Quality of Active Pharmaceutical Ingredients, Beijing, March 2010 Tutorial: WHO Prequalification Programme, Maryam MEHMANDOUST Specific quality topics

Quality of Active Pharmaceutical Ingredients, Beijing, March 2010Tutorial: WHO Prequalification Programme, Maryam MEHMANDOUST

Specific quality topics on TB APIs

Maryam MEHMANDOUST, PhDAFSSAPS

On behalf of WHO Prequalification medicines


Rifampicin (rifampin) Ph. Eur., USP, BP, Ph. Int.

Ethambutol 2HCl Ph. Eur., USP, BP, Ph. Int., JP

Pyrazinamide Ph. Eur., USP, BP, Ph. Int., JP

Isoniazid Ph. Eur., USP, BP, Ph. Int., JP

Streptomycin Ph. Eur., USP, BP, Ph. Int.

Amikacin Ph. Eur., USP, BP, Ph. Int., JP

Kanamycin Ph. Eur., USP, BP

Capreomycin USP, Ph. Int.

Cycloserine USP, JP

Ethionamide Ph. Eur., USP, BP, Ph. Int., JP

Ofloxacin Ph. Eur., USP

Levofloxacin Draft USP

Moxifloxacin Ph. Eur., USP, BP

Prothionamide Ph. Int., JP

p-Aminosalicylic acid (and sodium salt) Ph. Eur., USP

Terizidone Non pharmacopoeial, in the workplan of Ph. Int. 2010

Prequalification Medicines Programme TB drugs in the latest (9th) Expression of Interest


First line anti-TB drugs / APIs PQP latest (9th) Expression of Interest


RifampicinRifampicin

.Rifampicin is described in internationally recognised pharmacopoiae i.e. Ph. Eur., USP, BP and Ph. Int.

. Rifampicin belongs to the family group « Rifamycins », a group of antibiotics obtained from fermentation themselves from family of « Ansamycins »

. Rifampicin was discovered during 60 decade as a successful antibiotic against tuberculosis


Rifampicin / RifampinRifampicin / Rifampin

Ansamycins characterised by a quinone or naphtoquinone-type element, the two extremes linked together by an aliphatic chain, called ansa



Florey Vol 2. Analytical Profiles of Drug Substances



- Rifampicin is not a true fermentation product according to the provisions of Ph. Eur. general monograph « fermentation products » (1468),

Rifampicin is a semi-synthetic antibiotic

- Rifamycin B or Rifamycin S, the starting materials of Rifampicin, are true fermenation products

- Rifamycin B obtained during growth of certain strains of Amycolatopsis mediterranei- Rifamycin S from A. mediterranei mutants



- If Rifamycin S or B are obtained from fermentatin, then a minimum description of the fermentation step and assurance for removal of fermentation residues is needed.

Reminder: after Rifamycin S, there are only few steps to obtain Rifampicin


Rifampicin – Rifampicin – starting material obtained from fermentationstarting material obtained from fermentation

- Characterisation of the producer microorganism

identification, source, purity and stability of master cell bank and working cell bank, deposition in a recognised culture collection

- Details of fermentation process

media ingredients and their specifications, their heat/sterilisation treatment, description of the process including conditions and controls accompagnied by a flow diagram

- In process controls to show the reproducibility of the process

- Release and collection of the desired product

- Extraction and purification steps

- TSE and viral aspects to be addressed for any material of animal or human origin

- Overview of the potential impurities and how they are removed (cellular residue, substrates, precursors and other media ingredients, unwanted metabolic products whether related substance or not)


Rifampicin / Rifampin - Rifampicin / Rifampin - PropertiesProperties

- Rifampicin is a Reddish-brown or brownish-red crystalline powder, slightly soluble in water

- Rifampicin presents the phenomenon of polymorphism: two crystalline forms I and II, an amorphous form and several solvates from different solvents (water, tetrahydrofuran, carbon tetrachloride)

- Commercial production is constituted of form II

- Presence of amorphous form slows down dissolution characteristics of the solid dosage form

- The infrared (IR) test and differential scanning calorimetry (DSC) can distinguish between the different forms to be used as identification test


