Molecular Details Of The Mitochondrial Iron Sulfur Cluster Assembly Pathway

MOLECULAR DETAILS OF THE MITOCHONDRIAL IRON SULFUR CLUSTER ASSEMBLY PATHWAY Iron-sulfur clusters are an important class of prosthetic group involved in electron transfer, enzyme catalysis, and regulation of gene expression. Their biosynthesis requires complex machinery located within the mitochondrion since free iron and sulfide are extremely toxic to the cell. Defects in this pathway results in several diseases such as Friedreich\u27s Ataxia (FRDA), Sideroblastic Anemia and ISCU Myopathy. Therefore molecular details of the biogenesis pathway will provide deep insight in the pathway and treatment options for these diseases. FRDA is caused by deficiency of a single protein called as `Frataxin\u27. Frataxin is a mitochondrial protein shown to regulate cellular iron homeostasis. Frataxin is highly conserved from prokaryotes to eukaryotes but its cellular function has not been completely characterized. The focus of the research presented in this dissertation is to characterize frataxin\u27s interaction with the partner proteins during the iron sulfur cluster assembly pathway. This will provide us important information regarding modulation of metal delivery by frataxin and how it interacts with partner proteins, which can be used for treatment of several iron disregulation disorders. Research on two orthologs of frataxin (yeast and drosophila) is presented in this dissertation. Drosophila frataxin binds ferrous iron and exists as an alpha-beta sandwich structure. In both, yeast and drosophila, frataxin is able to deliver iron to Isu scaffold (on which transient cluster synthesis takes place) through a metal dependent protein protein interaction. Cluster binding stabilizes the fold of Isu scaffold protein. There is a separate initial metal loading site on ISU scaffold proteins other than the cysteine rich active site

OPTIMIZATION OF PANTOPRAZOLE ENTERIC PELLETS COATING PROCESS BY QBD: EFFECT OF COATING PROCESS VARIABLES ON THE INTERMEDIATE QUALITY OF THE PRODUCT AND SCALE UP

Objective: The aim of this study was to optimize pantoprazole enteric coating process based on Quality by Design (QbD) principle and successful scale up.Methods: The critical process parameters (CPP) were identified based on Failure Mode and Effect Analysis (FMEA) tool. A full factorial design was applied to develop design space and determine control strategy for pantoprazole enteric coating process, have promising yield, assay and reduced process time. The coating process variables studied were air volume (X1), spray rate (X2) and atomization air pressure (X3), versus percentage fines (Y1), percentage agglomerates (Y2) and assay (Y3) as responses. The pellets were coated in Wurster and characterized for assay, dissolution, scanning electron microscopy and loss on drying.Results: When X2 at low level and X3 at high level, spray drying increased hence fines increased while X2 at a high level and X3 at a low level, agglomeration increased. The optimization performed to decide level of X2 and X3 for fines and agglomerated free process. The operating ranges, for robust coating process of desired pellets yield and quality, X1, X2 and X3 were 46-58 CFM, 6-9 g/min and 1.1-1.3 bar respectively. In scale up of pellets, physical and chemical parameters reproduced based on process ran as per scale up factor calculation.Conclusion: It was concluded that a promising pellets coating process was successfully designed using QbD approach and successfully scale upscale up possible based on complete optimization of process variables, understanding of risk associated with variables and implementation of scale-up factor calculation provided by the vendor.Â

Preparation, optimization and in vivo evaluation of Eletriptan HBR fast dissolving oral films

The present investigation was aimed with the objective of developing fast dissolving oral films of Eletriptan HBr in order to attain quick onset of action for the better management of migraine attack. Twenty five formulations were prepared by solvent casting method using different polymer types, plasticizer types, surfactant concentrations and different ratio of hydroxypropyl methyl cellulose and maltodextrin. The prepared films were evaluated for folding endurance, thickness, drug content, in vitro/in vivo disintegration time, drug release and tensile test. The optimized formulation F17 containing HPMC 15cp and maltodextrin showed minimum in vitro disintegration time 11 seconds, highest dissolution rate i.e. 98.5% of drug within 10 min. The optimized film was further evaluated for bioavailability compared with a marketed product (Relpax-20mg). The pharmacokinetic results revealed that the fast dissolving oral films has higher peak blood concentration (Cmax, 0.455±0.1µg/ml) within shorter time (Tmax, 0.5 hours), indicating rapid absorption and faster onset of action with acceptable bioavailability value. Therefore, the oral fast dissolving film is considered to be potentially useful for the treatment of migraine disease where quick onset of action is desired, also improved patient compliance

