Mitigation of Oxidation in Therapeutic Antibody Formulations: a Biochemical Efficacy and Safety Evaluation of <Emphasis Type="Italic">N</Emphasis>-Acetyl-Tryptophan and L-Methionine

Purpose

Biotherapeutics can be susceptible to oxidation during manufacturing and storage. Free L-methionine is known to protect methionine residues in proteins from oxidation. Similarly, free tryptophan and other indole derivatives have been shown to protect tryptophan residues from oxidation. N-acetyl-DL-tryptophan was previously identified as a potentially superior antioxidant to tryptophan as it has a lower oxidation potential and produces less peroxide upon light exposure. This study sought to confirm the antioxidant efficacy and safety of N-acetyl-DL-tryptophan and L-methionine as formulation components for biotherapeutic drugs.

Methods

Antibodies were subjected to AAPH and light exposure in the presence of N-acetyl-DL-tryptophan and L-methionine. Oxidation in relevant CDR and Fc residues was quantified by peptide map. In silico, in vitro, and in vivo studies were performed to evaluate the safety of N-acetyl-DL-tryptophan and L-methionine.

Results

Peptide mapping demonstrated that N-acetyl-DL-tryptophan was effective at protecting tryptophans from AAPH stress, and that the combination of N-acetyl-DL-tryptophan and L-methionine protected both tryptophan and methionine from AAPH stress. The safety assessment suggested an acceptable safety profile for both excipients.

Conclusions

N-acetyl-tryptophan and L-methionine effectively reduce the oxidation of susceptible tryptophan and methionine residues in antibodies and are safe for use in parenteral biotherapeutic formulations.

     

Demonstration of pharmaceutical tablet coating process by injection molding technology

We demonstrate the coating of tablets using an injection molding (IM) process that has advantage of being solvent free and can provide precision coat features. The selected core tablets comprising 10% w/w griseofulvin were prepared by an integrated hot melt extrusion-injection molding (HME-IM) process. Coating trials were conducted on a vertical injection mold machine. Polyethylene glycol and polyethylene oxide based hot melt extruded coat compositions were used. Tablet coating process feasibility was successfully demonstrated using different coating mold designs (with both overlapping and non-overlapping coatings at the weld) and coat thicknesses of 150 and 300?μm. The resultant coated tablets had acceptable appearance, seal at the weld, and immediate drug release profile (with an acceptable lag time). Since IM is a continuous process, this study opens opportunities to develop HME-IM continuous processes for transforming powder to coated tablets.     

Second generation antipsychotic-induced mitochondrial alterations: Implications for increased risk of metabolic syndrome in patients with schizophrenia

Metabolic syndrome (MetS) is seen more frequently in persons with schizophrenia than in the general population, and these metabolic abnormalities are further aggravated by second generation antipsychotic (SGA) drugs. Although the underlying mechanisms responsible for the increased prevalence of MetS among patients under SGA treatment are not well understood, alterations in mitochondria function have been implicated. We performed a comprehensive evaluation of the role of mitochondrial dysfunction in the pathophysiology of drug-induced MetS in schizophrenia. We found a downregulation in genes encoding subunits of the electron transport chain complexes (ETC), enzyme activity, and mitochondrial dynamics in peripheral blood cells from patients at high-risk for MetS. Additionally, we evaluated several markers of energy metabolism in lymphoblastoid cell lines from patients with schizophrenia and controls following exposure to antipsychotics. We found that the high-risk drugs clozapine and olanzapine induced a general down-regulation of genes involved in the ETC, as well as decreased activities of the corresponding enzymes, ATP levels and a significant decrease in all the functional parameters of mitochondrial oxygen consumption in cells from patients and controls. We also observed that the medium-risk SGA quetiapine decreased oxygen consumption and respiratory control ratio in controls and patients. Additionally, clozapine and olanzapine induced a downregulation of Drp1 and Mfn2 both in terms of mRNA and protein levels. Together, these data suggest that an intrinsic defect in multiple components of oxidative metabolism may contribute to the increased prevalence of MetS in patients under treatment with SGAs known to cause risk for MetS.