The document provides an extensive overview of liquid dosage forms, detailing their advantages, such as ease of swallowing and faster absorption, particularly beneficial for specific patient groups like children and the elderly. It also discusses the disadvantages, including lower stability, susceptibility to contamination, and complex manufacturing processes. Various classifications and types of liquid formulations, such as syrups, suspensions, and emulsions, are explained along with methods of preparation and key components involved.

1. LIQUID DOSAGE FORM

2. Liquid dosage form
• The active ingredients may be dissolved in aqueous
media, an organic solvent, or a combination of the
two, by suspending the drug (if it is insoluble) in an
appropriate medium or by incorporating the active
pharmaceutical ingredient into one of the phases of
an oil and water emulsion.
• Such solutions, suspensions, and emulsions are
further defined in subsequent paragraphs, but
some, with similar properties and
applications.

3. Advantage
• The major advantage of the liquid dosage method is that it is better for patients
who have difficulty swallowing solid medicines because it is easier to swallow
than solid dosage forms.
• Liquid dosage forms have faster absorption than solid dosage forms.
• It is suitable for use patients with infants, geriatric, and mental health problems.
• Doses may vary from per tablespoon to milliliter, which is difficult in solid dosage
forms.
• Liquid dosage forms are absorbed faster than solid dosage forms because APIs are
already dissolved.
• This may provide greater flexibility in achieving the appropriate dose of the drug.
• It can be designed for any route of administration.
• It is the best choice for children and old people.
• This can be attractive by container and color.
• Flavors (sweetening agents/sugar) can be added to mask the bitter or unpleasant
taste and odor.

4. Disadvantage
• The major disadvantage of the liquid dosage form is that, is less stable than other
doses and has a shorter shelf life which is due to the nature of being in a liquid.
• The liquid dosage form is more susceptible to bacterial microorganisms than
tablets and capsules.
• Some drugs are poorly soluble hence difficult to formulate.
• It is bulky so it is difficult to handle, transport and store.
• It requires special storage conditions because it is less stable.
• Its manufacturing process is complex, so the production cost is high.
• It is easily affected by temperature, light, and microorganisms.
• Each time of dose needs to be measured, so the accuracy of the dose may vary
each time.
• A loss can occur as the container breaks and falls.
• Difficult to mask the unpleasant taste or odor compared to tablets and capsules.

5. CLASSIFICATION

6. EXCIPIENTS

7. HLB Scale
(Hydrophilic - Lipophilic Balance)

9. MONOPHASIC LIQUID

10. • Monophasic dosage form refers to liquid preparation
containing two or more components in one phase system, it
is represent by true solution.
• A true solution is a clear homogenous mixture that is
prepared by dissolving solute in a suitable solvent.

11. 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.
• Composition of Syrup
• Most syrups contain the following components in addition to
the purified water and drugs:
• (a) Sugar, or other sugar substitutes are used to provide sweetness and
viscosity, (Sugar-free alternative- Sorbitol, Saccharine, Aspartame)
• (b) Antimicrobial preservatives,
• (c) flavorings & coloring agents,
• (d) Syrups may also contain solubilizing agents, thickeners, or stabilizers.

12. • Advantages of Syrup
• Retard oxidation because it partly hydrolyzed into
dextrose & levulose (reducing sugary )
– So prevent decomposition of many substances
– No preservative needed.
• Exert high osmotic pressure
– prevents the growth of MOs (Bacteria, Fungi, molds etc)
• Palatable sweet
– a vehicle for bitter / Nouseous substances.

13. TYPE OF SYRUP

14. Method of Preparation For Syrup
1. Hot Process:
• This method is used when active constituents are neither volatile nor heat-labile.
• Procedure:
• Weighed sucrose is taken in a beaker.
• Purified water is added.
• Heated on a water bath (less than 70°C) till a solution is obtained.
• The product is filtered.
• Volume is made upto q.s.
• Excessive heat may lead to the inversion of sucrose.
2. Percolation:
• Sucrose is placed in percolator.
• Water is passed through sucrose slowly.
• The neck of the percolator is packed with cotton.
• The rate of percolation regulates the rate of dissolution.
• After complete dissolution, the final volume is made up to q.s.

