Preparation and Characterization of a Rifampicin Coamorphous Material with Tromethamine Coformer: An Experimental-Theoretical Study.

Rifampicin (RIF) is an antibiotic used to treat tuberculosis and leprosy. Even though RIF is a market-available drug, it has a low aqueous solubility, hindering its bioavailability. Among the strategies for bioavailability improvement of poorly soluble drugs, coamorphous systems have been revealed as an alternative in the increase of the aqueous solubility of drug systems and at the same time also increasing the amorphous state stability and dissolution rate when compared with the neat drug. In this work, a new coamorphous form from RIF and tromethamine (TRIS) was synthesized by slow evaporation. Structural, electronic, and thermodynamic properties and solvation effects, as well as drug-coformer intermolecular interactions, were studied through density functional theory (DFT) calculations. Powder X-ray diffraction (PXRD) data allowed us to verify the formation of a new coamorphous. In addition, the DFT study indicates a possible intermolecular interaction by hydrogen bonds between the available amino and carbonyl groups of RIF and the hydroxyl and amino groups of TRIS. The theoretical spectra obtained are in good agreement with the experimental data, suggesting the main interactions occurring in the formation of the coamorphous system. PXRD was used to study the physical stability of the coamorphous system under accelerated ICH conditions (40 °C and 75% RH), indicating that the material remained in an amorphous state up to 180 days. The thermogravimetry result of this material showed a good thermal stability up to 153 °C, and differential scanning calorimetry showed that the glass temperature (Tg) was at 70.0 °C. Solubility studies demonstrated an increase in the solubility of RIF by 5.5-fold when compared with its crystalline counterpart. Therefore, this new material presents critical parameters that can be considered in the development of new coamorphous formulations.

Reaction of KHP with excess NaOH or TRIS as standard reactions for calibration of titration calorimeters from 0 to 60 °C.

Calibration of titration calorimeters is an ongoing problem, particularly with calorimeters with reaction vessel volumes < 10 mL in which an electrical calibration heater is positioned outside the calorimetric vessel. Consequently, a chemical reaction with a known enthalpy change must be used to accurately calibrate these calorimeters. This work proposes the use of standard solutions of potassium acid phthalate (KHP) titrated into solutions of excess sodium hydroxide (NaOH) or excess tris(hydroxymethyl)aminomethane (TRIS) as standard reactions to determine the collective accuracy of the relevant variables in a determination of the molar enthalpy change for a reaction. KHP is readily available in high purity, weighable for easy preparation of solutions with accurately known concentrations, stable in solution, not compromised by side reactions with common contaminants such as atmospheric CO2, and non-corrosive to materials used in calorimeter construction. Molar enthalpy changes for these reactions were calculated from 0 to 60 °C from reliable literature data for the pKa of KHP, the molar enthalpy change for protonation of TRIS, and the molar enthalpy change for ionization of water. The feasibility of using these reactions as enthalpic standards was tested in several calorimeters; a 50 mL CSC 4300, a 185 µL NanoITC, a 1.4 mL VP-ITC, and a TAM III with 1 mL reaction vessels. The results from the 50 mL CSC 4300, which was accurately calibrated with an electric heater, verified the accuracy of the calculated standard values for the molar enthalpy changes of the proposed reactions.

A comparison of the mixed and sequential use of acetaminophen and dexketoprofen in painful vaso-occlusive crises.

