Semisolid dosage forms. Aerosol

Department of Pharmacology & Toxicology Medical Faculty, Medical University – Sofia Dr. Rumen Nikolov, PhD

SEMISOLID DOSAGE FORMS AEROSOLS PRESCRIPTION WRITING

Vehicles (bases)

A vehicle is defined as the inert carrier of the active ingredient

Lipophilic base: paraffin oil, petroleum jelly, wool fat (lanolin)

A lipophilic drug moves more readily into the epidermis if it is in an aqueous vehicle (to which it is less tightly bound)

The main rule of the local therapy is: if the skin is dry, use an ointment; if it is wet, use a cream. Dry, chronic inflammation often improves more with drugs administered in lipophilic vehicles, whereas moist acute inflammation is best treated with aqueous preparations.

Semisolid dosage forms:

Ointment (unguentum - ung.)Paste (pasta)Cream (creme)Gel (gel)Adhesive plaster (emplastrum)Transdermal therapeutic systems – TTSSuppositories (suppositoria - supp.)

Ointments

Ointments are greases with the permissible addition of up to 25% of powder by weight.

According the place of application they are: 1) unguentum dermaticum 2) unguentum ophthalmicum 3) unguentum nasale

Ointments are useful in any conditioncharacterized by dry skin (e.g. atopic dermatitis).

Pastes Pastes are greases containing more than 25% powder by weight

They are useful for dry surfaces

Pastes are very difficult to remove

19. OINTMENTS

19. A) Prescribe 2,5 g Nemybacin in the form of eye ointment.

Rp/ Ung. ophth. Nemybacini 2,5 g D. tub. № 1 S. Apply in the lower conjunctival sac of the affected eye twice daily.

19b) Prescribe 30 g ointment, containing 2 g Salicylic acid and 4 g Benzoic acid. Rp/ Acidi salicylici 2 g Acidi benzoici 4 g Vaselini albi ad 30 g M. f. unguentum D. S. Apply to the affected skin twice daily.An ointment containing Benzoic acid and Salicylic acid in a ratio of 2:1 is calls Whitfield’s ointment.It is used mainly in the treatment of tinea pedis.

20) Prescribe 100 g officinal paste, containing Zinc.

Rp/ Pasta Zinci 100 g D. S. Apply to the burned

areas once daily

Creams These are either oil-in-water (O/W) orwater-in-oil (W/O) emulsions and contain preservatives to prevent bacterial and fungal growthThe commonest preservatives areparabensOil-in-water emulsions rub into the skin and are easily washed offWater-in-oil emulsions are greasier

Gels

Gels are semi-colloids which liquefy on contact with the skin

For use on the scalp and face gels or lotion are acceptable

Gels are a common form for acne preparations (e. g. Acnederm)

21. Cream and gel21a) Prescribe Lamisil (1% 15 g) as officinal cream. Rp/ Creme Lamisili 1% 15 g D. tub. №1 S. Apply to the affected skin areas twice daily.

21b) Prescribe Troxevasin 2% 40 g as gel

Rp/ Gel Troxevasini 2% 40 g D. tub. № 1 S. Apply to the affected area twice daily.

Suppositories

Rectal suppositories – they can be produced a local (to treat haemorrhiods and ulcerative colitis) or systemic effects (for example anti-emetic effect)

Vaginal suppositories – they are produced a local antimicrobial effect (e. g. Flagyl, Canesten Gyn 3)

22. Suppositories22a) Prescribe Paracetamol assuppositories each of 150 mg.

Rp/ Supp. Paracetamoli 150 mg D. scat. № 1 S. Insert 1 supp. in rectum 3 times daily.

22. Suppositories. 22b) Prescribe Ultraproct as officinal suppositories.

Rp/ Supp. Ultraprocti D. scat. № 1 S. Insert 1 supp. in rectum once daily.

Plasters

Adhesive plasters – e. g. Citoplast

Transdermal patches (TTS)• Scopoderm TTS – 1,5 mg/72 h• Climara TTS – 25 µg/24 h• Nitroderm TTS – 25 mg/24 h • Duragesic TTS – 50 mcg/h

23.) Prescribe Fentanyl TTS

50 mcg/h (10 numbers).

Rp/ Fentanyl TTS 50 mcg/h

D.t.d. № 10 S. Stick 1 plaster of the skin once daily.

AerosolsMost drug are intended for inhalationare administered by a pressurized aerosolor, less frequently, a powder inhaler. Aerosols for oral inhalation 1. Metered-dose inhaler (e. g. 250 µg/puff) 2. Spacers – is a large volume chamber that is attached to the metered-dose inhaler used to decrease the deposition of drug in the mouthNasal aerosols (e.g. Olynth, Flixonase)

Aerosols for external application

24. Aerosols.24a) Prescribe 100 g 0,05% Fluticasone as an officinal nasal aerosol.

Rp/ Flixonase nasal 0,05% 100 g D. t. d. № 1 in flac. S. 1-2 sprays/nostril/d.

24b) Prescribe one vial Salbutamol as an officinal aerosol (Ventolin 0,1 mg/dose).

Rp/ Fl. Ventolini 0,1 mg/dose D. t. d. № 1 S. One puff in the mouth.