Drometrizole trisiloxane



Drometrizole trisiloxane is an UV ray absorbing agent used in sunscreens to protect skin from UV radiation.

Generic Name
Drometrizole trisiloxane
DrugBank Accession Number

Drometrizole trisiloxane is a photostable UVA and UVB light filter 1,3,4,5,6,9. The compound is a lipophilic benzotriazole derivative marketed as Meroxyl XL by L'Oreal, although sunscreens with drometrizole trisiloxane are currently only approved for use in the EU, Canada, Australia, and Japan, among other countries.

Despite being used elsewhere in the world with relatively few reports of adverse reactions, the FDA continues to cite that the existing scientific record is not sufficient to establish the compound as being generally recognized as safe and effective for over-the-counter sunscreen use 8,10.

Small Molecule
Average: 501.849
Monoisotopic: 501.229921733
Chemical Formula
  • Silatrizole
External IDs
  • OR 10154
  • OR-10154



Drometrizole trisiloxane is used as an active ingredient in various sunscreens for the indication of protecting the skin by absorbing the damaging UV radiation of sunlight 1,3,4,5,6,9,10.

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Associated Conditions
Indication TypeIndicationCombined Product DetailsApproval LevelAge GroupPatient CharacteristicsDose Form
Used in combination for prophylaxis ofSunburn••• •••
Contraindications & Blackbox Warnings
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As an active ingredient in sunscreen products, drometrizole trisiloxane is applied directly onto human skin where it acts as a chemical sunscreen layer between skin and sunlight that also directly absorbs the UV sunlight radiation 1,3,4,5,6,9. Since drometrizole trisiloxane is also considered to have little to no absorption through the skin 1,3,4,5,6,9, little systemic exposure and pharmacokinetics are expected and users can freely wash off and re-apply the compound as necessary.

Mechanism of action

Ultraviolet radiation is the invisible energy component to sunlight and consists of three wavelength ranges:

(a) UVA is long-range UV radiation between 320-400nm 7. Although not as energetic as UVB, UVA can penetrate deep into the dermis 7. UVA can cause immediate tanning, premature skin aging, and can also play a role in the formation of some skin cancers 7. Approximately 95% of UVA from the sun passes through Earth's ozone layer 7.

(b) UVB is short-wavelength UV radiation between 280-320nm 7. It is capable of penetrating the outer protective layer of the skin and is responsible for delayed tanning, sunburns, and most skin cancers 7. A large amount of UVB is absorbed by the ozone layer, however, as only 5% reaches the Earth's surface 7.

(c) UVC is comprised of wavelengths between 100-280nm and is very energetic 7. It is very dangerous to all forms of life, even when the exposure is short 7. However, UVC radiation is generally filtered out by the ozone layer and never reaches the Earth 7.

Ultimately, the shorter the wavelength, the more harmful the UV radiation - although shorter wavelength UV radiation is less able to penetrate the skin 7.

Subsequently, drometrizole trisiloxane is a broad spectrum lipophilic benzotriazole derivative chemical sunscreen that is capable of absorbing UVA and UVB radiation 1,3,4,5,6. It is also photostable, meaning that it will not degrade in the presence of sunlight, unlike other UV filters like the widely used UVA absorber avobenzone 6. When combined with the UV blocker ecamsule, it has been shown that the two UV blockers elicit a synergistic effect involving an enhanced protective action for the skin against UVA and UVB radiation 1,3,4,5,6. Additionally, drometrizole trisiloxane is usually combined with other active sunscreen agents like titanium dioxide, avobenzone, and others to ensure the combined product covers or protects against as broad a spectrum of UV radiation as possible, considering drometrizole trisiloxane does not absorb against the entire range of UV radiation 6.

And finally, at the molecular level, it is believed that the general structure of various UV blockers like drometrizole trisiloxane as aromatic molecules conjugated with carbonyl groups is capable of absorbing high energy ultraviolet rays and then consequently releasing that energy as less harmful, lower energy rays.


Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. At this time, however, studies demonstrate that the components of most commonly used sunscreens are likely absorbed into the skin at least to some extent - although penetration to deeper tissues and the cutaneous circulation remains limited 2. Despite the extensive use of sunscreen products around the world, there have been few reports of adverse effects related to their use 2.

Volume of distribution

Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. The systemic presence of the compound is consequently expected to be minimal.

Protein binding

Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. The systemic presence of the compound is consequently expected to be minimal.


Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. The systemic presence of the compound is consequently expected to be minimal.

Route of elimination

Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. The systemic presence of the compound is consequently expected to be minimal.


Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. The systemic presence of the compound is consequently expected to be minimal.


Drometrizole trisiloxane is reported as having little to no absorption through the skin 3,6. The systemic presence of the compound is consequently expected to be minimal.

Adverse Effects
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Drometrizole trisiloxane is reported as having little to no absorption through the skin, which leads most national health agencies that approve its use in sunscreens (including the EU, Canada, Australia, Japan, and other countries) to consider it safe, given that most of their toxicity studies return little risk of adverse reactions as well 1,3,4,5,6,9.

Not Available
Pharmacogenomic Effects/ADRs
Not Available


Drug Interactions
This information should not be interpreted without the help of a healthcare provider. If you believe you are experiencing an interaction, contact a healthcare provider immediately. The absence of an interaction does not necessarily mean no interactions exist.
Not Available
Food Interactions
No interactions found.


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International/Other Brands
Mexoryl XL
Mixture Products
NameIngredientsDosageRouteLabellerMarketing StartMarketing EndRegionImage
45 SPF High Protection Uva Uvb CreamDrometrizole trisiloxane (3.0 %) + Avobenzone (3.5 %) + Ecamsule (2.0 %) + Octocrylene (10 %) + Titanium dioxide (3.3 %)CreamTopicalLaboratoires La Roche Posay Canada2008-04-162016-08-31Canada flag
60 SPF Stick Protection Ciblee Uva Uvb Anthelios XLDrometrizole trisiloxane (2.00 %) + Avobenzone (3.00 %) + Octocrylene (10.00 %) + Titanium dioxide (6.25 %)StickTopicalLaboratoires La Roche Posay Canada2007-04-12Not applicableCanada flag
Anthelios 50+Drometrizole trisiloxane (4 % w/w) + Avobenzone (5 % w/w) + Bemotrizinol (6 % w/w) + Ecamsule (0.5 % w/w) + Homosalate (10 % w/w) + Octisalate (5 % w/w) + Titanium dioxide (2.5 % w/w)LotionTopicalLaboratoires La Roche Posay CanadaNot applicableNot applicableCanada flag
Anthelios Age CorrectDrometrizole trisiloxane (1.3 % w/w) + Avobenzone (2.3 % w/w) + Bemotrizinol (3.8 % w/w) + Ecamsule (1 % w/w) + Ensulizole (3.5 % w/w) + Octisalate (5 % w/w)CreamTopicalLaboratoires La Roche Posay Canada2023-05-01Not applicableCanada flag
Anthelios Dermo-kidsDrometrizole trisiloxane (4.5 % w/w) + Avobenzone (3 % w/w) + Ecamsule (1.5 % w/w) + Octisalate (5 % w/w) + Octocrylene (2.5 % w/w) + Titanium dioxide (5.85 % w/w)LotionTopicalLaboratoires La Roche Posay Canada2015-05-04Not applicableCanada flag


Drug Categories
Chemical TaxonomyProvided by Classyfire
This compound belongs to the class of organic compounds known as phenyl-1,2,3-triazoles. These are organic compounds containing a 1,2,3-triazole substituted by a phenyl group.
Organic compounds
Super Class
Organoheterocyclic compounds
Sub Class
Direct Parent
Alternative Parents
Siloxanes / Phenylpropanes / Benzotriazoles / Para cresols / Toluenes / Trialkylheterosilanes / Heteroaromatic compounds / Organic metalloid salts / Azacyclic compounds / Organopnictogen compounds
show 3 more
Aromatic heteropolycyclic compound / Azacycle / Benzenoid / Benzotriazole / Heteroaromatic compound / Hydrocarbon derivative / Monocyclic benzene moiety / Organic metalloid salt / Organic nitrogen compound / Organic oxygen compound
show 13 more
Molecular Framework
Aromatic heteropolycyclic compounds
External Descriptors
Not Available
Affected organisms
  • Humans and other mammals