PURPOSE: Opioids are widely used to treat painful vaso-occlusive crises (VOC) in sickle cell disease (SCD). However, due to opioids' significant adverse effect profiles, the search for alternative therapies continues from the past to the present. The study aimed to investigate the efficacy of acetaminophen and dexketoprofen in the treatment of painful VOC. METHODS: This study is a single-center, prospective, non-randomized, single-blinded, controlled study. The study comprised two groups: the first administered acetaminophen and dexketoprofen mixed group, while the second received them sequential group. Opioids were used in patients with persistent pain despite these analgesics. Demographic and laboratory information, pain scores, opioid requirement, dose amount, side effects, and length of hospital stay of the patients were recorded. RESULTS: The study comprised 56 (100%) patients with painful VOC, 29 (51.8%) from the mixed group, and 27 (48.2%) from the sequential group. Opioid use was seen in 16 (55.2%) patients in the mixed group and 21 (77.8%) patients in the sequential group (p = 0.074). The median amount of opioid used was significantly lower in the mixed group than in the sequential group (p < 0.001). Also, the median length of hospital stay was significantly lower in the mixed group than in the sequential group (p < 0.001). CONCLUSION: Our study suggests that administering acetaminophen and dexketoprofen in the mix for the treatment of painful VOC in patients with SCD may be a more efficient approach compared to sequential administration. This approach appears to reduce opioid usage and shorten hospital stays.

Influence of liquid extender, preservation temperature and time on the sheep sperm quality.

In this study, we evaluated sheep sperm quality after using Tris-citrate-fructose-based extender with and without egg yolk, a Tris-citrate without fructose and with egg yolk and the commercial extender Biladyl®, preserving diluted semen at 15 and 23°C for different times (4, 24, 48 and 72 h). The results showed that the diluents with fructose and egg yolk gave the best results of seminal quality. Moreover, the production of ROS was higher for the temperature of 23°C compared to the temperature of 15°C (control). In addition, VCL and the percentage of spermatozoa with intact acrosome decreased with temperatures of 23°C. Finally, a drastic decrease in sperm quality was observed after 24 hours of preservation for most of the parameters evaluated.

Simultaneous Determination of Enantiomeric Purity and Organic Impurities of Dexketoprofen Using Reversed-Phase Liquid Chromatography-Enhancing Enantioselectivity through Hysteretic Behavior and Temperature-Dependent Enantiomer Elution Order Reversal on Polysaccharide Chiral Stationary Phases.

A reversed-phase high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of the potential impurities of dexketoprofen, including the distomer R-ketoprofen. After screening the separation capability of four polysaccharide columns (Lux Amylose-1, Lux Amylose-2, Lux Cellulose-1 and Lux Cellulose-2) in polar organic and in reversed-phase modes, appropriate enantioseparation was observed only on the Lux Amylose-2 column in an acidified acetonitrile/water mixture. A detailed investigation of the mobile phase composition and temperature for enantio- and chemoselectivity showed many unexpected observations. It was observed that both the resolution and the enantiomer elution order can be fine-tuned by varying the temperature and mobile phase composition. Moreover, hysteresis of the retention times and enantioselectivity was also observed in reversed-phase mode using methanol/water mixtures on amylose-type columns. This could indicate that the three-dimensional structure of the amylose column can change by transitioning from a polar organic to a reversed-phase mode, which affects the enantioseparation process. Temperature-dependent enantiomer elution order and rare enthalpic/entropic controlled enantioseparation in the operative temperature range were also observed in reversed-phase mode. To find the best methodological conditions for the determination of dexketoprofen impurities, a full factorial optimization design was performed. Using the optimized parameters (Lux Amylose-2 column with water/acetonitrile/acetic acid 50/50/0.1 (v/v/v) at a 1 mL/min flow rate at 20 °C), baseline separations were achieved between all compounds within 15 min. Our newly developed HPLC method was validated according to the current guidelines, and its application was tested on commercially available pharmaceutical formulations. According to the authors' knowledge, this is the first study to report hysteretic behavior on polysaccharide columns in reversed-phase mode.

Low Calcium-High Magnesium Krebs-Henseleit Solution Combined with Adenosine and Lidocaine Improved Rat Aortic Function and Structure Following Cold Preservation.

