DEVELOPMENT AND EVALUATION OF DROTOVERINE TASTE MASKED TABLETS WITH IMPROVED DISSOLUTION EFFICIENCY USING SOLID DISPERSION TECHNIQUE
The purpose of this research is to mask the bitter taste of the drug, Drotoverine using solid dispersion technique. The taste-masked drug is formulated in to a conventional tablet by direct compression method for ease of administration. Taste masking was done by solid dispersion using polymer such as urea and mannitol by melting/fusion method Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were performed to identify the physicochemical interaction between drug and carrier, hence its effect on dissolution. Conventional taste masked tablets were evaluated for weight variation, disintegration time, hardness and friability. In vitro drug release studies were performed for conventional tablets of drotoverine. Bitterness score was evaluated on volunteers. FTIR spectroscopy and SEM showed no interaction between drug and carriers. Conventional tablets prepared using solid dispersion, showed faster disintegration and complete bitter taste masking of drotoverine. In addition the prepared tablets exhibited better dissolution profile. Taste evaluation of taste masked tablets in human volunteers rated tasteless with a score of 0. Thus, results conclusively demonstrated successful masking of taste and oral disintegration of the formulated tablets in the oral cavity with improved dissolution.
FORMULATION AND EVALUATION OF FAST DISSOLVING TABLETS OF OLMESARTAN MEDOXOMIL BY USING CO- PROCESSED EXCIPIENTS TECHIQUE
In the present work, fast dissolving tablets of Olmesartan medoxomil were prepared using novel co-processed superdisintegrants consisting of crospovidone and croscarmellose sodium in different ratios (1:1, 1:2 and 1:3).Olmesartanmedoxomil (OLM) is an angiotensin II receptor blocker used for the treatment of hypertension. In present work an attempt was made to mask the metallic taste and enhance the solubility and dissolution rate of poorly soluble OLM by formulating it as inclusion complexesby kneading method with β-cyclodextrins (β-CDs) as complexing agentin 1:1 molar ratio. Effect of co-processed superdisintegrants on pre-formulation parameters, wetting time, disintegrating time, drug content and in-vitro release have been studied. Drug compatibility with excipients was checked by FTIR and DSC studies. The co-processing of the superdisintegrants was done by solvent evaporation. The values of pre-compression parameters evaluated were within prescribed limits and indicated good free flowing property. From the prepared inclusion complexes and co-processed excipients, fast dissolving tablets (FDTs) were formulated. In all the formulations, hardness test indicated good mechanical strength results ranging from 2.89 to 3.81 kg/cm 2 , friability is less than 1%indicated that tablets have good mechanical resistance. Wetting time is an important criteria for understanding the capacity of disintegrants to swell in presence of little amount of water were found to be in the range of 7.33 to 14.66 seconds. Disintegration time was found to be in the range of 8.33 to 20.00 seconds. Drug content was found to be in the range of 97.36 to 99.72 %. Among all the designed formulations, formulation CPI3 i.e.co-processed excipients having ratio CSS:CP (1:3) containing 5% w/w of co-processed superdisintegrants, was found to be promising and was displayed an in-vitro dispersion time of 8.33 seconds, which
Evolution of carbide precipitates in Hastelloy N joints during welding and post weld heat treatment
Abstract The effects of welding and post weld heat treatment (PWHT) on the morphology, composition and lattice parameter of the precipitates in the welding joints of Hastelloy N alloy have been investigated. Joint samples were prepared using a gas tungsten arc welding process with ERNiMo-2 fillers, and then solid-solution treated at 1100 °C for 20 min. After welding, eutectic M6C carbides can be observed in the heat affected zones (HAZ) and weld zones (WZ). These eutectic M6C carbides become spheroidized during the following PWHT. The concentration of Si decreases during the transformation from the primary ones to eutectic ones, and then increases during the spheroidizing process. The total concentration of Si + Cr in M6C carbides remains stable during welding and PWHT. At the same time, the heat leads to the outward diffusion of Mo from the M6C carbides, which results in a decrease of the lattice parameter.