This document summarizes key aspects of liquid dosage forms. It defines liquid dosage forms as solutions or suspensions for oral or injectable administration. It describes various types of liquid formulations including syrups, elixirs, tinctures, and discusses advantages and disadvantages. It also discusses important excipients used in liquid formulations such as vehicles, solubilizers, preservatives, stabilizers and how they impact properties. Finally, it provides examples of specific liquid dosage forms including ear drops, nasal sprays, mouthwashes and their intended use and advantages.
2. Liquid dosage form
• Liquid form of a dose of a chemical compound used as
a drug or medication intended for administration or
consumption.
• May be administered systematically by mouth or
injected, by using different techniques, into the skin,
muscles, or veins.
3. Preparation
• Liquid dosage forms are prepared:
• By dissolving the active drug substance in an aqueous
or non-aqueous (e.g. alcohol, ether, glycerin) solvent,
• By suspensing the drug in appropriate medium, or
• By incorporating the drug substance into an oil or
water phases.
4. ADVANTAGE & DISADVANTAGE
• Advantages:
• Better for patients who
have trouble
swallowing
• Faster absorption
than solids
• More flexibility in
achieving the proper
dosage of the
medication.
• Disadvantages:
▫ Shorter life before
expiration thanother
dosage forms.
▫ More difficult to
administer
▫ Harder to measure
accurately
▫ May have special storage
requirements
5. Excipients of liquid dosage form
• Excipients are defined as components of a formulation
other than the active ingredients.
• They can be natural or synthetic substance combined
with the drug for the purpose of long term stability,
making up formulation that contain drug or to confer a
therapeutic enhancement on the drug in the final
dosage form.
• Selection of excipients depends on upon its physico-
chemical properties, characteristics of active drug and
route of drug administration.
6. Ideal properties of excipients
• Excipients have efficient functionality for intended use
• They must be physiologically inert
• They must have good physical and chemical stability
• They should be less sensitive to equipment and process
• They must be non-toxic
• They must be acceptable with regards to organoleptic characteristics
• No influence on drug bioavailability
• Excipients needs to be free form pathogenic microorganisms
• They must be in conformance with the regulatory agency requirement
• They must be economical
7. Excipients used in liquid dosage form
• Vehicles/ Solvents
• Solubilizers
• Preservatives
• Stabilizers
• Organoleptic properties
8. Vehicles
• These are major components used as a base in which
drugs and other excipients are dissolved or dispersed.
• They function by breaking of bond and reducing
effective charge on ions thus, increasing solute-solvent
forces of attraction which are eventually greater than
solute-solute and solvent-solvent forces of attraction.
• They may be:
• Aqueous (e.g., water, polyhydric alcohols, hydro-
alcoholic solutions and buffers)
• Oily (e.g., vegetable or mineral oils, organic oily
bases, emulsified bases etc).
9. Solubilizers
• To increase the solubility of the drug
• pH adjustment
• By addition of buffer to the formulation they act by binding
hydrogen formulations to control potential changes in the pH.
E.g. phosphate buffers, acetate buffers, citric acid phosphate
buffers etc.
• Co-solvency:
• By addition of water miscible solvent in which drug has good
solubility. The solvent known as co-solvent.
• Wetting agents and surfactants:
• They adsorb air at solid particles surfaces and keep them away
from vehicles, which ultimately promotes penetration of the
vehicle into pores and capillaries of the particles. E.g. Sodium
lauryl sulphate
10. Preservatives
• Preservatives becomes unavoidable in liquid dosage form to prevent the
growth of micro-organisms during production and over storage time.
• Preservatives should be effective against broad spectrum of
microorganisms.
• Physically, chemically and microbiologically stable for lifetime of the
product.
• Non toxic, non sensitizing, soluble, compatible and with acceptable
taste and odour.
• Types of Preservatives:
• Acidic : phenol, benzoic acid, sorbic acid
• Neutral preservatives : chlorobutanol, benzylalcohol
• Quarternary ammonium compounds : Benzalkonium chloride
11. Stabilizers
• Oxidation, photolysis, solvolysis and dehydration are common
transformations taking place in liquid dosage forms.
• Antioxidants: They act as chain terminators where it reacts with
free radicals in solution to stop the free-radical propagation
cycle. Eg: acetone sodium bisulfite, acetylcysteine, ascorbic
acid, thiourea
• Antifoaming agents: These agents are effective at discouraging
the formation of stable foams of stable foams by lowering
surface tension and cohesive binding of the liquid phase. Eg:
Simethicone, organic phosphates, alcohols, paraffin oils etc
• Suspending: These agent excipients help active pharmaceutical
ingredients stay suspended in the formulation and prevent
caking at the bottom of the container. Eg: clays, natural gums,
synthetic gums
12. Organoleptic properties
• Flavouring agent: Flavours are used to mask the taste of
drugs, many of which have a very unpleasant taste. E.g.
vanilla, raspberry, orange oil, lemon oil are used for oral
solutions.
• Colourants: They are largely incorporated into pharmaceutical
products to standardize or improve an existing drug colour, to
mask a colour change and improve appearance and/ or
sometimes to complement a flavour or match the colour of a
medicine with its taste. E.g. red colour with cherry flavour,
yellow with lemon, green with mint, purple with blackcurrant,
etc.
• Sweeteners: They are employed in liquid pharmaceutical
dosage forms intended for oral administration specifically to
increase the palatability of the therapeutic agent. E.g. sucrose,
sorbitol, mannitol, saccharin sodium, xylitol, high fructose corn
syrup etc.
