2 research outputs found
Deamidation of Collagen
Collagen is the major component of skin, tendons, ligaments,
teeth, and bones, it provides the framework that holds most multicellular
animals together, and collagen type I constitutes the major fibrillar
collagen of bone. Because of the complexity of collagen’s structure,
the study of post-translational modifications such as deamidation
for this protein is challenging. Although there is no evidence of
this protein being used for age assessment, it has been shown that
deamidation of collagen is remarkably increased in old bones from
mammals. Nonspectrometric methodologies have been used for the determination
of the extent of deamidation as a measure of the amount of amide nitrogen
released in ammonia as well as constant rates for deamidation of asparagine
in collagen. In general, these methodologies required more sample
and separation processes. To understand if collagen plays a significant
role in the aging process of fossil materials, a simpler and more
accurate method is needed to determine the extent of deamidation at
the whole protein level. The present work shows a method to determine
the extent of deamidation in collagen using Fourier transform ion
cyclotron resonance-mass spectrometry (FTICR-MS) along with collisionally
activated dissociation (CAD) and electron capture dissociation (ECD).
The measured deamidation half-life for three different tryptic peptides
from collagen (I) ranged from 2000 to 6000 s under high temperature
conditions (∼62 °C) and pH 7.5
Use of High Resolution Mass Spectrometry for Analysis of Polymeric Excipients in Drug Delivery Formulations
Two polymeric excipients, typically used in enabling
drug delivery
approaches, are Gelucire 44/14 (a product of Gattefosse s.a, St Priest,
France) and polysorbate 80; these are known to improve solubility
of poorly water-soluble drugs and, hence, increase their effective
bioavailability. In addition to the use of Gelucire 44/14 and polysorbate
80 as excipients in drugs, they are also widely used as cosmetic and
food additives. In general, complex structures and compositions of
drug excipients impact performance of the formulation in vivo and
consequently affect drug absorption. Therefore, a comparison between
excipients from different suppliers and batches to batch would provide
an indication of the impact on drug product performance and also the
study of the effectiveness of the system and any problems associated
with the formulation. In this study, high resolution Fourier transform
ion cyclotron resonance mass spectrometry (FTICR MS) is used to compare
two different batches of Gelucire 44/14 and polysorbate 80. With the
high resolving power of FTICR MS, it was possible to differentiate
between batches of excipients from differences in the identified components.
The improved resolution offered by FTICR MS allowed assignment of
four polymeric series differences in the two batches of polysorbate
80 and the presence of one compound and three polymeric series differences
in the two batches of Gelucire 44/14. The increase in the number of
components assigned in the excipients batch using FTICR-MS, compared
to the numbers previously assigned by lower resolution TOF MS, underlines
the importance of high resolution techniques in analysis of highly
complex mixtures