NOTES: Formation of Amide- and Imide-Linked Degradation Products Between the Peptide Drug Oxytocin and Citrate in Citrate-Buffered Formulations

Poole, Robert A.; Kasper, Piotr T.; Jiskoot, Wim

doi:10.1002/jps.22495

Cited by 25 publications

(32 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, as also shown by Poole et al, 14 it is reactive itself and can attack the N-terminal amino group from the cysteine residue to form an adduct. Second, as shown in our previous study, 15 it protects oxytocin from degradation in the presence of divalent metal ions.…”

Section: Discussionmentioning

confidence: 85%

A New Strategy To Stabilize Oxytocin in Aqueous Solutions: II. Suppression of Cysteine-Mediated Intermolecular Reactions by a Combination of Divalent Metal Ions and Citrate

Avanti¹,

Permentier²,

Dam³

et al. 2012

Mol. Pharmaceutics

Self Cite

View full text Add to dashboard Cite

A series of studies have been conducted to develop a heat-stable liquid oxytocin formulation. Oxytocin degradation products have been identified including citrate adducts formed in a formulation with citrate buffer. In a more recent study we have found that divalent metal salts in combination with citrate buffer strongly stabilize oxytocin in aqueous solutions (Avanti, C.; et al. AAPS J. 2011, 13, 284−290). The aim of the present investigation was to identify various degradation products of oxytocin in citrate-buffered solution after thermal stress at a temperature of 70°C for 5 days and the changes in degradation pattern in the presence of divalent metal ions. Degradation products of oxytocin in the citrate buffer formulation with and without divalent metal ions were analyzed using liquid chromatography−mass spectrometry/mass spectrometry (LC−MS/MS). In the presence of divalent metal ions, almost all degradation products, in particular citrate adduct, tri-and tetrasulfides, and dimers, were greatly reduced in intensity. No significant difference in the stabilizing effect was found among the divalent metal ions Ca 2+ , Mg 2+, and Zn 2+ . The suppressed degradation products all involve the cysteine residues. We therefore postulate that cysteine-mediated intermolecular reactions are suppressed by complex formation of the divalent metal ion and citrate with oxytocin, thereby inhibiting the formation of citrate adducts and reactions of the cysteine thiol group in oxytocin.

show abstract

Section: Discussionmentioning

confidence: 85%

A New Strategy To Stabilize Oxytocin in Aqueous Solutions: II. Suppression of Cysteine-Mediated Intermolecular Reactions by a Combination of Divalent Metal Ions and Citrate

Avanti¹,

Permentier²,

Dam³

et al. 2012

Mol. Pharmaceutics

Self Cite

View full text Add to dashboard Cite

show abstract

“…As reported, formation of citric acid anhydride occurs between pH 3.0 to 6.0, with the maximum at pH 4.0 to 4.5. 56 At pH 5.2 for our formulation, citric acid anhydride can still accumulate to a significant degree and modify the antibodies. Increasing the pH to neutral conditions, however, would markedly diminish the formation of the anhydride, thus little modification of the antibodies (see Figure S-1 in the Supporting Information, pH 7 data).…”

Section: Resultsmentioning

confidence: 93%

“…This mechanism is consistent with the results reported on citrate modification of peptides and the propensity of citric acid to form an anhydride under acidic conditions. 56−60 …”

Section: Resultsmentioning

confidence: 99%

Discovery of a Chemical Modification by Citric Acid in a Recombinant Monoclonal Antibody

et al. 2014

View full text Add to dashboard Cite

Recombinant therapeutic monoclonal antibodies exhibit a high degree of heterogeneity that can arise from various post-translational modifications. The formulation for a protein product is to maintain a specific pH and to minimize further modifications. Generally Recognized as Safe (GRAS), citric acid is commonly used for formulation to maintain a pH at a range between 3 and 6 and is generally considered chemically inert. However, as we reported herein, citric acid covalently modified a recombinant monoclonal antibody (IgG1) in a phosphate/citrate-buffered formulation at pH 5.2 and led to the formation of so-called “acidic species” that showed mass increases of 174 and 156 Da, respectively. Peptide mapping revealed that the modification occurred at the N-terminus of the light chain. Three additional antibodies also showed the same modification but displayed different susceptibilities of the N-termini of the light chain, heavy chain, or both. Thus, ostensibly unreactive excipients under certain conditions may increase heterogeneity and acidic species in formulated recombinant monoclonal antibodies. By analogy, other molecules (e.g., succinic acid) with two or more carboxylic acid groups and capable of forming an anhydride may exhibit similar reactivities. Altogether, our findings again reminded us that it is prudent to consider formulations as a potential source for chemical modifications and product heterogeneity.

show abstract

“…1) were different regarding physico-chemical properties, e.g., partition coefficient and ionization properties, but all contained either carboxylic acid or amine functionalities capable of participating in ester or amide formation. Examples of the formation of ester and amide reaction products in relation to stability and drug-excipient compatibility testing have been published (Kochling et al, 2007;Larsen et al, 2009aLarsen et al, , 2009bPoole et al, 2011), but systematic investigations have not been performed regarding the relative reactivity of commonly employed excipients.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of microwave oven heating for prediction of drug–excipient compatibilities and accelerated stability studies

Schou-Pedersen

Østergaard

Cornett

et al. 2015

International Journal of Pharmaceutics

View full text Add to dashboard Cite

NOTES: Formation of Amide- and Imide-Linked Degradation Products Between the Peptide Drug Oxytocin and Citrate in Citrate-Buffered Formulations

Cited by 25 publications

References 10 publications

A New Strategy To Stabilize Oxytocin in Aqueous Solutions: II. Suppression of Cysteine-Mediated Intermolecular Reactions by a Combination of Divalent Metal Ions and Citrate

A New Strategy To Stabilize Oxytocin in Aqueous Solutions: II. Suppression of Cysteine-Mediated Intermolecular Reactions by a Combination of Divalent Metal Ions and Citrate

Discovery of a Chemical Modification by Citric Acid in a Recombinant Monoclonal Antibody

Evaluation of microwave oven heating for prediction of drug–excipient compatibilities and accelerated stability studies

Contact Info

Product

Resources

About