You are here

Scheduling delegate's final decisions, June 2017

Scheduling medicines and poisons

29 June 2017

Book pagination

2.3. Sodium α-olefin sulfonates

Part A - Final decisions on matters referred to an expert advisory committee

Joint meeting of the Advisory Committee on Chemicals and Medicines Scheduling (ACCS/ACMS #15)

2.3. Sodium α-olefin sulfonates

Referred scheduling proposal

An application was submitted for consideration by the delegate to seek advice from the Joint Advisory Committees on Chemicals and Medicines Scheduling (ACCS-ACMS) on an application submitted by the National Industrial Chemicals Notification and Assessment Scheme (NICNAS) under their IMAP program to create a Schedule 6 entry for sodium α-olefin sulfonate and sodium alkyl sulfate.

Current scheduling status and relevant scheduling history

Sodium α-olefin sulfonate and sodium alkyl sulfate are not specifically scheduled and have not been previously considered for scheduling.

However, lauryl sulfate salts are similar surfactants listed in Schedule 6 and Appendix E, Part 2, as follows:

Schedule 6

LAURYL SULFATE SALTS (excluding their derivatives) except:

  1. in wash-off preparations containing 30 per cent or less of lauryl sulfates and, if containing more than 5 per cent of lauryl sulfates, when labelled with a warning to the following effect:

  2. IF IN EYES WASH OUT IMMEDIATELY WITH WATER;

  3. in leave-on preparations containing 1.5 per cent or less of lauryl sulfates;
  4. in toothpaste and oral hygiene preparations containing 5 per cent or less of lauryl sulfates;
  5. in other preparations for animal use containing 2 per cent or less of lauryl sulfates; or
  6. in other preparations containing 30 per cent or less of lauryl sulfates and, if containing more than 5 per cent of lauryl sulfates, when labelled with warnings to the following effect:

  7. IF IN EYES WASH OUT IMMEDIATELY WITH WATER; and
    IF SKIN OR HAIR CONTACT OCCURS, REMOVE CONTAMINATED CLOTHING AND FLUSH SKIN AND HAIR WITH RUNNING WATER.
Appendix E, Part 2:
LAURYL SULFATE SALTS
  • leave-on or wash-off preparations above 5 per cent.
E1 [If in eyes wash out immediately with water].
  • other preparations above 5 per cent.
E1 (as above) and S1 [If skin or hair contact occurs, remove contaminated clothing and flush skin and hair with running water].
Scheduling application

This was a general application.

In July 2016, NICNAS, under its Inventory Multi-tiered Assessment and Prioritisation (IMAP) program, submitted a proposal to create new entries for sodium α-olefin sulfonate (sodium AOS) and sodium alkyl sulfate (sodium AS) in Schedule 6, paralleling that for lauryl sulfates, in order to restrict their use in cosmetic and domestic products. Exemption to scheduling might be applicable at low concentrations.

The applicant's reasons for the request are:

  • Sodium α-olefin sulfonate and sodium alkyl sulfate have reported uses in a range of cosmetic and domestic products in Australia;
  • Reported use of sodium α-olefin sulfonate and sodium alkyl sulfate in cosmetic and domestic products overseas, potentially available for use in Australia, at concentrations up to 16.5%;
  • Sodium α-olefin sulfonate and sodium alkyl sulfate are potential moderate to strong skin irritants at 10% concentration;
  • Sodium α-olefin sulfonate and sodium alkyl sulfate are severe eye irritants at concentrations ≥30%; and
  • Sodium α-olefin sulfonate and sodium alkyl sulfate present similar issues as other surfactants already scheduled in the SUSMP, including sodium lauryl sulfate (SLS).
  • There is potential for dermal and ocular exposure to occur at irritating concentrations based on its use pattern. This can be mitigated by labelling and concentration controls. Sodium α-olefin sulfonate and sodium alkyl sulfate are among a large number of surfactants used in Australia that are toxicologically similar to SLS, and these have been identified to be used in comparatively high concentrations.
Australian regulatory information

Sodium α-olefin sulfonate (as SODIUM C14-16 OLEFIN SULFONATE) is in the Therapeutic Goods (Permissible Ingredients) Determination No. 1 of 2017 as an excipient only for use in topical medicines for dermal application.

Sodium C14-16 olefin sulfonate is in 3 registered products on the ARTG. It is allowed to be used as an excipient in biologicals, devices, export-only, listed medicines, OTC and prescription medicines; and as an active ingredient in biologicals and prescription medicines. Sodium α-olefin sulfonate is a declarable excipient (i.e. it is required to be declared on the label of a medicine) in accordance with Therapeutic Goods Orders 69, 91 and 92. When used in biologicals, sodium α-olefin sulfonate can be displayed as a starting material.