Background and objectives: The main problem of vascular preservation is the maintenance of vessel graft quality and function following extended storage. Conventional preservation solutions such as histidine-tryptophan-ketoglutarate (HTK) solution, Phosphate-Buffer Solution (PBS), or sodium chloride 0.9% has been shown to be inadequate in preserving vascular physiological function after 3 days of cold storage. This study aimed to evaluate whether adenosine and lidocaine (AL) in a modified Krebs-Henseleit (KH) solution can preserve the function and histological structure of rat aortic rings after 6 days. Materials and Methods: Thirty-five aortic rings from male Wistar rats (200-300 g) were harvested and immediately immersed in one of the assigned cold preservation solutions: standard KH, modified KH (mod KH) with lower calcium (Ca2+) and higher magnesium content (Mg2+) with or without adenosine and lidocaine (mod KH-AL), and modified KH with AL, insulin, and melatonin (Mod KH-ALMI). The contraction and relaxation function of the aortic rings were examined using an isometric force transducer after 6 days of cold preservation. Hematoxylin and eosin staining were used to analyze the rings' histological structure. Results: Vascular contraction and relaxation functions were severely affected after a 6-day cold storage period in standard KH. Modifying the KH solution by reducing the Ca2+ and increasing the Mg2+ levels greatly recovered the vessel functions. The addition of AL or ALMI to the modified KH did not further recover vascular contractility. However, only the addition of AL to the modified KH increased the ACh-induced relaxation at 6 days when compared to the conventional KH, suggesting that endothelium preservation is improved. From histological analysis, it was found that the addition of AL but not ALMI further improved the endothelial lining and the structure of the elastic membrane layers of the preserved vessels after 6 days of cold preservation. Conclusions: The addition of AL to low calcium-high magnesium KH solution significantly enhanced endothelial preservation and improved endothelial-induced relaxation of preserved vessels after 6 days of cold storage.

Effectiveness of fosfomycin trometamol as oral step-down therapy for bacteraemic urinary tract infections due to MDR Escherichia coli: a post hoc analysis of the FOREST randomized trial.

BACKGROUND: Fosfomycin is a potentially attractive option as step-down therapy for bacteraemic urinary tract infections (BUTI), but available data are scarce. Our objective was to compare the effectiveness and safety of fosfomycin trometamol and other oral drugs as step-down therapy in patients with BUTI due to MDR Escherichia coli (MDR-Ec). METHODS: Participants in the FOREST trial (comparing IV fosfomycin with ceftriaxone or meropenem for BUTI caused by MDR-Ec in 22 Spanish hospitals from June 2014 to December 2018) who were stepped-down to oral fosfomycin (3 g q48h) or other drugs were included. The primary endpoint was clinical and microbiological cure (CMC) 5-7 days after finalization of treatment. A multivariate analysis was performed using logistic regression to estimate the association of oral step-down with fosfomycin with CMC adjusted for confounders. RESULTS: Overall, 61 patients switched to oral fosfomycin trometamol and 47 to other drugs (cefuroxime axetil, 28; amoxicillin/clavulanic acid and trimethoprim/sulfamethoxazole, 7 each; ciprofloxacin, 5) were included. CMC was reached by 48/61 patients (78.7%) treated with fosfomycin trometamol and 38/47 (80.9%) with other drugs (difference, -2.2; 95% CI: -17.5 to 13.1; P = 0.38). Subgroup analyses provided similar results. Relapses occurred in 9/61 (15.0%) and 2/47 (4.3%) of patients, respectively (P = 0.03). The adjusted OR for CMC was 1.11 (95% CI: 0.42-3.29, P = 0.75). No relevant differences in adverse events were seen. CONCLUSIONS: Fosfomycin trometamol might be a reasonable option as step-down therapy in patients with BUTI due to MDR-Ec but the higher rate of relapses would need further assessment.

Tris(hydroxymethyl)aminomethane Linker-Bearing Triazine-Based Triglucosides for Solubilization and Stabilization of Membrane Proteins.

