Recognized Your Sunscreen And Sunblock’s Ingredient Before Buy!

There are two basic types of skin cream or lotion protection :

1. absorb and deflect (or reflect) the sun's rays via a chemical reaction.
2. blocks : zinc oxide and titanium dioxide (which create a physical barrier against rays).

PABA

• Though rarely used now in sunscreens, beware of products that contain the ingredient.
  40 % of the population is sensitive to it, experiencing red, itchy skin.

Benzophenone (benzophenone-3), homosalate, and octy-methoxycinnamate (octinoxate)

• They have shown estrogenic activity; shown to disrupt hormones, affecting the development of the brain (particularly the hypothalamo-pituitary-gonadal system) and reproductive organs in laboratory rats.
• Because people are exposed simply by eating fish (where benzophenone accumulates in the fat), using sunscreen containing these chemicals unduly increases the exposure.

Parabens (butyl-, ethyl-, methyl-, and propyl-)

• Parabens may also mimic estrogen, but because they are common in sunscreens, avoiding them may prove difficult.

Padimate-O and Parsol 1789 (2-ethylhexyl-4-dimethylaminobenzoic acid and avobenzone)

• These chemicals have the potential to damage DNA when illuminated with sunlight.
• On the skin's surface, these chemicals do protect from UV damage; however, once absorbed into the skin, these same chemicals can prove destructive.
• Padimate-O and Parsol 1789 are excited by the UV energy which they absorb and become reactive, acquiring the potential to attack cellular components, including DNA.
• DNA damage inflicted by an excited sunscreen is much less capable of being repaired by naturally occurring repair mechanisms than the DNA damage inflicted by UV alone.

Although insect repellents with sunscreen may seem like an easy option, Doctors recommend avoiding them because of the dangers of overexposure to DEET, which can cause eye and skin irritations, headaches, nausea, when the product is reapplied after swimming or exercise.

Most titanium dioxide used in sunscreens is coated with materials that reduce its photoactivity. According to current evidence titanium dioxide is much less likely than other chemical sunscreens to penetrate human skin. Read More..

Sunscreen Ingredients

In the US, recently approved sunscreen chemicals lists 16 UV filters :

• 14 of which are organic UV filters (absorb UV rays)
• 2 inorganic particulates (absorb and reflect UV rays)

Sunscreen	Maximum Allowable Dose (%)	Spectral max	Extinction Coefficient
Organic Filters
UV B
Cinoxate	3	305	11,000
Ensulizole	4	310	26,000
Homosalate	15	306	4300
Octocrylene	10	303	12,600
Ocinoxate	7.5	310	23,300
Octisalate	5	307	4900
Padimate-O	8	307	27,300
PABA (paraaminobenzoic acid)	15	290	14,000
Trolamine salicylate	12	298	3000
UV B/partial UV A
Dioxybenzone	3	327	10,440
Meradimate	5	336	5600
Oxybenzone	6	325	9400
Sulisobenzone	10	324	8400
UV A I
Avobenzone	3	357	30,500
UV A II
None
Inorganic Particulates
Zinc Oxide	25	Broad Spectrum
Tianium Dioxide	25	Broad Spectrum

Source : From Shaat, N., Ed., The Chemistry of Sunscreens in Sunscreen,3^rd ed., Taylor & Francis, NewYork, 2005.

Outside the US, there are many other available sunscreens that are more powerful. Some of these are Tinasorb and mexoryl that absorb strongly in the UV A II region. Tinasorb has been submitted as a Time and Extent Application and is currently going through the regulatory process in the US for approval in a few years.

Type	INCI Name	Trade Name	Spectral Max	Approval Status
UV B
	EHT	Univul T 150	314	Europe, TEA application US
	DBT	Uvasorb HEB	312	Europe
	BMP	Parsol SLX	312	Europe
UV A II
	TDSA	Mexoryl SX	345	Europe, NDA application
	DPDI	Neo Heliopan AP	334	Europe
	DHHB	Univul A Plus	354	Europe
UV A and UV B
	DTS	Mexoryl XL	303 and 341	Europe, Japan, TEA application US
	MBBT	Tinosorb M	305 and 360	Europe, Australia , TEA application US
	BEMT	Tinosorb S	310 and 343	Europe, TEA application US

Source: Tuchinda, C. et al., Dermatol. Clin., 2006

Some of the filters approved outside the US and the maximum wavelength at which they absorb UV light. Most of these filters posses a very high extinction coefficient and are very broad and, in fact, absorb at two different wavelengths. Sunscreens effective in prevention of polymorphic light eruption in photosensitive patients and in those patients with lupus erythematosis. Read More..

Skin Care

Vehicle for sunscreen is as important as the effectiveness of the sunscreen system chosen. One of the water soluble and easily washed off the skin is sunscreen spray milks.

Blend cyclomethicone, stearyl methicone, menthol, and ethylhexylethoxycinnamate as the sunscreen, produce O/W microemulsions. Various surfactants/lipids/sunscreen were characterized by microscopy and laser light scattering.

This following formula is one of the stable O/W microemulsions that were waterproof and had a great humectants.

Ingredients	% Weight
Surfactant/lipid	70:30
1:2 Hexanediol	30
Water	62.2
Decylpolyglucose	2.5
Soya lecithin	2.3
Cyclomethicone	0.55
Ethanol	0.25
C12-15 alkyl benzoate	1
Ethylhexyl methoxycinnamate	1.2

There is no risk of the oil-soluble sunscreens not being adsorbed into the skin, since microemulsions are one-phase systems.

There are two factors that determine whether an emulsion will be O/W or W/O :

1. Phase volume
2. Surfactant used

Sun care products means positioning the sun filter to absorb or scatter UV rays. Conventional O/W vehicles fall short in that the sunscreens are found in the internal phase, as stated previously. At the other side, W/O vehicles are more effective. Its sunscreens are more effective coz the sunscreen was in the external phase. Usually, this sunscreen are more water resistant. The problems is, higher concentration of the lipophilics, means higher cost of the formula.

This problem can be slove. To reduce the cost, incorporating a polymeric surfactant such as PEG 30 dipolyhydrxystearate. The cost advantage of using this surfactant is that it allows formulating W/O close to the cost of O/W formulations. The incorporation of inorganic sunscreen into the formula is also enhanced due to the dispersing property of the surfactant. Read More..