Pharmaceutical Syrup
The syrup is a saturated or concentrated, viscous aqueous solution of sucrose/sugar substitute with or without flavor/medicinal substances in purified water.
Simple syrup contain 85% w/v (65% w/w); specific gravity 1.313 (USP) or 66.7% w/w as per Indian Pharmacopeia/BP.
Difference between Simple Syrup IP & USP
| Simple syrup IP | Simple syrup USP |
|---|---|
| 66.7 w/w % solution of sugar/sucrose in purified water. | 85 % w/w solution of sugar/sucrose in purified water. |
| Prepared by hot process. | Prepared by cold process. |
| It can be checked during the process by using saccharometer | It cannot be checked during the process. |
| Invert sugar- Sucrose is heated during preparing → Invert sugar | Sucrose |
| More stable | Less stable |
Composition of Syrup
Most syrups contain the following components in addition to the purified water and drug(s):
- (a) Sugar, usually sucrose or other sugar substitutes are used to provide sweetness and viscosity, (Sugar-free alternative- Sorbitol, Saccharine, Aspartame)
- (b) Antimicrobial preservatives,
- (c) flavorants & colorants,
- (d) Syrups may also contain solubilizing agents, thickeners, or stabilizers.
Note:
Syrup may contain preservatives. Glycerin, methylparaben, benzoic acid, and sodium benzoate may be used to prevent bacterial and mold growth. Glycine, benzoic acid (0.1%–0.2%), sodium benzoate (0.1%– 0.2%), and various combinations of methylparaben, propylparaben, and butylparaben or alcohol are commonly used as antimicrobial preservatives.
Types of Syrup
1. Simple Syrup
When Purified Water alone is used in making the solution of sucrose, the preparation is known as “syrup,” or “simple syrup
or
Simple syrup contains only sucrose (sugar) & Purified water.
Example:
a. Simple Syrup IP
| Sucrose | 66.7 gm |
| Purified water q.s. | 100 gm |
b. Simple Syrup USP
| Sucrose | 85 gm |
| Purified water q.s. | 100 mL |
2. Medicated syrup
When Syrup contains medicinal substance is know as medicated syrup – cough syrup, Ginger syrup
Ginger syrup
| Strong Ginger tincture | 5 mL |
| Syrup q.s. | 100 mL |
3. Flavoured Syrup
Syrups containing flavoring agents but not medicinal substances are called flavored vehicles; Containing Aromatic/ Flavoured – Flavoured syrup
Example: Cherry & Raspberry syrup
Advantages of Syrup
- Act as Antioxidant- Retard oxidation because sugar partly hydrolyzed into dextrose & levulose (reducing sugary ) – So prevent decomposition of many substances – No preservative needed.
- Act as preservative- Exert high osmotic pressure – prevents the growth of MOs (Bacteria, Fungi, molds etc)
- Act as Palatable sweet – a vehicle for bitter / Nouseous substances.
- Prevent decomposition of many vegetable drugs.
Method of Preparation of Syrups
Syrups are prepared using one of four techniques:
- Solution with heat,
- Solution by agitation,
- Addition of sucrose to a liquid medication or flavored liquid
- Percolation.
1. Solution with Heat/Hot process
- This method is a suitable preparation method, if the constituents are not volatile or not degraded by heat.
- Purified water is heated to 80–85°C, and then removed from its heat source.
- Weight desired amount of Sucrose is added with vigorous agitation.
- Then, other required heat-stable components are added to the hot syrup, the mixture is allowed to cool, and its volume is adjusted to the proper level by the addition of purified water.
- In instances in which heat-labile agents or volatile substances, such as flavors and alcohol, are added, they are incorporated into the syrup after cooling to room temperature.
Example: Syrup IP, Acacia Syrup NF, Cocoa syrup NF, Tolu Syrup IP
Inversion of sugar
Invert sugar: When heat is used in the preparation of syrups, inversion of a slight portion of the sucrose (a disaccharide) into monosaccharides, dextrose (glucose), and fructose (levulose) by hydrolyzation process. This hydrolytic reaction is referred to as “inversion,” and the combination of the two monosaccharide products is “invert sugar.”
