Semisolids Flashcards
Ointments
- Semisolid preparations intended for external application to the skin or mucous membranes
- Medicated or non-medicated
- Used for physical effects - protectants, emollients, lubricants
Ointment Bases (4)
- Oleaginous (hydrocarbons)
- Absorption bases
- Water removable bases
- Water soluble bases
More hydrophilic as you go down
Oleaginous Bases
-Emollient effect on skin (occlusive)
-Reside on skin for prolonged periods
-Difficult to wash off
-Small amounts of water and aqueous preparations can be incorporated with difficulty
-Solids can be incorporated with levigation
EX: Petrolatum, White Petrolatum, Yellow & White Ointment
Absorption Bases
-Those that permit the incorporation of aqueous solutions resulting in W/O emulsions
-W/O Emulsions permit additional quantities of aqueous solutions
-Not as occlusive as oleaginous bases, semi-occlusive, not easily removed with water
EX: Hydrophilic Petrolatum, Lanolin
Water Removable Bases
-O/W Emulsions resemble creams
-Easily washed from skin
-Able to be diluted with water or aqueous solutions
-Can absorb serous discharge
EX: Hydrophilic ointment
Water Soluble Bases
-No oleaginous components
-Completed water-washable (greaseless)
-Does not incorporate water or aqueous solutions well (softens)
-Cetyl or steryl alcohol is added to increase firmness
-Mostly used for incorporation of solids
EX: Polyethylene Glycol Ointment
Selection of Appropriate Bases Considerations (7)
- Desired release rate
- Topical or percutaneous absorption
- Degree of occlusion of moisture from the skin
- Stability of drug in base
- Effect, if any, of drug on consistency of base
- Water washability
- Surface to be applied (dry/scaly v.s. weeping skin)
Preparations of Ointments (2)
- Fusion
2. Incorporation
Fusion
- All or some of the components of an ointment are combined by melting together and cooled with constant stirring until congealed
- Highest MP substances are melted first then others follow in order based on MP
- Non-melting components are added during constant stirring in the cooling stages
Incorporation
- Components are mixed until uniform
- Can use a mortar and pestle or an ointment slab and spatula
Solids
- Use geometric dilution to combine base and fine powders (mixed in mortar/pestle) together uniformly
- Use levigation to mix solid material in a vehicle in which it is insoluble (like glycerin or mineral oil) to make a smooth dispersion
Liquids
- Need to consider base capacity to absorb liquid
- May use small amount of hydrophilic base (incorporated with liquid) to add to hydrophobic base
- Small amounts of alcohol solutions can also be added to oil bases
Compendial Requirements (5)
- Microbial content
- Minimal Fill
- Packaging
- Storage
- Labeling
Microbial Content
- Not sterile (unless ophthalmic), but has requirements
- Preservatives (Sorbic acid, phenols, Methyl or Propylparaben are examples)
- Preparations with water tend to have a larger chance of harboring growth
- Certain preparations are checked for specific agents
Dermatologicals + Microbial Content
Checked for P. Aerginosa and S. Aureus
Rectal/Urethral/Vaginal + Microbial Content
Checked for yeast and mold
Minimal Fill
Used to determine net weight and volume of contents of filled containers to ensure labeled amounts.
Packaging
- Packaged in well-closed, large mouth jars or metal/plastic tubes to protect against contamination
- Store light sensitive products in opaque or light resistant containers
Storage
Cool place to protect against heat which can cause separation.
Labeling
Normal labeling requirements plus USP directions that labeling for some ointments include the base used (water soluble or insoluble).
