Intra-articular corticosteroid injections in haemophilic arthropathy: are they recommended?

Introduction: Intra-articular (IA) corticosteroid (CS) injections are commonly used in the treatment of osteoarthritis. However, they are rarely utilized in haemophilic arthropathy. In fact, the efficacy of this method in haemophilic arthropathy is frequently discussed and debated in clinical practice.

Aim: To investigate the effectiveness of IA CS injections in patients with painful haemophilic arthropathy.

Methods: A review of the literature on the topic was performed.

Results: In osteoarthritis, reports with a high level of evidence state that the efficacy of IA injections of CS is controversial. In haemophilic arthropathy, some low-level evidence reports seem to indicate that short-term pain alleviation can be achieved.

Conclusions: Considering that pain relief after IA injections of CS is controversial and that the cost of the haematologic treatment required to perform the procedure is high in haemophilic arthropathy, we do not recommend the routine use of CS IS injections in haemophilia. Moreover, point of care (POC) ultrasound (US)-guided injections are not advised, because the injection procedure is so simple that the use of POC-US will unnecessarily prolong the duration of the procedure.     

Evaluation of Hydrogen Exchange Mass Spectrometry as a Stability-Indicating Method for Formulation Excipient Screening for an IgG4 Monoclonal Antibody

Antibodies are molecules that exhibit diverse conformational changes on different timescales, and there is ongoing interest to better understand the relationship between antibody conformational dynamics and storage stability. Physical stability data for an IgG4 monoclonal antibody (mAb-D) were gathered through traditional forced degradation (temperature and stirring stresses) and accelerated stability studies, in the presence of different additives and solution conditions, as measured by differential scanning calorimetry, size exclusion chromatography, and microflow imaging. The results were correlated with hydrogen exchange mass spectrometry (HX-MS) data gathered for mAb-D in the same formulations. Certain parameters of the HX-MS data, including hydrogen exchange in specific peptide segments in the C_H2 domain, were found to correlate with stabilization and destabilization of additives on mAb-D during thermal stress. No such correlations between mAb physical stability and HX-MS readouts were observed under agitation stress. These results demonstrate that HX-MS can be set up as a streamlined methodology (using minimal material and focusing on key peptide segments at key time points) to screen excipients for their ability to physically stabilize mAbs. However, useful correlations between HX-MS and either accelerated or real-time stability studies will be dependent on a particular mAb's degradation pathway(s) and the type of stresses used.     

Impact of Glycosylation on the Local Backbone Flexibility of Well-Defined IgG1-Fc Glycoforms Using Hydrogen Exchange-Mass Spectrometry

We have used hydrogen exchange–mass spectrometry to characterize local backbone flexibility of 4 well-defined IgG1-Fc glycoforms expressed and purified from Pichia pastoris, 2 of which were prepared using subsequent in vitro enzymatic treatments. Progressively decreasing the size of the N-linked N297 oligosaccharide from high mannose (Man8-Man12), to Man5, to GlcNAc, to nonglycosylated N297Q resulted in progressive increases in backbone flexibility. Comparison of these results with recently published physicochemical stability and Fcγ receptor binding data with the same set of glycoproteins provide improved insights into correlations between glycan structure and these pharmaceutical properties. Flexibility significantly increased upon glycan truncation in 2 potential aggregation-prone regions. In addition, a correlation was established between increased local backbone flexibility and increased deamidation at asparagine 315. Interestingly, the opposite trend was observed for oxidation of tryptophan 277 where faster oxidation correlated with decreased local backbone flexibility. Finally, a trend of increasing C'E glycopeptide loop flexibility with decreasing glycan size was observed that correlates with their FcγRIIIa receptor binding properties. These well-defined IgG1-Fc glycoforms serve as a useful model system to identify physicochemical stability and local backbone flexibility data sets potentially discriminating between various IgG glycoforms for potential applicability to future comparability or biosimilarity assessments.     

Demonstration of In Vitro Host-Guest Complex Formation and Safety of para-Sulfonatocalix[8]arene as a Delivery Vehicle for Two Antibiotic Drugs

The macrocycle para-sulfonatocalix[8]arene, sCX[8], was examined with 2 antibiotic drugs, ciprofloxacin (CIP) and isoniazid. The drugs were shown to form complexes with sCX[8] using proton nuclear magnetic resonance, thermogravimetric analysis, fluorescence spectroscopy, and molecular modeling. Both drugs form 1:1 hydrated (H₂O: 13%-14% w/w) host-guest complexes, with sCX[8] binding around the pyridine ring of isoniazid, and around the piperazine and cyclopropane rings of CIP. From proton nuclear magnetic resonance, the binding constant of isoniazid to sCX[8] was 6.8 (±0.3) × 10³ M^?1. Addition of 2 equivalents of sCX[8] to CIP resulted in a 58% decrease in fluorescence, and time-resolved fluorescence anisotropy of CIP doubles with sCX[8]. Each drug binds into the cavity of the macrocycle, with binding stabilized via combinations of hydrogen bonding, electrostatic interactions, π-π stacking, and hydrophobic effects. The safety of sCX[8] was examined in vitro with human embryonic kidney 293 cells. The IC₅₀ of sCX[8] was 559 μM, which is a minimum of 5-fold higher than the concentration that would be used in the clinic. The in vitro effect of sCX[8] on the action of CIP was examined on a panel of bacterial lines. The results showed that sCX[8] has no inherent antibiotic activity and had no negative effect on the action of CIP.