Sucrose solutions are dextrorotary, but, as hydrolysis proceeds, the optical rotation decreases and becomes negative when the reaction is complete. The rate of inversion is increased greatly by the presence of acids; the hydrogen ion acts as a catalyst in this hydrolytic reaction.
Fructose is responsible for the darkening of syrup.
Invert sugar is more readily fermentable than sucrose and tends to be darker in color. But, its two reducing sugars prevent the oxidation of other substances.
2. Solution by Agitation (without Heat)
This method is used for substances that degradation on heating or volatilize formulation constituents. i.e suitable for heat labile substances.
Sucrose & other ingredients are dissolved in purified water through agitation (without heat).
Example– Sulphate syrup
3. Addition of Sucrose to a Liquid Medication or Flavored Liquid:-
- This method is often used with fluidextracts or tinctures.
- Fluid extract or tinctures are added to a syrup.
- Addition of these may cause precipitation of alcohol soluble materials due to dilution.
- Example- Aromatic eridictyon syrup NF
4. Percolation (Cold process)
In the percolation method, either purified water or the medicinal component (dissolve in purified water) is passed slowly through a bed of crystalline sucrose, thus, dissolving it and forming a syrup.
- Sucrose is placed in suitable percolator.
- Purified water (with medicament) is allowed to slowly pass through sucrose
- Percolate may return back in necessary
- final volume is adjusted by purified water
Example: Ipecac syrup
Formulation of Syrup
1. Vehicle-
Purified water is used to prepare syrups.
2. Additives
a. Chemical Stabilizers
Glycerin, sorbitol & propylene glycol are addded in a small quantity to prevent Crystallization of Sucrose.
b. Colouring agents
Coal tar dyes like Amaranth, tartrazine & green S are added to syrup.
c. Flavouring agents
- Tincture- tincture, lemon & ginger
- Fruit juice- rasbberry juice, wild cherry
- Essence- Vanilla, orange
d. Preservatives
Benzoic acid & Its derivatives, Sod. benzoate, Methyl paraben etc
Storage of Syrup
Store in dried, well closed bottles in a coll dark place, below 25 oC.
- Syrup on Storage subject to Crystallisation which causes locking of Cap of the container. Glycerine, Sorbital & Propylene glycol is added in small quantity to the syrup to prevent crystallization of sucrose.
- Storage: completely filled & well-stoppered bottle and stored in a cool place (not exceeding 25-degree centigrade)
- Syrup may be dark color due to the fermentation of sugar.
MCQ Quiz on Syrups
- Syrup is a concentrated aqueous solution of
a) Alcohol
b) Sucrose or sugar substitute
c) Oil
d) Salt
Answer: b) Sucrose or sugar substitute - Simple syrup contains how much sucrose as per Indian Pharmacopoeia?
a) 60% w/w
b) 70% w/w
c) 66.7% w/w
d) 80% w/w
Answer: c) 66.7% w/w - Specific gravity of simple syrup as per USP is
a) 1.250
b) 1.313
c) 1.400
d) 1.100
Answer: b) 1.313 - Simple syrup IP contains
a) Fructose and sucrose
b) Glucose and sucrose
c) Sucrose and purified water
d) Alcohol and sucrose
Answer: c) Sucrose and purified water - Which of the following is a sugar-free syrup substitute?
a) Fructose
b) Lactose
c) Sorbitol
d) Maltose
Answer: c) Sorbitol - In medicated syrup, the syrup contains
a) Only sucrose
b) Medicinal substance
c) Flavouring agent
d) Coloring agent
Answer: b) Medicinal substance - Which of the following is an example of medicated syrup?
a) Raspberry syrup
b) Cherry syrup
c) Ginger syrup
d) Lemon syrup
Answer: c) Ginger syrup - Flavoured syrups are also known as
a) Medicated syrup
b) Flavouring vehicles
c) Sugar syrups
d) Anti-crystallizing syrups
Answer: b) Flavouring vehicles - Example of flavoured syrup is
a) Cough syrup
b) Ipecac syrup
c) Cherry syrup
d) Ginger syrup
Answer: c) Cherry syrup - Syrup acts as antioxidant because sugar partly hydrolyzes into
a) Lactose and maltose
b) Dextrose and levulose
c) Glucose and sucrose
d) Mannitol and lactose
Answer: b) Dextrose and levulose - Which of the following methods of syrup preparation involve heat?