Creams
- Semisolid preparations with 1+ medicinal agents dissolved or dispersed in W/O or O/W emulsion
- Vanishing creams - larger amount of water that dissolve after application and leaves behind a thin residue of oleaginous base
- Primarily used topically, but also vaginally and rectally
- Many patients and physicians prefer creams due to their spreadability and ease of removal
Gels
- Semisolid system consisting of dispersions of small or large molecules in an aqueous, liquid behicle made jellylike by a gelling agent
- Gelling agents - synthetic macromolecules, cellulose derivatives, natural gums
- Can have varying viscosities, thicken upon standing (thixotrope), must shake before use to allow pouring
Single Phase Gels
Macromolecules are uniformly distributed throughout liquid with no boundaries
Two Phase Gels
Floccules of small, distinct particles. AKA - Magma
Paste
- High proportion of solid materials (25%)
- Stiffer than ointments
- Prepared similarly to ointments but levigation agent is part of base
- Remain in place after application and can absorb serous secretions
- Not suited for hairy body parts (difficult to remove)
Plasters
- Solid or semisolid masses spread on some sort of backing
- Also have an adhesive and are applied to skin for prolonged contact
- Different sizes to conform to site being covered
- Used today in pain relief “patches” (EX: Tiger Balm)
Glycerogelatins
- Plastic masses containing 15% gelatin, 40% glycerin, 35% water, and 10% medicinal agent
- Applied to skin for long term effect
- Following application, glycerogelatin hardens and is covered with bandage & allowed to stay in place
Liquid Bandage
- Topical skin treatment which creates polymer layer on skin and protects the wound from dirt and germs
- Also keeps moisture in
- Similar to glycerogelatins but use water and oil-based polymers
Semisolid Application Sites (6)
- Topical
- Transdermal
- Ophthalmic
- Rectal
- Vaginal
- Nasal
Topical Application
Designed to deliver drug into the skin with the skin as the target organ.
Transdermal Application
Designed to deliver drug through the skin to general circulation with the skin not being the target organ.
Semisolid Use of Dermatological Preparations
- Topical treatment of skin diseases
- Penetration depends on physicochemical properties of active ingredient, characteristics of vehicle, and the condition of the skin
- Therapeutically effective drug concentrations are NOT known; treatment should be based on qualitative measures which can vary between products and patients
Ophthalmic Preparations
- Topical treatment of conditions and diseases of the eye
- Application of drug to eye or conjuctiva affects the surface of eye and underlying tissues
- Major role of entry is diffusion through cornea
- Conjunctiva and sclera are alternate routes
- Lipophilic drugs penetrate easier
- Limited drug penetration due to lack of residence time, decreased surface area, and the eye’s natural resistance to penetration
- Ophthalmic ointments can mitigate the decreased residence time
Ophthalmic Base Properties (4)
- Non-irritating
- Must permit diffusion of medicine in secretions that bathe the eye
- Should have softening point that is near body temperature to comfort patient and allow for drug release
- Drugs are added as solution or micronized particles
Ophthalmic Preparation Tests (2)
- Sterility Tests
2. Metal Particle Tests
Sterility Tests
- Normalizing sterilizing procedures may not be appropriate for ophthalmic
- Strict methods for aseptic processing are employed including each component and the active ingredient being sterilized before creating the product and adding preservatives
Metal Particle Tests
- Melted ointment is physically examined under microscope for metal particles
- Passing requires there to be <50 metal particles per 50 um or larger from 10 product tubes
- Can have no more than 8 metal particles in each tube
Nasal Preparations
- Topical treatment of nasal mucosa
- Nasal surface coated with mucous layer that contains lysosomes, glycoproteins, and immunoglobulins that act as defenses to protect the lungs
- Move by cilliary action and can cause the sneeze reflex
- Drugs are primarily used for local affects like decongestants
- Can also use systemically since they have access to a rich blood supply
Rectal Preparations
-Topical application to perianal area and insertion into rectal canal
-Healthy skin is a barrier to drug penetration and infections
-Drugs may be systemically absorbed but systemic affect is limited by drug insolubility
-Treats local conditions like inflammation or pain form hemorrhoids
EX: Astringents, protectants, lubricants, local anesthetics, and anti-inflammatories
Perianal Area
Skin that is immediately surrounding anus, has mucous linings.
Vaginal Preparations Uses (4)
- Vulvovaginal infections - clotrimazole, micronazole, clindamycin, nystatin, sulfonamides
- Vaginitis - anti-inflammatories
- Endometrial Atrophy - locally with dienestrol and progesterone
- Contraception - spermicidal agents