Rifampicin / Rifampin - Rifampicin / Rifampin - PropertiesProperties

-The Ph. Eur. monograph has no test to distinguish these polymorphs,

- The USP monograph has a test for crystallinity (distinction between a crystalline form and an amorphous form)

- It is up to the manufacturer of the API/ the applicant to Prequalification to ensure that the form II is used in the manufacture of solid dosage forms of rifampicin or if other forms are present, they will not affect the performance of the FPP

- Appropriate conditions of the final crystallisation of the API is necessary to obtain only one polymorphic form in a consistent way

- Production of consistent polymorphic form is to be shown in the dossier (at least on 3 consecutive lots)


Rifampicin- Rifampicin- Potential isomerism / chirality

-The molecule consists of a naphtohydroquinone part spanned by an aliphatic chain, the ansa

- The ansa contains 9 asymmetric (chiral) carbon atoms (512 isomers theroretically possible) and 3 double bonds however Rifampicin is formed only of one isomer

- The 9 chiral centres are obtained in the course of fermentation step of the API starting material The microorganism specifically produces only one isomer of Rifamycin B or Rifamycin S

- These centres do not undergo further reactions in chemical steps leading to Rifampicin

- USP and Ph. Eur. monographs do not contain any test in routine

for control of chirality as not relevant


Rifampicin - Impurities Ph. Eur. monograph

Rifampicin quinone (imp A) at not more than (NMT) 1.5% as specified impurity

Any other impurity at NMT 1.0%

The impurity list of the Ph. Eur. contains Rifampicin quinone (imp A) and Rifampicin N-Oxide. Rifampicin N- Oxide can be limited therefore to NMT 1.0%.

Total of impurities at NMT 3.5%

USP monograph

Rifampicin quinone at NMT 1.5% as specified impurity

Any other impurity at NMT 1.0%

Total of impurities at NMT 3.5%

The USP monograph has no specific section for impurities

Ph. Int. MonographTLC method for related substances, can detect 3-formyl rifamycin


Rifampicin - Impurities Rifampicin quinone is the major degradation product of Rifampicin and arised from the oxidation of the naphtohyydroquinone moiety

Rifampicin N-oxide is the other oxidation product/degradation product of rifampicin, arising from oxidation of the tertiary amine present on the piperazine moiety

3- formyl Rifamycin is synthesis impurity and degradation product by hydrolysis of the imine group in aqueous acidic media leading to loss of aminomethylpiperazine

Desacety and transacetyl Rifampicins are obtained upon alkaline treatment: 25-desacetyl obtained by ester hydrolysis which may lead stepwise to C-21 and C-23 acetylation

The Ph. Eur. and USP monographs do not cover all the impurities

Up to the manufacturer to propose and justify test and limits e.g. by referring to the literature)


Rifampicin - Impurities

Oxidation to quinone N-oxidation

25-desacetyl

Hydrolysis to 3-formyl

Ph. recommendations for storage: store under nitrogen in airtight container, protected from light, subject to oxidation by exposure to light and/or air


Isoniazid- Isoniazid is described in Ph. Eur., USP, BP, Ph. Int., JP

- A white crystalline powder , freely soluble in water

- Isoniazid can be obtained by condensation of isonicotinamide and hydrazine, the first step is preparation of isonicotinamide from 4-cyanopyridine Simple route of synthesis

- USP monograph does not have any test for impurities

- Ph. Eur. monograph has a related substances test with a limit of NMT 0.2% for any impurity. Not clear which ones? Old monograph, no list for impurities

Ph. Eur. monograph permits a limit of 0.05% (500 ppm) for residues of hydrzine

• it is up to the manuafcturer to present a discussion and investigation on impurities


Isoniazid

Primary amine

Nucleophile and can react with aldehydes

Careful fformulation of the FPP

The amide can be subject to hydrolysis leading to hydrazine and isonicotinic acid

Can be oxidised in presence of strong oxidants but not in normal condition of use


Ethambutol dihydrochloride – critical points

Ethambutol dihydrochloride is described in Ph. Eur., USP, BP, Ph. Int., JP / freely soluble in water

General mode of preparation: condensation of 2 moles of D-2-amino-1-butanol with one mole of 1,2-dichloroethane

