Field induced single molecule magnet behavior in Dy-based coordination polymer

A new mononuclear Dysprosium based Coordination Polymer {Dy-CP} was investigated magnetically using dc and ac magnetic susceptibility. The dc magnetic susceptibility does not exhibit any long-range ordering down to 1.8 K and the negative value of Curie Constant (~ - 4 K) indicate the dominance of antiferromagnetic interactions between the Dy (III) spins. Ac susceptibility exhibits absence of single molecular magnet behavior at zero dc magnetic field and shows signal of quantum tunneling magnetization (QTM) below 8 K. However, on the superimposition of dc magnetic field (3 kOe), frequency dependent relaxation peak emerged at T_f = 5 K and QTM signal suppress at higher fields. The intermediate value of Mydosh parameter calculated from the shift in peak position (T_f) in ac susceptibility reflects the formation of superparamagnetic state. Further, the temperature dependence of Tf is analyzed with Arrhenius and Cole-Cole plot. The magnetic susceptibility analysis yields characteristics pre-relaxation factor 1.40x10^(-12) sec and energy barrier {\Delta}E/k_B = 93.4 K, indicating the slow spin relaxation. The Cole-Cole fit to the ac susceptibility data shows further evidence for the single ion spin relaxation. Thus, the magnetic measurements support the single-molecule magnet behavior in Dy-CP under the application of dc magnetic field.Comment: 4 pages, 3 figure

Microparticle surface layering through dry coating: impact of moisture content and process parameters on the properties of orally disintegrating tablets

Objectives: The aim of this study was to investigate the influence of process parameters during dry coating on particle and dosage form properties upon varying the surface adsorbed moisture of microcrystalline cellulose (MCC), a model filler/binder for orally disintegrating tablets (ODTs). Methods: The moisture content of MCC was optimised using the spray water method and analysed using thermogravimetric analysis. Microproperty/macro-property assessment was investigated using atomic force microscopy, nano-indentation, scanning electron microscopy, tablet hardness and disintegration testing. Key findings: The results showed that MCC demonstrated its best flowability at a moisture content of 11.2% w/w when compared to control, comprising of3.9% w/w moisture. The use of the composite powder coating process (without air) resulted in up to 80% increase in tablet hardness, when compared to the control. The study also demonstrated that surface adsorbed moisture can be displaced upon addition of excipients during dry processing circumventing the need for particle drying before tabletting. Conclusions: It was concluded that MCC with a moisture content of 11% w/w provides a good balance between powder flowability and favourable ODT characteristics

A pragmatic approach for engineering porous mannitol and mechanistic evaluation of particle performance

The importance of mannitol has increased recently as an emerging diluent for orodispersible dosage forms. The study aims to prepare spray dried mannitol retaining high porosity and mechanical strength for the development of orally disintegrating tablets (ODTs). Aqueous feed of d-mannitol (10% w/v) comprising ammonium bicarbonate, NH4HCO3 (5% w/v) as pore former was spray dried at inlet temperature of 110-170°C. Compacts were prepared at 151MPa and characterized for porosity, hardness and disintegration time. Particle morphology and drying mechanisms were studied using thermal (HSM, DSC and TGA) and polymorphic (XRD) methods. Tablet porosity increased from 0.20±0.002 for pure mannitol to 0.53±0.03 using fabricated porous mannitol. Disintegration time dropped by 50-77% from 135±5.29s for pure mannitol to 75.33±2.52-31.67±1.53s for mannitol 110-170°C. Hardness increased by 150% at 110°C (258.67±28.89N) and 30% at 150°C (152.70±10.58N) compared to pure mannitol tablets (104.17±1.70N). Increasing inlet temperature resulted in reducing tablet hardness due to generation of 'micro-sponge'-like particles exhibiting significant elastic recovery. Impact of mannitol polymorphism on plasticity/elasticity cannot be ruled out as a mixture of α and β polymorphs formed upon spray drying

Morphological evolution of two-dimensional porous hexagonal trimesic acid framework

Hexagonal single crystal structure (Form II) of trimesic acid (TMA) has been isolated by dissolving the interpenetrated Form I of TMA in tetrahydrofuran. Form II (hexagonal) was converted to Form I (interpenetrated) at room temperature through some intermediate structures. A detailed time-dependent FESEM study shows that the external morphology of Form II (hexagonal) is a hollow hexagonal tube that mimics its crystal structure. The block-shaped (morphology) of Form I (interpenetrated) was converted to the hollow hexagonal tube through some intermediate morphologies which are corresponding to particular crystal structures. Here, we have established a strong correlation between crystal structures with the morphology. These hollow tubes have been employed for Rhodamine B dye adsorption studies and showed an uptake of 82%, much more significant than Form I (interpenetrated) (39%) due to the presence of a pore channel in the crystal structure

A comparative study on surgical management of distal end radius fracture with ulnar styloid fracture with and without ulnar styloid fixation

