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Compositional guideline: Larix arabinogalactan

12 February 2018

Name of the ingredient

Larix arabinogalactan (AAN)

Definition of the ingredient

Larix arabinogalactan is a highly branched polysaccharide derived from Larix occidentalis (Western larch) or Larix laricina (Eastern larch) wood by extraction with water. The ratio of galactose and arabinose subunits occurring in the substance is approximately 6:1.

Molecular formula (nominal): [(C5H8O4)(C6H10O5)6]x

Molecular mass range: 15000-60000

Cas Number: 9036-66-2

Table 1. Ingredient specific requirements
Test Method reference Acceptance criteria
Free flowing powder Visual Complies
Colour Visual White to light brown
Odour Organoleptic Pine
Bulk density USP <616> 0.27 - 0.40 g/mL
Viscosity (30%) Ph Eur method 2.2.8 ≤ 15 mPas
Loss on drying Ph Eur method 2.2.32 ≤ 6.0%
Solubility in water BP (General notice) Freely soluble in water
Test 1: IR Ph Eur method 2.2.24 IR and 1H-NMR spectra comply with those of authenticated references
Test 2: 1H-NMR NMR
Polysaccharides (as arabinogalactan) HPLC ≥ 85.0%
Table 2. Incidental constituents
Test Method reference Acceptance criteria
Incidental metals and non-metals
Total heavy metals USP <231>; Ph Eur method 2.4.8 ≤ 5 ppm
Lead USP <730>; Ph Eur method 2.2.57 ≤ 0.1 ppm
Arsenic USP <730> ≤ 0.4 ppm
Cadmium ≤ 0.25 ppm
Mercury ≤ 0.3 ppm
Pesticide residues and environmental contaminants:
(including agricultural and veterinary substances)
BP (Appendix XI L); Ph Eur method 2.8.13 Complies
Other organic or inorganic impurities or toxins
Ash AOAC 923.03 ≤ 12.0%
Related substances:
Fat AOAC 922.06 / 920.85 ≤ 1.0%
Protein AOAC 930.29 / 991.20 ≤ 0.3%
Phenolics Not specified - an appropriately validated method should be used ≤ 2.0%
Microbiology While substance manufacturers are encouraged to include limits for objectionable microorganisms, it is the product into which those substances are formulated that is subject to a legally binding set of criteria. The Therapeutic Goods Order No. 77 'Microbiological Standards for Medicines' mandates that any finished product which contains the ingredient, alone or in combination with other ingredients, must comply with the microbial acceptance criteria set by Clause 9 of the Order.

Key to abbreviations

AOAC = Association of Analytical Communities

BP = British Pharmacopoeia

mPas = millipascal second

HPLC = High-pressure liquid chromatography

IR = Infrared spectrophotometry

1H-NMR = Nuclear magnetic resonance spectroscopy

Ph Eur = European Pharmacopoeia

USP = United States Pharmacopoeia

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