TOPIC 7 Product Evaluation & Storage Stability Flashcards
what are the types of product evaluation parameters ? (6)
● appearance, colour, odour, flavour, etc.
● physical-chemical eg. pH value, viscosity, density, etc.
● microbiological parameter eg. microbial count and challenge test of preserving system
● performance test
● sensory evaluation
● container parameters eg. interaction, migration of components between package, container deformity, etc.
what microbes are tested for in microbial preservation testing ? (5)
bacteria
● Staphylococcus aureus
● Escherichia coli
● Pseudomonas aeruginosa
yeast
● Candida albicans
mould
● Aspergillus niger
how are bacteria plate counts carried out according to USP <61> Total Microbial Count (3)
- sample of product taken and placed in suitable neutraliser broth
- dilutions plated to appropriate bacterial growth agar plates
- plates incubated and then analysed to determine presence of aerobic bacteria (if contaminated, further evaluation / reformulation may be necessary)
how is the preservative challenge test carried out using USP <51> test method ? (2)
- product separated out into 5 containers each being challenged with one of the 5 method-specified microbes at fairly high concentrations
- remaining concentration of each microbe counted at specified intervals for no less than 28 days
how does a preservative system pass the preservative challenge test (2)
● no increase in microbes
● sufficient decrease by day 14
what exempts a product from undergoing preservative challenge test ? (5)
● anhydrous (no water)
● pH < 3 or > 10
● contains > 20% alcohol
● filled in containers at > 65 deg C
● packaged in pressurised container, pump dispenser, or single-dose units
sunscreen efficacy testing (in-vivo on human subjects)
● 3 days
● participants treated with product on small section of skin exposed to UV light and evaluated for erythema after specific periods
regression method by Kligman (skin moisturising) (3)
- product applied on subject’s body twice daily
- test sites are evaluated on day 7 and 14 and dry skin scores given
- treatment stopped after day 14 but evaluation continues for 2 more weeks to determine duration for regression to original condition
methods to determine skin condition for Kligman’s regression method (3)
● corneometer
● spectroscopy imaging
● adhesive tape stripping
levels of testing for product functionality test (3)
● lab testing
● salon testing
● consumer testing
advantages of lab testing (2)
● most control over experimental variables
● provides most technical precise data
limitation of lab testing (1)
does not provide info on consumers’ perception
characteristics of salon testing (3)
● evaluation during actual usage on consumers while maintaining measure of control
● trained technicians generate data on product characteristics
● test product usually evaluated in comparison to designated control product
how is consumer testing carried out ?
product is provided for consumer to test at home for certain period of time according to their usual habit / practice
advantage of consumer testing (1)
provides accurate info on consumer perception of product
limitation of consumer testing (1)
poor control over variables eg. frequency of usage, amount used