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Development and investigation of gastro retentive dosage form of weakly basic drug
Shah Samip,Pandya Shridhar,Waghulade Mahesh
Asian Journal of Pharmaceutics , 2010,
Abstract: The release of drug substance from controlled-release dosage forms is often pH-dependent since most drugs are either weak acids or weak bases. A system that permits the drug release to be changed freely while maintaining pH-independent drug release (model drug was Domperidone) was developed. Powder mixture of drug and HPMC K4M, eudragit L100, sodium bicarbonate (as gas-generating agent) and other excipients were mixed and directly compressed using single-punch tablet compression machine. It was found that sodium bicarbonate reacts with HCl and produce carbon dioxide which creates pores in tablet and elevates swelling by wetting the polymer. So it helps in maintaining the buoyancy. The release rate could be modified by varying the polymer ratio. The prepared tablets were evaluated for general appearance, content uniformity, hardness, friability, buoyancy, in vitro drug release and in vivo studies. The best formulation (D 1 ) was selected based on in vitro characteristics and was used in vivo radiographic studies by incorporating BaSO 4 . These studies revealed that the tablets remained in the stomach for 250±30 min in fasted rabbits and indicated that gastric retention time was increased by the floating principle, which was considered desirable for the absorption window drugs. The linear regression analysis and model fitting showed that all these formulations followed Higuchi model, which had a higher value of correlation coefficient (r). The scanning electron microscopy images of the tablet (D 1 formulation) were taken before and after dissolution and images showed that the drug was released from matrix by diffusion mechanism. Stability studies of all formulations were carried out at elevated temperature and humidity conditions of 40±2 o C/75±5% RH and a control sample was placed at an ambient condition for 12 months. It was found that there was no significant change in buoyancy property as well as in drug content from initial drug content of all the formulations at the end of 12 months, indicating that the formulations are stable.
Formulation and evaluation of transdermal patches of papaverine hydrochloride
Shah Samip,Rahul Joshi,Prabhakar Prabhu
Asian Journal of Pharmaceutics , 2010,
Abstract: Transdermal patches of papaverine hydrochloride were prepared by the solvent casting method using ethyl cellulose: PVP, PVA: PVP and Eudragit RL-100: Eudragit RS-100 using different ratios. The physicochemical parameters such as flexibility, thickness, smoothness, weight variation, moisture content, hardness and tensile strength were evaluated for the prepared patches. The formulation exhibited flexibility, uniform thickness and weight, smoothness, good drug content (92 to 96%), and little moisture content. The in vitro diffusion studies were carried out using modified Keshery-Chein cell using cellophane as the diffusion membrane and the formulation followed the Higuchi diffusion mechanism. The formulation containing PVA: PVP as polymers showed faster release rate (hydrophilic polymers) compared to Eudragit RL-100: Eudragit RS-100 (hydrophobic polymers) or combination of hydrophilic and hydrophobic polymers (ethyl cellulose and PVP). The stability studies indicated that all the patches maintained good physicochemical properties and drug content after storing the patches in different storage conditions. Compatibility studies indicated that there was no interaction between the drug and polymers. In vivo studies showed that papaverine hydrochloride helps in decreasing the effect of isoproterenol-induced myocardial necrosis. Hence, the aim of the present study was to prepare the sustained release formulation (Transdermal patches) of the drug using different blend of polymers. The formulated patches containing the hydroplilic polymers showed best release rate of drug.
Control chart : A statistical process control tool in pharmacy
Shah Samip,Shridhar Pandya,Gohil Dipti
Asian Journal of Pharmaceutics , 2010,
Abstract: Control chart is the most successful statistical process control (SPC) tool, originally developed by Walter Shewhart in the early 1920s. A control chart can easily collect, organize and store information, calculate answers and present results in easy to understand graphs. It helps to record data and allows to see when an unusual event, e.g., a very high or low observation compared with "typical" process performance, occurs. Computers accept information typed in manually, read from scanners or manufacturing machines, or imported from other computer databases. The resulting control charts can be examined in greater detail, incorporated into reports, or sent across the internet. A stable process is a basic requirement for process improvement efforts. A computer collecting information in real time can even detect very slight changes in a process, and even warn you in time to prevent process errors before they occur. First, control charts demonstrate how consistently process is performing, and whether you should, or should not, attempt to adjust it. Next, the statistical process control chart compares the process performance to standard pharmaceutical requirements, providing a process capability index as an ongoing, accurate direction for quality improvement. Finally, control charts and its resulting process capability index quickly evaluate the results of quality initiatives designed to improve process consistency. This review focuses on elements of control chart and types of various control charts along with example. Advantages of various control charts are also included.
Numerical Simulation of Two-Dimensional Dendritic Growth Using Phase-Field Model  [PDF]
Abdullah Shah, Ali Haider, Said Karim Shah
World Journal of Mechanics (WJM) , 2014, DOI: 10.4236/wjm.2014.45015
Abstract:

In this article, we study the phase-field model of solidification for numerical simulation of dendritic crystal growth that occurs during the casting of metals and alloys. Phase-field model of solidification describes the physics of dendritic growth in any material during the process of under cooling. The numerical procedure in this work is based on finite difference scheme for space and the 4th-order Runge-Kutta method for time discretization. The effect of each physical parameter on the shape and growth of dendritic crystal is studied and visualized in detail.