Sodium alkyl sulfate is not on the ARTG or on the Therapeutic Goods (Permissible Ingredients) Determination No. 1 of 2017.

International regulations
New Zealand

Sodium α-olefin sulfonate is included in one cosmetic product in New Zealand as an excipient.

Canada

Sodium α-olefin sulfonate (as sodium C14-16 olefin sulfonate) is listed as a surfactant – cleansing agent for topical use. Further, sodium α-olefin sulfonates (of chain lengths C12-14, C14-16, C14-18 and C16-18) are considered to be safe when used in rinse-off products and safe up to 2% in leave-on products. The concentration of the gamma sultone impurity of any formulation (leave-on or rinse-off) is limited to unsubstituted alkane sultones 10 ppm; chlorosultones 1 ppm; and unsaturated sultones 0.1 ppm. Sodium alkyl sulfate (as sodium C12-15 alkyl sulfate) is listed as a non-medical ingredient.

Substance summary
Table 2.3A: General information
Property Sulfonic acids, C14-16-alkane hydroxyl and C14-16-alkene, sodium salts Sulfuric acid, mono-C12-18-alkyl esters, sodium salts
CAS name sodium C14-16-olefin sulfonate sulfuric acid, mono-C12-18-alkyl (even numbered) esters, sodium salts
CAS number 68439-57-6 68955-19-1
IUPAC and/or common and/or other names sodium α-olefin sulfonate; sodium AOS (INCI) sodium alkyl sulfate; sodium AS (INCI)

The following information has been extracted from the NICNAS IMAP Human Health Tier II group assessment report for sodium α-olefin sulfonate and sodium alkyl sulfate.

Table 2.3B: Acute toxicity end-points for sodium α-olefin sulfonate and sodium alkyl sulfate
Toxicity Species Sodium α-olefin sulfonate and sodium alkyl sulfate SPF (2015) Classification
Acute oral toxicity LD50 (mg/kg bw) Rat
Mice
>2000
1400->2000
Schedule 5
Acute dermal toxicity LD50 (mg/kg bw) Rabbit >2000 Schedule 5
Acute inhalational toxicity LC50 (mg/m3/4h) Rat Low -
Skin irritation Rabbit Moderate to severe skin irritants Schedule 6
Eye irritation Rabbit Severe eye irritants Schedule 6
Skin Irritation

Sodium α-olefin sulfonate and sodium alkyl sulfate are considered skin irritants:

  • In a skin irritation study conducted on six New Zealand White (NZW) rabbits, 0.5 mL of sodium AOS solution (38% active) was applied dermally to shaved, intact and abraded skin for 24 hours under occlusion. The treated site was not washed after the test substance was removed. Very slight irritation was observed on intact skin in 5/6 animals. One of the six animals had well-defined erythema, which had completely reversed by 72 hours after dosing. Five of the six animals showed well-defined erythema on the abraded skin at 24 hours after dosing. Very slight erythema in all animals and oedema in 2/6 animals were reported, which persisted after 72 hours post dosing on abraded skin (REACH).
  • In another skin irritation study conducted in six NZW rabbits, 0.5 mL of sodium AOS solution (38% active) was applied dermally to shaved, intact and abraded skin for four hours under semi-occlusion. The applied site was washed to remove the test substance. All six animals showed moderate to severe reactions with eschar formation, one with cracking at the treatment site at 72 hours after dosing. The reactions were slightly worse in abraded skin than intact skin (REACH).
  • In an irritation study conducted according to OECD Test Guideline (TG) 404, 0.5 g of sodium AS powder (88.7% purity) was applied dermally (semi-occlusive) to three New Zealand White rabbits for four hours. Erythema and moderate oedema were observed up to seven days after the patches were removed. All signs of irritation were completely resolved 14 days after dosing (REACH).
  • Skin irritation (erythema and oedema) was also reported following a four-hour application of 5–25% sodium lauryl sulfate (SLS) solution on intact rabbit skin (NICNAS).
Eye irritation

Based on the data available, sodium α-olefin sulfonate and sodium alkyl sulfate are considered severe eye irritants:

