flow property
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Author(s):  
Madhivardhana P ◽  
Rajalakshmi A N ◽  
Padmapriya S

The aim of this research work is to formulate and evaluate Levothroxine sodium immediate release tablets prepared by direct compression method . Five formulations were evaluated for different pre and post compression parameter and in vitro drug release studies.The results of pre compression parameters of formluation 1 to 5 were compared with prescribed limits. It showed that formulation 1 to 5 powder blend exhibit good flow property and compressibility property. The disintegration time of all formulation was found to be in the range 2mins 09 secsto 4mins 03 secs.Thus, based on evaluation of different parameters it was concluded that formulation of immediate release tablet Levothyroxine sodium was successfully done and F-5 showed almost 93% drug release at 45 mins in Alkaline borate buffer( pH 10). Keywords: Thyroid hormone (T4), Immediate release tablets, Direct compression, Dissolution.


Author(s):  
Sonali Agarkar

To effectively manage the diabetic mellitus type-II hyperglycemic problem, Gliclazide tablet is the sustained- release tablet that has been designed and fabricated for years. This research evaluated the effects of different grades of hydrophilic polymers in sustained release of Gliclazide tablets made with direct compression technique. HPC GF GRADE, HPMC K4M, and PARTECK® SRP 80 were used as the polymer, Avicel pH 101 (MCC) was used as the highly compressible diluent and Starch 1500 was used as insoluble tablet filler. Aerosil 300 and Magnesium Stearate was used as a Glidant and lubricant for improving the flow property of powder and to decrease the friction between dying wall and punches. Pre-compression characteristics were evaluated for angle of repose, bulk density, compressibility, tapped density, and Hausner's ratio and DSC, XRD, FT-IR. Tablets were prepared on a rotary tablet press machine (Eliza press) and after compression tablets were evaluated for weight variation, thickness, hardness, friability, drug content, and in-vitro drug release study. The physico-chemical properties of blends were estimated accelerated stability study was also developed formulations were kept for stability study for three months as per ICH guidelines and found to be stable. Advantages of formulating insoluble drugs such as Gliclazide is that if it is used in the preparation of capsules or tablets of the drug,its dose might be reduced which is economically beneficial.


Author(s):  
Ranjitha R ◽  
Elango K ◽  
Devi Damayanthi R ◽  
Sahul Hameed Niyaz U

The present investigations was aimed to improve the solubility, to release the drug in a controlled manner for extended period of time, reduce dose dependent side effects and improve the bioavailability of a poorly water soluble BCS class II drug of Lovastatin by formulating it as Nanosponges drug delivery system. Lovastatin Nanosponges were formulated by emulsion solvent evaporation method using Eudragit RS 100 and Ethyl Cellulose as a polymers, PVA as a stabilizer and finally enclosed in hard gelatin Capsules. The prepared Nanosponges were evaluated for FTIR, particle size, polydispersity index (PDI), zeta potential, morphological characteristics by scanning electron microscopy (SEM), production yield, entrapment efficiency, solubility studies, in vitro drug release studies, release kinetics study, stability studies, Flow property and porosity. The optimized formulation filled in capsules and Post formulation parameters of capsule were determined. FTIR studies showed no interaction between drug and excipients. Percentage yield of all the formulation (F1-F10) was found to be in the range of 85.83 to 99.85%. The entrapment efficiency of all the formulations was found to be in the range of 61.68 to 91.18%, among all the formulations F3 (90.04%) and F8 (91.18%) shows high entrapment efficiency. The solubility of all formulation improved (from insoluble to slightly soluble) compared to pure drug of Lovastatin. Among all the formulations F3 (98.15%) and F8 (97.57%) shown complete drug release at the end of 12th hrs. The average particle size of optimized formulation F3 and F8 was found to be 727.0 nm and 769.5 nm respectively. SEM images of optimized formulation showed that the Nanosponges were spherical with numerous pores on their surface, uniform and spongy in nature. The release kinetics of the optimized formulation was best fitted into Higuchi model and showed zero order drug release with Non Fickian diffusion. Stability studies indicated that the formulation is stable as per ICH guidelines. The flow property measurements for optimized formulation observed good were its filled in capsules. Post formulation parameters of capsule were comply with official specifications. They concluded that the both polymers used were efficient carriers for Lovastatin Nanosponges.


