A tablet has an expiry of 2–3 years.
But a liquid syrup? Often just 6 months after opening — sometimes even less.
So what’s going on? Why the huge gap in shelf life?
Here’s the in-depth but simple truth:
1. Water = Life… for Bacteria Too
Liquids contain water, and water is the perfect breeding ground for:
- Bacteria
- Fungi
- Microbial growth of all kinds
To prevent this, manufacturers add preservatives (like sodium benzoate or parabens).
But even preservatives break down over time, and once they do…
The liquid is no longer safe for consumption.
2. Tablets Are Dry — And Dry Means Stable
Tablets have almost zero moisture.
This makes them:
- Chemically stable
- Less prone to microbial attack
- Easier to store long-term
The lower the water, the longer the life.
It’s literally a case of “dry = durable.”
3. Evaporation and Volatility
Some liquids contain volatile solvents, flavoring agents, or alcohol.
These slowly evaporate after opening, especially with improper storage.
Result?
- Dose changes subtly over time
- Taste or smell may degrade
- Stability drops
4. Susceptibility to Oxidation
Ever seen a syrup turn darker over time?
That’s often due to oxidation — especially in:
- Iron supplements
- Multivitamin syrups
- Antioxidant suspensions
Oxygen slowly reacts with active or inactive ingredients, leading to:
- Loss of potency
- Unwanted byproducts
- Shorter expiry
5. Packaging + Contamination Risk
Once opened, liquid medications face contamination from:
- Air
- Light
- Improper handling
Tablets? They’re mostly individually sealed, and rarely exposed to air.
So naturally, liquids degrade faster.
Bonus: Reconstitution Matters Too
Think of dry syrups you mix with water —
Once reconstituted, the clock starts ticking.
Why?
Because now there’s water in the system.
And that means higher risk, shorter life.
So What’s the Takeaway?
Liquids aren’t “worse” — they’re just more delicate.
- Always check expiry after opening
- Store them in cool, dry places
- NEVER assume it’s safe just because it “looks okay”
Read also:
- Types of Dosage Forms with Examples
- Why Do Some Medicines Say ‘Store in a Cool Place’ While Others Say ‘Refrigerate’?
Resource Person: Dev Soni