15. 3. Agitation Without Heat:
• Procedure for heat-labile constituents
• Sucrose and other ingredients are weighed properly.
• Dissolved in purified water.
• Kept in a bottle of about twice the volume of syrup followed by
continuous agitation.
• Prepared syrup volume is made up to q.s.
4. Addition of Medicating or Flavouring Liquid to Syrup:
• This method is used when fluid extracts, tinctures, or other liquids are
to be added to syrup.
• Alcohol is added to dissolve the resinous or oily substances.
• Alcohol acts as a preservative also.

16. Syrup
1. Vehicle: Syrups are prepared by using purified water.
2. Adjuncts: The following adjuncts are generally added to improve the formulation
of syrup.
– Chemical Stabilizer: Glycerin, sorbitol, propylene glycol is added in small quantity to syrup
to prevent the crystallization.
– Colouring agent: Many syrups are attractively coloured with coal tar dyes such as amaranth,
compound tartrazine and Green S.
– Flavouring agents:
• (i) Tinctures: Lemon and ginger tincture
• (ii) Fruit juice: Cherry, Raspberry
• (iii) Essence: Vanilla, orange
– Preservatives: Use sterilized and closures container for prevent contamination. Benzoyl
acid, sodium bentonite, methy paraben.
3. Storage : store at room temperature
4. Label : Shake well before use

17. Gargles
• Gargles are aqueous solutions frequently containing antiseptics,
antibiotics, and anesthetics used in the mouth and throat.
• It is dispensed in conc. Forms with directions for dilution with
warm water before use.
• It is highly medicament than mouth wash.
• Pleasant flavor
• 5.0-9.5 pH to be safe.
• Relieved soreness of throat infection
• Containers: Fluted glass bottles with plastic screw cap;
• Label : External Use only; Dilute before use
• Example : phenol gargle , thymol glycerin compound.

18. Mouth wash
• Mouth wash are Aqueous Solution with a pleasant taste &
odor used to make clean & deodorize the buccal cavity.
• It Contain sweetening, antibacterial flavoring agent, alcohol &
coloring agents, glycerin, surfactant, sweeteners.
• Container : Mouth wash are dispensed in white fluted bottles
• Direction : Two teaspoonful to be diluted in a glass of water
before use.
• Example
Antisceptic: Listerine or phenolic mouthwash
Analgesic: lidocaine hydrochloride
Anticavity: Floride rinse

19. Throat Paint
• Viscous liquid preparation used for mouth & throat infection.
• Base- Glycerin (most commonly used)- provide adheres to mucous
membrane for a longer period.
• They may be aqueous or alcoholic solutions.
• Supplied in Fluted bottle to distinguish from preparation used for
internal use.
• Storage : airtight containers in a cool place
• Example
– Compound Iodine Paint : used for pharyngitis or tonsillitis. Iodine throat
paint is designed to kill germs. It can be used on sore throats and ulcers to
ease them
– Crystal Violet Paint – used for thrush.
– Tannic acid Glycerin, has astringent action, relieve from sore throat.

20. Ear drops
• These are solutions that are instilled into the ear with a dropper.
• Drops are Prepared in water, glycerine, propylene glycol & dilute
alcohol as vehicles.
• Ear drops are used for Cleaning the , Softening the wax,Treating
the infection, antiseptic-anaesthetic.
• Containers = colored fluted glass bottle with a dropper in the cap
or suitable plastic container.
• Example :
– chloramphenicol ear drops
– Phenol ear drops
– Spirit ear drops
– Sodium bicarbonate ear drops

21. Nasal drops
• These are isotonic solution that are installed into the nose with a
dropper.
• Nasal drops should:
– Isotonic with 0.9% NaCl
– Neutral pH 5.5-7.5 – (phosphate buffer of pH 6.5 as a vehicle)
– Viscosity similar to nasal secretion by using 0.5% methylcellulose.
– Preparation must not interfere with the cleansing action of epithelial cilia of
the nasal mucosa.
– Dispensed in–colored fluted bottles filter with a dropper plastic container.
• CONTAINER: fluted colored glass bottel with plastic screw cap and
dropper.
• LABEL: External Use only , stored in a cool place

