This document discusses semi-solid pharmaceutical dosage forms. It defines semi-solid forms as those that tend to alleviate or treat pathological conditions when applied to skin or mucous membranes. Ideal properties include a smooth texture, non-greasy feel, and ability to release drugs efficiently. Some common semi-solid forms are ointments, creams, pastes, gels, and suppositories. Ointments contain a high percentage of insoluble solids and are used as emollients or to apply active ingredients to the skin. Pastes have good adhesion and are less greasy. Gels and jellies contain a liquid phase constrained within a polymeric matrix. Bases can be oleaginous, absorption, emulsion

2.  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.

3. Ideal properties of Semi solid dosage form
Physical properties
a) Smooth texture
b) Elegant in appearance
c) Non dehydrating
d) Non gritty
e) Non greasy and non
staining
f) Non hygroscopic
Physiological properties
a) Non irritating
b) Do not alter membrane
function
c) Miscible with skin
secretion
Application properties
a. Easy applicable with efficient drug release
b. High aqueous washibility

4. Ointment Creams Pastes Gels
Poultices Plaster Suppositories

5. Ointments are homogenous, translucent, viscous, semi solid
preparation intended for external application to skin or mucous
membranes. Ointment may be medicated or not..
Applied to mucous membrane or skin
Uses
Emollient
Applcation for active ingredients to the skin
Occulsive

6. Contains high percentage of insoluble
solid(usually 50% or more)
Pastes are usually prepared by incorporating
solids directly into a congealed system by
levigation with a portion of base to form paste like
mass.
They have good adhesion on skin and less
greasy.

7. i. Gels are semi solid system in which liquid phase is
constrained
ii. With a 3-d polymeric matrix having a high degree of
physical
iii. Or chemical cross linking
iv. Gels are aqueous colloidal system of hydrated forms of
insoluble medicaments.
v. Jellies are transparent or translucent non greasy
semisolid and contain more water than gels.
vi. Used for medication,lubrication and carrier for
spermicidal agents to be used intra vaginally with
diaphargm..

8. BASES
OLEAGENOUS
BASE
ABSORBTION
BASE
EMULSION
BASE
WATER
SOLUBLE
BASE

9. Oleaginous ( hydrocarbon) bases:
They consist of a combination of more than one oleaginous material such as
water insoluble hydrophobic oils and fats
They are highly compatible ; occlusive ; good emollients
They are anhydrous, do not absorb water, readily(hydrophobic) insoluble in
water, non washable
Example : Vaseline,hard parafin, liquid paraffin,white ointment.
Uses : protective, emollient and vehicle for solid drugs.

10. Absorption (Emulsifiable) base:
Have capacity to absorb considerable quantities of water or aqueous
solution and turns to w/o without marked changes in the consistency.
They are anhydrous, water insoluble and water unwashable.
They have good emollient but poor occlusive property.
Uses: protective, emollient and vehicle for aqueous solutions and solid drug.

11. Emulsion bases:
According to the type of emulsion these bases are classified as either W/O
or O/W.
W/O EMULSION BASE O/W EMULSION BASE
Hydrous Hydrous
Will absorb water Will absorb water
Insoluble in water Insoluble in water
Not washable washable

12. Water soluble Bases:
 These include both hydrous and non hydrous dermatological non- emulsion
bases which are water soluble and contain no oil phase.
 Water soluble, water washable, non greasable
 Because they softens with the addition of water, large amount of aqueous
solutions are not effectively incorporated into the bases.
Example : carbowax compounds such as the poly ethylene glycol bases containing
pectin, cellulose, bentonite and gelatin.

13. Anionic Cationic Non ionic
•Alkyl sulphates
•Soaps
•D odecyl benzene
•Sulfonates
•Lactylates
•Sulfosuccinates
•Monoglycerides
•Sulfonates
•Phosphate esters
•Silicones
•Taurates
•Quaternary
ammonium
compounds
•alkoxyalkylamines
•Polyoxyethylene
•Alkyl-aryl ethers
•Polyoxy ethylene
•Sorbitan esters
•Sorbitan fatty acid
esters
•Glyceryl fatty acid esters

14. Some bases , although, resist microbial attack but because of their
high water content, it require an anti microbial preservative.
Commonly used preservative include:
Methyl hydroxy benzoate
Propyl hydroxy benzoate
Chlorocresol
Benzoic acid
Phenyl mercuric nitrate

15. Oxygen is highly reactive atom that is capable of becoming of potentially
damaging molecules commonly called “free radicals”.
Free radicals are capable of attacking the healthy cells of the body,
causing them to loose their structure and functions
To prevent this an anti oxidant are added.
Example : Butylated hydroxy anisole , Butylated hydroxy toluene

16.  The Theory and Practice of Industrial pharmacy by
Leon Lachman, Herbert lieberman, 3rd edition, page
no.534-563