Development and Characterization of Eudragit RS 100 Loaded Microsponges and its Colonic Delivery Using Natural Polysaccharides

In the present work, paracetamol loaded eudragit based microsponges were prepared using quasi-emulsion solvent diffusion method. The compatibility of the drug with various formulation components was established. Process parameters were analyzed in order to optimize the formulation. Shape and surface morphology of the microsponges were examined using scanning electron microscopy. The colon specific formulations were prepared by compression coating of microsponges with pectin:hydroxypropylmethylcellulose (HPMC) mixture followed by tabletting. The in vitro dissolution studies were done on all formulations and the results were evaluated kinetically and statically. The kinetics of release study showed that the release data followed Higuchi matrix and the main mechanism of drug release from microsponges was diffusion. In vitro studies exhibited that compression coated colon specific tablet formulations started the release the drug at the 6th hour corresponding to the arrival time to proximal colon

What Makes ERP Systems to Deliver? Impact of Post-Implementation Capabilities on ERP Value

More than two decades of research on information technology (IT) value still leaves the issue of ITvalue in an organization a less understood concept. The issue of IT value is particularly important incase of systems such as Enterprise Resource Planning (ERP) because these systems involve significantfinancial investments. Evidence from the current literature indicates that a high number of ERPimplementations fail to deliver the anticipated benefits. While successful implementation of ERPsystems is essential before any benefit can be expected from them, success of the implementation itselfcannot ensure that ERP systems will add value to the organization subsequently. Extant literature onERP systems is overly focused on capabilities that help an organization to successfully implement anERP system and lacks studies that focus on capabilities required to derive benefits from ERP systemsin the post-implementation stage. To address this gap in the literature, in this research in progressstudy, we develop a theoretical model and related hypotheses to examine the effect of post-ERPimplementation capabilities on value delivered by ERP systems. In this paper, we also outline themethodology to validate the theoretical model using the data that would be collected in the next step.Broadly, the research suggests that value of ERP systems after successful implementation is impactedby three sets of capabilities, end users’ capability to use ERP system functionalities, managerialcapability to use information generated through ERP systems to achieve organizational objectives,and overall organizational IT capability

Assessing Value of ERP Systems: A Formative Construct Analysis

ERP systems have the potential to provide value across multiple dimensions: from operational and managerial to strategic. As with any other information technology, the value of ERP systems can be assessed using different metrics. The available methods of ERP value assessment such as financial performance indicators for the organization do not provide multidimensional contribution of ERP systems. Very few studies in ERP value literature have quantitatively measured and validated ERP value across multiple dimensions. Using the Balanced Scorecard (BSC) approach, this study conceptualizes and validates measures of ERP value across four dimensions of BSC: internal business oriented ERP value, customeroriented ERP value, learning and growth-oriented ERP value, strategic and financial-oriented ERP value. The measurement model for ERP value indicates the robustness of measures used in the study