22. Liniment and lotion
Liniment
1. Also known as embrocains
2. Liquid or semisolid preparation
3. Meant for application to skin with
friction & Rubbing of the skin
4. May contain alcohol or oily solution or
emulsion
5. Liniment should not be applied to
broken skin or broken skin
6. Liniment should be dispersed
in colored fluted Bottles in order to
distinguish it from preparation meant
for internal use
7. Label – External Use only; shake well
before use & not to be applied to open
wound and broken skin.
8. Higher viscosity than lotion
9. Example: Terpintine liniment
Lotion
1. Also known as Moisturizer, or emollient
2. a thick, smooth liquid preparation for
medicinal or cosmetic purposes.
3. Meant for external application without
friction with the help of absorbent
material like cotton wool or gauze soaked
in it.
4. It should be applied to broken skin
5. Used for local action cooling, soothing,
protective, antiseptic
6. Dispensed in Fluted bottles in order to
distinguish it from preparation meant
for internal use
7. Label: External Use only; shake well
before use
8. Lower viscosity than liniments
9. Example: Bentonite lotion, Calamine
lotion

23. Biphasic liquids
Suspensions
Emulsions

24. Suspension
• A Pharmaceutical suspension is a coarse dispersion in which internal
phase (API) is dispersed uniformly throughout the external phase.
• The internal phase consisting of insoluble solid particles having a range of
size(0.5 to 5 microns) which is maintained uniformly through out the
suspending vehicle with aid of single or combination of suspending agent.
• The external phase (suspending medium) is generally aqueous in some
instance, may be an organic or oily liquid for non oral use.
• Suspensons are widely used for –
– Oral route
– External use
– Ophthalmic use
– Lotions and washes
– Eye drops
– I.M. injections
– Parenteral use

25.  The reasons for the formulation of a pharmaceutical suspension:
– when the drug is insoluble in the delivery vehicle.
– To mask the bitter taste of the drug.
– To increase drug stability.
– To achieve controlled/sustained drug release.
 SOME PHARMACEUTICAL SUSPENSIONS
 Antacid oral suspensions
 Antibacterial oral suspension
 Dry powders for oral suspension (antibiotic)
 Analgesic oral suspension
 Anthelmentic oral suspension
 Anticonvulsant oral suspension
 Antifungal oral suspension

26. Advantage
• Pharmaceutical suspensions may be formulated to mask
the unpleasant odor / taste of drug. E.g. Chloramphenicol.
• Suspensions may serve as an alternative means used to
administer drugs to children including paediatric and
geriatric patients and older patients who have difficulty
swallowing solid dosage forms.
• Drug in suspension exhibits higher rate of bioavailability
than other dosage forms. Bioavailability is in following
order, Solution > Suspension > Capsule > Compressed
Tablet > Coated tablet.
• It may be formulated to provide controlled drug delivery,
e.g. as intramuscular injections.

27. • Chemical stability of certain drugs e.g., Procaine penicillin
G can be improved when formulated as suspensions.
• Pharmaceutical suspension offers resistance to
degradation of drugs due to hydrolysis, oxidation or
microbial activity.
• Duration and onset of action can be controlled e.g.,
Protamine Zinc-Insulin suspension.
• When compared to solution dosage forms, relatively
higher concentration of drugs can be incorporated into
suspension products.

28. • Suspension is the only choice if the drug is not
soluble in water and non-aqueous solvent is
not acceptable, e.g., corticosteroids
suspension.

29. Disadvantage
• Accuracy of dosage is less reliable than with solution unless
suspension is packed in unit dosage form.
• Suspension formulations may be bulky and therefore difficult for a
patient to carry.
• Preparation must be shaken prior to measuring a dose.
• Pourability and syringeability issues (e.g., injectable suspensions)
• Crystal formation (Ostwald ripening) and breaking of suspension.
• Sedimentation of solids occasionally gives poor form of product.
• It may lead to caking (formation of compact mass), which is difficult
to dispense.

