Semi-Solid Dosage Forms and Transdermal Delivery Systems Flashcards
Types of semisolid dosage forms intended for topical application
creams, gel, and ointments
T/F. Topical Preparations are used for both local and systemic effects.
True
product designed to deliver drug into the skin in treating dermal disorders, with the skin as the target organ
Topical dermatological product
product is designed to deliver drugs through the skin (percutaneous absorption) to the general circulation for systemic effects, with the skin not being the target organ
transdermal product
Semisolid preparations intended for external to the skin or mucous membranes
+ may be medicated or not
+ unmedicated: emollient, protectant, lubricant
ointments
Ointment bases.
+ also known as hydrocarbon bases
+ effective as occlusive dressings
Oleaginous bases
Examples of Oleaginous bases
Petrolatum
White Petrolatum
White Ointment
Yellow Ointment
Other names for petrolatum
Yellow petrolatum
Petroleum Jelly
White Petrolatum
White Petroleum jelly
White soft paraffin
Vaseline
Yellow Ointment is obtained from
APIS MELLIFERA
2 types of Absorption bases
- Anhydrous bases
- w/o emulsions (emulsion bases) and permit the incorporation of small additional quantities of aqueous solutions
bases that permit the incorporation of aqueous solutions, resulting in the formation of w/o emulsions. These absorption bases are anhydrous vehicles composed of a hydrocarbon base and an additive
Anhydrous (Absorption base) `
Example of Absorption bases
Hydrophilic Petrolatum, Aquaphor, Aquabase, Eucerin Lanolin (Anhydrous lanolin)
also known as water - washable base
+ o/w resembling creams
+ absorb serous discharge
Water Removable Bases
Example of WaR base in Ointment
Hydrophilic ointment
often referred as greaseless
do not have oleaginous components
+ example: PEG
water - soluble bases
How to select appropriate Ointment bases?
- Desired release rate of the drug substance from the ointment base
- Desirability of topical or percutaneous drug absorption
- Desirability of occlusion of moisture from the skin
- Stability of the drug in the ointment base
- Effect, if any, of the drug on the consistency or other features of the
ointment base - Desire for a base easily removed by washing with water
- Characteristics of the surface to which it is applied
Where is ointment generally applied to?
Dry, Scaly skin
Where is cream generally applied to?
Weeping or oozing surfaces
Where is lotion generally applied to?
Intertriginous areas
Prep of Oint.
+ Components are mixed until uniform prep is attained
+ rubber/silicone spatula is used if drug reacts to metals
Incorporation
What to used during incorporations
Parchment paper, Ointmnet Slab. Unguator
Fusion
All or some of the components of an ointment are combined by being melted together and cooled with constant stirring until congealed
+ heat labile substances and any volatile substance are added last
Compendial Requirements for Ointments
- Microbial Content
- Minimum Fill
- Packaging (large-mouth jars, metal or plastic tubes)
- Storage
- Labeling
Semisolid preparations containing one or more medicinal agents dissolved or dispersed in either a W/O emulsion or an oil-in-water emulsion or in another type of water-washable base
Pharmaceutical Creams
O/W emulsions containing large percentages of water and stearic acid or other oleaginous component; evaporation → thin residue film of stearic acid/oleaginous components
Vanishing Creams
Semisolid systems consisting of dispersions of small or large molecules in an aqueous liquid vehicle rendered jellylike by the addition of gelling agent
Gels
also known as jellies
Gels
Type of gel where macromolecules are uniformly distributed throughout a liquid with no apparent boundaries between the dispersed macromolecules and the liquid
Single phase gel
Type of gel where a gel mass consisting of floccules of small distinct particles. Often referred to as Magmas.
Two phase gels
- Semisolid preparations intended for application to the skin.
- Generally contain larger proportion of solid material (25%) than ointments→ stiffer
- Not suited for application to hairy parts of the body
Pastes
Example and other name for that paste
Zinc Oxide Paste (Lassar’s Plain Zinc Paste)
Solid/semisolid adhesive masses spread upon a backing material of paper, fabric, moleskin or plastic
+ applied to skin to provide prolong contact at site
Plasters
Example of Plasters
Salicylic Acid Plasters
Components of glycerogelatins
Gelatin (15%)
Glycerin (40%)
Water (35%)
Medicinal Substances (10%)
Glycerogelatins are melted before application. It is applied by a brush. How long is applied in the skin?
