Coloring agents are used mainly to impart an elegant appearance, identification and protection to:
- Tablet (coated or uncoated)
- Oral liquid/ Hard & Soft gelatin capsules
- Topical creams and ointments
Color Index Number (C.I. No.) is the identifier number of color “dye” or “lake”.
- For Dye: C.I. No (***)
- For Lake: C.I. No (*** : 1 )
Example
- Brilliant Blue FCF dye C.I. No = 42090
- Brilliant Blue FCF lake C.I. No = 42090 : 1
Dyes vs Lakes
- Dyes are soluble in water
- Lakes are Insoluble in water
Regulations
- 21 CFR part 73, 74 & 82
- Commission Regulation (EU) No 231/2012
3 main sources to set specification of dyes
- 21 CFR Part 73 & 74
- COMMISSION REGULATION (EU) NO 231/2012
- JECFA
Common Tests of Dyes
- Sum of volatile matter at 135 °C (275 °F) and chlorides and sulfates,
- Water-insoluble matter,
- Leuco base,
- Impurities,
- Subsidiary colors,
- Chromium (as Cr),
- Arsenic (as As),
- Lead (as Pb),
- Mercury (as Hg),
- Total color, not less than 85 percent.
Common Tests of Lakes
Same tests like the color from which the lake is prepared.
Except
- Water-insoluble matter
and add two tests
- Soluble chlorides and sulfates (as sodium salts), not more than 2.0 percent.
- Inorganic matter, insoluble HCl, not more than 0.5 percent.
Analytical methods
- In Combined Compendium Of Food Additive Specifications, volume 4
- By Joint FAO/WHO Expert Committee on Food Additives (JECFA)
Coloring Agent in CTD File
As an Excipient, Information on Coloring agent used in a medicinal product should be provided in:
- Part 3.2.P.1
- Part 3.2.P.2
- Part 3.2.P.4 and 3.2.A.3 of the CTD dossier.
Coloring Agents in Paediatric Preparations
In paediatric preparations, Coloring agents should be discussed and justified in terms of:
- Allergenic potential,
- Minimal toxicological implications,
- Azo-dyes, like: (tartrazine, sunset yellow and new coccine) should be avoided in children’s medicines,
- Natural colorants may cause allergic -reactions.
Read also:
- Excipients in Pharmaceutical Applications
- WHO GMP Guideline for Excipients Used in Pharmaceutical Products
Resource person: Raghda Fayed