Background/Objectives: Myasthenia Gravis (MG) and myasthenic syndrome (MSyn) are neurological disorders induced by different types of autoantibodies, characterized by generalized muscle weakness, sometimes involving the respiratory muscles and necessitating ventilatory support. One therapeutic option for severe Myasthenia Gravis (MG) is total plasma exchange (TPE). This procedure reduces the concentration of autoantibodies by extracting the patient’s plasma and replacing it with donor plasma. The TPE efficacy varies among different types of MG, and patient response to TPE is evaluated solely through clinical markers, such as muscle strength. So far, no laboratory method is available for monitoring TPE treatment progress. Objective: In this study, we aimed to determine whether differential scanning calorimetry (DSC) of blood plasma from myasthenic patients is an appropriate tool to monitor and evaluate their condition and the TPE effect. Methods: We performed DSC prior to and after TPE course on blood plasma from three patients with different types of MG: Case 1. Patient with Acetylcholine Receptor Myasthenia Gravis (AChR MG); Case 2. Patient with Muscle-specific tyrosine kinase Myasthenia Gravis (MuSK MG); Case 3. Patient with Myasthenic syndrome (MSyn). Results: DSC thermogram examination revealed increased plasma protein fractions, primarily immunoglobulins (IG), as well as to some extent fibrinogen, relative to a suppressed serum albumin fraction. Successive TPE procedures resulted in IG fraction decline in AChR MG (Case 1) and MSyn (Case 3), and upsurge of the IG fraction in MuSK MG (Case 2). These findings aligned with the clinical presentation of all three cases. Conclusions: DSC revealed distinct, very significant differences in the heat capacity profiles of blood plasma from MG patients relative to healthy controls, as well as strong TPE influence on the plasma thermal behavior. DSC showed promise as a reliable and informative technique for the monitoring of myasthenia and TPE effects across diverse myasthenic patient populations. Further research is needed to confirm and expand on these findings.

In this study, we investigated the interaction of a dapagliflozin-containing medicinal product (the commercial drug Forxiga^®) with human serum albumin (HSA) at different temperatures using steady-state fluorescence spectroscopy, competitive displacement assays, UV–Vis absorption spectroscopy, and thermodynamic analysis. Increasing concentrations of Forxiga induced a gradual, concentration-dependent quenching of the intrinsic fluorescence of HSA (${\lambda }_{\mathrm{ex}}=284$ nm; ${\lambda }_{\mathrm{em}\max }\approx 334$–339 nm), indicating perturbation of the microenvironment surrounding Trp-214 located in subdomain IIA. Stern–Volmer analysis showed that the quenching constants were temperature-dependent. Meanwhile, the high apparent bimolecular quenching constants suggested a predominantly static quenching mechanism associated with ground-state complex formation. By performing a modified Scatchard-type double-logarithmic analysis, we identified a primary binding site, particularly at lower temperatures. Van’t Hoff analysis revealed negative enthalpy and entropy changes. This indicates that the interaction was spontaneous and exothermic, mainly driven by hydrogen bonding and van der Waals forces. The competitive displacement assays confirmed preferential binding at Sudlow’s site I, in proximity to Trp-214. Additionally, the UV–Vis spectroscopy, supported by ligand-induced perturbation of aromatic residues, confirmed the absence of significant inner-filter effects. Differential scanning calorimetry suggested partial thermal stabilization of HSA upon ligand binding. This finding is consistent with the formation of a stabilized protein–ligand complex. These results suggest that Forxiga forms a relatively stable ground-state complex with HSA, primarily at Sudlow’s site I, and that the interaction is influenced by temperature-dependent conformational changes in the protein.