• Sunscreen (also known as sunblock or suntan
lotion is a lotion, spray, gel or other topical
product that absorbs or reflects the sun's
ultraviolet (UV) radiation and protects the skin.
• Sunlight reaching the surface of the earth contains :
UV Rays (particularly wave-length below 320mµ) are responsible for
most of the therapeutic as well as noxious effects that we attribute to
4. SKIN - DAMAGE
• The UV Spectrum is broken into three parts:
Very High Energy (UVC)
High Energy (UVB)
Low Energy (UVA)
• Visible and IR radiation don’t harm the skin.
5. SKIN-DAMAGE II
• Very High Energy Radiation
(UVC) is currently blocked by
the ozone layer.
• High Energy Radiation (UVB)
does the more immediate
• But Lower Energy Radiation
(UVA) can penetrate deeper
into the skin, leading to long
Effects on Human Skin Visible to
UVC ~200-290 nm
DNA Damage No
UVB ~290-320 nm
UVA ~320-400 nm
Vis ~400-800 nm None
IR ~800-120,000 nm Heat Sensation
(high l IR)
Sun Radiation Summary
7. WHY USE SUN-SCREEN
• Too much unprotected sun exposure
Premature skin ageing
8. PRINCIPLE OF EFFECTIVENESS OF
I. A protective layer can be provided to the skin that
prevents the UV-rays to reach the skin either by
absorbing or by reflecting them.
– Zinc oxide and titanium dioxide both have such tendency.
– Preparations reflecting UV-rays are very effective and used
9. II. To incorporate substances in
preparations to filter the sun-rays
by absorbing medium range
UV-rays (280 mµ-320mµ)but
allowing rays of higher
wavelengths to pass.
All modern sun-tan preparations
are based on this principle and
contain such substances.
PRINCIPLE OF EFFECTIVENESS OF
10. UV filters (Three types)
• Organic chemical:
– compounds that absorb ultraviolet light
• Inorganic particulates:
– that reflect, scatter, and absorb UV light
– titanium dioxide, zinc oxide
• Organic particulates:
– that mostly absorb light like organic chemical compounds, but contain
– may reflect and scatter a fraction of light like inorganic particulates,
– Tinosorb M
11. III. Biologically effective substances
can be used effectively to prevent
symptoms of inflammation with-out
reduction of tanning.
– Sunlight liberates histamine in the
the tissues-anti histaminic substances
• HC’s and FC’s are useful in treating sun-burn
but not recommended in sun-tan preparation.
PRINCIPLE OF EFFECTIVENESS OF
12. IV. Substances that cause or accelerate tanning of the skin
can be applied.
– Dioxyacetone causes tanning by forming a brown complex with
the keratin of the corneal layer.
– 8-methoxypsoralene when taken 10-20 mg internally 2 hours
before exposure to the sun, accelerates tanning and avoids sun-
PRINCIPLE OF EFFECTIVENESS OF
13. IDEAL SUN-SCREEN CHARACTERS
Absorb light preferentially over the range of 280 - 320mµ.
Resistance to water
Be stable to heat, light and perspiration.
Preferably odorless, if mild odor: accepted by user.
Be non-toxic, non-irritant, non- sensitizing
Capable of retaining sunscreening property for several hours.
Stable under condition of use.
Not be rapidly absorbed.
Be rapidly soluble in suitable vehicles.
14. SUNSCREEN CLASSIFICATIONS
– Opaque formulations containing:
• titanium dioxide
• talc, kaolin
• zinc oxide
• ferric chloride
• icthyol, red petrolatum
– Mechanism: scatters or reflects UV radiation due
to large particle size
16. SUNSCREEN AGENTS
PABA (Para-amino benzoic acid)
– Very effective in the UVB range (200-320 nm).
– Most effective in conc. of 5% in 70% ethanol.
– Maximum benefit when applied 60 minutes prior to exposure (to
ensure penetration and binding to stratum corneum).
