Pharmaceutics Laboratory
Preparation and evaluation of Simple Syrup
Calculate the formula for your batch, tare and weigh the sucrose, dissolve it in purified water with gentle heat and stirring, make up to volume when cool, pack, label and evaluate it — with a batch record of everything you did.
Objectives
- Scale a formula to a batch size
- Weigh on a tared top-pan balance within tolerance
- Dissolve sucrose without inverting or caramelising it, and make up to volume at room temperature
- Evaluate appearance, volume and density, and complete a batch record
Principle
Simple Syrup is a nearly saturated solution of sucrose in purified water. The USP proportions — 850 g sucrose made up to 1000 mL — give 85 % w/v, about 64.7 % w/w, with a density near 1.31 g/mL.
At this concentration there is too little free water for bacteria and moulds to grow, so the syrup preserves itself. A weaker syrup can ferment; a stronger one crystallises on standing.
Sucrose dissolves faster with gentle heat and stirring. Strong or prolonged heating hydrolyses (inverts) sucrose to glucose and fructose and caramelises it, colouring the syrup.
The finished batch is made up to volume with purified water only when it has cooled, because a hot syrup contracts as it cools.
The official texts differ in detail: USP Syrup is 850 g sucrose made up to 1000 mL with specific gravity not less than 1.30, and the USP prefers dissolving it without heat (percolation); BP Syrup is 66.7 % w/w with a weight per mL of 1.315–1.333 g. This lab uses the USP proportions with the hot method commonly taught in dispensing practicals.
Illustrative formula: quantities and limits on this page are teaching values (configurable), not a validated clinical or manufacturing formula.
Safety
- Hot syrup sticks to skin and burns. Handle the hot beaker with tongs or a heat-resistant glove.
- Never leave the hot plate on and unattended; switch it off before moving the beaker.
- Wipe sugar spills at once — a sticky floor is a slip hazard.
- This is a practice preparation: it is labelled 'For practice — not for use' and never given to anyone.
Apparatus and materials
- Top-pan balance
- Weighing boat
- Sucrose (labelled jar)
- Beaker, 150 mL (borosilicate)
- Measuring cylinder
- Glass stirring rod
- Purified water
- Hot plate with thermometer
- Dispensing bottle and label
- Lab notebook (batch record)
Sucrose · Purified water
Curriculum
Listed in the UoK Pharm-D practical syllabus (PHT-402 Pharmaceutical Dosage Forms Lab, 2nd year, 2nd semester: “Preparation of simple syrups”). The formula used here is illustrative (USP proportions). Not faculty-reviewed.
- UoK — PHT-402 Pharmaceutical Dosage Forms (Lab), pceutics.pdf p. 10 — “Preparation of simple syrups, …”
- HEC Pharm-D curriculum (2025) — Drug Delivery Systems and Formulation Science-I, Semester III, PDF p. 78 — Practical list includes “Syrups”.
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