Microbiological Challenges with Cosmetic Products

Ben Elmadi

Head of Stability and Preservative efficacy testing

Microbiological Solutions Limited

Ben.Elmadi@MSL.io

Challenges

• Maintaining Quality

• Complying with regulations

• Knowing when to test

• Knowing what test to use

• Correctly Preserving

Risks

UK

US

Maintaining Quality

Maintaining Quality - GMP

Maintaining Quality – Factory Isolate

Preservative Efficacy

Cosmetic Regulation and Preservative Efficacy Testing

• Testing not performed on all products

• No specified test

• Plenty to choose from – ISO 11930, USP 51, E.P 5.1.3.

• Creating the argument

Risk Assessing • BS EN ISO 29621:2017

• Definition of a low risk product

• Low risk characteristics

• BACKED BY LITERATURE!

Risk Assessment Workshop Product 1 1. Oil based 2. Lip Balm 3. No Preservative

Product 2 1. 2 in 1 Shower Gel and Conditioner 2. Aqueous

Product 3 1. Nail Polish 2. Alcohol Based

Product 4 1. Pressed powder compat

Product Characteristic Workflow

Reference

Summary of approach

All Powder A1* Risk assessed – no Challenge test req’d

Low water activity ≤0.75 (Confirmed) N/A Risk assessed – no Challenge test req’d

Suspect low water activity ≤0.75** A2 Reduced Challenge

Wipes A3 Full Challenge test req’d

Extreme pH (≤3/≥10) N/A Risk assessed – no Challenge test req’d

≥20% Alcohol content N/A Risk assessed – no Challenge test req’d

Organic Solvent Based (Ethyl acetate, Butyl acetate) N/A Risk assessed – no Challenge test req’d

Alkaline compounds (Ammonia, Monoethanolamine) N/A Risk assessed – no Challenge test req’d

Hydrogen peroxide N/A Risk assessed – no Challenge test req’d

≥20% Aluminium chlorohydrate and related salts N/A Risk assessed – no Challenge test req’d

≤0.75 Water activity AND was filled at ≥65oC N/A Risk assessed – no Challenge test req’d

Pressurised, single dose (e.g. sachet/canister) N/A Risk assessed – no Challenge test req’d

Flow Chart A1- Robust Powder test

7 day reduced test/Surface mould

test shows formulation to be low

risk.

PRODUCT NOT SUITABLE FOR

MARKET.

Historic data shows formulation to

be low risk.

PRODUCT SUITABLE FOR

MARKET.

NO

NO

Yes

Yes

Product Characteristic Workflow

Reference

Summary of approach

All Powder A1* Risk assessed – no Challenge test req’d

Low water activity ≤0.75 (Confirmed) N/A Risk assessed – no Challenge test req’d

Suspect low water activity ≤0.75** A2 Reduced Challenge

Wipes A3 Full Challenge test req’d

Extreme pH (≤3/≥10) N/A Risk assessed – no Challenge test req’d

≥20% Alcohol content N/A Risk assessed – no Challenge test req’d

Organic Solvent Based (Ethyl acetate, Butyl acetate) N/A Risk assessed – no Challenge test req’d

Alkaline compounds (Ammonia, Monoethanolamine) N/A Risk assessed – no Challenge test req’d

Hydrogen peroxide N/A Risk assessed – no Challenge test req’d

≥20% Aluminium chlorohydrate and related salts N/A Risk assessed – no Challenge test req’d

≤0.75 Water activity AND was filled at ≥65oC N/A Risk assessed – no Challenge test req’d

Pressurised, single dose (e.g. sachet/canister) N/A Risk assessed – no Challenge test req’d

Flowchart A2 – Suspect low Water activity

7 day reduced test shows

formulation to be low risk.

PRODUCT NOT SUITABLE FOR

MARKET.

PRODUCT SUITABLE FOR

MARKET.

