Facile Coating of HAP on Ti6Al4V for Osseointegration

Ti6Al4V alloy is a material with great strength, low-slung modulus, inferior density, and a virtuous blend of mechanical and exceptional corrosion resistance. However, it does not offer good osseointegration and bone development properties. Conversely, hydroxyapatite (HAP) is highly bioactive in nature to bind with the nearby bone tissues when implanted in the host body. In this work, we have extracted HAP from bovine bones by using the thermal decomposition method. This was followed by its deposition onto the Ti6Al4V alloy using the Electrophoretic Deposition (EPD) technique. TiO2 is used as a bond coat layer to increase the adhesion between HAP and Ti6Al4V alloy substrates. The coated samples after sintering exhibited excellent adhesion. This was followed by characterization using Scanning Electron Microscopy (SEM) and Fourier Transformed Infrared Spectroscopy (FTIR). FTIR and SEM confirm the formation of HAP and its presence after the immersion in SBF. Vicker hardness tester confirms the increase in hardness value of coated samples up to 35%. Potentiostat tests were conducted to compare the corrosion rate of both samples. In addition, the particle sizes were also identified by a laser particle analyzer, whereas X-Ray Diffraction (XRD) technique was also used to determine the crystalline phases of alloy and HAP.

Rubber-to-steel adhesives based on natural rubber grafted with poly(acetoacetoxyethyl methacrylate)

The present study aimed to develop adhesives for bonding natural rubber (NR) to steel based on modified NR bearing grafted poly(acetoacetoxyethyl methacrylate), NR-g-PAAEM. Graft copolymers of NR-g-PAAEMs were prepared by emulsion polymerization at 50 °C. A significant increase in the polar component of NR from 1.62 to 6.84 mN/m was observed after grafting modification, indicating an increase in its hydrophilicity. After that, both one-coat and two-coat adhesives (or adhesive/cover-coat system) were then prepared, using polyisocyanate (poly‐HDI) as a bonding agent. The NR/steel joints were made by vulcanization bonding, using the NR-g-PAAEM adhesive in the presence or absence of cover-coat layer. The results reveal that the NR/steel joint bonded using the two-coat system exhibited higher peel strength than that bonded using the one-coat system. For the two-coat system, the peel strength of 874 N/m was attained when the NR-g-PAAEM adhesive was used in combination with the NR cover-coat. The replacement of the NR cover-coat by the NR-g-PAAEM20 cover-coat led to 49% increase in peel strength of the NR/steel joint. Moreover, the X-ray photoelectron spectroscopy analysis also indicated the formation of urethane-like bonding in this adhesive system, as a result of the reaction between the poly‐HDI and metal oxides on the steel surface.

Interactions of Bacillus subtilis Basement Spore Coat Layer Proteins

Bacillus subtilis endospores are exceptionally resistant cells encircled by two protective layers: a petidoglycan layer, termed the cortex, and the spore coat, a proteinaceous layer. The formation of both structures depends upon the proper assembly of a basement coat layer, which is composed of two proteins, SpoIVA and SpoVM. The present work examines the interactions of SpoIVA and SpoVM with coat proteins recruited to the spore surface during the early stages of coat assembly. We showed that the alanine racemase YncD associates with two morphogenetic proteins, SpoIVA and CotE. Mutant spores lacking the yncD gene were less resistant against wet heat and germinated to a greater extent than wild-type spores in the presence of micromolar concentrations of l-alanine. In seeking a link between the coat and cortex formation, we investigated the interactions between SpoVM and SpoIVA and the proteins essential for cortex synthesis and found that SpoVM interacts with a penicillin-binding protein, SpoVD, and we also demonstrated that SpoVM is crucial for the proper localization of SpoVD. This study shows that direct contacts between coat morphogenetic proteins with a complex of cortex-synthesizing proteins could be one of the tools by which bacteria couple cortex and coat formation.

Development, Feasibility Assessment and in-vitro Evaluation of Diclofenac Potassium Multilayered Tablets

Introduction: Diclofenac potassium has widely been utilized as an analgesic and anti-inflammatory agent. To achieve rapid onset of action with prolonged therapeutic action is an immense need of time. In present project a study was conducted on preparation with physicochemical determination of diclofenac potassium tablets, this unique tablet have duel characteristics like rapid onset of action due to orodispersible coat and extended release of API due to sustained release core. Methodology: As diclofenac potassium is not sensitive to water so wet granulation method was efficiently employed to prepare the granules of sustained release core, while direct compression was done to prepare orodispersible outer coat layer in order to give rapid release. Results and Discussion: In evaluations granules characteristics and tablet properties were studied. Result of both pre compression and post compression studies were coming in pharmacopeia acceptable ranges. The orodispersible layer disintegrated with in 18sec, which gives sufficient amount of API as loading dose, in order to maintain the plasma drug concentration in therapeutic range the core will release drug in sustained manner within 10 hours in gastrointestinal tract (GIT) fluid (pH 6.8). The results of kinetic models were complying with Higuchi model. Conclusion: In present work, a rapid release outer dispersible layer of drug was constructed on a sustained release core. Results of study gives expected outcomes to maintained initial concentration of drug which persist for long time. The combination of sodium starch glycolate, dry starch, and cross povidone exhibited promising super disintegrant efficiency while Hydroxypropylmethyl cellulose K15 showed excellent sustained release properties.