Author(s):  
Nisarg C Patel ◽  
Anita P Patel ◽  
Jayvadan K Patel

Curcumin (CURC) is a natural polyphenolic compound obtained from Curcuma longa which shows preventive and therapeutic actions against cancer. Epigallocatechin gallate (EGCG) is a potent phytomolecule obtained from Camellia sinensis, with wide biological activity. The therapeutic effect is limited, owing to poor stability and limited membrane permeability across the intestine. The aim of this study was to develop and evaluate colon-targeted microspheres of CURC and EGCG, using natural polymers. W/O emulsion crosslinking technique was used to prepare microspheres of CURC and EGCG using interpenetrating network (IPN) of Chitosan (CS) and Gum acacia (GA) and glutaraldehyde was used as a crosslinking agent. Prepared microspheres were filled in capsules coated with Eudragit S100. The prepared microspheres were evaluated in vitro for preformulation studies, encapsulation efficiency, micromeritic properties, dissolution studies and stability studies. FTIR and DSC studies had proved that the drug and polymers are compatible. The good flow property of microspheres showed that the microspheres are not aggregated. SEM micrographs of microspheres show a rough and folded surface morphology. The microspheres are spherical and uniform in shape. Formulations showed good encapsulation efficiency. Formulation F1 to F6 showed sustained release of drug for 10 h. The in-vitro drug release of batches was best explained by Higuchi models showing anomalous diffusion mechanism. The coated batch showed better release results. The optimized formulation for a period of 3 month at 40±2°/75 ± 5% RH showed no significant changes. The current approach was helpful to develop polysaccharide based microspheres of CURC and EGCG to enhance colonic drug delivery.


Author(s):  
Mingxia Yuan ◽  
Xin Lin ◽  
Hualin Lin ◽  
Yuan Xue ◽  
Sheng Han

The poor cold flow property is one of the main obstacle factors in affecting the utilization of high-proportional biodiesel blends in engines. In this study, methcyclohexyl methacrylate-methacrylate copolymers (MCHMA-R1MC, R1 = C12, C14, C16, C18) were synthesized at various molar ratios by radical polymerization and characterized by FTIR, GPC, and 1H NMR. Their structures and properties areanalyzed and characterized by FTIR, GPC, and 1H NMR. The resulting copolymers were tested as the cold flow improver in terms of cold filter plugging point (CFPP) and solid point (SP) measurement for treated and untreated B20 biodiesel blends (20 vol.% biodiesel + 80 vol.% diesel). Results showed that the CFPP and SP of B20 decreased to a varied extent after MCHMA-R1MC treatment. When the monomer ratio of is 1:7, MCHMA-C14MC (1:7) proved the greatest depression in CFPP and SP of B20 by 18 and 25℃ at 2000 ppm dosage. The effects of MCHMA-R1MC copolymers on crystal behavior was studied through polarizing optical microscope(POM), differential scanning calorimetry(DSC) and viscosity-temperature curves. The results indicated that MCHMA-C14MC could effectively delay the aggregation of wax crystals and change their crystalline behavior by changing the shape of the crystals and inhibiting the formation of large wax crystals, and then lower the low-temperature viscosity of biodiesel blends and make it exhibiting better cold flow properties.


2021 ◽  
Vol 40 (9) ◽  
pp. 662-666
Author(s):  
Mita Sengupta ◽  
Shannon L. Eichmann

Digital rocks are 3D image-based representations of pore-scale geometries that reside in virtual laboratories. High-resolution 3D images that capture microstructural details of the real rock are used to build a digital rock. The digital rock, which is a data-driven model, is used to simulate physical processes such as fluid flow, heat flow, electricity, and elastic deformation through basic laws of physics and numerical simulations. Unconventional reservoirs are chemically heterogeneous where the rock matrix is composed of inorganic minerals, and hydrocarbons are held in the pores of thermally matured organic matter, all of which vary spatially at the nanoscale. This nanoscale heterogeneity poses challenges in measuring the petrophysical properties of source rocks and interpreting the data with reference to the changing rock structure. Focused ion beam scanning electron microscopy is a powerful 3D imaging technique used to study source rock structure where significant micro- and nanoscale heterogeneity exists. Compared to conventional rocks, the imaging resolution required to image source rocks is much higher due to the nanoscale pores, while the field of view becomes smaller. Moreover, pore connectivity and resulting permeability are extremely low, making flow property computations much more challenging than in conventional rocks. Elastic properties of source rocks are significantly more anisotropic than those of conventional reservoirs. However, one advantage of unconventional rocks is that the soft organic matter can be captured at the same imaging resolution as the stiff inorganic matrix, making digital elasticity computations feasible. Physical measurement of kerogen elastic properties is difficult because of the tiny sample size. Digital rock physics provides a unique and powerful tool in the elastic characterization of kerogen.