High-resolution membrane protein structures are essential for a fundamental understanding of the molecular basis of diverse cellular processes and for drug discovery. Detergents are widely used to extract membrane-spanning proteins from membranes and maintain them in a functional state for downstream characterization. Due to limited long-term stability of membrane proteins encapsulated in conventional detergents, development of novel agents is required to facilitate membrane protein structural study. In the current study, we designed and synthesized tris(hydroxymethyl)aminomethane linker-bearing triazine-based triglucosides (TTGs) for solubilization and stabilization of membrane proteins. When these glucoside detergents were evaluated for four membrane proteins including two G protein-coupled receptors, a few TTGs including TTG-C10 and TTG-C11 displayed markedly enhanced behaviors toward membrane protein stability relative to two maltoside detergents [DDM (n-dodecyl-ß-d-maltoside) and LMNG (lauryl maltose neopentyl glycol)]. This is a notable feature of the TTGs as glucoside detergents tend to be inferior to maltoside detergents at stabilizing membrane proteins. The favorable behavior of the TTGs for membrane protein stability is likely due to the high hydrophobicity of the lipophilic groups, an optimal range of hydrophilic-lipophilic balance, and the absence of cis-trans isomerism.

Heat-induced antigen retrieval utilizing modified Tris-EDTA buffer for reprobing of Western blots on nitrocellulose paper.

The development of heat-induced antigen retrieval technologies with Tris-EDTA buffer has dramatically improved immunostaining of specific antigens for routine immunohistochemical detection (Krenacs et al., 2010) [1]. However, little evidence exists on whether heat-Induced antigen retrieval utilizing Tris-EDTA buffer can strip western blot (WB) membranes and allow sequential reprobing. Here, we serendipitously discover that ∼95 °C Tris-EDTA buffer with 0.01% Tween 20 could repeatedly strip the Nitrocellulose membranes (NC). After electroblotting, NC blots were soaked into Tris-EDTA stripping buffer (∼95 °C, 10-25min) and we could perform at least five rounds (the following antibodies used: Vinculin, Atg7, Caspase-3, UBA5, JNK and ERK1/2) stripping in sequential chemiluminescent detections. The NC membranes also show clear western signals and background without losing transferred proteins during the reprobing process of WB. Hence, this study report additional new roles of the heat-Induced antigen retrieval Tris-EDTA buffer with 0.01% Tween 20. The method is simpler, more affordable and harmless for the nitrocellulose paper, which will be helpful for effective reprobing in western blotting applications.

Exploration of the effects of chloride ions on the analysis of polar compounds at low concentrations by hydrophilic interaction liquid chromatography coupled to a charged aerosol detector: Application to tromethamine.

In this study, we discuss the origin of the slightly increased response of the charged aerosol detector when low-concentration polar drugs formulated with sodium chloride are analyzed by hydrophilic interaction liquid chromatography coupled to the charged aerosol detector. In the case of tromethamine mixed with saline solutions, we investigated several levels including the mobile phase, sample matrix, and detection. We show that the analysis of the rich-salted sample results in both interactions with the mobile phase modifiers and the stationary phase during the run time. With 150 mM NaCl as a compounding solution, a slight increase in the tromethamine peak area was observed (<5.5%). Our study suggests that chloride ions in excess sequentially interact firstly with the counterions from the organic modifiers and secondly with the analyte via the stationary phase and the contribution of hydrophilic interaction liquid chromatography retention mechanisms. Because of these effects, the hydrophilic interaction liquid chromatography-charged aerosol detector analysis of drugs in saline solutions requires particular attention, and a correction factor for quantitative purposes that accounts for formulation ions remains appropriate.

Optimizing Exosome Preparation Based on Size and Morphology: Insights From Electron Microscopy.