30. CLASSIFICATION
Classified into 4 main class:
1) Oral suspension : Paracetamol suspension antacids,
cefixime, cefpodoxime, sucralfate, Tetracycline HCl
2) Parenteral suspension : Procaine penicillin G, Insulin
Zinc Suspension
3) Ophthalmic suspension : Fluorometholone drops,
Natamycin, Ciprofloxacin
4) Suspension For external use : Topical
formulations(antifungal), calamine lotion

31. Flocculated and non flocculated suspensions
 When individual particles are in contact with each other and form a
network like structure is called as flocculated suspension.
 When the individual particles exists as separate entity is called as
deflocculated suspension.

32. Flocculated
1. Sedimentation rate is fast
2. Particles are loosely packed
3. Inelegant
4. Clear supernant
5. High sediment volume
6. Particle size attractive force
7. Bioavailability is less
8. Rheology plastic and
pseudoplastic
9. Redispersibility easy
Deflocculated
1. Sedimentation rate is low
2. Particles are very closely
packed
3. Good appearance
4. Cloudy supernant
5. Low sediment volume
6. Particle size repulsive force
7. Bioavailability is high
8. Rheology dialent
9. Redispersibility difficult
Comparison

33. API Therapeutic active substance
Wetting agents
•The concentration used is less than 0.5 %.
•Added to disperse solids in the continuous phase.
•Decrease interfacial tension between solid particles and liquid
mediums.
E.g. Alcohol in tragacanth mucilage, Glycerin in sodium alginate.
Flocculating
agents
(Surfactant &
Polymer)
•. To floc the drug particles.
•They lead to a decrease in repulsion potential and make particles
come together to form loosely arranged floccules.
•Act by reducing the surface tension.
• E.g. SLS, Tweens, Span, Carbowax
Thickened &
Suspending
agents
Impart viscosity of the suspension
a. Polysaccharide=> Natural- Acacia, Starch, Talc ; Synthetic- MC,
b. HPMC
b. Inorganic agents=> Clay, AI(OH)3
c. Synthetic => Carbomer, Collodial SiO2
Buffer/ pH
adjusting
To stabilize the suspension at the desired pH range
Formulation of suspensions

34. Osmotic agent To adjust osmotic pressure (Specially Parenteral preparation)
Organoleptic
additive
To impart desire color to improve elegance Coloring agent,
sweetening agent, Flavoring agents
Preservative To prevent Microorganism growth Benzoic acid, Methylparaben,
Benzoic acid, Sodium benzoate
Protective
Colloids
They are absorbed on insoluble particles and increase the strength
of the hydration layer formed around suspended particles through
hydrogen bonding and molecular interaction. E.g- Gelatin, natural
gum and cellulosic derivatives.

35. List of Suspending Agents
• Alginates
• Methylcellulose
• Hydroxyethylcellulose
• Carboxymethylcellulose
• Sodium
Carboxymethylcellulose
• Microcrystalline
cellulose
• Acacia
• Tragacanth
• Xantham gum
• Bentonite
• Carbomer
• Carrageen
• Powdered cellulose
• Gelatin

36. Evaluation of Suspensions
• Sedimentation method
• Rheological method
• Electro kinetic method
• Micromeritic method

37. • Sedimentation method
• It is most important parameter in the evaluation of the stability of
suspension.
• Sedimentation volume was calculated according to the equation:
F = Vu/Vo
Where,
F = sedimentation volume,
Vu = ultimate height of sediment
Vo = initial height of total suspension

38. • Rheological method
• It provide information about Settling behaviour.
• The arrangement of the vehicle and the particle structural
features.
• Brookfield viscometer is used to study the viscosity of the
suspension
• Electro kinetic method
• Measurement of Zeta-potential using Micro electrophoresis
apparatus & ZetaPlus
• It shows the stability of a disperse system

39. • Micromeritic method :
• The stability of suspension depends on the particle size
of the dispersed phase.
• Visual Inspection:
• With Visual Inspection, the ingredients and the final
products are carefully examined for purity and for
appearance .
• Physical appearance of products for patient adherence
and compliance is critical so it should be: Good looking
Elegance in appearance .