Stringent Response in Mycobacteria: Molecular Dissection of Rel

Adaptation to any undesirable change in the environment dictates the survivability of many microorganisms. Such changes generate a quick and suitable response, which guides the physiology of bacteria. Stringent response is one of the mechanisms that can be called a survival strategy under nutritional starvation in bacteria and was first observed in E. coli upon amino acid starvation, when bacteria demonstrated an immediate downshift in the rRNA and tRNA levels (Stent and Brenner 1961). Mutations that rendered bacteria insensitive to amino acid levels were mapped to an ‘RC gene locus’, later termed relA because of the relAxed behavior of the bacteria (Alfoldi et al. 1962). Later on, Cashel and Gallant, showed that two “magic spots” (MSI and MSII) were specifically observed in starved cells when a labeled nucleotide extract of these cells was separated by thin layer chromatography (Cashel and Gallant 1969). These molecules were found to be polyphosphate derivatives of guanosine, ppGpp and pppGpp (Cashel and Kalbacher 1970; Sy and Lipmann 1973), and were shown to be involved in regulating the gene expression in the bacterial cell, demonstrating a global response, thus fine-tuning the physiology of the bacterium. Two proteins in E. coli, RelA and SpoT, carry out the synthesis and hydrolysis of these molecules, respectively, and maintain their levels in the cell (Cashel et al. 1996; Chatterji and Ojha 2001). On the other hand, Gram-positive organisms have only one protein Rel carrying out the functions of both RelA and SpoT (Mechold et al. 1996; Martinez-Costa et al. 1998; Avarbock et al. 1999). Although Rel or RelA/SpoT has been studied from several systems in detail pertaining to the physiological adaptation, less information is available on the egulation of the protein activity under different conditions. Our studies show that the RelMsm is composed of several domains (HD, RSD, TGS and ACT) with distinct function. HD and RSD domains, present in the N-terminal half of the protein, harbor catalytic sites for the hydrolysis and the synthesis of (p)ppGpp, respectively. TGS and ACT domains, on the other hand, are present at the C-erminal half of the protein and have regulatory function. It, therefore, appears that a communication exists between these domains, to regulate protein activity. It was shown earlier, while studying Rel from S.equisimilis, that there exists an interaction between the C-terminal and the N- terminal of the protein which determines the kind of activity (synthesis/hydrolysis), the protein should demonstrate (Mechold et al. 2002). Later, the N-terminal half crystal structure of the same protein suggested an inter-domain “cross-talk” between the HD and the RSD domain that controls the synthesis/hydrolysis switch depending on cellular conditions (Hogg et al. 2004). In the present work, studies have been carried out to understand a Gram- positive Rel in greater detail and to find out how the opposing activities of Rel are regulated so that a futile cycle of synthesis and hydrolysis of (p)ppGpp, at the expense of ATP, can be avoided. The work has been divided into several chapters describing studies on various aspects of the protein. Chapter 1 outlines the history of the stringent response and summarizes the information available about the stringent response in various systems including plants. Several roles that (p)ppGpp plays in different bacteria have been examined. A special mention on the crystal structure of RelSeq has been made with respect to the regulation of activity. Also, the information available regarding the effects of (p)ppGpp on RNA polymerase has been documented. Role of ppGpp in plants has been discussed in great detail with special emphasis on abiotic stresses. Since different functional domains have been identified in RelMsm, the protein has been divided into two halves and they have been discussed separately in the form of two chapters. Chapter 2 describes the N-terminal half of the Rel protein of M. smegmatis in greater detail. Out of the several domains identified, the role of the two domains present in the N-terminal half of the protein has been studied. The N-terminal half shows both synthesis and hydrolysis activities. Importantly, we find that the protein is active even in the absence of accessory factors such as ribosome and uncharged tRNA, unlike RelA of E. coli. Moreover, deletion of the C-terminal half of the protein leads to a much higher synthetic activity, clearly indicating that the C-terminus is involved in regulating the activity of the protein. Both TGS and ACT domains (the two domains found in the C-terminal half of the protein) have been found to play a regulatory role. The results also indicate that all the deleted constructs are active both in vitro and in vivo. Chapter 3 discusses the C-terminal half of the protein and its role in the multimerization observed in RelMsm. We show that multimerization of Rel protein is due to the inter-molecular disulfide cross-linking. Furthermore, we find that the monomer is the active species in vivo. One of the fascinating points about the C- terminal half is that it is largely unstructured. Additionally, the C-terminal half cannot complement the N-terminal part of the protein when provided in trans, demonstrating further, the requirement of an intact protein for bringing about regulation of Rel activity. This requirement in cis suggests the presence of an intra-molecular communication between the N- and the C-termini, as a mediator of protein regulation. Further, presence of uncharged tRNA increases pppGpp synthesis and down-regulates its hydrolysis in the wildtype protein. However, the uncharged tRNA-mediated regulation is absent in the deleted construct with only the N-terminus half, indicating that uncharged tRNA binds to the C-terminal half of the protein. Several cysteine mutants have been constructed to understand their role in the regulation of Rel activity. The results suggest that one cysteine, present at the C-terminus, is required for intra-molecular cross-talk and the uncharged tRNA-mediated regulation. A detailed characterization of the communication between the two halves of the protein has been attempted in Chapter 4. Surface plasmon resonance experiments carried out on the different cysteine mutants discussed in Chapter 3, for uncharged tRNA binding indicate that all the mutants bind to uncharged tRNA with near-equal affinities as the wildtype protein. This study suggests that the non-responsiveness for tRNA seen in one of the cysteine mutants is due to the loss of inter-domain interaction, while the binding of protein to accessory factors is unaffected. Fluorescence resonance energy transfer has been carried out to observe domain movement in the presence of accessory factors. Distances between the different domains scattered in this ~90 kDa protein, measured by FRET technique, are suggestive of an inter-domain cross-talk, specifically between C338 and C692, thereby regulating the activity of this enzyme. We show, for the first time, that the product of this protein, (p)ppGpp can bind to the C-terminal half making it unstructured, and can, therefore, regulate the protein activity. Chapter 5 is an effort to characterize the promoter of rel from M. tuberculosis. This study was undertaken in order to develop an expression system in mycobacteria. The +1 transcription and the translation start sites have been identified. The –10 hexamer for the RNA polymerase binding has also been mapped using site-directed mutagenesis and is found to be TATCCT. This promoter is also unusually close to the +1 transcription start site. The promoter is specific for mycobacteria and does not function in E. coli. Additionally, the promoter is found to be constitutive in M. smegmatis; however, the possibility of it being regulated in M. tuberculosis cannot be ruled out. Appendix section discusses, in short, the phylogenetic analysis of the mycobacterial Rel sequences. Diagrams of the plasmids used in this study have been provided. Mass spectra recorded for the in vitro synthesized and purified pppGpp and the trypsin digest of the full-length Rel protein have also been given. O O O