– Contact dermatitis can develop.
– May stain clothing.
17. SUNSCREEN AGENTS
PABA Esters (Padimate A, Padimate O, Glyceryl PABA)
– Also very effective in UVB range (280-320)
– Most effective in conc. 2.5-8% in 65% alcohol
– May penetrate less effectively than PABA
– Similar application and adverse effect
– Less staining
18. Benzophenones (oxybenzone, dioxybenzone, sulisobensone)
– Slightly less effective than PABA.
– Absorbs from 250-400 nm spectrum (i.e, UVA & UVB).
– Combined with PABA or PABA ester improves penetration
and is superior to either agent used alone (200-400 nm
– Beneficial in preventing photosensitivity reactions.
– Contact dermatitis is rare.
21. SPF & Important of SPF
• SPF Value = MED (PS) / MED (US)
– MED (PS) : minimum erythemal dose for protected skin
(product applied skin)
– MED (US) : minimum erythemal dose for unprotected skin
(product not applied)
22. Types of skin & SPF
Type Description SPF Character
I Always burns easily & never tans More than 8 Sensitive
II Always burns & tans minimally 6 – 7 Sensitive
III Burns moderately & tans gradually 4 – 5 Normal
IV Burns minimally & always tans well 2 – 3 Normal
V Barely burns & tans profusely 2 Insensitive
VI Never burns & becomes deeply
• Suitable base can be used to make a final product of an aqueous or
alcoholic lotion, a fatty cream, oil, or an emulsion.
• The vehicle and selection of other components of the product may
contribute to its effectiveness.
• Certain natural oils such as coconut oil, peanut oil, muster seed oil
and olive oil have a fairly high absorption ability of UV light.
• An Anti-oxidant is to be incorporated if a natural oil is used to prevent
24. GENERAL PROCEDURE FOR
• The product can be
– Simple oil type,
– Cream type,
– Lotion type,
– Aqueous solution type,
– Gel type, the general method will be different.
• Solution types, aqueous or oily, can be prepared by mixing and
dissolving the sun-screen and other ingredients in the vehicle, i.e.
water and oil. Perfume should be added all of last.
• Cream preparations are emulsion type and thus employ general
procedures of emulsion.
• Lotions can be solutions or emulsion type and can be prepared
• Some special tests are also necessary for these types
• Spectrophotometric evaluation.
• Erythemal damage
• Sun-screen index
• In-vivo skin testing
1. SPECTROPHOTOMETRIC EVALUATION:
This is basically to evaluate the UV radiation
absorption ability of the sun-screen compounds.
Using a UV Spectrophotometer and taking specific
concentration of the substance on the preparation,
molar extinction coefficient or absorbency can be
determined and compared with any other standard
27. 2.ERYTHEMAL DAMAGE:
It is important to estimate the erythemally effective
radiation or E-vitons/sq.cm., transmitted by a sun-tan
The erythemal energy is the product of the solar energy
transmitted through the film of sun-tan preparation and
the effectiveness factor at that wave-length
3. SUN-SCREEN INDEX:
This is evaluation of the relative screening activity of the
This is measurement of EXTINCTION CO-EFFICIENT (E
0.1cm) at 308mµ and comparison with other.
308 mµ is the peak wavelength for effective sun-burn.
4. IN-VIVO SKIN TESTING:
• This is a direct test on animal skin, particularly rabbit, the site
normally used is either back-side as this sites have maximum
• Preparations are applied on a specific site and exposed to radiation
along with a control unprotected site, for a specified period of time.
• The effects are observed at the end of the period.
• Several factors or variables are to be taken care of during the test as
they may influence the results.
• Such variables or factors are radiation source, size of the test field,
30. ADVANCES IN SUN-SCREENS
1. Nano-sun screen.
2. Sun sport.
3. Sun-screen sprays.
4. Roll-on sun screen.
5. Sun-screen for children.