Extracellular vesicles (EVs), including exosomes, are crucial in intercellular communication, but differentiating between exosomes and microvesicles is challenging due to their similar morphology and size. This study focuses on multivesicular bodies (MVBs), where exosomes mature, and optimizes exosome isolation using transmission electron microscopy (TEM) for size information. Considering that EVs are nanocolloidal particles, a salt-free Bis-Tris buffer is found to maintain EV integrity better than phosphate-buffered saline (PBS). Dynamic light scattering (DLS) and TEM analysis confirm that intact exosome fractions under the salt-free Bis-Tris buffer condition exhibit polydispersity, including a unique population of <50 nm vesicles resembling intraluminal membrane vesicles (ILVs) in MVBs, alongside larger populations. This <50 nm population disappears in PBS or Bis-Tris buffer with 140 mM NaCl, transforming into a monodisperse population >100 nm. Immunoelectron microscopy also validates the presence of CD63, an exosome biomarker, on approximately 50 nm EVs. These findings provide valuable insights into exosome characterization and isolation, essential for future biomedical applications in diagnostics and drug delivery.

Does preventive single dose of intravenous dexketoprofen reduce pain and swelling after orthognathic surgery? A prospective, randomized, double blind clinical trial.

BACKGROUND: The purpose of this study was to evaluate the effect of a single-dose intravenous dexketoprofen administration for preventive analgesia on postoperative pain and reducing swelling in double jaw surgery. MATERIAL AND METHODS: The authors designed a prospective, randomized, and double-blind cohort study. Patients who have Class III malocclusion were randomly divided in two groups. 50 mg intravenous dexketoprofen trometamol were administrated 30 minutes before incision in treatment group, while intravenous sterile saline was administrated 30 minutes before incision in placebo group. The primary predictor variable was treatment group. Primary outcomes were pain, swelling and 24-hour opioid intake. Patient- controlled analgesia with tramadol was given for management of postoperative pain. Other variables were demographic and operation related parameters. Visual analogue scale was used to evaluate postoperative pain. 3dMD Face System (3dMD, USA) was used to measure postoperative swelling. Data were analysed using two independent samples t test and Mann Whitney U test. RESULTS: The study sample was composed of 30 patients with a mean age of 20,63 years and 21 were female. Preemptive dexketoprofen administration decreased postoperative tramadol consumption by 25.9% compared to placebo group, and there was a statistically significant decrease in VAS scores (p<0,05). There was no statistically significant difference between the groups in terms of swelling (p>0,05). CONCLUSIONS: Preventive administration of intravenous dexketoprofen provides adequate analgesic effect in the postoperative 24-hour period and reduces opioid consumption in orthognathic surgery.

[Effect of adjunctive drug therapy on early expulsion of distal ureteral calculi after extracorporeal shock wave lithotripsy].

Objective: To evaluate the efficacy of ketochromate tromethamine and phloroglucinol combination therapy in early expulsion of ureteral calculi after extracorporeal shockwave lithotripsy (ESWL) in patients with distal ureteral clculi. The clinical and follow-up data of 275 patients with lower ureteral calculi who underwent ESWL were collected retrospectively in Civil Aviation General Hospital from January 1st 2021 to June 30th 2021. According to whether adjunctive medication used before ESWL patients were divided into control group and medication group (with ketochromate tromethamine 30 mg and phloroglucinol 80 mg before ESWL). Primary endpoint is the clearance rate of ureteral calculi after ESWL, secondary endpoint are the other outcomes and drug allergy. There were 138 cases in control group [117 were males and mean age (42±13) years]. Meanwhile, there were 137 cases in medication group [118 were males and mean age (42±12) years]. The clearance rate of ureteral calculi at 24 h (67.88% vs 48.55%, P=0.001)、one week (76.64% vs 57.97%, P=0.001) and four weeks (89.05% vs 76.08%, P=0.005)after ESWL in medication group were significant higher than that in control group. There was a significant difference in the VAS score of pain scale after ESWL (1.77±0.80 vs 2.06±1.04, P=0.012) and re-ESWL rate (8.03% vs 17.39%,P=0.02) between two groups, but no difference with gross hematuria in 6 h after ESWL and drug allergy. Conclusions combination use of ketochromate tromethamine and phloroglucinol significantly improve early expulsion of ureteral calculi after ESWL in patients with distal ureteral calculi, with no side effect.