Urban Green Spaces and an Integrative Approach to Sustainable Environment  [PDF]
Shah Md. Atiqul Haq
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.25069
Abstract: This paper explains the benefits and challenges of urban green spaces based on the critical discussion of study results from different studies in different cities. The important roles played by green spaces are social, economic, cultural and environmental aspects of sustainable development. Urban green spaces can be a comprehensive tool for long term protection of environmental sustainability through improving the quality of life and air quality, increasing property value due to their amenity and aesthetic characteristics, and reducing the energy costs of cooling buildings. Urban green spaces also can provide ecosystem services in which the recreation and relaxation facilities are especially available to urban dwellers and tourists too. To confirm the multiple roles played by green spaces, certain level of qualitative improvements and distribution of green spaces within the urban area should be considered and incorporated effectively into the environmental sustainability agenda. To do this, an integrated approach regarding the planning, monitoring, designing and maintaining of urban green spaces is required for improving the environmental sustainability in cities in different countries.
Vibration Analysis of an Infinite Poroelastic Circular Cylindrical Shell Immersed in Fluid  [PDF]
Syed Ahmed Shah
Open Journal of Acoustics (OJA) , 2012, DOI: 10.4236/oja.2012.22010
Abstract: The purpose of this paper is to study the effect of presence of fluid within and around a poroelastic circular cylindrical shell of infinite extent on axially symmetric vibrations. The frequency equation each for a pervious and an impervious surface is obtained employing Biot’s theory. Radial vibrations and axially symmetric shear vibrations are uncoupled when the wavenumber is vanished. The propagation of axially symmetric shear vibrations is independent of presence of fluid within and around the poroelastic cylindrical shell while the radial vibrations are affected by the presence of fluid. The frequencies of radial vibrations and axially symmetric shear vibrations are the cut-off frequencies for the coupled motion of axially symmetric vibrations. The non-dimensional phase velocity as a function of ratio of thickness to wavelength is computed and presented graphically for two different types of poroelastic materials for thin poroelastic shell, thick poroelastic shell and poroelastic solid cylinder.
A Survey of High Performance Concrete Developments in Civil Engineering Field  [PDF]
Vatsal Patel, Niraj Shah
Open Journal of Civil Engineering (OJCE) , 2013, DOI: 10.4236/ojce.2013.32007
Abstract:

High Performance concrete (HPC) has received increased attention in the development of infrastructure Viz., Buildings, Industrial Structures, Hydraulic Structures, Bridges and Highways etc. leading to utilization of large quantity of concrete. This paper presents a comprehensive coverage of High Performance concrete developments in civil engineering field. It highlights the High Performance concrete features and requirements over conventional concrete. Furthermore, recent trends with regard to High Performance Concrete development in this area are explored. This paper also includes effect of Mineral and Chemical Admixtures used to improve performance of concrete.

Stochastic Logistic Model for Fish Growth  [PDF]
Md. Asaduzzaman Shah
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.41002
Abstract:

Two extensions of stochastic logistic model for fish growth have been examined. The basic features of a logistic growth rate are deeply influenced by the carrying capacity of the system and the changes are periodical with time. Introduction of a new parameter \"\", enlarges the scope of investing the growth\"\"of different fish species. For rapid growth lying between 1 and 2 and for slowly growing\"\".

Role of Videonystagmography (VNG) in Epley’s Maneuver  [PDF]
Saloni Shah, Rajesh Vishwakarma
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2014, DOI: 10.4236/ijohns.2014.36056
Abstract: Aims and Objectives: To study benefit of videonystagmography in confirmation of canalolith repositioning in patients with Benign Paroxysmal Positional Vertigo after Epley’s manouver. Study Design: Prospective study of 35 cases of BPPV. Materials and Method: 35 patients of BPPV presenting at vertigo clinic of ENT department at Civil Hospital Ahmedabad were treated with canalolith repositioning procedure and improvement in nystagmus was studied and confirmed by VNG. Observation: 31 patients out of 35 patients were improved with 1st CRP, 2 out of 3 patients improved with 2nd CRP and 1 patient improved with 3rd CRP. This improvement is confirmed using VNG. Conclusion: Videonystagmography is a very useful tool for ensuring the otolith repositioning by the canalith repositioning manouver. It is a confirmatory adjunct to visual analysis.
A Solution of the Burger’s Equation Arising in the Longitudinal Dispersion Phenomenon in Fluid Flow through Porous Media by Mixture of New Integral Transform and Homotopy Perturbation Method  [PDF]
Kunjan Shah, Twinkle Singh
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.34004
Abstract: The main aim of the paper is to examine the concentration of the longitudinal dispersion phenomenon arising in fluid flow through porous media. These phenomenon yields a partial differential equation namely Burger’s equation, which is solved by mixture of the new integral transform and the homotopy perturbation method under suitable conditions and the standard assumption. This method provides an analytical approximation in a rapidly convergent sequence with in exclusive manner computed terms. Its rapid convergence shows that the method is trustworthy and introduces a significant improvement in solving nonlinear partial differential equations over existing methods. It is concluded that the behaviour of concentration in longitudinal dispersion phenomenon is decreases as distance x is increasing with fixed time t > 0 and slightly increases with time t.
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