The document discusses semisolid dosage forms such as ointments, describing their uses, types of ointment bases, advantages and disadvantages of ointments, preparation methods, and factors to consider when selecting vehicle bases for dermatological formulations. Ointments can be used topically to treat skin conditions and provide local or systemic drug effects depending on the formulation. Selection of the appropriate ointment base depends on factors like absorption, skin compatibility, stability, and consistency.

1. Semisolid Dosage Forms
OINTMENT
Parag Jain
Assistant Professor
Chhattrapati Shivaji Institute
of Pharmacy
Durg, Chhattisgarh
Presented by

2. • Topical preparations are used for both local and
systemic effects.
• Systemic drug absorption should always be
considered when using topical products if the
patient is pregnant or nursing, because drugs
can enter the fetal blood supply and breast milk
and be transferred to the fetus or nursing infant.
Semisolid Dosage Forms

3. • A topical dermatological product is designed to
deliver drug into the skin in treating dermal
disorders, with the skin as the target organ.
• A transdermal product is designed to deliver
drugs through the skin (percutaneous
absorption) to the general circulation for
systemic effects, with the skin not being the
target organ
Semisolid Dosage Forms

4. Semisolid Dosage Forms
• Ointments, creams, and gels are semisolid dosage forms
intended for topical application.
• They may be applied to the skin, placed on the surface
of the eye, or used nasally, vaginally, or rectally.
• Most of these preparations are used for the effects of
the therapeutic agents they contain.
• The unmediated ones are used for their physical effects
as protectants or lubricants.

5. Ointment
• Any greasy or oily semi-solid preparation, usually
medicated, that can be applied externally to the skin in
order to heal, soothe or protect it.
• It is a viscous semisolid preparation used topically on a
variety of body surfaces.
• Drug ingredients can be dissolved, emulsified or
suspended in ointment base.

6. Types of ointments
The various types of ointments are:
• Unmedicated ointments
• Medicated ointments

7. UNMEDICATED OINTMENTS
• These ointments do not contain any drugs.
• They are useful as emollients, protectants.
• Example: Petroleum jelly.
MEDICATED OINTMENTS
• These ointments contain drugs which show local or systemic effects.
• These are of several sub-types:
• Dermatologic ointments
• Opthalmic ointments
• Rectal ointments
• Vaginal ointments
• Nasal ointments

8. DERMATOLOGIC OINTMENTS
• These ointments are applied topically on the external skin. The
ointment is applied to the affected area as a thin layer and spread
evenly using gentle pressure with the fingertips. These are of three
types:
• Epidermic ointments: The drugs present in these type of
ointments exert their action on the epidermis of the skin.
Example: Ketoconazole ointment.
• Endodermic ointments: The drugs present in these types of
ointments exert their action on the deeper layers of cutaneous
tissue.
Example: Demodex ointment.
• Diadermic ointments: The drugs present in these types of
ointments enter into the deeper layers of skin and finally in the
systemic circulation and exert systemic effects.
Example: Nitroglycerine ointment.

9. OPTHALMIC OINTMENTS
• These are sterile preparations which are applied inside
the lower eye lid. Only anhydrous bases are used in
their preparation. The ointment is applied as a narrow
band of approximately 0.25 - 0.5 inch.
• Example: Sulfacetamide sodium ointment.
RECTAL OINTMENTS
• These are the ointments to be applied to the peri- anal
or within the anal canal. The bases used are
combinations of PEG 300 and PEG 3350, cetyl alcohol
and cetyl esters, wax, liquid paraffin and white paraffin.
• Example: Benzocaine ointment.

10. VAGINAL OINTMENTS
• These ointments are applied to the vulvo-vaginal area or
inside the vagina. As vagina is more susceptible to
infections, the ointment should be free from micro-
organisms, moulds and yeasts.
• Example: Candicidin ointment.
NASAL OINTMENTS
• These are used in the topical treatment of nasal mucosa.
Drugs get absorbed into the general circulation through
the rich blood supply of the nasal lining.
• Example: Ipratropium bromide ointment.

11. Advantages
• Handling of ointments is easier than bulky liquid dosage
forms.
• They are chemically more stable than liquid dosage forms.
• They facilitate application of the directly to the effected body
part and avoid exposure of other parts to the drug.
• They are suitable for patients who find it difficult to take the
drugs by parenteral and oral routes.
• They prolong the contact time between the drug and effected
area.
• The bioavailability of drugs administered as ointments is more
since it prevents passage through liver.

