The preparation of MnSO4 by reacting pyrolusite at high temperatures with SO2 generated from pyrite was followed by DTA, and the process conditions were optimized to fix the minimum time and temperature of reaction required to obtain the maximum yield of pure MnSO4 from stoichiometric amounts of reactants in a natural draught of air. The presence of MnO and Fe304 in the reaction products, detected by DTA, indicates that the SO2 is initially oxidized to SO 3 by reducing MnO2, Mn203 and Fe203 to MnO and Fe30,. SO3 finally attacks MnO to form MnSO,. When an intimate stoichiometric blend of pyrite and pyrolusite is heated at temperatures ranging from 873 K to 973 K for 3 hrs, about 93% of the Mn is converted to ironfree MnSO4.When intimate mixtures of pyrite (FeS2) and pyrolusite (MnO2) are reacted at high temperatures, about 80% of the Mn is converted to MnSO 4 in a period of 7 hrs [1]. A higher yield (92%) is obtained when MnO 2 is directly reacted with SO 2, but the amount of SO 2 used is high [2]. In view of this, the DTA technique was used to study the changes that take place'in pyrite and pyrolusite during their reaction at high temperatures, and optimization studies were undertaken to fix the minimum time and temperature of reaction at which the maximum yield of pure MnSO, could be obtained.
Aim:The present study deals with preparation of zidovudine loaded microparticle by counter ion induced aggregation method. During this study effect of polyacrylates and hypromellose polymers on release study were investigated.Materials and Methods:The ion induced aggregated alginate based microparticles were characterized for surface morphology, particle size analysis, drug entrapment study, in-vitro study, Fourier-transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC) study.Results and Discussion:The result showed Eudragit RL-100 (ERL) based formulations had smoother surface as well as their mean particle sizes were found greater compared with Eudragit RS-100 (ERS) microparticles. Furthermore, drug entrapments were found to be more in ERL formulae as compared with ERS. RL3 released 101.05% drug over a period of 8th h and followed Higuchi profile and Fickian diffusion. Moreover, data obtained illustrated that, higher amount of quaternary ammonium group, alkali value, and glass transition temperature may be possible reason for improving permeability of ERL based formulations. It was also noticed, hyroxypropyl methylcellulose (HPMC) K4M premium grade polymer sustained drug release more than HPMC K15M. In addition, drug-excipient interaction study was carried out by FTIR and DSC study.
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