Syrup, Types & Preparation of Syrup:
Table of Contents
Pharmaceutical Syrup
- Composition of Syrup
1. Simple Syrup
2. Medicated syrup
3. Flavoured Syrup
Advantages of Syrup
Method of Preparation of Syrups
1. Solution with Heat/Hot process
2. Solution by Agitation (without Heat)
3. Addition of Sucrose to a Liquid Medication or Flavored Liquid:-
4. Percolation (Cold process)
Formulation of Syrup
1. Vehicle
2. Additives
Storage of Syrup
Pharmaceutical Syrup
Syrup
Syrup is a saturated or concentrated, viscous
aqueous solution of sucrose/sugar substitute with or without flavor/medicinal
substances in purified water.
Simple syrup
contains 85% w/v (65% w/w); specific gravity 1.313 (USP)
or 66.7% w/w as per Indian
Pharmacopeia/BP.
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
Simple Syrup IP
b. Simple Syrup USP
Sucrose 85 gm
Purified
water q.s. 100 mL
Simple Syrup USP
2. Medicated syrup
When Syrup
contains medicinal substances is known as medicated syrup – cough syrup, Ginger
syrup
Ginger syrup
Strong Ginger
tincture 5 mL
Syrup q.s. 100 mL
Simple Syrup
USP
3. Flavoured Syrup
Syrups
containing flavoring agents but not medicinal substances are called flavored
vehicles; Containing Aromatic/ Flavoured – Flavoured syrup (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 a 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 the decomposition of many vegetable drugs.
Method of Preparation of Syrups
Syrups are prepared using one of four
techniques:
- Solution by agitation,
- The addition of sucrose to a liquid medication or flavored liquid, and
- 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. Inverted 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 degrade 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 the precipitation of alcohol-soluble materials due to dilution.
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 the suitable percolator.
- Purified water (with medicament) is allowed to slowly pass through sucrose
- Percolate may return back 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
- Chemical Stabilizers
Glycerin, sorbitol & propylene glycol are added in small quantities to prevent the Crystallization of Sucrose.
- Colouring agents
Coal tar dyes like Amaranth, tartrazine & green S are added to the syrup.
- Flavouring agents
Tincture- tincture,
lemon & ginger
Fruit juice-
raspberry juice, wild cherry
Essence- Vanilla, orange
- Preservatives
Benzoic acid
& Its derivatives, Sod. benzoate, Methylparaben etc.
Storage of Syrup
Store in
dried, well-closed bottles in a cool dark place, below 25 ˚c.
- Syrup on Storage is subject to Crystallisation which causes the locking of the Cap of the container. Glycerine, Sorbital & Propylene glycol is added in small quantity to the syrup to prevent the crystallization of sucrose.
- Storage: completely filled & well-stoppered bottle and stored in a cool place (not exceeding 25-degree centigrade)
- Syrup may be dark in color due to the fermentation of sugar.
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