison bottle to the designated area

7.2.2 Excipients
Excipients are other ingredients that is needed to prepare your formulation. These include
emulsifying agent, suspending agent, vehicles, preservatives, colouring agent and flavouring
agents, among others.

In the dispensing lab, these ingredients are available in their designated racks, at the middle
area of the lab. They are arranged based on their physical characteristics (liquid and solid
materials are separated) and are alphabetically arranged.

REMEMBER that the number of bottles containing each excipient available on the racks are
limited. It is very important to return the bottle to its respective places immediately after you
have taken the necessary amount.

If you need something that is not available on the rack, please ask the lecturer in-charge or
any of the graduate assistant/lab staff available.

7.2.3 Weighing
You will have a weighing balance available on your bench. Each time before you start your
practical, ensure that the balance is in good condition and is functioning properly. The resting
point of the balance must be stable at 0 mg when not in use. At all time, please ensure that
your balance is clean and free from any residual powder or liquid. Always use a weighing
boat/paper to weigh the necessary ingredients. Use a new weighing boat/paper for each
ingredient.

Your balance is labelled with its minimum and maximum weighable quantity, besides
its decimal points (sensitivity). Usually, your balance’ minimum weighable quantity (MWQ)
is 200 mg. Hence, you could only weigh accurately at 200 mg or more, meaning to say that if
your formula requires an amount smaller than 200 mg, a dilution method will be necessary.
You will learn this technique as we go through this course.