1. Drug Substance General Information (ICH 3.2.S.1)

1.1. Nomenclature (ICH 3.2.S.1.1)

International non-proprietary name:  Deferiprone, L1 (Brand Name: Ferriprox)

Compendial name: Deferiprone, L1

Chemical name:    3-Hydroxy-1,2-dimethyl-4(1H)-pyridone

Arasto’s code: DEF

CAS Registry Number: CAS [30652-11-0]


1. Drug Substance General Information (ICH 3.2.S.1)

1.2 Structure (ICH 3.2.S.1.2)

Empirical formula: C7H9NO2

Molecular Weight: 139.15

1. Drug Substance General Information (ICH 3.2.S.1)

1.3. General Properties (ICH 3.2.S.1.3)

Deferiprone is a while to off-while crystalline substance.  It is a bidentate iron chelator administered orally for the treatment of iron overload condition caused by routine blood transfusion in thalassemia major.  It is soluble in water and highly soluble in most polar organic solvents and water at acidic pH (<3). pKa Values for Deferiprone have been reported to be 3.3 and 9.7 ( and its log p 0.61 (http://www.chemical!mol=deferiprone). Oral LD50 in rats is 2 g/kg and 1 g/kg in guinea pig (

The determination of purity and assay of APIs require comparison of the product with their respective Reference Standards (RS) and Related Compounds (RC or known impurities).  Accordingly, ICH regulations on the purity and assay of reference standard and related compounds are clearly defined and must be followed by drug substance and drug product manufacturers.

According to ICH Q7, 11.1 there are 3 types of standards.  This is summarized in the following chart and discussed in detail below.

The impurities provided in the following table represent Secondary Reference Standards (SRS) that are prepared in-house by synthesis or by isolation. Each SRS has undergone extensive characterization (IR, UV, 1HNMR, 13CNMR. Mass Spec) and determination of its purity and assay (HPLC). For specification of the SRS of those products that have a monograph, the SRS is compared with a pharmacopoeia Primary Reference Standard (UV, HPLC retention time). For specification of those products that do not have a monograph (known as House Primary Standard), we compare their UV ε or ג /max, IR major absorptions, 1HNMR d(ppm), 13CNMR d(ppm) or HPLC retention time with values reported in the chemical literature for these compounds.

5. Primary and Secondary Reference Standard (ICH 3.2.S.5)

5.1. Active Pharmaceutical Ingredient

Primary Reference Standard for deferiprone is not available from any recognized pharmacopoeia. We will use a House Primary Standard (previously referred to as Working Standard) for direct control of all batches of deferiprone.

As per ICH (Q7, 11.1) and ICH (Q6, 2.11, 3.2, 3.3) the House Primary Standard, which include the API and its Related Compounds, must be examined for their proof of structure (characterization), assay and purity and specification (identification by comparison). Furthermore, ICH Guideline on the Preparation of Common Technical Document (Q4M) requires that the data obtained from characterization, assay and purity and specification must be included in section 3.2.S.3.2 for Related Compounds (already discussed in that section) and section 3.2.S.5 of the DMF for the API. To this end, the House Primary Standard of the API Deferiprone has undergone extensive characterization (UV, IR, 1 H NMR, 13C NMR, Mass Spec) to assure its structure, assay and purity (HPLC and/or titration) and specification (UV, IR, HNMR, CNMR and Mass) with the data reported in the chemical literature for DEF International patent WO 108679 A1, 2004.

The House Primary Standard for Deferiprone was produced from a released batch of Deferiprone by subjecting it to an additional crystallization from the final solvent system used in the production of the API to avoid the possibility of other polymorph formation.


Product: DeferiproneCAS No.: 30652-11-0Spec. No.: APC-QC-SPEC-376-00
Issue Date: Apr, 2023Valid up to: Apr, 2024Reference: In-house


AppearanceWhite to pinkish white crystalline powder.
SolubilityInsoluble in acetone, sparingly soluble in methanol and water.
IdentificationIR spectrum.

UV: 8.0 ppm solution in methanol exhibits maxima at 220±2 and 284±2 nm.

Residual SolventsMethanol: Max. 3000 ppm (Class II)
Loss on DryingNMT 1.0%
Residue on IgnitionNMT 0.1%
Heavy MetalsNMT 0.002%
Water ContentNMT 1.0%
Related substances (HPLC)Impurity B (Maltol): NMT 0.2%

Any unidentified impurity: NMT 0.1%

Total impurities: NMT 0.5%

Assay (HPLC)98.0% to 102.0% (on the dried basis)
Mesh Size

Pass Through Mesh 100 (150µ)

NLT 90%
Prepared by: M. Shahbazi, B.Sc.Chem.Checked by: A. Forghani, B.Sc.Chem.
Approved by: F. Javadizadeh, M.Sc.Chem.
Storage: Store in well-closed container, protected from light and humidity.