Semi-Solid Dosage Forms: Ointments, Creams, Pastes & Gels
Semi-Solid Dosage Forms: Ointments, Creams, Pastes & Gels
Semi-Solid Dosage Forms: Ointments, Creams, Pastes & Gels
DOSAGE FORMS
OINTMENTS, CREAMS, PASTES & GELS
INDUSTRIAL PROCESSING
REFERENCE
INDUSTRIAL PROCESSING
INTRO, PROPERTIES, EXAMPLES
BASIC INTRODUCTION
• Definition: Semi solid pharmaceutical system comprise a body
of product ,which when applied to skin or accessible mucous
membranes tends to alleviate or treat a pathological condition
or other protection against harmful environment.
Ointment
s
Pastes
Creams
Gels/
Jelly
IDEAL PROPERTIES OF
SEMI SOLID DOSAGE FORM
Physical properties
Physiological properties
a) Smooth texture
b) Elegant in a) Non irritating
appearance b) Do not alter
c) Non dehydrating membrane function
d) Non gritty c) Miscible with skin
e) Non greasy and secretion
non staining
f) Non hygroscopic
Application properties
a. Easy applicable with efficient drug release
b. High aqueous washibility
OINTMENTS
• Two Phase(Domain)
When the gel mass consists
of floccules of small distinct
particles
Usually involve inorganics
Gel Composition Gelation
•Gelling agent •As a hot, colloidal dispersion of
•Water gelatin cools, the gelatin
•Cosolvents macromolecules lose kinetic
•Preservatives energy.
•Stabilizers •With a reduction of kinetic energy
or thermal agitation.
Kinds of Gels •Gelatin, agar, pectin, Irish moss,
pectin, tragacanth form gels by
this mechanism.
•Hydrogels
Silica, bentonite, pectin, sodium alginate,
methylcellulose, alumina
•Organic Gels
Contain an organic liquid (e.g., Plastibase)
•Carbomer Gels
Aqueous dispersion neutralized with sodium hydroxide or
triethanolamine
•Methylcellulose Gels
•Starch Glycerite
•Aluminum Hydroxide Gel
FORMULATION OF SEMI-SOLIDS
Ointments and suppository base do not merely acts as the carrier of the
medicaments, but they also control the extent of absorption of
medicaments incorporated with them
IDEAL PROPERTIES
They should be:
BASES
Water-in-oil:
Cold Cream (Petrolatum-Rose Water Ointment) Emulsion
Lanolin Bases
Oil-in-water:
Hydrophilic Ointment
Velvachol
Polyethylene Glycol Ointment
Biozyme Ointment, Desenex Ointment, Whitfields Ointment
Water Soluble
Bases
Veegum 10% Dermatological base
Veegum 5% Thixotropic lotion
PRESERVATIVES
Chorocresol
Benzoic acid
• Oxygen is highly
reactive atom that is ANTIOXIGENS REDUCING ANTIOXIDANT
capable of becoming of AGENT SYNERGIST
potentially damaging
Acts by Have lower Chelating or
molecules commonly reacting with redox potential sequestering
called “free radicals”. the free than agents,
• Free radicals are radicals. drug,hence enhance the
capable of attacking the gets oxidized effect of anti
healthy cells of the body, e.g. first. oxidants.
causing them to loose •Butylated e.g.
their structure and hydroxy anisole •Ascorbic acid e.g.
(BHA) •Potassium and •Citric acid
functions
•Butylated sodium •Tartaric acid
• To prevent this an anti hydroxy metabisulfite •Lacithin
oxidant are added. tocopherols •Thiosulfite
• Example : Butylated (BHT) (used for
hydroxy anisole , aqueous
Butylated hydroxy (used for oil system)
toluene system)
HUMECTANTS
A humectant is a hygroscopic substance . It is often a molecule with
several hydrophilic groups, most often hydroxl group.
Drug solubility
Drug Stability
Trituration Chemical
method reaction
method
Ex. Ointments Ex. Ointments
creams creams
pastes
Fusion Emulsification
method method
LEVIGATION
SPATULATION OR TRITURATION
HOMOGENIZATION
FILLING
PREPARATION OF OIL AND AQUEOUS
PHASES
The components of the oil mixtures are placed into a stainless steel steam
jacketed kettle, melted and mixed.
Some of the solid components e.g. stearic acid, cetyl alchol are available
in many different forms like cakes, flakes or powder. The flakes are more
preferable because of the convenience of handling.
The oil phase is then strained through several layers of cheese cloth to
remove any foreign matter.
The components of the aqueous phase are dissolved in the purified water
and filtered, A soluble drug may be added to this aqueous phase.
MIXING OF PHASES
• The phases are usually mixed at a temperature of 70 to 720C,because at
this temperature intimate mixing of the liquid phases can occur.
Advantages:
1.It creates a minimum dead space
during mixing.
2.It is used for wet granulation
process.
Disadvantages:
1.It works at a fixed speed.
Colloidal mill:
It consists of two steel discs. Here one
disc rotates and another one is
stationary. When the material is
passed through these discs they get
sheared. Thus coarse particles are
break down to small particles due
to shear.
Advantages:
1.It can be used in the production
of sterile products.
Disadvantages:
1.It is not used for dry milling.
2.Heat is generated during milling.
STORAGE CONDITIONS OF SEMISOLIDS
STORAGE OF SEMI-SOLIDS
• The active substance in the cream or ointment may react with the
storage container unless a Highly resistant, stainless steel, is used for bulk
storage.
• It must be able to resist the shear stress developed in the transfer of the
product, as well as that due to the mechanical action of the filling
equipment.