OPTIMIZATION OF PANTOPRAZOLE ENTERIC PELLETS COATING PROCESS BY QBD: EFFECT OF COATING PROCESS VARIABLES ON THE INTERMEDIATE QUALITY OF THE PRODUCT AND SCALE UP

ABSTRACT Objective: The aim of this study was to optimize pantoprazole enteric coating process based on Quality by Design (QbD) principle and successful scale up. Methods: The critical process parameters (CPP) were identified based on Failure Mode and Effect Analysis (FMEA) tool. A full factorial design was applied to develop design space and determine control strategy for pantoprazole enteric coating process, have promising yield, assay and reduced process time. The coating process variables studied were air volume (X1), spray rate (X2) and atomization air pressure (X3), versus percentage fines (Y1), percentage agglomerates (Y2) and assay (Y3) as responses. The pellets were coated in Wurster and characterized for assay, dissolution, scanning electron microscopy and loss on drying. Results: When X2 at low level and X3 at high level, spray drying increased hence fines increased while X2 at a high level and X3 at a low level, agglomeration increased. The optimization performed to decide level of X2 and X3 for fines and agglomerated free process. The operating ranges, for robust coating process of desired pellets yield and quality, X1, X2 and X3 were 46-58 CFM, 6-9 g/min and 1.1-1.3 bar respectively. In scale up of pellets, physical and chemical parameters reproduced based on process ran as per scale up factor calculation. Conclusion: It was concluded that a promising pellets coating process was successfully designed using QbD approach and successfully scale upscale up possible based on complete optimization of process variables, understanding of risk associated with variables and implementation of scale-up factor calculation provided by the vendor

Oxidation of Methane by a Biological Dicopper Centre

Vast world reserves of methane gas are underutilized as a feedstock for the production of liquid fuels and chemicals owing to the lack of economical and sustainable strategies for the selective oxidation of methane to methanol1. Current processes to activate the strong C–H bond (104 kcal mol−1) in methane require high temperatures, are costly and inefficient, and produce waste2. In nature, methanotrophic bacteria perform this reaction under ambient conditions using metalloenzymes called methane monooxygenases (MMOs). MMOs thus provide the optimal model for an efficient, environmentally sound catalyst3. There are two types of MMO. Soluble MMO (sMMO),expressed by several strains of methanotrophs under copper-limited conditions, oxidizes methane with a well-characterized catalytic di-iron centre4. Particulate MMO (pMMO) is an integral membrane metalloenzyme produced by all methanotrophs and is composed of three subunits, pmoA, pmoB and pmoC, arranged in a trimeric α3β3γ3 complex5. Despite 20 years of research and the availability of two crystal structures, the metal composition and location of the pMMO metal active site are not known. Here we show that pMMO activity is dependent on copper, not iron, and that the copper active site is located in the soluble domains of the pmoB subunit rather than within the membrane. Recombinant soluble fragments of pmoB (spmoB) bind copper and have propylene and methane oxidation activities. Disruption of each copper centre in spmoB by mutagenesis indicates that the active site is a dicopper centre. These findings help resolve the pMMO controversy and provide a promising new approach to developing environmentally friendly C–H oxidation catalysts

Formulation Development and Evaluation of Aqueous Injection of Poorly Soluble Drug Made by Novel Application of Mixed Solvency Concept

It is commonly recognized in the pharmaceutical industry that on average more than 40% of newly discovered drug candidates are poorly water-soluble. The objective of present research is to explore the application of mixed solvency technique in the injection formulation of poorly soluble drugs and to reduce concentration of individual solubilizers (used for solubility enhancement) to minimize the toxic effects of solubilizers. In the present work poorly soluble drugs Ofloxacin are selected as model drugs. Ofloxacin is an antibiotic drug tried to formulate the aqueous injection by the use of various physiologically compatible solubilizing agent like Lignocaine Hydrochloride, Niacinamide, Sodium benzoate, Sodium citrate, PEG 400, PEG 4000, PVP 40000, Ethanol, and Propylene Glycol. For expected synergistic enhancement effect on solubility of these poorly soluble drugs various blends of solubilizers shall be tried to decrease the amounts of Solubilizer employed for a desired solubility enhancement ratio. The study further opens the chances of preparing dry powders for injection of drug which are not stable in aqueous solution, ready to use injection. Key word- Mixed solvency solubilization, Ofloxacin, solubility enhancement, synergistic enhancement effect