  • In an eye irritation study conducted according to OECD TG 405, 0.1 mL of sodium AOS (30% active) was applied to eyes of three NZW rabbits and observed for 21 days. Observed effects included slight corneal redness, slight iritis and conjunctival effects (erythema, swelling and chemosis). Except for chemosis, all eye irritation effects persisted for up to 21 days (REACH).
  • In another eye irritation study conducted in six NZW rabbits, 0.1 mL of sodium AOS (38% active) was applied to the eyes with or without washing. Observation times were 24, 48 and 72 hours after administration. Eye irritation effects, which persisted for up to 72 hours, were reported (REACH; HERA 2002).
  • The eyes of three NZW rabbits were treated with concentrated (0.08 mL of 90% solution) sodium AOS. The test material was washed off and effects were observed at 24, 48 and 72 hours after application. Observed effects included clear to diffused beefy red erythema and severe swelling of the conjunctivae. Circumcorneal injection (enlargement of the ciliary and conjunctival blood vessels), corneal opacity and discharge (colourless, which changed to white viscous discharge) were also reported. The effects persisted for up to 21 days after dosing (REACH).
  • Sodium AS administered at 6% resulted in eye irritation in rabbits, which was reversible within 72 hours of dosing (REACH).

The SLS chemical at 25% in an aqueous solution also caused eye irritation in rabbit eyes, which were not reversible within the 21-day observation period (NICNAS).

Observation in humans

Sodium α-olefin sulfonate and sodium alkyl sulfate are reported to have irritation potential in humans. Data on SLS are provided as read across since SLS has similar physicochemical properties and reactivity to sodium AOS and sodium AS.

  • In a dermal irritation study, human cadaver skin was soaked in sodium olefin sulfonates (C10, 12, 14, 16 and 18) for one, three, six and 24 hour and was compared with skin soaked in distilled water for the same period. Maximum swelling was seen for the C12 and C14 olefin sulfonates (REACH).
  • In a controlled human exposure, repeated application of 1% alkyl sulfates to the skin of human volunteers did not produce adverse reactions, while concentrations of 10% were regarded as moderate to strong irritants (HERA, 2002).
  • Clinical studies in humans reported that SLS caused skin irritation following patch testing at a ≥2% concentration. The irritation increases with increasing concentration and length of contact with the skin (NICNAS).
  • SLS has been reported to cause irritation in the respiratory tract and oral mucosa, especially in individuals predisposed to recurrent mouth ulcers (NICNAS).
  • It has also been reported that SLS was the most common cause of eye irritation in commercial shampoos (NICNAS).
Sensitisation

Sodium α-olefin sulfonate and sodium alkyl sulfate are not expected to be skin sensitisers, based on the available information.

Repeat-dose toxicity

Based on the data available, sodium α-olefin sulfonate and sodium alkyl sulfate are not expected to cause serious damage to health from repeated oral and dermal exposure. No information was available for repeated dose toxicity by the inhalation route.

Genotoxicity

Based on the negative results observed in several in vitro and in vivo genotoxicity studies, sodium α-olefin sulfonate and sodium alkyl sulfate are not expected to be genotoxic.

Carcinogenicity

Based on available data, sodium α-olefin sulfonate and sodium alkyl sulfate are not considered to be carcinogenic.

Reproduction and developmental toxicity

Based on the limited available data, Sodium α-olefin sulfonate and sodium alkyl sulfate are not expected to have reproductive and developmental toxicity.

Public exposure

Sodium α-olefin sulfonate and sodium alkyl sulfate are reported to be used in cosmetic and domestic products in Australia.

Australian and overseas information suggests that sodium α-olefin sulfonate and sodium alkyl sulfate are generally used at concentrations up to 16% in cosmetics and at up to 16.5% for domestic purposes (i.e. hand dishwashing liquid) (HERA 2002).

Considering the critical health effects identified for sodium α-olefin sulfonate and sodium alkyl sulfate, the highest concern relates to skin and eye irritation. There is the potential for skin contact to occur when using domestic products such as laundry detergents or hand washing liquid.

However, such products are intended to be rinsed off from the skin after use. There is also the potential for ocular exposure in a domestic setting.

Pre-meeting public submissions

Three (3) public submissions were received. All three submissions opposed the scheduling proposal. The main points were:

  • A generic group entry of C12-C18 alkyl length surfactants cannot be supported due to differing characteristics of varying lengths of alkyl chains and would hinder attempts by industry to formulate less irritating surfactants.
  • Due to surfactants being used for cleaning the body or domestic surfaces for decades, consumers are already knowledgeable in the appropriate use of surfactants and have a certain use pattern of these products due to this continued use over time.
  • Scheduling of all surfactants individually is opposed by most submissions, due to this not aligning with international requirements. These substances are not restricted in cosmetics in the EU and the USA permits their use in rinse-off products at ≤2%.
  • Scheduling will not generate a better risk management outcome.
  • These surfactants do not require scheduling when used in cosmetic products.
  • If scheduling is deemed appropriate, submissions suggested lauryl sulfates scheduling should act as a guide for concentration cut-offs and that a minimum of a 12 month lead-in time be implemented.

