Frequency of Diarrhea, Stool Specimen Collection and Testing, and Detection of Clostridioides Difficile Infection Among Hospitalized Adults in the Muenster/Coesfeld Area, Germany.

Clostridioides difficile infection (CDI) often manifests as diarrhea, particularly in adults of older age or with underlying comorbidities. However, only severe cases are notifiable in Germany. Moreover, failure to collect a stool specimen from inpatients with diarrhea or incomplete testing may lead to underdiagnosis and underreporting of CDI. We assessed the frequency of diarrhea, stool specimen collection, and CDI testing to estimate CDI underdiagnosis and underreporting among hospitalized adults. In a ten-day point-prevalence study (2019-2021) of nine hospitals in a defined area (Muenster/Coesfeld, North Rhine-Westphalia, Germany), all diarrhea cases (≥ 3 loose stools in 24 h) among adult inpatients were captured via medical record screening and nurse interviews. Patient characteristics, symptom onset, putative origin, antibiotic consumption, and diagnostic stool sampling were collected in a case report form (CRF). Diagnostic results were retrieved from the respective hospital laboratories. Among 6998 patients screened, 476 (7%) diarrhea patients were identified, yielding a hospital-based incidence of 201 cases per 10,000 patient-days. Of the diarrheal patients, 186 (39%) had a stool sample collected, of which 160 (86%) were tested for CDI, meaning that the overall CDI testing rate among diarrhea patients was 34%. Toxigenic C. difficile was detected in 18 (11%) of the tested samples. The frequency of stool specimen collection and CDI testing among hospitalized diarrhea patients was suboptimal. Thus, CDI incidence in Germany is likely underestimated. To assess the complete burden of CDI in German hospitals, further investigations are needed.

Intraarticular drug delivery in osteoarthritis.

Osteoarthritis (OA) is a primarily non-inflammatory, degenerative joint disease characterized by progressive loss of articular cartilage, subchondral bone sclerosis, osteophyte formation, changes in the synovial membrane, and an increased volume of synovial fluid with reduced viscosity and hence changed lubrication properties. As OA is the most common type of arthritis and a leading cause of disability, there is a largely unmet medical need for disease-modifying and symptomatic treatment. Due to the localized nature of the disease, intraarticular (IA) drug injection is an attractive treatment approach for OA. The various glucocorticoid and hyaluronic acid (HA) formulations, which are currently available on the market for IA treatment, provide only short-term pain relief or/and often do not provide adequate pain relief. The available oral drugs for symptomatic treatment also have shortcomings, most notably side effects. Therefore, there is still a large unmet need for novel OA drugs, which provide effective long-term pain relief and/or have disease-modifying properties. To achieve long-term drug exposure, different established formulations such as suspensions and hydrogels, and also novel approaches such as lipid based formulations and nano- or microparticles are currently in development. The development of novel drugs in combination with new formulations for IA treatment of OA, represents a promising approach in this challenging area of research.

Acylation of peptides by lactic acid solutions.

To simplify the search for effective mechanisms to suppress peptide acylation inside drug delivery devices made of poly(D,L-lactic acid) (PLA) and poly(lactic-co-glycolic acid), we were looking for a suitable model system that would allow screening of strategies for peptide stabilization. With their low pH and the presence of lactic acid oligomers, diluted lactic acid solutions promised to be a suitable test system that mimics the microclimate in degrading PLA devices. We created solutions of 1-50% (w/w) lactic acid by dilution of concentrated lactic acid. Using high performance liquid chromatography (HPLC) and high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis, oligomer hydrolysis was monitored during the equilibration process of the diluted solutions. Their final oligomer content was determined by titration and by calculations based on HPLC data. HPLC-MS analysis of human atrial natriuretic peptide (ANP) stability in different lactic acid solutions at 37 degrees C for 4 weeks demonstrated that ANP underwent acylation even in diluted solutions containing only 0.05% (w/w) lactic acid oligomers. Purity analysis of lactic acid solutions allowed us to compare the conditions in the solution test-system to the microclimate that prevails inside degrading PLA microspheres.

The effect of poly(ethylene glycol)-poly(D,L-lactic acid) diblock copolymers on peptide acylation.

The combination of poly(ethylene glycol) (PEG) with a biodegradable poly(ester), such as poly(D,L-lactic acid) (PLA), is an approach that has been successfully used for the stabilization of proteins and peptides in several biodegradable delivery devices. The acylation of peptides inside degrading PLA microspheres has been described only recently as another instability mechanism related to the accumulation of polymer degradation products inside eroding PLA. We investigated whether the block copolymerization of PLA with PEG reduces peptide acylation inside degrading microspheres. Diblock copolymers consisting of poly(D,L-lactic acid) covalently bound to poly(ethylene glycol)-monomethyl ether (Me.PEG-PLA) were used for these investigations. Human atrial natriuretic peptide (ANP) was incorporated into microspheres manufactured from Me.PEG5-PLA45, a diblock copolymer with an overall PEG content of 10%. Peptide integrity inside the microspheres was monitored by HPLC-MS analysis during 4 weeks of microsphere degradation in isotonic phosphate buffer (pH 7.4) at 37 degrees C. Inside the degrading Me.PEG5-PLA45 microspheres, acylation products as well as an oxidation product of ANP were formed. The results demonstrate that the combination of PEG with PLA does not necessarily display a favorable effect concerning peptide acylation inside degrading polymer microspheres. However, they also suggested that the acylation reaction is mainly driven by the formation and accumulation of polymer degradation products inside the degrading microspheres.

Peptide acylation by poly(alpha-hydroxy esters).

PURPOSE: Poly(lactic acid) (PLA) and poly(lactic-co-glycolic acid) (PLGA) microspheres were investigated concerning the possible acylation of incorporated peptides. METHODS: Atrial natriuretic peptide (ANP) and salmon calcitonin (sCT) were encapsulated into PLA and PLGA microspheres. Peptide integrity was monitored by HPLC-MS analysis during microsphere degradation for four weeks. sCT fragmentation with endoproteinase Glu-C was used for identifying modified amino acids. Peptide stability in lactic acid solutions was investigated to elucidate possible mechanisms for preventing peptide acylation. RESULTS: Both peptides were acylated by lactic and glycolic acid units inside degrading microspheres in a time-dependent manner. After 21 days, 60% ANP and 7% sCT inside PLA microspheres were acylated. Fragmentation of sCT with endoproteinase Glu-C revealed that besides the N-terminal amine group, lysine, tyrosine or serine are further possible targets to acylation. Stability studies of the peptides in lactic acid solutions suggest that oligomers are the major acylation source and that lower oligomer concentration and higher pH substantially decreased the reaction velocity. CONCLUSIONS: The use of PLA and PLGA for drug delivery needs substantially more circumspection. As, according to FDA standards. the potential hazards of peptide acylation products need to be assessed, our findings may have significant implications for products already on the market. Techniques to minimize the acylation reaction are suggested.