X-ray Structure and Properties of the Ferrous Octaethylporphyrin Nitroxyl Complex

The preparation and characterization of the iron octaethylporphyrin nitroxyl ion, [Fe(OEP)(NO)−], is reported. The complex was synthesized by the one-electron reduction of Fe(OEP)(NO) using anthracenide as the reducing agent. The compound was isolated as the potassium (2.2.2)cryptand salt. The anion was characterized using X-ray analysis with visible and infrared spectroscopy. The spectral features of the iron nitroxyl complex were consistent with previous literature reports. The important structural changes upon reduction were a significant decrease in the Fe–N–O bond angle from 142° to 127° and an increase in the N–O bond length from that in the starting nitrosyl moiety. The porphyrin ring became significantly less planar upon reduction, but the displacement of the iron atom from the 24-atom plane was essentially unchanged. In spite of the attempt to encapsulate the potassium ion with the (2.2.2)cryptand, significant interaction between K+ and the oxygen of the nitroxyl were observed, indicating a contact ion pair in the crystal structure. Comparison between the experimental structure and the DFT-calculated parameters were reported. The results are consistent with the Fe–N–O moiety being the site of the reduction, with little evidence for the reduction of the iron itself or the porphyrin ring. The proton NMR spectrum was also obtained, and the chemical shifts were significantly different from other S = 0 metalloporphyrin complexes. These shifts, though, were consistent with the DFT calculations

PROCESS AND PARAMETERS AFFECTING DRUG RELEASE PERFORMANCE OF PREPARED CROSS-LINKED ALGINATE HYDROGEL BEADS FOR EZETIMIBE

Objective: The objective of this study was to formulate an oral sustained release delivery system of ezetimibe mucoadhesive beads by ionic gelation technique based on sodium alginate used as a hydrophilic carrier in combination with carbopol 934P which acts as a rate modifier.Methods: Microbeads of ezetimibe were prepared using an easy method of ionotropic gelation by little modification while in addition of drug. The prepared beads were characterised for mean particle size, entrapment efficiency, swelling capacity, and in vitro release. They were also subjected to various studies such as Fourier Transform Infrared Spectrophotometer (FTIR) Spectroscopy for drug polymer reaction, Scanning Electron Microscopy for surface morphology, and Differential Scanning Calorimetric Analysis to determine the physical state of the drug in the beads.Results: The microspheres of ezetimibe were formulated successfully. The addition of drug concentration gives higher drug loading and higher conc. of Alcl+3 yields small diameter beads and lower drug entrapment. Analysis of the release profiles showed that the data corresponds to zero order release and the diffusion-controlled mechanism as suggested by Higuchi concept.Conclusion: It can be concluded that beads produced by the sequential method had higher drug entrapment. Beads produced by simultaneous yields larger beads in diameter. The concept was cleared that drug release was dependent upon the quantity of polymer and increase in conc. of. aluminium chloride retarded the drug release in the sequential method. Prepared beads enhance the dissolution of ezetimibe and the oral bioavailability and also reduce the fluctuations in the oral bioavailability

THE ROLE OF NEEDLE IN FORMULATION OF pH SENSITIVE SWELLABLE MICROBEADS PREPARED WITH HYDROPHILIC POLYMERS FOR ATORVASTATIN AND THEIR CHARACTERIZATION STUDIES

Objective: The aim of the study was to develop and characterize mucoadhesive microbeads for oral sustained release of atorvastatin by using hydrophilic polymers and application of different process variables in designing of pH sensitive swellable microbeads.Methods: Microbeads were prepared by ionic gelation method. The compatibility studies of atorvastatin with polymers were investigated by differential scanning calorimeter and fourier transform infrared spectroscopy studies. In this work process variable like optimization of curing agents and their quantity, effect of rpm, and their influence in drug entrapment were studied. Prepared beads were characterized for particle size, swelling index, erosion studies and drug release studies.Results: Mixture of alginate and carbopol 934 P at 3.3 % w/v shows sustained release and good mucoadhesive capacity. Furthermore, drug loading and swelling increased with the use of a combination of polymers. On basis of in vitro release studies and swelling studies, it was observed that sodium alginate coated with carbopol 934 P showed sustained release of 84.5 % at end of 10 h in 6.8 phosphate buffer. The optimised batch followed peppas and higuchi release mechanism and releasing the drug by non-fickian transport.Conclusion: The alginate beads with a combination of carbopol 934P showed a sustain release pattern. The release rate and swelling of atorvastatin beads could be adjusted by adding other hydrophilic polymers or by optimising curing agents, curing time and their volume. The zero order of drug release was confirmed for all the batches. The in vitro data was better fit to Higuchi's diffusion model and diffusion rate limited