Quality of starting material: the 2-amino-1-butanol used should be optically pure and of D configuration

Ethambutol hydrochloride has 2 asymmetric centres of configuration

S, S. (the RS diastereoisomer is less active 16 times and RR inactive)

• Ph. Eur. monograph is the only monograph which has a test and limit for the undesired diastereoisomers: RS NMT 1.0%, RR NMT 0.10%

• USP monograph has an optical specific rotation test: between + 6.0° and + 6.7° with a test solution of 100mg/ml in water, this may allow presence of RS up to 10%. Pharmacopoeial Forum

Vol. 33(2), March-April 2007


Ethambutol dihydrochloride – Critical points

General mode of preparation: condensation of 2 moles of D-2-amino-1-butanol with one mole of 1,2-dichloroethane (considered as ICH class I solvent, to be avoided)

Impurities: the final substance should be in compliance with the ICH limits for residual 1,2-dichloroethane even used as starting material

• A specification should be present for determination of residual 1,2-dichloroethane i.e. NMT 5 ppm only can be permissible

• A suitable method for determination of these residues with the complete validation of the method


Pyrazinamide

Pyrazinamide is described in Ph. Eur., USP, BP, Ph. Int., JP Substance sparingly soluble in waterFour (4) formes polymorphic seem to exist

Form is the only form produced from water Forms , and are formed in particular drastic conditions

Route of synthesis not complex

. Product directly crystallised from the reaction mixture

. No residual solvents (only water used)

. 2-CPZ to be included as a possible synthesis impurity in API specifications


Second line anti-TB drugs / APIs

Amikacin Ph. Eur., USP, BP, Ph. Int., JPsemi-synthetic from Kanamycin

Kanamycin Ph. Eur., USP, BPtrue fermentation product

Capreomycin USP, Ph. Int.true fermentation product

Cycloserine USP, JP2 FPPs PQed

Ofloxacin Ph. Eur., USP racemate

Levofloxacin Draft USPMoxifloxacin Ph. Eur., USP, BP

Ethionamide 1 FPP PQed Ph. Eur., USP, BP, Ph. Int., JPProthionamide Ph. Int., JPp-Aminosalicylic acid (and sodium salt) Ph. Eur., USP

1 FPP PQedTerizidone


Common deficiencies - site, process

- Chain of manufacturing of the API not clear

- Workshop, block not specified

- GMP certificate and/or manufacturing autorisation not valid. Old documents are presented (less than 3 years required)

- Flow diagram available but scheme of synthesis missing

- Detailed description of the synthesis missing: step by step description with mention of quantities of materials used and operating conditions needed

- Lack of concordance between the flow diagram and description, when the latter is available


Common deficienciesprocess, control of materials

-Starting material not well justified: too complex molecules

-Routes of synthesis generally short

-Outline of preparation of starting material not given

-See slide 7 for starting materials prepared by fermentation (Rifampicin, Amikacin) and information to be provided

-Specifications of the starting material not sufficient: lack of limit and test for specified, unidentified and total impurities

-Source of starting material unclear along with number of sources

-Specifications of reagents and solvents not complete: at least identification and assay needed


Common deficienciesSpecifications

Adequacy between the process and specifications not shown

-Reagents/ solvents listed in the specifications but not described in the description of the process

OR vice versa described in the process but not controlled

Recognised pharmacopoeias in PQP: Ph. Int, Ph. Eur., USP, BP-In-house methods are acceptable if well justified to be at least equivalent or superior to the pharmacopoeial method

Suitability of use of related substances method of a Ph monograph should be always discussed with regard to the impurities from the manufacturer’s specific route of synthesis


Recommendations

Follow the CTD S section and its sub-sections

for APIMFs mandatory

The CTD permits a logical flow of the information

The CTD drives the necessary infomation that assessors need to evaluate

Consult ICH M4Q: location issues for CTD for the registration of pharmaceuticalsfor human use. Quality- questions and answers

Bring evidence on what is claimed in the dossier and justuify well !


Thank you for your attention

Documents

Quality of Active Pharmaceutical Ingredients, Beijing, March 2010 Tutorial: WHO Prequalification Programme, Maryam MEHMANDOUST Specific quality topics