Evaluation of enzymatic proteoglycan loss and collagen degradation in human articular cartilage using ultrashort echo time-based biomarkers: A feasibility study.

The objective of the current study was to investigate the feasibility of quantitative 3D ultrashort echo time (UTE)-based biomarkers in detecting proteoglycan (PG) loss and collagen degradation in human cartilage. A total of 104 cartilage samples were harvested for a trypsin digestion study (n = 44), and a sequential trypsin and collagenase digestion study (n = 60), respectively. Forty-four cartilage samples were randomly divided into a trypsin digestion group (tryp group) and a control group (phosphate-buffered saline [PBS] group) (n = 22 for each group) for the trypsin digestion experiment. The remaining 60 cartilage samples were divided equally into four groups (n = 15 for each group) for sequential trypsin and collagenase digestion, including PBS + Tris (incubated in PBS, then Tris buffer solution), PBS + 30 U col (incubated in PBS, then 30 U/ml collagenase [30 U col] with Tris buffer solution), tryp + 30 U col (incubated in trypsin solution, then 30 U/ml collagenase with Tris buffer solution), and tryp + Tris (incubated in trypsin solution, then Tris buffer solution). The 3D UTE-based MRI biomarkers included T1 , multiecho T2 *, adiabatic T1ρ (AdiabT1ρ ), magnetization transfer ratio (MTR), and modeling of macromolecular proton fraction (MMF). For each cartilage sample, UTE-based biomarkers (T1 , T2 *, AdiabT1ρ , MTR, and MMF) and sample weight were evaluated before and after treatment. PG and hydroxyproline assays were performed. Differences between groups and correlations were assessed. All the evaluated biomarkers were able to differentiate between healthy and degenerated cartilage in the trypsin digestion experiment, but only T1 and AdiabT1ρ were significantly correlated with the PG concentration in the digestion solution (p = 0.004 and p = 0.0001, respectively). In the sequential digestion experiment, no significant differences were found for T1 and AdiabT1ρ values between the PBS + Tris and PBS + 30 U col groups (p = 0.627 and p = 0.877, respectively), but T1 and AdiabT1ρ values increased significantly in the tryp + Tris (p = 0.031 and p = 0.024, respectively) and tryp + 30 U col groups (both p < 0.0001). Significant decreases in MMF and MTR were found in the tryp + 30 U col group compared with the PBS + Tris group (p = 0.002 and p = 0.001, respectively). It was concluded that AdiabT1ρ and T1 have the potential for detecting PG loss, while MMF and MTR are promising for the detection of collagen degradation in articular cartilage, which could facilitate earlier, noninvasive diagnosis of osteoarthritis.

Not just a background: pH buffers do interact with lanthanide ions-a Europium(III) case study.

The interaction between Eu(III) ion and different pH buffers, popular in biology and biochemistry, viz. HEPES, PIPES, MES, MOPS, and TRIS, has been studied by solution nuclear magnetic resonance spectroscopy (NMR) and time-resolved laser-induced fluorescence spectroscopy (TRLFS) techniques. The Good's buffers reveal non-negligible interaction with Eu(III) as determined from their complex stability constants, where the sites of interaction are the morpholine and piperazine nitrogen atoms, respectively. In contrast, TRIS buffer shows practically no affinity towards Eu(III). Therefore, when investigating lanthanides, TRIS buffer should be preferred over Good's buffers.

Tromethamine and dodecanol appear to be the major secondary metabolites of Streptomyces decoyicus M.