40. Application of Suspension in Pharmaceutics
• Suspension is usually applicable for drug which is insoluble (or ) poorly
soluble; E.g. Prednisolone suspension
• To prevent degradation of drug or to improve stability of drug; E.g. Oxy
tetracycline suspension
• To mask the taste of bitter of unpleasant drug.E.g. Chloramphenicol palmitate
suspension
• Suspension of drug can be formulated for topical application. e.g. Calamine
lotion
• Suspension can be formulated for parentral application in order to control rate
of drug absorption.E.g. penicillin procaine
• Vaccines as a immunizing agent are often formulated as suspension.E.g.
Cholera vaccine
• X-ray contrast agent are also formulated as suspension. eg: Barium sulphate
for examination of alimentary tract

41. EMULSIONS

42. EMULSIONS
• Emulsion is a thermodynamically unstable two-phase system
consisting of at least two immiscible liquids, one of which is
dispersed in the form of small droplets throughout the other, and an
emulsifying agent.
• The dispersed liquid is known as the internal or discontinuous phase
• the dispersion meadium is known as the external or continuous
phase.
• Emulsions are used in many routes of administration.
• Oral administration can be used, but patients generally object to the
oily feel of emulsions in the mouth.
• But some times, emulsions are the formulation of choice to mask the
taste of a very bitter drug

43. • emulsions are used for topical administration. Topical emulsions
are creams which have emollient properties. They can be either o/w or
w/o and are generally opaque, thick liquids or soft solids.
• Emulsions are also the bases used in lotions, as are suspensions.
• The term "lotion" is not an official term, but is most often used to
describe fluid liquids intended for topical use.
• Lotions have a lubricating effect.
• They are intended to be used in areas where the skin rubs against itself
such as between the fingers, thighs, and under the arms.
• Emulsions are also used a ointment bases and intravenously
administered as part of parenteral nutrition therapy.
• Examples of emulsions: Milk (fat in water), Butter (water in oil), Liquid
paraffin (paraffin in water), etc.

44. Uses of Emulsion:
• Pharmaceutical Application: Due to the high bioavailability
and absorption rate, it used in the pharmaceutical
industry. Mostly it used for topical preparations like creams,
lotions, etc.
• Cosmetic industry: There is a huge application of emulsion in
the cosmetic industry. Example: creams, lotions, hair
conditioners, etc.
• Food industry: Food products like milk, peanut butter, ice
cream, etc. are some examples of emulsion. So you can easily
understand the application of emulsion in this industry.
• Paint industry: Examples like emulsion paints and inks.
• Fire extinguisher: Thixotropic
high internal phase ratio emulsion is non-flammable. So
used as a fire extinguisher.

45. • Advantages of Emulsion:
• 1.Cover up the unpleasant taste.
• 2.Increase the bioavailability of the dose.
• 3.Sustained release medication.
• 4.Very cost-effective
• Disadvantages of Emulsion:
• 1.Problem of creaming and sedimentation
• 2.Phase inversion
• 3.problem of handling

46. TYPE OF EMULSION

47. Oil in Water Emulsion (O/W)
1. Oil is the dispersed phase and water is
the dispersion medium.
2. They are nongreasy and easily washed
from the skin surface.
3. They are used externally to provide a
cooling effect, for example, vanishing
cream.
4. Water-soluble drugs are more quickly
released from O/W emulsions.
5. They are preferred for oral
formulations as the taste of oils can be
masked.
6. O/W emulsions give a positive
conductivity test since the external
phase is water, which is a good
conductor of electricity.
Water in Oil Emulsion (W/O)
1. Water is the dispersed phase and oil
is the dispersion medium.
2. They are greasy and not easily
washed by water.
3. They are used externally to prevent
evaporation of moisture from the
surface of the skin, for example, cold
cream
4. Oil-soluble drugs are more quickly
released from W/O emulsions
5. They are preferred for topical
preparations such as creams.
6. W/O emulsions do not give a
positive conductivity test since the
external phase is oil, which is a poor
conductor of electricity.

