Pharmaceutical excipients are the substances other than active pharmaceutical ingredients in the formulation.  Additives donot have any therapeutic activity. The following additives are commonly used  Vehicles  Preservative  Antioxidant  Organoleptic additives  Colouring agent  Flavouring agent  Sweetening agent  Surfactants  Hydrocolloids  Stabilizers VEHICLES:  Vehicles are the solvents needed for dispensing the following preparations,  Monophasic liquid dosage forms  Biphasic liquid dosage forms  Sterile dosage forms  Ophthalmic products. PRESERVATIVE  Many pharmaceutical preparations are liable to undergo deterioration on storage due to microbial growth.  In order to avoid microbial growth, it is desirable to use a suitable preservative. Quality of an ideal preservative  It should be effective in low concentration.  It should be odourless and tasteless.  It should be non-toxic and non-irritant.  It should be stable and unaffected by pH.  It should be economical.  It should be soluble in suitable vehicle. Examples  Benzoic acid  Methyl p-hydroxybenzoate  Propyl p-hydroxybenzoate  Sodium metabisulphite  Benzoic acid  Benzyl alcohol  Phenol ANTIOXIDANTS  Antioxidants are compounds that inhibit oxidation.  Both inorganic and organic compounds are used as antioxidants in food, drugs and cosmetics. Quality of an ideal preservative  It should be effective in low concentration.  It should be colourless, odourless and tasteless.  It should be non-toxic and non-irritant.  It should be stable and unaffected by pH.  It should be economical.  It should be soluble in suitable vehicle. Examples Tocopherol Ethyl gallate Propyl gallate Butylated hydroxy anisole (BHA) Butylated hydroxy toluene (BHT) Ascorbic acid Citric acid ORGANOLEPTIC ADDITIVES  Organoleptic agents are one of the important members of pharmaceutical aids.  Organoleptic additives promote appearance and palatability of pharmaceutical dosage forms.  Colouring agent  Flavouring agent  Sweetening agent Colouring agent  The pharmaceutical preparations are coloured due to following reasons,  For identification of preparations  To increase acceptability to patients  To give warning Quality of an ideal preservative  It should be readily soluble in water.  It should have good colouring power.  It should have no physiological activity.  It should be economical Types of colouring agent 1. Mineral colours – Iron oxide, Carbon black, Titanium dioxide 2. Natural colours from plants and animals – Cochineal, Caramine 3. Coal tar colours – Amaranth, Erythrosine, Brilliant blue. Flavouring agent  Flavours are used to make the preparation more palatable.  Flavouring agents are used to mask the unpleasant taste and odour of the preparation. Examples Flavoured syrup – Cherry, Black current, Citrus fruits (Orange, Lemon) Aromatic oils – Volatile oils such as Anise, Careway, Chinnamon, Clove Synthetic flavours – Chloroform water, Benzaldehyde, Vanillin.

1. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 1
ADDITIVES or EXCIPIENTS USED IN LIQUID DOSAGE FORM
 Pharmaceutical excipients are the substances other than active
pharmaceutical ingredients in the formulation.
 Additives donot have any therapeutic activity.
The following additives are commonly used
 Vehicles
 Preservative
 Antioxidant
 Organoleptic additives
 Colouring agent
 Flavouring agent
 Sweetening agent
 Surfactants
 Hydrocolloids
 Stabilizers
VEHICLES:
 Vehicles are the solvents needed for dispensing the following
preparations,
 Monophasic liquid dosage forms
 Biphasic liquid dosage forms
 Sterile dosage forms
 Ophthalmic products

2. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 2
NAME OF THE VEHICLE PROPERTIES USES
1.Water
I) Purified water
II) Water for injection
III) Sterile dosage forms
Free from volatile and non
volatile impurities.
Purified water free from
pyrogens.
Water for injection free from
microorganisms.
Liquid preparations meant for
internal and external use.
Parentral preparations.
Parentral preparations.
2.Alcohol
I) Ethyl alcohol
II) Propylene glycol
III) Glycerin
Clear, Colourless, Volatile
liquid having characterstic
odour, soluble in water, ether &
chloroform.
Clear, Viscous, Hygroscopic
liquid miscible with water
chloroform and acetone
Clear, Viscous, Hygroscopic
liquid miscible with water and
alcohol.
Liquid preparations both for
external and internal use.
Liquid preparations both for
external and internal use.
Oral preparations and external
preparation.
3. Aromatic water Aqueous saturated solution of
volatile oil or volatile
substances.
Vehicle for many oral liquid
preparations.
4. Syrups Saturated solution of sucrose in
water.
Oral liquid preparations.
5. Elixirs Hydroalcoholic sweetened
aromatic liquid.
Vehicle for oral liquid
preparations.

3. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 3
PRESERVATIVE
 Many pharmaceutical preparations are liable to undergo deterioration
on storage due to microbial growth.
 In order to avoid microbial growth, it is desirable to use a suitable
preservative.
Quality of an ideal preservative
 It should be effective in low concentration.
 It should be odourless and tasteless.
 It should be non-toxic and non-irritant.
 It should be stable and unaffected by pH.
 It should be economical.
 It should be soluble in suitable vehicle.
Examples
 Benzoic acid
 Methyl p-hydroxybenzoate
 Propyl p-hydroxybenzoate
 Sodium metabisulphite
 Benzoic acid
 Benzyl alcohol
 Phenol

4. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 4
ANTIOXIDANTS
 Antioxidants are compounds that inhibit oxidation.
 Both inorganic and organic compounds are used as antioxidants in food,
drugs and cosmetics.
Quality of an ideal preservative
 It should be effective in low concentration.
 It should be colourless, odourless and tasteless.
 It should be non-toxic and non-irritant.
 It should be stable and unaffected by pH.
 It should be economical.
 It should be soluble in suitable vehicle.
Examples
Tocopherol
Ethyl gallate
Propyl gallate
Butylated hydroxy anisole (BHA)
Butylated hydroxy toluene (BHT)
Ascorbic acid
Citric acid

5. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 5
ORGANOLEPTIC ADDITIVES
 Organoleptic agents are one of the important members of
pharmaceutical aids.
 Organoleptic additives promote appearance and palatability of
pharmaceutical dosage forms.
 Colouring agent
 Flavouring agent
 Sweetening agent
Colouring agent
 The pharmaceutical preparations are coloured due to following reasons,
 For identification of preparations
 To increase acceptability to patients
 To give warning
Quality of an ideal preservative
 It should be readily soluble in water.
 It should have good colouring power.
 It should have no physiological activity.
 It should be economical
Types of colouring agent
1. Mineral colours – Iron oxide, Carbon black, Titanium dioxide
2. Natural colours from plants and animals – Cochineal, Caramine
3. Coal tar colours – Amaranth, Erythrosine, Brilliant blue.

6. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 6
Flavouring agent
 Flavours are used to make the preparation more palatable.
 Flavouring agents are used to mask the unpleasant taste and odour of
the preparation.
S.NO TASTE MATCHES FLAVOUR
1. Alkaline Mint, Chocolate, Vanilla
2. Acid (Sour) Lemon, Orange, Cherry, Raseberry
3. Bitter Mint, Fennel, Chocolate
4. Sweet Fruity, Vanilla, Honey
5. Salty Fruity, Citrus, Melon flavour
6. Metallic Grape, Lemon
Examples
Flavoured syrup – Cherry, Black current, Citrus fruits (Orange, Lemon)
Aromatic oils – Volatile oils such as Anise, Careway, Chinnamon, Clove
Synthetic flavours – Chloroform water, Benzaldehyde, Vanillin
Sweetening agent
 In order to overcome the bitterness or unpleasant taste of the drug, it is
desirable to use suitable sweetening agent.
 Adjustment of taste is essential for oral preparations.
Examples
 Sucrose
 Invert syrup
 Sorbital & Saccharin sodium

7. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 7
SURFACTANTS
 Surfactants are organic compounds that lower the surface tension of a
liquid.
 Reduce the interfacial tension between two liquids.
 Surfactants may act as Solubilizing agents, Emulsifying agent, Foaming
agents, Detergents.
Example
 Sodium lauryl sulphate
 Polysorbates
 Span
 Cetostearyl alcohol
 Triethanolamine
HYDROCOLLOIDS
 Hydrocolloids are higher molecular weight solid substances used to
increase the viscosity of aqueous system.
Classification of hydrocolloids
1. Natural – Gum acacia, Gum tragacanth, Casein, Gelatin, Bentonite
2. Semi synthetic – Methyl cellulose, Sodium carboxymethyl cellulose
3. Synthetic – Carbopols, Polyox

8. PHARMACEUTICS-II LIQUID DOSAGE FORMS
M.NITHYA, B.PHARM, LECTURER, JKKMIHSCP Page 8
STABILIZERS
 They are used to stabilize the pharmaceutical preparations which are
required to be stored for long period of time.
 During storage, Change of pH, Oxidation, Hydrolysis, Microbial growth
affects the stability of preparations.
 In order to avoid these changes during storage, stabilizers like Buffers,
Antioxidants and Preservatives.