Chemical Identifiers

CAS number
InChI Key


General References
  1. Gonzalez S, Fernandez-Lorente M, Gilaberte-Calzada Y: The latest on skin photoprotection. Clin Dermatol. 2008 Nov-Dec;26(6):614-26. doi: 10.1016/j.clindermatol.2007.09.010. [Article]
  2. Benson HA: Assessment and clinical implications of absorption of sunscreens across skin. Am J Clin Dermatol. 2000 Jul-Aug;1(4):217-24. [Article]
  3. Dermascope: The State of Sunscreen Innovation in 2015 [Link]
  4. Skin Therapy Letter: Update on Sunscreens [Link]
  5. Current Trends in Photoprotection - A New Generation of Oral Photoprotectors [Link]
  6. PhaMix: Mexoryl SX/XL Sunscreens [Link]
  7. Government of Canada: What is ultraviolet radiation? [Link]
  8. Chemical & Engineering News: After More Than A Decade, FDA Still Won't Allow New Sunscreens [Link]
  9. Health Canada: Sunscreen Monograph [File]
  10. FDA Drometrizole Trisiloxane Safety Assessment Denial Letter [File]
Download (186 KB)

Clinical Trials

Clinical Trials
2CompletedTreatmentEpidermal p53 Expression / Solar Elastosis1
Not AvailableCompletedDiagnosticDermatitis, Photocontact1


Not Available
Not Available
Dosage Forms
Not Available
Not Available


Experimental Properties
Not Available
Predicted Properties
Water Solubility0.000703 mg/mLALOGPS
pKa (Strongest Acidic)9.96Chemaxon
pKa (Strongest Basic)-0.38Chemaxon
Physiological Charge0Chemaxon
Hydrogen Acceptor Count5Chemaxon
Hydrogen Donor Count1Chemaxon
Polar Surface Area69.4 Å2Chemaxon
Rotatable Bond Count9Chemaxon
Refractivity137.97 m3·mol-1Chemaxon
Polarizability54.24 Å3Chemaxon
Number of Rings3Chemaxon
Rule of FiveNoChemaxon
Ghose FilterNoChemaxon
Veber's RuleNoChemaxon
MDDR-like RuleYesChemaxon
Predicted ADMET Features
Not Available


Mass Spec (NIST)
Not Available
SpectrumSpectrum TypeSplash Key
Predicted GC-MS Spectrum - GC-MSPredicted GC-MSsplash10-00di-0090300000-cec55dc9fd0a2cc6ba29
Predicted MS/MS Spectrum - 10V, Positive (Annotated)Predicted LC-MS/MSsplash10-03di-0002900000-600be9da726a03d11270
Predicted MS/MS Spectrum - 10V, Negative (Annotated)Predicted LC-MS/MSsplash10-0a4i-9002010000-1f645c350cb20c3b9439
Predicted MS/MS Spectrum - 20V, Positive (Annotated)Predicted LC-MS/MSsplash10-0c03-2109000000-b3f456e9c69cfdb3d082
Predicted MS/MS Spectrum - 20V, Negative (Annotated)Predicted LC-MS/MSsplash10-0a4i-9001000000-0c77a69f8711105777bf
Predicted MS/MS Spectrum - 40V, Positive (Annotated)Predicted LC-MS/MSsplash10-0ab9-9400000000-03c10112dc36fc11eb91
Predicted MS/MS Spectrum - 40V, Negative (Annotated)Predicted LC-MS/MSsplash10-001j-3901300000-e400f2c38e0612bd2a30
Chromatographic Properties
Collision Cross Sections (CCS)
Not Available

Drug created at April 27, 2016 22:34 / Updated at June 12, 2020 16:53