12. Disadvantages
• They are bulkier than solid dosage forms.
• When applications of an exact quantity of ointment to
the affected area is required, it is difficult to ascertain
the same.
• They are less stable than solid dosage forms.

13. Application of medicated ointment
• Ointments are used topically for several purposes, e.g., as
protectants, antiseptics, emollients, antipruritics, kerotolytics, and
astringents.
• In the case of a protective ointment, it serves to protect the skin
against moisture, air, sun rays and other external factors.
• It is necessary that the ointment neither penetrates the human skin
barriers nor facilitates the absorption of substances through this
barrier.
• An antiseptic ointment is used to destroy or inhibit the growth of
bacteria. Frequently bacterial infections are deeply seated; a base
which has the capacity to either penetrate or dissolve and release
the medication effectively is therefore desired.
• Ointments used for their emollient effect should be easy to apply, be
non-greasy and effectively penetrate the skin.

14. PREPARATION OF OINTMENT
INGREDIENTS USED IN PREPARATION:
• Bases
• Preservative
• Humectants
• Antioxidants
• Emulsifier
• Gelling agent
• Permeation enhancer
• Buffers

15. BASES
• It is one of the most important ingredient used
in formulation of semisolid dosage form.
Ointment bases do not merely act as the
carriers of the medicaments, but they also
control the extent of absorption of
medicaments incorporated in them.

16. • There are five (5) classes or types of ointment bases
which are differentiated on the basis of their physical
composition. These are:
• Oleaginous bases.
• Absorption bases.
• Water in oil emulsion bases.
• Oil in water emulsion bases.
• Water soluble or water miscible bases.

17. Oleaginous bases
• These bases are fats, fixed oils, hydrocarbon or
silicones.
• They are anhydrous, greasy, non-washable does not
absorb water and occlusive (form a film on skin so it
increases the skin hydration by reducing the rate of
loss of surface water.
• They should not be applied to infected skin, they are
used as protectants, emollients , vehicles for
hydrolysable drugs.
• Example: White Petrolatum, White Ointment

18. Absorption bases
• Oleaginous base + w/o surfactant.
• Anhydrous but hydrophilic ointment bases, they can
absorb several times their weight of water to form
water-in-oil emulsion.
• They are non-washable, not water soluble
• They used as protectants, emollients (+/-), vehicles for
aqueous solutions, solids, and non-hydrolyzable drugs.
• Example: Hydrophilic Petrolatum, Anhydrous Lanolin,
AquabaseTM, Aquaphor®, Polysorb®

19. Water in oil emulsion bases
• These are anhydrous, hydrophilic, absorbs water and
non water removable, with low thermal conductivity and
occlusive.
• They have the same properties as the absorption bases.
• They are used as emollients, cleansing creams, vehicles
for solid, liquid, or non-hydrolysable drugs .
• Examples: Cold Cream type, Hydrous Lanolin, Rose
Water Ointment, HydrocreamTM, Eucerin®, Nivea® .

20. Oil in water emulsion bases
• These bases are anhydrous, water soluble, absorb water
and water washable.
• They are either carbowaxes Polyethylene Glycols (PEGs)
or hydrated gums (bentonite, gelatin, cellulose
derivatives).
• They are used as drug vehicles.
• Examples: PEG Ointment, PolybaseTM

21. Water miscible bases
• These bases are anhydrous, water soluble, absorb
water and water washable.
• They are either carbowaxes Polyethylene Glycols
(PEGs) or hydrated gums (bentonite, gelatin, cellulose
derivatives).
• They are used as drug vehicles.
• Examples: PEG Ointment, Polybase TM

22. ANTIOXIDANTS
Oxygen is a highly reactive atom that is capable of
becoming part of potentially damaging molecules
commonly called “free radicals.”
Free radicals are capable of attacking the healthy
cells of the body, causing them to lose their
structure and function. To prevent this an
antioxidants are added.
E.g. Butylated hydroxy anisole, Butylated hydroxy
toluene

23. PERMEATION ENHANCERS
• Skin can act as a barrier. With the introduction
of various penetration enhancers, penetration
of the drug through the skin can be improved.
• E.g. Oleic Acid

24. EMULSIFIER
• An emulsifier (emulgent) is a substance that
stabilizes an emulsion by increasing its kinetic
stability.
- Must reduce surface tension for proper
emulsification.
- Prevents coalescence.
- Ability to increase the viscosity at low
concentration.

25. HUMECTANT
A humectant is a hygroscopic substance,
Humectants are used to :
the active• increase the solubility of
ingredient
• to elevate its skin penetration.
• elevate the hydration of the skin.