a) Solution by agitation
b) Percolation
c) Solution with heat
d) Addition of sucrose to liquid medication
Answer: c) Solution with heat - Inversion of sugar produces
a) Monosaccharides
b) Disaccharides
c) Polysaccharides
d) Oligosaccharides
Answer: a) Monosaccharides - The hydrolytic reaction converting sucrose to glucose and fructose is called
a) Oxidation
b) Fermentation
c) Inversion
d) Reduction
Answer: c) Inversion - Which agent accelerates inversion of sugar?
a) Base
b) Salt
c) Acid
d) Alcohol
Answer: c) Acid - Fructose present in syrup is responsible for
a) Crystallization
b) Darkening of syrup
c) Cooling effect
d) Sweetness decrease
Answer: b) Darkening of syrup - Solution by agitation is suitable for substances which are
a) Heat stable
b) Heat labile
c) Oxidation resistant
d) Insoluble in water
Answer: b) Heat labile - In percolation method, purified water is passed through
a) Medicinal oil
b) Crystalline sucrose
c) Alcoholic mixture
d) Propylene glycol
Answer: b) Crystalline sucrose - Glycerin, sorbitol, and propylene glycol are added to syrup to
a) Improve color
b) Increase sweetness
c) Prevent crystallization of sucrose
d) Enhance preservative effect
Answer: c) Prevent crystallization of sucrose - Common preservatives used in syrup are
a) Citric acid and lactic acid
b) Benzoic acid and methylparaben
c) Ethanol and chloroform
d) Formaldehyde and acetone
Answer: b) Benzoic acid and methylparaben - The ideal storage condition for syrup is
a) Open bottle in sunlight
b) Well-closed bottle in a cool place below 25°C
c) Refrigerator at 0°C
d) Exposed to air
Answer: b) Well-closed bottle in a cool place below 25°C
FAQ on Pharmaceutical Syrup
1. What is a syrup in pharmaceutical preparation?
A syrup is a saturated or concentrated, viscous aqueous solution of sucrose or a sugar substitute with or without flavoring or medicinal substances in purified water.
2. What percentage of sucrose is present in simple syrup as per Indian Pharmacopoeia?
Simple syrup contains about 66.7% w/w sucrose according to the Indian Pharmacopoeia.
3. What is the specific gravity of simple syrup according to USP?
The specific gravity of simple syrup is 1.313 as per the United States Pharmacopeia (USP).
4. What are the main components of a syrup?
Syrups generally contain sugar or sugar substitutes, antimicrobial preservatives, flavorants, colorants, solubilizing agents, thickeners, and sometimes stabilizers.
5. What are commonly used sugar substitutes in syrups?
Common sugar-free alternatives include sorbitol, saccharine, and aspartame.
6. What are the types of syrups used in pharmacy?
The three main types are simple syrup, medicated syrup, and flavored syrup.
7. What is simple syrup made of?
Simple syrup contains only sucrose (sugar) and purified water.
8. What is a medicated syrup?
A medicated syrup is one that contains a medicinal substance, such as cough syrup or ginger syrup.
9. What is a flavored syrup?
A flavored syrup contains flavoring agents but no medicinal substances. Examples are cherry syrup and raspberry syrup.
10. What are the main advantages of syrups?
They act as antioxidants, preservatives, and sweet vehicles that improve taste and help prevent decomposition of certain drugs.
11. What are the four methods for preparing syrups?
The methods include solution with heat, solution by agitation (without heat), addition of sucrose to a liquid medication, and percolation.
12. When is the hot process method used in syrup preparation?
It is used when ingredients are not volatile and not degraded by heat.
13. What is inversion of sugar in syrup preparation?
It is the hydrolysis of sucrose into dextrose (glucose) and levulose (fructose), increasing reducing sugar content and improving stability.
14. Which agents are used to prevent crystallization in syrup?
Glycerin, sorbitol, and propylene glycol are added in small quantities to prevent crystallization of sucrose.
15. How should syrups be stored?
They should be stored in well-closed, completely filled bottles at a temperature below 25°C in a cool and dark place to prevent crystallization or fermentation.