Pharmacology (topical dermatological drugs)

1. @OSAMA_Z96

2. * Definitions :
Semisolids constitute a significant proportion of pharmaceutical dosage forms.
They serve as carriers for drugs that are topically delivered by way of :
1- The skin.
2- Mucus membrane, which include : (Cornea, recta tissue, nasal mucosa, vagina, buccal tissue, urethral membrane, external ear lining).
Semisolids can adhere to the skin for long periods, which helps prolong drug delivery at the application site.
* Advantages :
1- Easy application.
2- Rapid formulation.
3- Ability to topically deliver a wide variety of drug molecules.

3. - Semisolids are available as a wide range of dosage forms, each having unique characteristics :
A wide range of raw materials is available for the preparation of a semisolid dosage form.
Apart from the usual pharmaceutical ingredients such as preservatives, antioxidants, and solubilizers, the basic
constituents of a semisolid dosage form are unique to its composition.
CharacteristicsDosage form
1- Are semisolid preparations for external application to skin or mucous membranes.
2- Does not melt upon application to the skin.
3- Skin protectives and emollients (Water- in-oil).
4- Used primarily as vehicles for the topical application of drug substances.
1- Ointments
1- Contain one or more drug substances.
2- Dissolved or dispersed in a suitable base.
3- Oil- in-water emulsion or aqueous microcrystalline dispersion
4- Water-washable.
5- Osmetically and aesthetically acceptable.
2- Creams
1- Consist of small inorganic particles or large organic molecules interpenetrated by a liquid.
2- Gels can be water based (aqueous gels) or organic solvent based (organogels).
3- Gels
1- Contain one or more drug substances incorporated in a base with large proportions of Finely dispersed solids.4- Pastes

4. 1- Soft-media bases (petrolatum, lanolin etc.).
2- Substances which increase the melting point and viscosity of the base (paraffin,
spermaceti, hydrogenated vegetable oils).
3- Hydrophobic solvents, water and hydrophilic solvents.
4- Emulsifiers (sodium laurel sulphate, twins, cholesterol).
5- Gelling agents (carbomer, alginic acid and its salts etc.).
6- Antimicrobial preservatives (benzalkonium chloride, miramistin, cetrimide etc.).
7- Antioxidants (a-tocopherol, ascorbic acid).
8- Solubilizers (P-cyclodextrin).
9- Perfume and deodorant agents (menthol, essential oils).
10- pH regulators (citric acid, sodium phosphate etc.).

5. 1- Drug name :
Tabeta.
2- Pharmaceutical dosage form :
Ointment.
3- Concentration :
0.1%
4- Active ingredient :
Betamethasone
5- Vehicle (W/O or O/W) :
Water-in-oil
6- Clinical uses :
A- Eczema.
B- Psoriasis.
7- Main expected side effect :
A- Skin irritation
B- Thinning of the skin
C- Stretch mark

6. 1- Drug name :
Acretin.
2- Pharmaceutical dosage form :
Cream.
3- Concentration :
0.05
4- Active ingredient :
Tretinoin
5- Vehicle (W/O or O/W) :
Oil-in-water or Water-in-oil.
6- Clinical uses :
Acne treatment
7- Main expected side effect :
A- Dryness
B- Itching
C- Redness

7. 1- Drug name :
Rozex
2- Pharmaceutical dosage form :
Gel
3- Concentration :
0.75%
4- Active ingredient :
Metronidazole
5- Vehicle (W/O or O/W) :
Water-in-oil
6- Clinical uses :
A- Giardia infections
B- amebic liver abscess
C- Clostridium difficile infection
7- Main expected side effect :
A- Nausea
B- Headaches
C- Loss of appetite

8. 1- Drug name :
Derma-T
2- Pharmaceutical dosage form :
Lotion
3- Concentration :
1%
4- Active ingredient :
Clindamycin Phosphate
5- Vehicle (W/O or O/W) :
Oil-in-water
6- Clinical uses :
Acne treatment
7- Main expected side effect :
Signs of an allergic reaction