Author(s):  
DARSHIT RAM ◽  
HIMANSHU PANKHANIYA

Objective: Cisapride is a novel prokinetic agent is best candidate for GERD. Cisapride 20 mg can be given thrice in a day given along with Proton pump inhibitor. By developing the sustain release formulation of Cisapride, the frequency of both drug can be reduce to once only to obtain good therapeutic response. Methods: Cisapride SR Tablets were prepared by direct compression technique with HPMC K4M and HPMC K100M polymers. Followed by various evaluation tests including in vitro disintegration and dissolution, the formulation was optimized by 32 full factorial designs with drug release kinetic analysis, compatibility studies (FTIR) and stability studies. Results: Results of Preformulation studies of the Cisapride indicate that it has poor flow property and compressibility property. To improve the flow and compressibility property, it was beneficial to use the directly compressible grade components in the formulation of tablet. Results of DSC study shown that there is no change in drug’s melting peak after the preparation of tablet. Hydrophilic matrix of HPMC K4M and HPMC K100M in combination sustained the Cisapride release effectively for more than 12h. The result indicates that the combination of HPMCK4M and HPMCK100M can be successfully, On the basis of the preliminary trials in the present study a32 full factorial design was employed to study the effect of independent variables, i.e. concentration of HPMCK4M(X1) and concentration of HPMCK100M(X2)on dependent variables like% drug release Q2, Q6 and Q10. Drug release is also dependent on the size of matrix tablets so, size and surface area was kept constant. Factorial batches F018, F019, F020, and F021 give the f2 value 75-100. Factorial batch F019 gives the highest f2 value 86.04 and also all the hour’s drug release was within the specified limits. Conclusion: The prepared formulation of Cisapride sustains release matrix tablet was stable and effective in treatment.


Author(s):  
Khairnar Suhas Kishor ◽  
Shadab Husain Ashfaque Husain ◽  
Patil Pooja Ravsaheb ◽  
Gangurde A.B ◽  
Bairagi V.A

Natural disintegrant are widely used in the development of mouth dissolving tablets and other formulation because of easily available, low cost and rapide onset of action in the mouth dissolving tablet and it enhance the bioavalaibility and disintegration properties as comparaed to synthetic polymer. But aftrer freeze drying and spray drying technique the properties of dsintegrant is increases because its improve the bulkiness and flow property of a powder such as bulk density, tapped density, angle of repose, hausner raio, carrs index etc. by freeze drying the powder are dried and thereby increase the dissolution and disintegration time and highly porous powder is produced by spray drying technique.


2021 ◽  
Author(s):  
George Papadopoulos ◽  
Daniel Bivolaru ◽  
Nicholas Martin ◽  
Timothy Dawideit

Abstract When voltage is applied between two electrodes situated in close proximity to each other (10–100 μm), a weakly ionized, low temperature plasma discharge can be generated. This in turn creates a plasma sheath, an electrically ionized boundary layer (typically of the order of 10’s to 100’s of microns), where space charge effects dominate. The sheath acts like a virtual capacitor, with the plasma behaving as an inductor. Aerodynamic effects influence the plasma morphology (shape, thickness), thus making the plasma the transduction mechanism. The attraction to the use of plasma discharge as a transduction method for fluid flow property measurement stem from the fact that it lends itself to a probe implementation that is simple in design, can be miniaturized, and at the same time offers unmatched capability for handling ultra-high temperature environments. Sensing plasma discharge characteristics and their variation due to flow interaction can be done electrically, but also optically to yield time-varying intensity and spectral information from fluid-plasma interaction. The current paper focuses on the deployment of a micro-plasma sensor system as a new novel multi-parameter sensing approach for surface flow measurement. Results on pressure dynamics, shear flow, and other possible engineering parameters will be discussed in the context of results from several bench-level experiments.


Author(s):  
Alessandro Savo

AbstractWe study and classify smooth bounded domains in an analytic Riemannian manifold which are critical for the heat content at all times $$t>0$$ t > 0 . We do that by first computing the first variation of the heat content, and then showing that $$\Omega $$ Ω is critical if and only if it has the so-called constant flow property, so that we can use a previous classification result established in [33] and [34]. The outcome is that $$\Omega $$ Ω is critical for the heat content at time t, for all $$t>0$$ t > 0 , if and only if $$\Omega $$ Ω admits an isoparametric foliation, that is, a foliation whose leaves are all parallel to the boundary and have constant mean curvature. Then, we consider the sequence of functionals given by the exit-time moments $$T_1(\Omega ),T_2(\Omega ),\dots $$ T 1 ( Ω ) , T 2 ( Ω ) , ⋯ , which generalize the torsional rigidity $$T_1$$ T 1 . We prove that $$\Omega $$ Ω is critical for all $$T_k$$ T k if and only if $$\Omega $$ Ω is critical for the heat content at every time t, and then we get a classification as well. The main purpose of the paper is to understand the variational properties of general isoparametric foliations and their role in PDE’s theory; in some respects they generalize the properties of the foliation of $$\mathbf{R}^{n}$$ R n by Euclidean spheres.


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