Bulk Viscous LRS Biachi-I Universe with variable GG and decaying Λ\Lambda

The present study deals with spatially homogeneous and totally anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with variable $G$ and $\Lambda$ in presence of imperfect fluid. To get the deterministic model of Universe, we assume that the expansion $(\theta)$ in the model is proportional to shear $(\sigma)$. This condition leads to $A=\ell B^{n}$, where $A$,\;$B$ are metric potential. The cosmological constant $\Lambda$ is found to be decreasing function of time and it approaches a small positive value at late time which is supported by recent Supernovae Ia (SN Ia) observations. Also it is evident that the distance modulus curve of derived model matches with observations perfectly.Comment: 11 pages, 4 figures and 1 table, Accepted for publication in Astrophysics and Space Scienc

Some anisotropic universes in the presence of imperfect fluid coupling with spatial curvature

We consider Bianchi VI spacetime, which also can be reduced to Bianchi types VI0-V-III-I. We initially consider the most general form of the energy-momentum tensor which yields anisotropic stress and heat flow. We then derive an energy-momentum tensor that couples with the spatial curvature in a way so as to cancel out the terms that arise due to the spatial curvature in the evolution equations of the Einstein field equations. We obtain exact solutions for the universes indefinetly expanding with constant mean deceleration parameter. The solutions are beriefly discussed for each Bianchi type. The dynamics of the models and fluid are examined briefly, and the models that can approach to isotropy are determined. We conclude that even if the observed universe is almost isotropic, this does not necessarily imply the isotropy of the fluid (e.g., dark energy) affecting the evolution of the universe within the context of general relativity.Comment: 17 pages, no figures; to appear in International Journal of Theoretical Physics; in this version (which is more concise) an equation added, some references updated and adde

Non-Vacuum Bianchi Types I and V in f(R) Gravity

In a recent paper \cite{1}, we have studied the vacuum solutions of Bianchi types I and V spacetimes in the framework of metric f(R) gravity. Here we extend this work to perfect fluid solutions. For this purpose, we take stiff matter to find energy density and pressure of the universe. In particular, we find two exact solutions in each case which correspond to two models of the universe. The first solution gives a singular model while the second solution provides a non-singular model. The physical behavior of these models has been discussed using some physical quantities. Also, the function of the Ricci scalar is evaluated.Comment: 15 pages, accepted for publication in Gen. Realtiv. Gravi

Preparation and Characterization of Itraconazole Microsponges using Eudragit RSPO and Study the Effect of Stirring on the Formation of Microsponges

The purpose of the present study was to prepare and evaluate Itraconazole loaded microsponges using Eudragit for the controlled release of the drug and study the effect of stirring rate on the formation of microsponges. Microsponges containing Itraconazole were prepared by using quasi-emulsion solvent diffusion method at different stirring rate i.e. 500, 800, 1000, 1200 and 1500rpm.  Particle size of prepared microsponge was observed in the range of 78.43 to 23.18 µm. Scanning electron microscopy revealed the porous, spherical nature of the microsponges. The production yield, entrapment efficiency, and drug content were found to be 80.88%, 84.53% and 82.89%. The formulation with higher drug to polymer ratio 1:10 (i.e. F5) was chosen to investigate the effect of stirring rate on the morphology of microsponges. As the speed was increased, the particle size of microsponges was reduced and uniform spherical microsponges were formed. As drug polymer ratio increased, Production yield, drug content and entrapment efficiency was found to be increased while drug: polymer ratio has reverse effect on particle size, as drug: polymer ratio increase, particle size decreases. The cumulative percentage drug release upto 8hrs for F5 was 89.54% and the mechanism of drug release from the formulations during the dissolution was determined using the zero order, first order, higuchi equation and Peppas equation. All formulations were best fitted to Zero order and peppas plot. The best formulation F5 follows Zero order release. Keywords: Microsponges, Itraconazole, stirring rate, Quasi-emulsion solvent diffusion metho

A Review on Microsponge Delivery System

Microsponge is recent novel technique for control release and target specific drug delivery system. Microsponge technology has been introduced in pharmaceutical industry to provide the controlled release of active drug ingredient for the application into the skin in order to decrease systemic exposure and reduce local cutaneous reactions to active drugs. Microsponges comprises of microporous beads, typically 10-25 microns in diameter, loaded with active agent. The microsponge releases its active ingredient on a time mode, when applied to the skin,  and also in response to other stimuli that are used mostly for topical and recently for oral administration. Microsponge technology has many favourable characteristics which make It all around suitable as drug delivery vehicle. Microsponge systems can suspend or entrap a wide variety of substances, and then be incorporated into a formulated product such as a gel, cream, liquid or powder. The outer surface is mostly porous, allowing the sustained flow of substances out of the sphere. Microsponge drug delivery system causes increased efficacy for the topically active agents with enhanced safety and product stability for a longer period of time with reduction in side effects. In addition their non-allergenic, non-irritating, non-mutagenic and nontoxic behaviour makes them the suitable dosage form. The present review emphasis Microsponge drug delivery system along with its release mechanism. Keywords: Novel drug delivery system, Microsponges, Microsponge drug delivery system, Quasi-emulsion solvent diffusion method