An isolate of Streptomyces decoyicus M* (code of the isolate) was identified by the sequencing of 16S rRNA gene. It was grown on solid media and secondary metabolites were extracted with n-butanol. The extract was dried and run in a sodium dodecyl sulphate-polyacrylamide gel (SDS-PAGE, 10%). Two main bands obtained were sliced and the metabolites were regained in n-butanol. These two samples were then identified by gas-chromatography-mass spectrometry (GC-MS), and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that tromethamine- and 1-dodecanol were the main constituents (band 1: 61% and 17.7%; band 2: 41% and 54%, respectively). This finding maintained that the isolate of Streptomyces decoyicus produced high amounts tromethamine- and 1-dodecanol under the conditions investigated.

Intravenous lidocaine vs. NSAIDs for migraine attack in the ED: a prospective, randomized, double-blind study.

PURPOSE: Although different forms of lidocaine are used for migraine attack headaches, the effect of intravenous lidocaine is still limited. This study aimed to investigate the effects of intravenous lidocaine infusion for the treatment of migraine attack headaches. METHODS: A hundred patients with migraine attacks, aged between 18 and 65, were randomly divided into two groups. The lidocaine group (n = 50) received a 1.5 mg/kg lidocaine bolus and a 1 mg/kg infusion (first 30 min), followed by a 0.5 mg/kg infusion for a further 30 min intravenously. The non-steroidal anti-inflammatory drug (NSAID) group (n = 50) received 50 mg dexketoprofen trometamol and saline at the same volume as the lidocaine at the same time intervals intravenously. The Visual Analog Scale (VAS) pain scores, additional analgesia requirement, side effects, and revisits to the emergency department were recorded. RESULTS: The VAS score was significantly lower in the lidocaine group than in the NSAID group for the first 20th and 30th minutes (p = 0.014 and p = 0.024, respectively). There was no difference between the VAS scores for the remaining evaluation times (p > 0.05). In terms of secondary outcomes, rescue medication requirement was not different between the two groups at both the 60th and 90th minutes (p > 0.05). However, the number of patients revisiting ED within 48-72 h was statistically less in the lidocaine group than in the NSAID group (1/50 vs. 8/50; p = 0.031). CONCLUSION: Intravenous lidocaine may be an alternative treatment method for patients with migraine attack headaches in the emergency department.

Chiral analysis of ß-alanyl-d,l-tyrosine and its derivatives and estimation of binding constants of their complexes with 2-hydroxypropyl-ß-cyclodextrin by capillary electrophoresis.

Chiral CE methods were developed for the elucidation of l- or d-configuration of tyrosine residue in antimicrobial dipeptide ß-alanyl-tyrosine (ß-Ala-Tyr) isolated from the hemolymph of larvae of fleshfly Neobellieria bullata and for the evaluation of enantiopurity of its synthetic isomers (ß-Ala-d-Tyr and ß-Ala-l-Tyr), and enantiomers of their amidated and acetylated derivatives, ß-Ala-d,l-Tyr-NH2 and N-Ac-ß-Ala-d,l-Tyr, respectively. Baseline separations were achieved for all three pairs of enantiomers: (i) for ß-Ala-d,l-Tyr in acidic background electrolyte composed of 32/50 mM tris(hydroxymethyl)aminomethane/H3 PO4 , pH 2.5, and 20 mg/mL 2-hydroxypropyl-ß-cyclodextrin as chiral selector; (ii) for ß-Ala-d,l-Tyr-NH2 enantiomers in acidic background electrolyte consisting of 48/50 mM tris(hydroxymethyl)aminomethane/H3 PO4 , pH 3.5, and 30 mg/mL 2-hydroxypropyl-ß-cyclodextrin; and (iii) for enantiomers of N-Ac-ß-Ala-d,l-Tyr in alkaline background electrolyte composed of 50/49 mM Na2 B4 O7 /NaOH, pH 10.5, and 60 mg/mL 2-hydroxypropyl-ß-cyclodextrin. From CE analyses of mixed samples of isolated ß-Ala-Tyr and synthetic standards ß-Ala-l-Tyr and ß-Ala-d-Tyr, it turned out that isolated ß-Ala-Tyr was pure l-enantiomer. In addition, the average apparent binding constants, Kb , and average actual ionic mobilities of the complexes of ß-Ala-d,l-Tyr and its above derivatives with 2-hydroxypropyl-ß-cyclodextrin were determined. These complexes were weak, with Kb values ranging from 11.2 to 79.1 L/mol. Their cationic mobilities were equal to (5.6-9.2) × 10-9 m2 /V/s, and anionic mobilities to (-1.3-1.6) × 10-9 m2 /V/s.

