Semi-solid Dosage Forms

• Topical formulations


  Preparations used for both local & systemic effects
• Topical dermatological product


  • Designed to deliver drugs into the skin in treating dermal disorders, with the skin as the target organ
• Transdermal product


  • Designed to deliver drugs through the skin (percutaneous absorption) to the general circulation for systemic effects, with the skin not being the target organ
• Types of topical formulations


  • Epicutaneous: ointments, creams, aerosols, dusting powder
  • Inhalational
  • Eye drop, ear drop, tooth drop
• Effects of topical formulations

  • Topical effect = local effect
  • Systemic effect
  • Protectant
  • Absorbents
  • Lubricants
  • Emollients
  • Drying effects
  • Systemic effect (TDDS)
• Advantages of topical formulations

  • Avoidance of first pass metabolism
  • Convenient and easy to apply
  • Ability to easily terminate the medications, when needed
  • Ability to deliver drugs more selectively to a specific site
  • Avoidance of gastrointestinal incompatibility
• Limitations of topical formulations


  • Skin irritation of contact dermatitis may occur due to the drug or excipients
  • Poor permeability of some drugs through the skin
  • Drugs of larger particle size are not easily absorb through the skin
• Collodion


  Solution of nitrocellulose in ether and acetone, sometimes with the addition of alcohol
• Pyroxylin


  Left on the skin after evaporation of the volatile solutions
• Collodion example

  • Salicylic acid Collodion – used to treat common skin and foot wars, corns, and calluses
• Emulsion


  Liquid disperse system that used small globules of a liquid distributed through another liquid which it is immiscible
• Emulsion example

  • Biafine Topical Emulsion – water-based emulsion formulated for the dressing and management of superficial wounds, minor abrasions, dermal ulcers, donor sites, 1st and 2nd degree burns, including sunburns, and radiation dermatitis
• Foams


  Emulsified systems packaged in pressurized containers or special dispensing devices that contain dispersed gas bubbles, usually in a liquid continuous phase, that when dispersed have a fluffy, semisolid consistency
• Foam example

  • Tazarotene (Fabior) – treats both non-inflammatory and inflammatory lesions
• Lotions


  Fluid, somewhat viscid emulsion dosage forms for external application to the skin
• Lotion example

  • Triamcinolone Lotion – topical corticosteroid, used to treat the symptoms of topical inflammatory dermatosis and oral inflammatory of ulcerative lesions
• Topical Powders


  Solids or mixture of solids in a dry, finely divided state for external use
• Topical Powder example

  • Miconazole Nitrate (Daktarin) – medicine for treating infection of the skin by fungi including yeasts
• Topical Sprays


  Products formed by the generation of droplets of a solution containing the dissolved drug for application to the skin or mucous membrane
• Topical Spray example

  • Gentamicin Sulfate + Betamethasone valerate (Betagen) – treatment of infected superficial lesions in dogs caused by bacteria
• Topical Aerosols


  Products that are packaged under pressure, can be in liquid, solid, or foam forms
• Topical Aerosol examples

  • Minoxidil Topical Aerosol Foam – revitalizes hair follicles
  • Betadine Topical Aerosol Spray – wound antiseptic
• Topical Solutions


  Liquid preparations that contain one or more dissolved chemical substances intended for topical application to the skin, or in the mucosal surface
• Topical Solution examples

  • Clindamycin Topical Solution – antibacterial
  • Lidocaine Oral Topical Solution USP – anesthetic
• Topical Suspensions


  Liquid preparations that contain solid particles dispersed in a liquid vehicle intended for application to the skin
• Topical Suspension example

  • Ciclopirox Topical Suspension, USP – skin antifungal
• Semisolid dosage forms

  • Ointments
  • Creams
  • Gels
  • Pastes
  • Plasters
  • Glycerogelatins
• Ointments


  Semisolids intended for external application tot eh skin or mucous membrane, composed of fluid HC meshed in a matrix of higher melting solid hydrocarbons, usually contains less than 20% water and volatiles and more than 50% hydrocarbons, waxes, or polyols as the vehicle
• Ophthalmic Ointment


  Ointment application to the eye, all materials used should be impalpable to avoid eye irritation or discomfort, must be sterile
• Ophthalmic Ointment example

  • Erythromycin Ophthalmic Ointment USP – used for the treatment of prophylaxis of infections of the eye, particularly of neonatal conjunctivitis
• General uses of ointments

  • Acts as a protective or protectant – prevent skin irritation
  • Acts as an emollient – soften the skin, soothing agent, moisturizing
  • Carrier of medicament – vehicle/base with drug
• Oleaginous base (HC bases)


  Origin: petroleum, animal waxes, characteristic: water-free (immiscible with water), effects: emollient, occlusive, retained on the skin for prolonged periods, do not permit the escape of moisture from the skin to the atmosphere, disadvantage: difficult to wash of by H2O
• Petrolatum, USP


  Aka: yellow petrolatum, purified mixture of semisolid hydrocarbons obtained from petroleum, Brand: Vaseline
• White Petrolatum, USP


  Purified mixture of semisolid hydrocarbons obtained from petroleum, and wholly or nearly decolorized, Brand: White Vaseline, Formula: 950g white petrolatum, 50g white wax
• Yellow Wax, USP


  Aka: yellow beeswax, purified wax from the honeycomb of the bee (Apis mellifera L.), obtained after the honey has been removed by draining or centrifuging, Formula: 950g white petrolatum, 50g yellow wax
• White Wax, USP


  Aka: white beeswax, product of bleaching and purifying yellow wax
• Paraffin, NF


  Purified mixture of solid saturated hydrocarbons obtained from petroleum, MP: 35-750C
• Liquid Paraffin


  Colorless, odorless oily liquid consisting of a mixture of hydrocarbons obtained from petroleum, has the same character as paraffin, be used in combination with paraffin to adjust the viscosity
• Spermaceti Wax


  Weak surfactants (W/O) and used as stabilization against in O/W emulsive ointment, Cetyl ester wax
• Other HC Bases

  • Ozokerite – mined wax with MP of 65-750C
  • Ceresin – mixture of ozokerite and paraffin wax