Paclitaxel delivery by micro/nano encapsulation using layer-by-layer assembly

A novel formulation of paclitaxel (PTX) has been developed by providing multilayer assembly over drug loaded porous CaCO3 microparticles (CaCO3 MP) using combination of biocompatible and biodegradable polyelectrolytes (PE’s). PTX was encapsulated into the nanopores of preformed CaCO3 MP prepared by the co-precipitation method. Infrared (IR) and X-ray diffraction (XRD) provides evidences that PTX has been encapsulated into nanopores of CaCO3 MP and not crystallized on the surface. PTX loaded CaCO3 MP (CaCO3-PTX) was found to be highly stabilized against thermal decomposition as evinced by thermo gravimetric analysis (TGA) indicating decomposition at 600°C and 250°C for CaCO3-PTX and PTX respectively. The multilayer assembly over CaCO3-PTX was effectuated by alternate deposition of protamine sulfate (PRM) and sodium alginate (SA) using LBL technique followed by subsequent core removal [PTX- (PRM/SA)5]. The pay load efficiency of PTX in this system was found to be 78.98±2.14%. The developed system was further evaluated for surface morphology, size and size distribution, surface charge, core removal and layer-by-layer growth due to sequential adsorption of PE’s. The release data of PTX-(PRM/SA)5 was comparable with marketed formulation of PTX (PTX-M) and CaCO3-PTX when performed in simulated intestinal fluid (SIF pH=7.4). The release profile of PTX-(PRM/SA)5 indicates that PEs based multilayer matrix is capable to provide barrier to PTX release as it has been found to follow first order matrix diffusion kinetics with 64±4.8% release within 24 hrs. The t50% of PTX-M, CaCO3-PTX and PTX-(PRM/SA)5 was found to be 70, 90 and 480 minutes respectively. This alternative delivery system of PTX disguised in the form of LBL assembly could have immense application for the treatment of metastasized mammary glands vis-à-vis existing formulation of PTX which is by and large criticized for having certain toxic excipients to be given parentrally. Moreover, the proposed system provides ample of opportunity to modify the surface for targeted application of PTX.
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The significant others of subjective norm - A scientometric study of subjective norm in IS top-journals over two decades

The role of grounded approaches has been advocated for long in IS research. However, the inherent subjectivity of such approaches and the apparent lack of a basis to validate or even replicate such research has often been the subject of debate among IS researchers. As a result, many IS researchers tend to fall back on variance-theoretic approaches to conceptualize, design and operationalize their research. In this paper, we show how a grounded approach, interpretive structural modeling (ISM), can be used to qualitatively elicit individual cognitive structures. Further, we show how it can be applied to derive the shared aspects of such a structure across many individuals. We use the well-known technology acceptance model (TAM) to demonstrate the utility of our approach. We conclude the paper by discussing the strengths and weaknesses of this approach