48. Classification of Emulsifying Agent:
1. Natural emulsifying agents:
• Vegetable sources- Agar, Tragacanth, Gum acacia, etc.
• Animal sources- Wool fat, Gelatin, etc.
2. Semi-synthetic emulsifying agents: Methylcellulose, Sodium CMC, etc.
3. Synthetic emulsifying agents:
• Anionic emulsifying agents: Sodium lauryl sulfate(SLS)
• Cationic emulsifying agents: Benzalkonium Chloride
• Non-ionic emulsifying agents: Glyceryl ester
4. Inorganic emulsifying agents:
• Milk of magnesia
• Magnesium oxide
• Bentonite
• Magnesium trisilicate
5. Alcohols :
• Lecithins
• Cholesterol (cetyl alcohol, stearyl alcohol)
• Carbowaxes

49. Formulation or Preparation of Emulsion
• 1. Trituration Method:
• (i) Dry Gum Method
• (ii) Wet Gum Method
• 2. Bottle or Forbes Bottle Method
• 3. Auxiliary Method
• 4. Nascent Method or In Situ Soup Method
• 5. Beaker Method

54. Emulsion testing parameters and methods:
• Identification of type of emulsion:
• Dilution test: This test is important to know the solubility of
the continuous phase of the emulsion.
• For example- In O/W emulsion, a dilution test is done to
know it's diluted with water or not.
• Conductivity Test: This test is important to know, which is a
good conductor of electricity to find out the continuous
phase.
• For example- In O/W emulsion, water is a continuous phase.
Because water is a good conductor of electricity than oil.

55. • Dye-Solubility Test: This test is done by mixing
the emulsion with water or an oil-soluble dye,
and checked under a microscope to know
which is in a continuous phase or dispersed
phase.
• Fluorescence test: Oils have the property of
fluorescence under UV light, while water
doesn’t. Therefore, O/W emulsion shows a
spotty pattern while W/O emulsion fluoresces.

56. Evaluation of emulsion
1. Determination of particle size and particle count:
• Determination of changes in the average particle size or the
size distribution of droplets is an important parameter used
for the evaluation of emulsions.
• It is performed by optical microscopy, sedimentation by
using Andreasen apparatus and Coulter counter apparatus.
2. Determination of viscosity:
Determination of viscosity is done to assess the changes that
might take place during aging.
• Emulsions exhibit non-newtonian type of flow characterstics.
• The viscometers which should be used include cone and
plate viscometers

57. • 3. Determination of phase separation:
• This is another parameter used for assessing the stability of the
formulation.
• Phase separation may be observed visually or by measuring the volume
of the separated phases.
• 4. Determination of electrophoretic properties: Determination of
electrophoretic properties like zeta potential is useful for assessing
flocculation since electrical charges on particles influence the rate of
flocculation.
• O/W emulsion having a fine particle size will exhibit low resistance but if
the particle size increase, then it indicates a sign of oil droplet
aggregation and instability.

58. • Appearance
• p. H
• Viscosity
• Specific gravity
• Microbial count
• Leakage test for filled bottle
• Check the cap sealing
• Fill volume determination
• Particulate matter testing
• Stress test

59. SUSPENSION
1. It is heterogeneous mixture
2. There are two types:
1. Flocculated
2. Non flocculated
3. Dispersed particle settle on
standing
4. Particle size < 1000 nm
5. Particles are not visible through
the naked eye
6. Dispersed in solid, liquid, gas
7. Emulsifying agent are required
8. It cannot be separate by filtration
9. Freezing should be avoided during
as it leads to cracking
10. There are no test to identify the
type of suspension
EMULSION
1. It is heterogeneous of two
immiscible liquids mixture
2. There are two types:
1. o/w
2. w/o
3. Dispersed particle do not settle on
standing
4. Globule size > 1000 nm
5. Particles are visible through the
naked eye
6. Dispersed in liquid
7. Suspending agent are required
8. It can be separate by filtration
9. Freezing should be avoided during
as it leads to aggregation
10. There are several tests to confirm
the type of emulsion