Advancement in Novel Drug Delivery System: Niosomes

Niosomes represent a promising drug delivery module. Noisome same as to liposome and Noisome represent alternative vesicular drug delivery systems with respect to liposomes, due to the noisome ability to encapsulate the different type of drugs within their multi environmental structure. Niosomes are thoughts to be a better system for drug delivery as compared to liposomes due to various factors like cost, stability etc. They are many types of drug deliveries that can be possible using niosomes like targeting, ophthalmic, topical, parenteral, etc. In recent research, comprehensive research carried over noisome as a drug carrier. Various drugs are enlisted and tried in noisome surfactant vesicles. Niosomes proved to better drug carrier system and has the potential to reduce the side effects of drugs and increased therapeutic effectiveness in various diseases. Noisome used more than fifty drugs are tried in niosomal formulations by the intravenous route, per oral administration, trans-dermal route of administration, and inhalation preparation, ocular nasal route of administration. Treatment of infectious diseases and immunization has undergone a revolutionary work in recent years. The large numbers of disease-specific biological have been developed, and also emphasis has been made to effectively deliver these biological. Niosomes shows an emerging class of novel vesicular systems. Niosomes are self-assembled vesicles composed primarily of synthetic surfactant and cholesterol. Comprehensive research carried over noisome as a drug carrier. Various drugs are enlisted and tried in noisome surfactant vesicles. This article presents an overview of the techniques of preparation of noisome, types of noisome, characterization and their applications. Keywords-Niosomes; Method of preparation; Evaluation study; Application of Niosome

Formulation and Evaluation of Fluconazole Microsponge using Eudragit L 100 by Quasi Emulsion Solvent Diffusion Method

The aim of the present study is to formulate and evaluate the fluconazole microsponge by using Eudragit L 100. Microsponge was made because they provide controlled as well as target specific release of the drug. Thus study the effect of stirring rate on the formation of microsponge. Microsponge containing Fluconazole were prepared by quasi-emulsion solvent diffusion method at different stirring rate i.e 500, 800, 1000, 1200 and 1500 rpm. Particle size of prepared microsponge was observed in the range of 76.2 to 32.5μm. Scanning electron microscopy revealed the porous, spherical nature of the microsponges. The production yield, entrapment efficiency and drug content were found to be 78.24%, 82.76%, 81.36%. The impact of Drug: Polymer ratio and process variables i.e stirring speed and stirring time on the physical features of microsponges like production yield, mean particle size, entrapment efficiency were examined. It was shown that production yield, drug content and entrapment efficiency was found to be increase with increase in drug polymer ratio while drug: polymer ratio has reverse effect on particle size, as drug: polymer ratio increase, particle size decrease. As the polymer concentration increased, more amount of polymer surrounding the drug, thus increasing the thickness of the wall of the polymer matrix which lead to extended diffusion path and ultimately to lesser drug release or more sustained release. The effect of stirring rate on the morphology of microsponge. The formulation with higher drug to polymer ratio 1:8 (i.e F4) was chosen to investigate the effect of stirring rate on the morphology of microsponges. The dispersion of the drug and polymer within the aqueous phase was found to be dependent on the agitation speed. As the speed was increased the size of microsponges was reduced and the microsponges were found to be spherical and uniform. Keywords: Novel drug delivery system, Microsponges, Eudragit L 100, Fluconazole, Quasi-emulsion solvent diffusion method

Inflationary Cosmology and Quantization Ambiguities in Semi-Classical Loop Quantum Gravity

In loop quantum gravity, modifications to the geometrical density cause a self-interacting scalar field to accelerate away from a minimum of its potential. In principle, this mechanism can generate the conditions that subsequently lead to slow-roll inflation. The consequences for this mechanism of various quantization ambiguities arising within loop quantum cosmology are considered. For the case of a quadratic potential, it is found that some quantization procedures are more likely to generate a phase of slow--roll inflation. In general, however, loop quantum cosmology is robust to ambiguities in the quantization and extends the range of initial conditions for inflation.Comment: 15 pages, 8 figure