The public submissions are available on the TGA website.

Summary of ACCS-ACMS advice to the delegate

The committee advised that based on the information contained in the application no scheduling entry could be developed for sodium α-olefin sulfonate and sodium alkyl sulfate at this time.

Members agreed that the relevant matters under Section 52E(1) of the Therapeutic Goods Act 1989included: (a) risks and benefits of the use of a substance; (b) the purpose for which a substance is to be used and the extent of use; (c) the toxicity of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.

The reasons for the advice comprised the following:

  • As surfactants, these substances are widely used domestically, including leave-on and wash-off products and cleaning products.
  • There are major public health benefits for infection control within the domestic premises when alkyl sulphonate/sulphate surfactants are available without restriction. Despite their widespread use, there have been minimal adverse events associated with the use of these surfactant substances. However, the data may be inadequate to quantify the public health risks associated with this class of surfactants and that only one chain length tends to be hazardous.
  • The chemicals captured by this proposal are very closely related to sodium lauryl sulphate, which has previously been scheduled.
  • The toxicity profiles of these substances include potential eye damage at higher concentrations, possible cumulative dermal irritation in leave on applications, and eye irritancy at 30%. The short chain is more potent with strong irritation at lower concentrations compared with long chain. Skin irritation for leave-on products at is >2-5% with potency being chain-length dependent. SAS C16-18 appears to show only slight reactions at 31.5%, while C12 showed strong reactions at 25%, but slight at 5%.
  • Also considered was the feasibility of industry to implement any scheduling decision without substituting to an unregulated or more toxic substance/s. There may be public health ramifications of substituted surfactants in relation to their purpose, such as cleaning.
Delegate's considerations

The delegate considered the following in regards to this proposal:

  • Scheduling proposal
  • ACCS-ACMS advice
  • Public Submissions received
  • Section 52E of the Therapeutic Goods Act 1989
  • Scheduling Policy Framework (SPF 2015)
  • Other relevant information
Delegate's interim decision

The delegate's interim decision was that no schedule entry should be created for sodium α-olefin sulfonate and sodium alkyl sulfate.

The delegate considered the relevant matters under section 52E (1) of the Therapeutic Goods Act 1989: (a) the risks and benefits of the use of a substance; (b) the purposes for which a substance is to be used and the extent of use of a substance; (c) the toxicity of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.

The reasons for the interim decision comprised the following:

  • The delegate acknowledges the committee's advice.
  • As surfactants, these substances are widely used domestically, including leave-on and wash-off products and cleaning products.
  • There are major public health benefits for infection control within the domestic premises when alkyl sulphonate/sulphate surfactants are available without restriction. Despite their widespread use, there have been minimal adverse events associated with the use of these surfactant substances. However the data may be inadequate to quantify the public health risks associated with this class of surfactants and that only one chain length tends to be hazardous.
  • The chemicals captured by this proposal are very closely related to sodium lauryl sulphate, which has previously been scheduled.
  • The toxicity profiles of these substances include potential eye damage at higher concentrations, possible cumulative dermal irritation in leave on applications, and eye irritancy at 30%. The short chain is more potent with strong irritation at lower concentrations compared with long chain. Skin irritation for leave-on products at is >2-5% with potency being chain-length dependent. SAS C16-18 appears to show only slight reactions at 31.5%, while C12 showed strong reactions at 25%, but slight at 5%.
  • Also considered was the feasibility of industry to implement any scheduling decision without substituting to an unregulated or more toxic substance/s. There may be public health ramifications of substituted surfactants in relation to their purpose, such as cleaning.
Public submissions on the interim decision

One (1) submission was received which supported the interim decision. The main point in support was that the scheduling of individual surfactants is unnecessary due to their well-established history of safe use.

Delegate's final decision

The delegate notes the submission, and as no new evidence has been received to alter the interim decision; the delegate has confirmed that the final decision and reasons for the final decision are in keeping with those for the interim decision.

The delegate's final decision is that no scheduling entry be created for sodium α-olefin sulfonate and sodium alkyl sulfate.

Book pagination