Formulation studies on cyclodextrin complexes of Meloxicam

ABSTRACT β-Cyclodextrin (β-CD) and HP-β-Cyclodextrin (HP-β-CD) inclusion complexes of piroxicam (PRX) exhibited higher dissolution rates and dissolution efficiency values than the corresponding un-complexed drug. The feasibility of formulating the β-cyclodextrin and HP-β-cyclodextrin complexes of piroxicam (1:3) into tablet dosage forms is evaluated. Solid inclusion complexes of piroxicam prepared by kneading method were formulated into tablets by wet granulation and direct compression methods. All the tablets formulated employing β-cyclodextrin and HP-β-cyclodextrin complexes of piroxicam gave rapid and higher dissolution rates of when compared to that of piroxicam plain tablets. All the prepared tablets fulfilled the official (I.P.) disintegration time specification of uncoated tablets. Overall, tablets prepared by direct compression method disintegrate rapidly when compared to those prepared by wet granulation method. Analysis of dissolution data as per zero-order and first -order kinetic models indicated that the dissolution of piroxicam from all the tablets followed first-order kinetics. In both direct compression and wet granulation methods, tablets formulated employing cyclodextrin complexes (PRXT2, PRXT3, PRXT5, PRXT6) gave higher rates of dissolution (K 1 ) and dissolution efficiency (DE 30 ) values when compared to the corresponding tablets formulated with piroxicam as such (PRXT1, PRXT4). Among all the piroxicam tablets formulated, formulation PRXT2, which is based on PRX-βCD (1:3) kneaded complex, gave highest dissolution. A 17.0 fold increase in the dissolution rate of piroxicam was observed with PRXT2 when compared to its plain tablets ( PRXT1)

Ab initio and DFT studies on structure, vibrational spectra of 4-tert-butyl-1,3-thiazol-2-amine (BTA)

Theoretical studies have been carried out on 4-tert-butyl-1, 3-thiazol-2-amine (BTA) using both the B3LYP/6-311+G and HF/6-311+G methods. The geometrical parameters and vibrational spectra of BTA have been calculated and analyzed. The calculated IR wavenumbers have been compared with the observed FTIR wavenumbers. The complete assignments have been performed based on the potential energy distribution (PED) of the vibrational modes. The wavenumbers obtained from B3LYP method are in good agreement with the observed wavenumbers when compared to HF method. It has been found that there is an excellent correlation with 0.999 regression coefficient between the experiment and calculated vibrations. Thermal properties like rotational constants, zero point vibrational energies and nonlinear optical properties like dipole moment, hyperpolarizabilities, NBO analysis and the effect of temperature on various thermodynamic properties have been calculated and orted

DEVELOPMENT AND CHARACTERIZATION OF GASTRO RETENTIVE MUCOADHESIVE MICROBEADS CONTAINING SIMVASTATIN WITH DIFFERENT CROSS LINKING AGENTS

Objective: The aim of the present work was to prepare and examine drug release of the oral controlled release microbeads using different curing agents by emulsification internal ionic gelation technique. Methods: Cross-linked alginate microbeads were prepared with different cross linking agents by using mucoadhesive properties. The formation and compatibility of microbeads were confirmed by compatibility studies. Prepared microbeads evaluated for encapsulated efficiency, micromeritic properties, drug loading, in vitro wash off studies, in vitro dissolution studies, drug release kinetics and stability studies Results: The in vitro drug release was influenced by both type of curing agents and type of polymers and no significant changes in characterization parameters was observed after 3 mo stability studies. The sustained release profile of optimized batch was found to be 99.66±0.18% in comparison to pure drug profile of 28.64±0.02% at 12 h release study. Results of both wash-off and in vitro studies suggests that batch (SF2) prepared with aluminium chloride has shown better mucoadhesive property. Drug release of optimized batch follows zero order with non fickian mechanism according to Korsmeyer-Peppas equation. Conclusion: The data suggest the use of simvastatin mucoadhesive cross linked microbeads to offer the potential for oral controlled drug delivery with improved gastric retention and capable to provide sustained drug release by using cross linking agents

Performance of introduced confectionery lines for yield and quality characteristics at ICRISAT Center, India

About a third of the world's groundnut production is consumed in the form of edible nuts. Large-seeded groundnuts are preferred for direct consumption. Development of large-seeded varieties with improved seed quality characteristics is an important breeding activity at ICRISAT Center. India and at North Carolina State University (NCSU), Raleigh, USA. We obtained 65 largeseeded advanced breeding/germplasm lines from NCSU to broaden the genetic base.............

Inheritance of period from seedling emergence to first flowering in peanut (Arachis Hypogaeal)

F 1 progenies peanut (Arachis hypogaeal. L.) from a 6 x diallel, including reciprocals and their parents, were evaluated for the number of days seedlings emergence to first flower appearance during the 1981 and 1982 rainy seasons at ICRISAT Centre, Patancheru, India. Genetic analysis indicated the predominant role of additive genetic variance in the expression of this character. Genotype 91176 had the best general combining ability for early flowering and has the potential for use in breeding programs.Variety M 13 had the best general combining ability for late flowerin