NO Yes

Product Characteristic Workflow

Reference

Summary of approach

All Powder A1* Risk assessed – no Challenge test req’d

Low water activity ≤0.75 (Confirmed) N/A Risk assessed – no Challenge test req’d

Suspect low water activity ≤0.75** A2 Reduced Challenge

Wipes A3 Full Challenge test req’d

Extreme pH (≤3/≥10) N/A Risk assessed – no Challenge test req’d

≥20% Alcohol content N/A Risk assessed – no Challenge test req’d

Organic Solvent Based (Ethyl acetate, Butyl acetate) N/A Risk assessed – no Challenge test req’d

Alkaline compounds (Ammonia, Monoethanolamine) N/A Risk assessed – no Challenge test req’d

Hydrogen peroxide N/A Risk assessed – no Challenge test req’d

≥20% Aluminium chlorohydrate and related salts N/A Risk assessed – no Challenge test req’d

≤0.75 Water activity AND was filled at ≥65oC N/A Risk assessed – no Challenge test req’d

Pressurised, single dose (e.g. sachet/canister) N/A Risk assessed – no Challenge test req’d

Flowchart A3 – Wipes Undertake ISO 11930 test method

Does product pass criteria A of ISO

11930?

Does product pass criteria B of ISO

11930?

Does the product have a

short PAO assigned?

Does product have positive batch

release results for microbial limits

testing?

PRODUCT SUITABLE FOR MARKET. PRODUCT NOT SUITABLE FOR MARKET.

YES

YES

YES

YES

NO

NO

NO

NO

Product Characteristic Workflow

Reference

Summary of approach

All Powder A1* Risk assessed – no Challenge test req’d

Low water activity ≤0.75 (Confirmed) N/A Risk assessed – no Challenge test req’d

Suspect low water activity ≤0.75** A2 Reduced Challenge

Wipes A3 Full Challenge test req’d

Extreme pH (≤3/≥10) N/A Risk assessed – no Challenge test req’d

≥20% Alcohol content N/A Risk assessed – no Challenge test req’d

Organic Solvent Based (Ethyl acetate, Butyl acetate) N/A Risk assessed – no Challenge test req’d

Alkaline compounds (Ammonia, Monoethanolamine) N/A Risk assessed – no Challenge test req’d

Hydrogen peroxide N/A Risk assessed – no Challenge test req’d

≥20% Aluminium chlorohydrate and related salts N/A Risk assessed – no Challenge test req’d

≤0.75 Water activity AND was filled at ≥65oC N/A Risk assessed – no Challenge test req’d

Pressurised, single dose (e.g. sachet/canister) N/A Risk assessed – no Challenge test req’d

Aqueous • BS EN ISO 11930:2019 – Preservative efficacy test made for cosmetics

• Works in conjunction with BS EN ISO 29621:2017 – Risk assessment standard

• Criteria A & Criteria B

Undertake ISO 11930

test method

Does product pass criteria A of ISO 11930?

Does product pass criteria B of ISO 11930?

Does the product have

additional packaging

controls to reduce

microbial risk? E.g. Pump,

pipette applicator, low

volume container, no

direct contact with

consumer?

Does product have positive

batch release results for

microbial limits testing?

PRODUCT SUITABLE

FOR MARKET.

PRODUCT NOT

SUITABLE FOR MARKET.

YES

YES

YES

YES

NO NO

NO

NO

In use testing • Doesn’t simulate real life, it is real life.

• Not enough control over parameters

• Suitable for products that have low risk characteristics

• Good for additional data

Dealing with failure Common mistakes -

Some products require extra care to ensure homogenous.

• Powders – tendency to clump with wet inoculum

• Wipes – pooling of organisms

• Oils – pooling of organisms

• Contaminated at point of manufacture

Dealing with failure • Product Design

• Preservative choice

1. Compatibility

2. Activity requirements during manufacture (temperature/pH)

3. Final specification

The Future

• Vegan – VeganSure® Testing