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 – TTS Suppositories (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 condition characterized 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) or water-in-oil (W/O) emulsions and contain preservatives to prevent bacterial and fungal growth The commonest preservatives are parabens Oil-in-water emulsions rub into the skin and are easily washed off Water-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 gel 21a) 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. Suppositories 22a) Prescribe Paracetamol as suppositories 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. Aerosols Most drug are intended for inhalation are administered by a pressurized aerosol or, 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 mouth Nasal 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.