14. Otic Preparation (Ear drops)
• Are products that are applied to or in the ear to treat
conditions of the external and middle ear.
• These products are used to treat dermatitis of the ear,
cerumen build up and ear infection.
16. Nasal preparations
• Are liquid, semi-solid or solid preparations intended for
administration to the nasal cavities to obtain a systemic or
local effect.
• Are as far as possible non-irritating and do not adversely
affect the functions of the mucosa and its cilia.
• Supplied in multi-dose or single-dose containers
• With a suitable administration device.
17. Nasal drops
• A liquid preparation intended for intranasal
administration with a medicine dropper.
• Most frequently used for decongestion of the nasal
passages but can be used for any other appropriate
indication.
19. • The aim is to get the liquid to spread over all the
inside surface of the nose - including the upper
surface.
20. Nasal Spray
• Used for the nasal delivery of a drug or drugs, either locally to
generally alleviate cold or allergy.
• Advantages:
• Localized effect
• Convenient
• Fast effect
• “Mist”
• Decongestant – shrinks swollen tissues in the nose
• Salt-water solutions (saline) – loosen mucus, relieves mild
congestion
22. Syrup
• Are concentrated aqueous preparations of a sugar or sugar
substitute with or without flavoring agents and medicinal
substances.
• High sugar content
• Non medicated or flavored vehicles – syrups containing
flavoring agents but not medicinal substances
• Flavored Syrups - often used as vehicles for unpleasant
tasting medications; the result is medicated syrup
23. Advantages
• Ability to disguise bad taste of medication
• Thick character of syrup has soothing effect on
irritated tissues of throat
• Contain little or no alcohol
• Easy to adjust the dose for a child’s weight
25. Elixir
• Clear, sweetened hydro alcoholic solution
• Intended for oral use and are usually flavored to enhance
palatability.
• Usually less sweet than syrups and less viscous
• Non medicated elixirs – vehicles
• Medicated elixir – used for therapeutic effects
26. Advantages of Elixirs
• Better able to maintain both water-soluble and alcohol-
soluble components in solution
• Has stable characteristics
• Easily prepared by simple solution
Disadvantages of Elixirs
• Less effective than syrups in masking taste of
medicated substances.
• Contains alcohol, accentuates saline taste of
bromides
28. TINCTURES
• An alcoholic or hydro-alcoholic solution prepared
from animal and vegetable sources or from chemical
substances (USP)
• A liquid preparation produced by macerating prepared
plant material in a mixture of alcohol and water at room
temperature over a prescribed period of time, which is
then pressed and filtered to yield a fluid into which
active constituents of the herb have dissolved
29. • Made by soaking plant/animal material in alcohol for 72
hrs or so
• Commonly used solvent is ethanol
• Used by both complementary and traditional health
care providers to relieve the discomfort and pain
of the symptoms associated with outbreaks of cold
sores or fever blisters
30. Aromatic waters
• These are saturated solutions of volatile oils or other
• aromatic or volatile substances in distilled water.
• They are clear and free from solid impurities.
• They possess an odor similar to the plant or volatile substance
from which they are made, and are free from empyreumatic or
foreign odors.
• should be protected from strong light and preferably stored in
containers which are stoppered with purified cotton to allow
access of some air but to exclude dust.
• it is used as a flavoring agent, solvent or as a perfumed
vehicle.
31.
32. Spirit/Essence
• sometimes known as essences, are alcoholic or hydro
alcoholic solutions of volatile substances.
• maybe solid, liquid, or gas
• used pharmaceutically as flavoring agents and
medicinally for the therapeutic value of the aromatic
solute.
34. Douches
for the irrigative
▪ Douche = to wash or to soak
▪ A liquid preparation intended
cleansing of vagina ( Ansel’s)
▪ Douches are devices made up of certain douching supplies,
typically a bag and thin syringe that is placed inside the
vagina
▪Douching is washing or cleaning out the vagina (birth
canal) with water or other mixtures of fluids
37. Mouth-washes
• It is a medicated liquid used for cleaning the oral
cavity and treating mucous membranes of the mouth.
• Possess cleansing, germicidal and palliative properties
• For some it can mask the symptoms of oral health
disease.
• Only some are approved for treatment of gingivitis.
• More of a “cosmetic”, but some are therapeutic.
39. Oral rinses
• Are sold as over-the-counter products
• Help remove oral debris before or after brushing
• Temporarily suppress bad breath
• Diminish bacteria in the mouth
• Refresh the mouth with a pleasant taste
• Most dentists are skeptical about the value of over-the-
counter plaque-fighting mouth rinse products. Studies have
shown that they minimally reduce plaque.
40. Therapeutic rinses
• May be prescribed by your dentist
• Help remove oral debris before or after brushing
• Temporarily suppress bad breath
• Diminish bacteria in the mouth
• Refresh the mouth with a pleasant taste
• Contain an added active ingredient that helps protect
against some oral diseases
41. Gargle
• a medicated solution used for gargling and rinsing the
mouth
• Has more medicated substances than mouthrinses/
mouthwash
• Mostly prescribed by dentists
• Also called oral antiseptics
42. Advantages of Gargles
• Effective in
combating oral
health diseases.
• Localized effect
• Has medicated
substances Povidone-Iodine (Betadine Oral
Antiseptic)
1% m/v 0.1% m/v/100mL