Comparative evaluation of the effectiveness of intravenous paracetamol, dexketoprofen and ibuprofen in acute low back pain.

INTRODUCTION: Non-traumatic back pain constitutes roughly 5% of the admissions to emergency departments. This study seeks to compare the efficacy of intravenously administered paracetamol, dexketoprofen, and ibuprofen in patients with non-traumatic acute low back pain. METHODS: This study was designed as a randomized, double-blinded investigation and carried out at a tertiary hospital. 210 eligible patients without trauma who presented with low back pain were recruited for the study and randomized into paracetamol (n = 71), dexketoprofen (n = 70), and ibuprofen (n = 69) groups. The measurements at 0, 15, 30 and 60 min were noted down by using a 100 mm VAS, and the relevant comparisons were made. RESULTS: The VAS scores at 0 and 60 min in the paracetamol, dexketoprofen, and ibuprofen groups decreased on average by 40 mm, 42 mm, and 43 mm, respectively. The baseline and final pain scores of each drug group differed significantly (p < 0.05), though the between-group analysis revealed no significant difference (p > 0.05). CONCLUSION: Given the obtained data, we did not note a significant difference between intravenous paracetamol, dexketoprofen and ibuprofen with respect to pain efficacy in non-traumatic acute low back pain. Based on the patients' clinical conditions and histories, we concluded that the choice of medication might not change the efficacy of the treatment and patient comfort.

Development and Validation of an Innovative Analytical Approach for the Quantitation of Tris(Hydroxymethyl)Aminomethane (TRIS) in Pharmaceutical Formulations by Liquid Chromatography Tandem Mass Spectrometry.

A novel COVID-19 vaccine (BriLife®) has been developed by the Israel Institute for Biological Research (IIBR) to prevent the spread of the SARS-CoV-2 virus throughout the population in Israel. One of the components in the vaccine formulation is tris(hydroxymethyl)aminomethane (tromethamine, TRIS), a buffering agent. TRIS is a commonly used excipient in various approved parenteral medicinal products, including the mRNA COVID-19 vaccines produced by Pfizer/BioNtech and Moderna. TRIS is a hydrophilic basic compound that does not contain any chromophores/fluorophores and hence cannot be retained and detected by reverse-phase liquid chromatography (RPLC)-ultraviolet (UV)/fluorescence methods. Among the few extant methods for TRIS determination, all exhibit a lack of selectivity and/or sensitivity and require laborious sample treatment. In this study, LC−mass spectrometry (MS) with its inherent selectivity and sensitivity in the multiple reaction monitoring (MRM) mode was utilized, for the first time, as an alternative method for TRIS quantitation. Extensive validation of the developed method demonstrated suitable specificity, linearity, precision, accuracy and robustness over the investigated concentration range (1.2−4.8 mg/mL). Specifically, the R2 of the standard curve was >0.999, the recovery was >92%, and the coefficient of variance (%CV) was <12% and <6% for repeatability and intermediate precision, respectively. Moreover, the method was validated in accordance with strict Good Manufacturing Practice (GMP) guidelines. The developed method provides valuable tools that pharmaceutical companies can use for TRIS quantitation in vaccines and other pharmaceutical products.