Semi-solid pharmaceutical dosage forms Introduction •At normal temperature can be plastically deformed •At the body temperature they turn soft •Typical adjuvants – emulgators, tensides •For topic application • Drug can be dispersed • dissolved (oily drug in oily base, water soluble drugs in hydrophilic base) • suspended • emulsifyed - two-stage system - w/o or o/w • suspended in emulsion Examples • •Oinments - Unguenta •Eye oinments • (Unguenta ophtalmica) •Creams - Cremores •Pastes - Pastae •Transdermal plasters • (Emplastra transcutanea) • •Liniments – (Linimenta) Ointments •topical, semi-solid preparations, non-specific in shape, destined for application on skin or mucosas •melt at body temperature • •Suitable for chronic treatment –penetrate the skin slowly –but deep Types of ointments - oleophilic •Oleophilic (hydrophobic) ointments –Compatible with majority of the drugs –Bases are hydrocarbons, waxes or triacylglycerols – –Bases: –White vaseline – Vaselinum album; –Yellow vaseline – Vaselinum flavum; –Pork lard – Adeps suillus; –White bee wax – Cera alba; –Solid paraffine – Paraffinum solidum, –Liquid paraffine – Paraffinum liquidum. –Cacao oil – Cacao oleum –vegetable oils (olive, sunflower, peanut, coconut, almond) Types of ointments - oleophilic •Cannot be washed away by water •They macerate the skin (stop skin perspiration, but the penetration of the drug is better) •Are more difficult to spread on the skin (better when partially melted) •Protective and softening effects Types of ointments - hydrophilic •Hydrophilic (oleophobic) ointments -Miscible with water -Washable, suitable for application on hairy skin -base -mixture of liquid and solid macrogoles (polyethylene glycols) -macrogolum 300-1500 (molecular weight) Types of ointments - hydrophilic •dessicative (cleaning) effects •may react with some drugs (sulfonamides, salicylic acid, tanines) •macrogole base is bactericidal on its own Emusifying ointments - RM bases •An emulsifier (also known as an emulgent) is a substance which stabilizes an emulsion by • increasing its kinetic stability. • • Emulsifier w/o: –Synderman –Cutilan –Ambiderman – –Emulsifier o/w: –Neo-Aquasorb/Aquasorb Pharmacopoea - ointments •Unguentum simplex •Acidi borici unguentum 10% •Ichtamoli unguentum •Zinci oxidi unguentum •Unguentum ophtalmicum simplex (sterile emulsifying base) • – Usual amount prescribed •Eye, nose, ear 10-20g •Face, hands 20-30g •Legs 80-100g •Larger surface 150-200g Example •Rp. • Acidi borici 5.0 • Vaselini albi ad 50.0 • M.f.ung. • D.S. 3 times a day apply on focus Example (hydrophilic ointment): Rp. Benzocaini chloridi 0.5 Macrogoli 300 Macrogoli 1500 aa ad 50.0 M. f. ung. D.S. Pro medico •Gently made unguents, sterile base, non-irritating •For application into conjunctival sac •Today mostly RMP •Base: Unguentum ophtalmicum simplex (white vaseline, Adeps lanae, liquid paraffine) • •Always sterile!!! •Subscriptio: „Misce fiat unguentum ophthalmicum“ – „M. f. ung. oph.“ • •Example: 2% miotic unguent with pilocarpine Ocular ointments (Unguenta ophthalmica) Example •2% miotic unguent with pilocarpine •Rp. • Pilocarpini hydrochloridi 0.2 • Unguenti ophtalmici simplicis ad 10.0 • M.f.ung oph. • D. ad ollam • Adde bacillum! • D.S. Eye ointment, apply at night to both eyes. •Two-phase base •15 % of water at least, easier to apply (lower density) •Lipophilic creams (w/o) –Similar to physiologic skin film – often prescribed –Oily creams •Hydrophilic creams (o/w) –50-90 % of water –Cooling, may be dessicative –Light, not very oily creams Creams Pharmacopoea - creams •Cremor refrigerans – cooling cream (hydrophilic) •Alcoholum adipis lanae cremor • •Usually RMP Suspension oinments - Pastae •High density (suspension) •Apart from oinment base and drugs contain 25-50 % suspended solid particles (dust) (starch, ZnO) •Do not melt, topic use •Do not prevent perspiration •Oleophilic / hydrophilic Pharmacopoea – suspension ointments •Zinci oxidi pasta •Zinci oxidi pasta mollis • • • •Example: 50g of paste with 5 % coal tar • Example •50g of paste with 5 % coal tar •Rp. • Lithantracis picis 2.5 • Zinci oxidi pastae ad 50.0 • M.f.pasta • D.S. … Transdermal plasters •Modern form •Only RMP •Penetration through skin and into • blood flow = TTS (transdermal terapeutic • system) •Slow release of drug •Longer intervals of applications, • compliance •To avoid first-pass effect •Intake of the drug can be easily stopped Transdermal plasters •Enhancers – enhance penetration –Hydratation, influence on skin lipids –Urea, alcohols – – –Never cut into smaller parts!!! Transdermal plasters •Only some drugs –Estradiol, norelgestromin (Evra) and other hormones –Fentanyl (Durogesic) –Nicotine (Nicorette, Niquitin) –