Impact of trace level of excipient impurity in drug product stability

Ramesh K. Shanmugam DDF summit – Sep, 2019

Excipients required to establish and maintain TPP of DP

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• Excipients are required in the formulation to achieve target product profile (with regards to stability and efficacy) – improve stability, enhance delivery and targeting, modify safety / PK profile, aid manufacturing process1

– buffering agents, tonicity adjusting agents, antioxidants, antimicrobials and surfactants

• Traditionally, excipients are referred to as ‘inert’. – Although this is not always the case, it is essential that excipients within a formulation are

compatible with each other and the drug substance (i.e. they do undergo unfavourable interactions with other formulation components) 2

• Furthermore, excipients must be ‘biocompatible’ (i.e. not harmful to living tissue)

1Pramanick, S.et.al, 2013. Excipient selection in parenteral formulation development. Pharma Times, 45(3) 2United States v. Generix Drug Corp., 460 U.S. 453, 103 S. Ct. 1298, 75 L. Ed. 2d 198

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Excipient Impurity Drug impacted Drug loading (w/w) Reference

PEG 300 or PS80 Formaldehyde BMS-203452 1% Nassar MN et al. Pharmaceut Dev Tech. 2004;9(2):189–95.

PVP Peroxides Compound A 2-3%Freed AL et al. Int J Pharm. 2008;357(1–

2):180–8PVP Peroxides Compound B 2-3%

PVP Peroxides Raloxifene 12.5% Hartauer K et al. Pharm Dev Tech. 2000;5(3):303–10.

Microcrystalline cellulose Peroxides CP448187 0.50% Polizzi MA et al. Pharm Dev Tech. 2008;13:457–62.

Microcrystalline cellulose Peroxides BMS-A 0.83% Narang AS et al. Burlington: Elsevier; 2009. p. 125–46.

Microcrystalline cellulose Aldehydes Vigabatrin - George RC et al. Drug Dev Ind Pharm. 1994;20:3023–32.

PEG Formaldehyde Irbesartan - Wang G et al. Pharm Dev Tech. 2008;13:393–9.

PEG Formaldehyde Varenicline 0.68% Waterman K et al. J Pharm Sci. 2008;97(4):1499–507.

Wu, Y. et al., 2011. Reactive impurities in excipients: profiling, identification and mitigation of drug–excipient incompatibility. AAPS PharmSciTech, 12(4)

Excipients has trace level of aldehydes and peroxides

Trace level of impurities often impacts DP stability

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• Impurities can induce physical changes (e.g. covalent aggregation) and/or chemical changes (e.g. oxidation)

• Formaldehyde has the potential to act as a protein cross-linker, altering the 3D structure of proteins, as well as forming adducts

• Peroxides are frequently implicated in protein oxidation and aggregation

Wang, W., et.al, 2014. Impact of residual impurities and contaminants on protein stability. Journal of pharmaceutical sciences, 103(5), pp.1315-1330.

• the impurities and by-products poses high degree of immunogenicity risks

Formaldehyde as a pharmaceutical impurity: what we know so far

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• “Formaldehyde present in excipients has been implicated in the degradation of several drug products where it can form adducts with primary and/or secondary amine groups” Prabhu P. PerkinElmer Inc., 2011.

• Concentration-dependent impact seen in BMS-204352 (Nassar MN et al. Pharmaceut Dev Tech. 2004;9(2):189–95)

• Formaldehyde can react and crosslink with amino and imino groups of DNA and proteins Hoffman, EA et al... Journal of Biological Chemistry, 290(44), pp.26404-26411.

• “Formaldehyde was found to react with N-terminal amino groups and side chains of cysteine, histidine, lysine, tryptophan, and arginine” (using model peptides) Metz B et al., 2004. Journal of Biological Chemistry, 279, 6235-6243.

Pharmacopeia doesn’t mandate formaldehyde testing

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• Few excipients mentioned aldehyde testing#

• Pharmacopoeia limits: “Pharmacopoeial monographs for excipients in major compendia (U.S. Pharmacopoeia-National Formulary, European Pharmacopoeia, Japanese Pharmacopoeia) rarely require the testing for aldehydes, nor are excipient manufacturers willing to provide information on potentially damaging residues in their products for fear that this information could be exploited by a competitor” Li et al. Journal of Chromatography A, 2006. 1104(1): p. 1-10.

• Ph. Eur. limits specified - 30 ppm in ‘macrogols’ (PEG). Date of last revision: September 2018

• US Environmental Protection Agency (EPA) has established a maximum daily dose reference (RfD) of 0.2 mg/kg per day

• ‘Formaldehyde is not on the ICH guideline lists for solvents and thus a control limit cannot be found’ Soman et al. Journal of chromatographic science, 2008. 46(6): p. 461-465.

#Wu, Y. et al., 2011. Reactive impurities in excipients: profiling, identification and mitigation of drug–excipient incompatibility. AAPS PharmSciTech, 12(4)

Case study 1

Understand the impact of excipient source to the drug product stability

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DP stability impacted with excipient source

80.0

82.0

84.0

86.0

88.090.0

92.0

94.0

96.0

98.0

T0 1M 2M 3M 6M

Purit

y (%

)

Stability - 25C

Source ASource BSource C

Stability at 25C (Months)

80.082.084.086.088.090.092.094.096.098.0

100.0

T0 1M

Purit

y (%

)

Stability - 40C

92.0

93.0

94.0

95.0

96.0

97.0

98.0

0 1 3 6 9 12

Purit

y (%

)

Stability at 5C (Months)

Stability - 4C

• Drug product formulated with 1 mg/mL of model protein with Sugar alcohol (either from source A/B/C), preservative in 20 mM phosphate buffer at pH 8.1

• Purity measured by RP – UPLC

• From the study results, comparatively lower stability observed with formulation has excipient source C

Stability at 40C (Month)

Comparative analysis – Sugar alcohol content

All samples comply with the assay

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Content Insoluble matters Source A 98.3 % Nothing to report

Source B 98.7 % Nothing to report

Source C 98.5 % Nothing to report

Comparative analysis

No major observations

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Mannitol Maltitol Σ of all impurities Major cracking Σ of all cracking p.