26. BUFFERS
Buffers are added for various purpose such as :
- Compatibility with skin.
- Drug solubility.
- Drug stability.
- E.g. sodium acetate, sodium citrate,
potassium metaphosphate.

27. Selection of Dermatological Vehicle
• Following are the factors which govern the selection
of an ideal bases for ointments:-
1. Dermatological factors
1. Pharmaceutical factors

28. Dermatological Factors
1. Absorption & penetration
2. Effect on skin function
3. Miscibility with skin secretions & serum
4. Compatibility with skin secretions
5. Freedom from irritant effect
6. Emollient properties
7. Ease of application & removal

29. STRUCTURE OF SKIN

30. 1. Absorption & penetration:
• Absorption means actual entry into the blood
stream & penetration means passes through the
skin.
• The skin has 3 main layers epidermis, dermis &
hypodermis.
• Scientifically proved that the animal fats like wool fat
& fixed oils penetrate more readily through the skin
in comparison to mineral oils (paraffin).
• The substance which are soluble in both oil & water
are most readily absorbed.
• The o/w emulsion bases release medicaments more
readily than oleaginous bases means w/o emulsion
bases.

31. 2. Effect on skin function:
• Greasy bases may interfere with skin function like heat
radiation & sweat excretion & also they irritant to the
skin.
• The o/w bases means water soluble bases gives cooling
effect with healing effect & also they readily mix with
skin secretions.
3. Miscibility with skin secretions & serum:
• Emulsion bases are more readily miscible with skin
secretion compared to greasy material. For that reason
small amt of drug is needed when emulsion bases are
used.
• o/w type of emulsion bases are readily miscible with
serum & are very useful for ointment base for weeping
eczema.

32. 4. Compatibility with skin secretion:
• Neutral pH ointments are compatible with majority
of the medicaments & also they do not cause
discomfort in use.
• The ointment bases should have a pH around 5.5
which is the average pH of the skin secretions.
5. Freedom from irritant effect:
• Ointment bases should be non-irritant.
• Greasy bases causes irritation & may cause oedema.
• The ointment used for eye ointments should be
non-irritant & free from foreign particles.
• Also all ointment bases should be high standards of
purity.

33. 6. Emollient properties: The ointment bases should be
emollient properties that should be able to keep the
skin moist. The humectants like glycerin & propylene
glycol keep the skin surface moist & soft & wool fat,
paraffin used for the skin soft & preventing the loss of
moisture from the skin.
7. Ease of application & removal: Ointment bases
should be remove easily from the skin so, stiff &
sticky ointment suitable. Alsobases
ointment bases should
are not
be easily applicable &
should be spread on the skin surface.

34. Pharmaceutical Factors
1. Stability
2. Solvent properties
3. Emulsifying properties
4. Consistency

35. 1. Stability:
- The fats & oil obtained from animal & vegetable
source have to undergo oxidation so antioxidants
are used.
- O/W type of emulsion ointment bases are liable to
microbial growth so need to a preservatives.
- Emulsified bases are liable to phase separation due
to improper formulation or under influence of
temperature so required to store in suitable
temperature.

36. 2. Solvent properties:
- Most of the medicaments incorporated with
ointment bases are insoluble with it so, necessary to
mix finely powdered drug in ointment bases.
- If phenol used in solid form with ointment bases it
causes blisters. So, chose the suitable ointment base
which should keep phenol in solution form.
- Mixture of hard & soft paraffin, beeswax ointment
bases are used for phenol.
- Similarly, in the preparation of compound mercury
ointment, olive oil is used to keep camphor in
solution form.

37. 3. Emulsifying properties:
- Hydrocarbon bases absorbs less amount of water
compare with animal fats, which can absorbs a large
quantity of water.
- E.g. wool fat can absorbs 50 % of water but when it
mixed with other fats can take up several times of
water or hydro-alcoholic liquids. So, wool fat is
included as base in the eye ointment preparation.

38. 4. Consistency:
- The consistency of ointments should neither be too hard
or nor too soft.
- The consistency of an ointments can be adjusted in a
such way that, in soft ointments included have the high
melting point substance like hard paraffin, bees wax. So,
soft ointments must be stable in summer season.
- In hard ointments included the lower melting point
substance like liquid paraffin. so, hard ointments must
be stable in winter season.