INTRODUCTION Fractures of the distal radius are the most common fractures of the upper extremity and account for 17% of all fractures treated in the emergency room. Initially thought to be simple fractures, they are now recognized as complex injuries with a high percentage of long term complications. Aims and objectives : To Observe the results and assess the Functional outcome of the management of Distal End Radius Fractures by plating, with and without ulnar styloid fixation with Tension Band Wiring (TBW) and to know the complications associated. Materials and methods : This is a prospective study from January 2015 to December 2017. Out of 40 patients of this study, radius was fixed by volar plating in all patients,where as ulnar styloid - fixed by TBW in 20pts and in remaining left without fixation at Department of orthopedics, Pratima Institute of Medical Sciences, Karimnagar. All patients were selected among admissions, operated and results were assessed clinically and radiographically. Clinical evaluation was done using modified Demerit score system of Gartland and Werely. Perioperative complications recorded. Mean followup period was 6months. Results : We had 10(50%) in ulnar styloid fixation and 9(45%) in ulnar styloid non fixation cases rated as excellent, as they had no deformity of the wrist and there was no pain. None of the patient had poor modified Demerit score system of Gartland and Werely. Complications like irritation of EPL due to K- wire(25%), loosening of K-wire(5%), stiffness (5%) seen in patients with ulnar styloid fixation. Ulnar sided wrist pain is seen in 20% of cases without ulnarstyloid fixation. Conclusion : In fixation group of ulnar styloid , excellent to good results were seen in 90% of patients, In non fixation of ulnar styloid group , excellent to good results were seen in 80% of patients suggesting that stabilizing the distal radius fracture fragments with volar plate and screws ,is only required method [in both groups] to maintain the anatomical reduction which is crucial in maintaining stability of DRUJ, till union and to prevent collapse of the fracture fragments

Evaluating the role of amino acids and isothermal dry particle coating in modulating buccal permeation of large molecule drug vancomycin

The formulation and delivery of macromolecules through the oral route pose considerable challenges due to factors such as large molecular weight, pH sensitivity, and limited formulation approaches. This challenge is compounded if the drug is poorly permeable, necessitating innovative drug delivery strategies. Vancomycin, a widely prescribed glycopeptide antibiotic, has an oral bioavailability of less than 10%, leading to predominantly intravenous administration and potential patient discomfort. This study explores the potential of the buccal route as a non-invasive, highly vascularised alternative route of administration, offering a rapid onset of action while bypassing the first-pass metabolism. In this study, vancomycin was coated with L-glutamic acid using an isothermal dry particle coater to modulate permeation through the buccal cell line, TR146. Results confirm significant impact of both amino acid concentration and dry particle coating on the rate and extent of drug permeability. With the introduction of L-glutamic acid and utilisation of the isothermal dry particle coater, vancomycin's permeation profile increased six-fold compared to the control due to the formation of drug ion-pair complex. Imaging studies showed the presence of layered micronized glutamic acid particles on the surface of dry coated vancomycin particles which confirms the role of dry coating and amino acid concentration in modulating drug permeation. Microbiology experiments in Staphylococcus aureus, minimum inhibitory concentration and biofilm disruption studies, provided confirmatory evidence of antimicrobial activity of dry coated glutamic acid-vancomycin ion pair particulate structure. This study demonstrates, for the first-time, buccal delivery of dry coated large molecule drug, vancomycin, through controlled deposition of amino acid using innovative particle coating strategy

Current opinions and recommendations of paediatric healthcare professionals - The importance of tablets:Emerging orally disintegrating versus traditional tablets

The appropriate prescribing of paediatric dosage forms is paramount in providing the desired therapeutic effect alongside successful medication adherence with the paediatric population. Often it is the opinion of the healthcare practitioner that dictates which type of dosage form would be most appropriate for the paediatric patient, with liquids being both the most commonly available and most commonly used. Orally disintegrating tablets (ODTs) are an emerging dosage form which provide many benefits over traditional dosage forms for paediatric patients, such as rapid disintegration within the oral cavity, and the reduction in the risk of choking. However the opinion and professional use of healthcare practitioners regarding ODT's is not known. This study was designed to assess the opinions of several types of healthcare professionals (n = 41) regarding ODTs, using a survey across two hospital sites. Results reaffirmed the popularity of liquids for prescribing in paediatrics, with 58.0% of participants preferring this dosage form. ODTs emerged as the second most popular dosage form (30.0%), with healthcare practitioners indicating an increasing popularity amongst patients in the hospital setting, belief with 63.0% of practitioners agreeing that many liquid formulations could be substituted with a suitable ODT. The desired properties of an ideal ODT were also identified by healthcare practitioners preferring a small, fast disintegrating tablet (90.2% and 95.1% respectively), with the taste, disintegration time and flavour being the three most important attributes identified (29.5%, 28.7% and 21.7% respectively). This study provided a pragmatic approach in assessing healthcare professional's opinions on ODTs, highlighting the ideas and thoughts of practitioners who are on the frontline of paediatric prescribing and treatment and gave an indication to their preference for ODT properties

Determining Protease Substrate Selectivity and Inhibition by Label-Free Supramolecular Tandem Enzyme Assays

An analytical method has been developed for the continuous monitoring of protease activity on unlabeled peptides in real time by fluorescence spectroscopy. The assay is enabled by a reporter pair comprising the macrocycle cucurbit[7]uril (CB7) and the fluorescent dye acridine orange (AO). CB7 functions by selectively recognizing N-terminal phenylalanine residues as they are produced during the enzymatic cleavage of enkephalin-type peptides by the metalloendopeptidase thermolysin. The substrate peptides (e.g., Thr-Gly-Ala-Phe-Met-NH2) bind to CB7 with moderately high affinity (K ≈ 104 M–1), while their cleavage products (e.g., Phe-Met-NH2) bind very tightly (K \u3e 106 M–1). AO signals the reaction upon its selective displacement from the macrocycle by the high affinity product of proteolysis. The resulting supramolecular tandem enzyme assay effectively measures the kinetics of thermolysin, including the accurate determination of sequence specificity (Ser and Gly instead of Ala), stereospecificity (d-Ala instead of l-Ala), endo- versus exopeptidase activity (indicated by differences in absolute fluorescence response), and sensitivity to terminal charges (−CONH2 vs −COOH). The capability of the tandem assay to measure protease inhibition constants was demonstrated on phosphoramidon as a known inhibitor to afford an inhibition constant of (17.8 ± 0.4) nM. This robust and label-free approach to the study of protease activity and inhibition should be transferable to other endo- and exopeptidases that afford products with N-terminal aromatic amino acids