Evaluation of effects of temperature and humidity on the secondary structure of Ganirelix in an injectable formulation and comparison with Orgalutran® using circular dichroism spectroscopy

Abstract

Ganirelix, a drug used in in vitro fertilization (IVF), prevents ovulation in women who are not ready to have children by inhibiting a gene that produces gonadotropin. Peptides are macromolecules that are able to preserve a predetermined shape while carrying out the structural and regulatory roles for which they were originally intended. Peptide structures can be altered in the production and storage processes. Therapeutic peptides' biological activity can be drastically altered by even small modifications in their primary and secondary structures. The molecules' secondary structures can be monitored by subjecting them to different processing or storage conditions. In our investigation, we used circular dichroism (CD) spectroscopy with two different software programs for secondary structure evaluation to look at how environmental factors like temperature and humidity affected the secondary structure of Ganirelix in an injectable formulation. The CD results revealed that the alpha-helical (regular and distorted), beta-sheet, beta-strands (regular and distorted), beta-turn, and random coil structures of temperature and humidity stressed generic drug products are comparable to reference-listed drug.

Compatibility Study of Peptide and Glycerol Using Chromatographic and Spectroscopic Techniques: Application to a Novel Antimicrobial Peptide Cbf-14 Gel

“…For example, taking N-methylene-Cbf-14, even though the proton ions displayed identical m/z values ranging from 611.0705 to 611.0709 for impurities two, four, and six, the alkylidene sites in the Cbf-14 amino acid could be determined using secondary mass spectrometry. As shown in Figure 5, impurity two was identified as methylene-Cbf-14 at N-terminal due to the presence of a product ion at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)). Impurity four was recognized as methylene-Cbf-14 at K 9 , as evidenced by product ions at m/z 741.4825 (methylene-b10) and m/z 732.9859 ([methylene-b10]-NH 3 ), while lacking product ions at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)) or m/z 948.6092 (Cbf-14 (6-12)).…”

“…As shown in Figure 5, impurity two was identified as methylene-Cbf-14 at N-terminal due to the presence of a product ion at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)). Impurity four was recognized as methylene-Cbf-14 at K 9 , as evidenced by product ions at m/z 741.4825 (methylene-b10) and m/z 732.9859 ([methylene-b10]-NH 3 ), while lacking product ions at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)) or m/z 948.6092 (Cbf-14 (6-12)). Impurity six was identified as methylene-Cbf-14 at K 5 , supported by the presence of product ions at m/z 741.4816 (methylene-b10) and m/z 948.6092 (Cbf-14 (6-12)) but the absence of a product ion at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)).…”

“…Impurity four was recognized as methylene-Cbf-14 at K 9 , as evidenced by product ions at m/z 741.4825 (methylene-b10) and m/z 732.9859 ([methylene-b10]-NH 3 ), while lacking product ions at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)) or m/z 948.6092 (Cbf-14 (6-12)). Impurity six was identified as methylene-Cbf-14 at K 5 , supported by the presence of product ions at m/z 741.4816 (methylene-b10) and m/z 948.6092 (Cbf-14 (6-12)) but the absence of a product ion at m/z 640.9136 (Cbf-14 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)). Regarding N-(2hydroxyethylidene)-Cbf-14, impurities 10 and 11 were predicted based on the primary and secondary mass spectra information displayed in Figure 4b,d and electronic supplementary material (ESM, Figure S1g,h), respectively.…”

“…In alignment with International Conference on Harmonization (ICH) guidelines [ 10 ], impurities exceeding 0.1% of the API necessitate identification and characterization as part of a risk assessment, concerning their impact on patient safety and product efficacy. Typically, pharmaceutical research involving peptides employs various technologies, including liquid chromatography coupled with high-resolution mass spectrometry (LC–HRMS) [ 11 ], capillary electrophoresis (CE) [ 12 ], nuclear magnetic resonance (NMR) spectroscopy [ 13 ], circular dichroism (CD) spectroscopy [ 14 ], X-ray diffraction (XRD) [ 15 ], etc. During the development of Cbf-14 gel, an unusual degradation of APIs following long-term storage was encountered.…”