39. Methods of Preparation of ointments
1. Trituration
2. Fusion
3. Chemical reaction
4. Emulsification
Objectives:
•Free from lumps of separated high M.P ingredients of the base
•No tendency of separation of liquid constituents from the bulk
•Even distribution of insoluble powders
•Toobtain ointment free from grittiness
•Toobtain uniform ointment

40. 1. Trituration Method
Widely used method
For extemporaneous preparation of ointments.
When the base is soft and medicament is solid insoluble
Small amount of liquid to incorporated in the base
Advantage
Involves mixing as well as size reduction
Procedure:
1. Reduce the solid medicament to fine powder
2. Medicament is mixed with small amount of base on ointment slab
with a stainless steel spatula until a homogeneous product is
formed.

41. 3. Add remaining quantities of base with uniform mixing
4. Incorporate any liquid ingredient if present
(mortar and pestle to be used in case of large quantity of liquid)
Eg: Prepare and dispense 100 g of sulphur ointment
Rx
Sublimed sulphur, finely sifted - 10 g
Simple ointment - 90g
Prepare an ointment
Direction - Apply the ointment to the affected area as directed.

42. 2. Fusion method
• Fusion is the act or procedure of liquefying or melting
by the application of heat.
• By the fusion method, all or some of the components
of an ointment are combined by melted together and
cooled with constant stirring until congealed.
• Heat labile substances added last, when the
temperature of the mixture is low enough not to cause
decomposition of the ingredients.

43. 2. Fusion method:
Suitable when ointment base contains number of solid ingredients
of different melting points.
Procedure:
1. Ointment base are melted in decreasing order of their melting
point.
2. Highest melting point should be melted first, low melting point
next.
3. This avoids over heating of substances of low melting point
4. Incorporate medicament slowly to the melted mass
5. Stir thoroughly until mass cools down and homogeneous
product is formed.

44. • In a small scale, the fusion process conducted in a
porcelain dish or glass beaker.
• In large scale, it is carried out in large steam-jacketed
kettles. After congealing the ointment may be passed
through an ointment mill (in large scale), in small scale
rubbed with spatula or in a mortar to ensure uniform
texture.

45. 6. Liquid ingredients or aqueous substance should be heated to the
same temperature as the melted bases before addition.
7. If not, wax or solids will cool down quickly and get separated
Precautions:
➢Strring is done continously- homogeneous mass
➢Vigorous stirring should be avoided to prevent entrapment of air
➢Rapid cooling should be avoided to get a uniform product.
➢Toremove the dust or foreign particles strain through muslin cloth

46. Eg: Prepare and dispense 100 g of Citrimide ointment
Rx
Cetrimide - 1 g
Cetostearyl alcohol – 10 g
White soft paraffin – 10 g
Liquid paraffin – 29 g
Pure water – 50 g
Procedure:
1. Melt ointment bases in decreasing order of M.Pt.
2. Dissolve cetrimide in water and heat the solution
3. Mix cetrimide solution to hot molten mass and stir.

47. 3. Chemical reactionmethod
Preparation of some ointment involves chemical reactions
Eg – (a)Iodine ointment (iodine free form)
(b)Iodine ointment (iodine combined form with ointment base)
(a)Ointments containing free iodine
➢Iodine is slightly soluble in fats and vegetable oils.
➢Readily soluble is potassium iodide solution in water due to
formation of polyiodides (KI. I2, KI. 2I2 ,KI.3I2)
➢Poly iodides are readily soluble in water, alcohol and glycerin.
➢These solutions may be incorporated with the molten absorption
type ointment base.

48. (b) Ointments containing combined iodine
Fixed oils and many fats obtained from vegetable and animal sources
contain unsaturated constituents
Iodine combines with double bonds
CH3 (CH2)7 CH=CH (CH2)7 COOH + I2 (Oleic acid)
CH3 (CH2)7 CHI.CHI (CH2)7 COOH (Di-iodo stearic acid)
Free iodine is not available, So ointments appear dark, greenish black
in colour
Leaves no stain when rubbed into the skin, Hence known as non-
staining iodine ointment

49. 4. Emulsification method
1. Facts, oils and waxes an melted together to a temperature and 700c.
2. Aqueous solution of the heat stable, water soluble compounds
is also heated to the same temperature.
3. Solution is slowly added to the melted bases, with
continuous stirring until cool.
Emulsifying agent is needed to make a stable emulsion
Water soluble soaps are commonly used as emulsifier for semisolid o/
w emulsions.
Combination of triethanolamine stearate soap and cetyl alcohol is
used in o/w emulsion
Bees wax and divalent calcium ions used in w/o emulsion.

50. Website: www.probecell.com Email: probecellinfo@gmail.com
Ph: 7415211131
Office: Smriti Nagar, Bhilai, Chhattisgarh - 490020
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