For a long time
Example of Glycerogelatins
Zinc glycerogelatin
Where is zinc glycerogelatin used for?
varicose ulcers
Package. Made of clear or opaque glass or plastic. Some are colored green, amber, or blue
Ointment Jars
Used for light-sensitive products, are porcelain white, dark green or amber
Opaque Jars
Made of aluminum or plastic (HDPE or LDPE or a blend of PP, PET)
+ for opthalmic, nasal, vaginal , rectal products
Ointment tubes
Examples of Gelling agents
CMC, HPMC, carbomers, tragacanth
facilitate the passage of therapeutic quantities of drug
substances thru the skin and into the general circulation for their
systemic effects
Transdermal Drug Delivery System
First transdermal system
Scopolamine patch
Types of TDDS
Microneedles
Iontophoresis
Sonophoresis
Electroporation
Transdermal Patches
Absorption Enhancers
What skin layer behaves as a semipermeable membrane and drug moleceules can penetrate through passive diffusion?
Stratum Corneum
Percentage of Protein and Water in SC
40% protein
40% water
Factors affecting drug movement across percutaneous skin layer
drug concentration in the vehicle aqueous solubility
oil–water partition coefficient between the stratum corneum and the product’s
vehicle
conditions of the skin
Transepidermal penetration
penetration through SC
Transappedegeal penetration
via appendages i.e. eccrine ducts and hair follicles
Types of transepidermal penetration
Intracellular
Intercellular
Penetration Sites for Percutaneous Absorption
- Between the cells of stratum corneum
- Through the walls of the hair follicles
- Through sweat glands
- Through sebaceous glands
- Through cells of stratum corneum
Factors Affecting PA
Drug Formulation
Patient Factor
Miscellaneous Factor
Increases skin permeability by reversibly damaging or altering the physicochemical nature of the SC to reduce its diffusional resistance
Chemical Enhancers
How do chemical enhancers alter physicochemical nature of SC?
hydration, structural change, or denaturation of SC
Types of Chemical Enhancers
Acetone
azone
ethanol
oleic acid
dimethylsulfoxide
propylene glycol
glycerin
PEG
urea
dimethylacetamide
sodium lauryl sulfate
poloxamers
Spans
Tweens
lecithin
terpenes
delivery of a charged chemical compound across the
skin membrane using an electrical field
Iontophoresis
also known as high frequency ultrasound
Sonophoresis
used where the semisolid dosage form is placed on a membrane → drug is released from the dosage form and passes through the membrane into the receptor solution where it is sampled and analyzed for content
Franz diffusion cell
the drug matrix layer composed of polymeric material in which the drug is dispersed is found between the backing and frontal layer
Monolithic systems
designed to contain a
drug reservoir, or pouch, usually in liquid or gel form; a rate-controlling
membrane; and backing, adhesive, and protecting layers
Membrane controlled TS
Transdermal Scopolamine
Transderm Scop
Transdermal Clonidine
Catapres
Transdermal Nicotine
NicoDerm CQ
Transdermal Estradiol
Estraderm
Transdermal NTG
Deponit
Transdermal Testosterone
Testoderm
Transdermal Contraceptive System
Norelgestromin, ethinyl astradiol
Trandermal Methylphenidate
tx ADHD
Lidocaine patch (for pain associated with
postherpetic neuralgia
patches
Solid DFs designated to be inserted under the
skin of special injections or by surgery to provide continuous long drug
therapy thru slow release of medication
Subdermal implants
Implant protection from pregnancy
Norplant system of levonorgestrel implants
It consists of a drug that is impregnated into a flexible, durable woven fabric or extruded synthetic material that is coated with an
adhesive agent.
Tapes
Animals tested in Percutaneous Absorption Models (in Vivo)
Weaning Pig, Rhesus Monkey, Hairless Mouse or Rat
What to verify and quantify first in PA Models (in vivo)?
Cutaneous bioavailability
Systemic bioavailability
Drug diffusion in PA Models in vitro is determined through
Periodic sampling
assay of the drug content in receptor solution
Matrix that controls the rate at which the drug is released
Polymer Matrix in Monolithic Systems
