Derm 6 Flashcards
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What are the learning outcomes of the Lotions and Gels lecture?
Describe pharmaceutical lotions and gels, discuss formulation considerations, describe types of polymers used in gel formulations.
What are pharmaceutical lotions?
Liquid dosage forms, typically emulsions, solutions, or suspensions, used externally on skin.
How do lotions differ from creams and ointments?
Lotions are less viscous, easier to spread over large areas, suitable for hairy skin, and often need shaking before use.
What are the types of lotions?
Emulsions (multi-phase), solutions (single-phase), suspensions (insoluble particles dispersed in liquid).
What are characteristics of lotions?
Viscous liquid, good wetting properties, easy to spread, suitable for large and hairy skin areas.
Why are suspending agents used in lotion suspensions?
To keep particles suspended, reduce sedimentation by increasing viscosity (Stokes’ Law).
Give examples of suspending agents in lotions.
Xanthan gum, methylcellulose, carboxymethylcellulose, gelatin, bentonite.
What are key formulation components of lotions?
API, vehicle, preservative, suspending agent (for suspensions), antioxidant, pH regulator, co-solvents, emulsifier.
What is Calamine Lotion BP?
A suspension containing zinc oxide and iron oxide for symptomatic relief of skin conditions.
What does Calamine Lotion BP require before use?
It must be shaken to ensure homogeneous dispersion.
What is Betnovate Scalp Application used for?
Contains betamethasone valerate; treats scalp dermatoses (e.g. psoriasis, seborrheic capitis).
What type of lotion is Betnovate Scalp Application?
Aqueous solution.
What is Locoid Crelo Lotion?
Hydrocortisone butyrate emulsion used to treat eczema, psoriasis, and dermatitis.
What are key formulation considerations for lotions?
Emulsion stability, solubility, pH regulation, preservatives to prevent microbial growth.
What is a pharmaceutical gel?
A semi-solid dosage form consisting of a polymer network interpenetrated by a liquid phase.
What are the types of gels?
Type I: Irreversible polymer network (e.g. polyacrylamide); Type II: Reversible network (e.g. agarose gels).
What are key gel formulation considerations?
Ensure drug solubility, prevent skin irritation, use co-solvents, pH regulators, or alternate drug forms.
What are common co-solvents used in gels?
Ethanol, isopropanol, propylene glycol, acetic acid.
What are examples of gelling agents?
Natural: xanthan, tragacanth; Semi-synthetic: methylcellulose, HEC, HPMC; Synthetic: carbomers, poloxamers.
Why are preservatives important in gels?
Gels are water-based and susceptible to microbial growth; preservatives extend shelf life to 24–36 months.
What are common gel preservatives?
Parabens (methyl, ethyl, propyl, butyl), benzoic acid, benzyl alcohol, disodium edetate.
What are penetration enhancers in gels?
Increase drug diffusion by opening skin pathways; examples: alcohols, surfactants, natural oils, fatty acids, sulfoxides.
What is Ibuprofen gel used for?
Anti-inflammatory analgesic; contains drug, polymer gelling agent, pH regulator, preservative, co-solvent, solvent.