Source A 0.7 0.3 1.4 0.09 0.2

Source B 0.6 0.3 1.0 0.07 0.2

Source C 0.5 0.4 0.9 0.14 0.3

Analysis: related substances and cracking products HPLC

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Description 24 Mg [ He ]

27 Al [ He ]

43 Ca [ H2 ]

52 Cr [ He ]

55 Mn[ He ]

56 Fe [ He ]

59 Co [ He ]

60 Ni [ He ]

63 Cu [ He ]

66 Zn [ He ]

78 Se [ He ]

Source A 14 <0.000 <0.000 6 0 8 0 5 2 64 <0.000Source B 14 <0.000 16 5 2 9 0 1 1 <0.000 <0.000Source C 3 <0.000 <0.000 6 0 2 0 3 1 <0.000 <0.000

Comparative analysis

No major observations

Analysis: Elemental analysis by ICP-MS

Comparative analysis

Differences

Reducing sugars could react with proteins.

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Reducing sugars (ppm) Reducing sugars (Ph.Eur.) (<1000 ppm)

Source A 550 Pass

Source B 610 Pass

Source C 740 Pass

Analysis: reducing sugars (glucose)

Somogyi Nelson method

PrincipleThe reducing sugars when heated with alkaline copper tartrate reduce the copper from thecupric to cuprous state and thus cuprous oxide is formed. When cuprous oxide is treated witharsenomolybdic acid, the reduction of molybdic acid to molybdenum blue takes place. Theblue color developed is compared with a set of standards in a colorimeter at 620nm.

Comparative analysis

Differences • Source C seems to be more charged with organic acids and has significant amount of

formaldehyde

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Gluconate Lactate Acetate Formate HCHO content#

Source A <2 15.0 2.0 2.0 221.1 ppb

Source B 2.0 3.0 2.0 2.0 163.4 ppb (<LOQ)

Source C 5.0 6.0 2.0 4.0 1552.0 ppb

Analysis: organic acids

Other analysed acids: Succinate, Oxalate, Citrate: <2 ppm

# LOQ > 200 ppb

Presence of aldehydes, reducing sugar and organic acids impacts drug product stability

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The formaldehyde could directly

interact with protein to form

crosslinking impurity (James

Ashenhurst)

The reducing sugars could further interact

with reducing sugars in presence of organic

acids, could degrade protein#

Ajit.et.al, Reactive Impurities in Excipients: Profiling, Identification and Mitigation of Drug–Excipient Incompatibility,AAPS

Case study 2

Impact of storage and handling of excipients on DP stability

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Excipient Purity results by RP – UPLC HCHO

content# (ppm)Total purity +12 Da Other impurities

U.S.P. Multi-Compendial

90.6 % *3.5 % *5.9 % 6.07

98.2 % 0.09 % 0.09 % 0.07

Comparative study

DP from lot 1

DP from lot 2

Store 25C for 1 week and test Purity

DP from lot 1DP from lot 2

RP-UPLC overlay

DP stability impacted with one lot of excipient

• Degradation due to high amount of formaldehyde

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Improper handling of bulk excipient leads to formaldehyde generation*

*Viktoriia V.Torbina, et.al. 2016

Insight into Excipient storage stability#: q Most of pharmacopeia excipients (Eg. PG) are sensitive to UV

light, which can act as a radical initiator and initiate oxidation reactions. For this reason, it is recommended that glycols be stored in opaque containers and avoid frequent or prolonged exposure to sunlight.

q Propylene glycols will degrade slowly in the presence of oxygen. Metal contamination, acidic or basic contaminants and higher temperatures all accelerate the degradation reactions aldehydes, ketones, acids and dioxolanes.

q A strong odor, higher acidity, higher ultra-typical oxidation products are violet (UV)-absorption or high color are indicators that a propylene glycol has been not been stored properly and has started to degrade.

#https://dowanswer.custhelp.com/app/answers/detail/a_id/5207/related/1

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Learnings…

q Excipients stored at ambient temperatures in closed containers and away from sunlight and other sources of UV light.

q If possible, the bulk excipients to be stored under nitrogen, ideally, but the use of dry air is also effective

q Continuous stability testing programs (TBD)

q Where product heating is utilized (i.e. for bulk storage and/or transport containers) the product temperature should be controlled to prevent unintentional overheating over extended periods as this may potentially lead to accelerated oxidative degradation of the product

q If possible, consider using smaller pack size

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• Presence of aldehyde impurity significantly impacts DP stability• Understanding the quality/compatibility and controlling is critical • Current investigational studies provides insights into possible mechanisms of

formaldehyde generation Ø could present as residual impurity – wont be tested by manufacturer

Ø could form with age / storage of excipient

• Important to have aldehyde identification / quantification method to support development

Early Prediction & Prevention is the Best Mitigation Strategy!

Worth to suspect the excipients instead of formulation …

• Ana Gomes dos Santos

• DFDD team• Max Avazhanskiy

• Natalia Schoch Lopez

• Olaf Hausler and Team Roquette

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Acknowledgements

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