EVALUATION AND QUALITY CONTROL OF NASAL SPRAY

Nasal drug delivery has now been recognized as a very promising route for delivery of therapeutic compounds including biopharmaceuticals. This route is also advisable for drugs undergoing extensive first pass effect. The present article highlights the evaluation parameters of nasal spray, suspension, and solutions. While formulating the nasal drug delivery formulations various parameters are to be consider such as Appearance, Color, and Clarity, Identification, Drug content (Assay), Impurities and Degradation Products, Preservative(s) and Stabilizing Excipient(s) Assay, Pump Delivery, Spray content uniformity, Spray Content Uniformity (SCU) through Container Life, Spray Pattern and Plume Geometry, Droplet Size Distribution, Particle size distribution (suspension),  Microscopic Evaluation (Suspensions), Foreign Particulates,  Microbial limit,  Preservative Effectiveness, Net Content and Weight Loss (Stability), Leachables (Stability), PH, Osmolality.   Key words: Nasal spray, Evaluation, Quality control, Drug delivery system

Mechanisms of Action of Human Mesenchymal Stem Cells in Tissue Repair Regeneration and their Implications

Cell replacement therapy holds a promising future in the treatment of degenerative diseases related to neuronal, cardiac and bone tissues. In such kind of diseases, there is a progressive loss of specific types of cells. Currently the most upcoming and trusted cell candidate is Mesenchymal Stem Cells (MSCs) as these cells are easy to isolate from the tissue, easy to maintain and expand and no ethical concerns are linked. MSCs can be obtained from a number of sources like bone marrow, umbilical cord blood, umbilical cord, dental pulp, adipose tissues, etc. MSCs help in tissue repair and regeneration by various mechanisms of action like cell differentiation, immunomodulation, paracrine effect, etc. The future of regenerative medicine lies in tissue engineering and exploiting various properties to yield maximum output. In the current review article, we have targeted the repair and regeneration mechanisms of MSCs in neurodegenerative diseases, cardiac diseases and those related to bones. Yet there is a lot to understand, discover and then understand again about the molecular mechanisms of MSCs and then applying this knowledge in developing the therapy to get maximum repair and regeneration of concerned tissue and in turn the recovery of the patient

AN APPROACH TO ENHANCE THE SOLUBILITY OF RIFAPENTINE BY SOLID DISPERSION TECHNIQUE USING HYDROPHILIC CARRIERS

The aim of this present work was to improve the dissolution profile of Rifapentine (RPT) using solid dispersions technique with PVP K-30 or HPMC as the carrier, in different ratios of 1:1, 1:2, 1:3, 1:4, 1:5 by the kneading method and solvent evaporation method. For the purpose of comparison, another formulation was prepared by the method of physical mixture with the drug and carrier weight ratios of same. The prepared solid dispersions (SDs) were optimized on the basis of evaluation of Solubility, Drug Release rate and % drug content. Optimized formulation is than characterized by Fourier Transform Infrared Spectroscopy (FTIR), Powder X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Particle size analysis and Scanning Electron Microscopy (SEM) in order to ascertain any physicochemical interactions between the drug and carrier that could affect the dissolution profile of the drug. The dissolution studies were conducted for pure RPT and all the formulated solid dispersions. All the solid dispersions prepared by kneading method and solvent evaporation method showed an enhanced dissolution profile of Rifapentine, as compared to that of pure drug alone but among them all the solid dispersion prepared with PVP-K30 by solvent evaporation method in 1:3 ratio showed better enhancement of solubility and dissolution rate

FORMULATION DEVELOPMENT & EVALUATION OF EFFERVESCENT TABLET OF ALENDRONATE SODIUM WITH VITAMIN D3

Alendronate sodium is a bisphosphonates which has antiresorptive effect which is implicated in the prophylaxis and treatment of osteoporosis. The objective of this study was to formulate effervescent tablet of Alendronate sodium with Vitamin D3 against osteoporosis thereby improving patient compliance.                                                                                                                          As per revised definition proposed to US FDA, Effervescent tablet is a tablet intended to be dissolved or dispersed in water before administration.         Effervescent tablets were formulated using citric acid and sodium bicarbonate as effervescent composition by wet granulation. The drug-excipient compatibility study done by DSC & FTIR analysis and it reveals absence of interaction between the drug and excipients. The flowability study of precompression blend shows good flow properties. Formulation was evaluated for weight variation, thickness, hardness, solution time, pH of solution & content uniformity. All the evaluation parameters were within the limit and complies specifications as per U.S.P. & B.P. From the Stability analysis may be inferred that there was no degradation and change in the formulation.                                                                                                                                                  The Effervescent tablet of Sodium Alendronate and Vitamin D3 is a new pharmaceutical formulation to be taken orally and offering a considerable advantage: avoidance of gastro-intestinal disorders, to the limits of the possible. As compared to the pure drug and marketed tablet, this formulation displayed significantly effective in the oral osteoporosis treatment in post menopausal women