scholarly journals Mathematical optimization of formulation of indomethacin/polyvinylpolypyrrolidone/methyl cellulose solid dispersions by the sequential unconstrained minimization technique.

1985 ◽  
Vol 33 (1) ◽  
pp. 292-300 ◽  
Author(s):  
KOZO TAKAYAMA ◽  
HIROYUKI IMAIZUMI ◽  
NAOKI NAMBU ◽  
TSUNEJI NAGAI
Keyword(s):  
Solid Dispersions ◽  
Methyl Cellulose ◽  
Mathematical Optimization ◽  
Unconstrained Minimization ◽  
Minimization Technique

Optimization and development of orodispersible films for ledipasvir and sofosbuvir through solid dispersion using Box-Behnken design

2021 ◽  
pp. 201-208
Author(s):  
Uday Kumar Thummala ◽  
Eswar Guptha Maddi ◽  
Prameela Rani Avula
Keyword(s):  
Solid Dispersions ◽  
Methyl Cellulose ◽  
Fixed Dose ◽  
Polyethylene Glycol 400 ◽  
Disintegration Time ◽  
Box Behnken Design ◽  
Orodispersible Films ◽  
Low Viscosity ◽  
Dose Combination ◽  
Formulation Parameters

The fixed dose combination of ledipasvir (LDV) and sofosbuvir (SBV) is approved by USFDA in 2014 for the treatment of Hepatitis C virus infection and is available in the form of tablets. In the present work, the principal aim is to explore orodispersible films type dosage form to impart its characteristic advantages to these poorly soluble drugs so as to improve their bioavailability and ease of administration. Solid dispersions with low viscosity grade methyl cellulose A 15-LV (MC A 15-LV) at different ratios with LDV and SBV were prepared and evaluated to check their ability in improving the solubility of the drugs. The best drug to polymer ratio was selected to develop the films, using other excipients including plasticizer and superdisintegrant. Solvent casting method was used to develop the films. Three formulation parameters were selected as independent factors viz. thickness of the film (50-150 µm), concentration of superdisintegrant (sodium starch glycolate 6-10%) and concentration of plasticizer (polyethylene glycol 400, 10-20%). Disintegration time (DT), time for 90% dissolution (T90%) of LDV and time for 90% dissolution of SBV were taken as the response variables. The experiment was designed using Box-Behnken design. Among the polymers, MC A 15-LV produced maximum solubility at 1:2 ratio. The films obtained were found to have good tensile strength and % elongation with disintegration times in the range of 43-162 sec. The T90% values for LDV and SDV were found to be in the range of 8.4-21.2 min and 7.2-18.4 respectively. All the three formulation factors were found to have significant effect on the three responses. The optimum formulation was identified at 100 µm thickness, 10% superdisintegrant and 20% plasticizer which showed DT of 89 sec with T90% values of 8.4 min and 7.2 min for LDV and SBV respectively. The rapid disintegration and dissolution of the films signified that the set objective was achieved.

Optimal Thermal Design of Fin-and-Tube Heat Exchangers by Integration of a SUMT and a SCGM

2016 ◽  
Author(s):  
Xinyi Li ◽  
Ting Ma ◽  
Qiuwang Wang
Keyword(s):  
Heat Exchangers ◽  
Optimization Technique ◽  
Unconstrained Minimization ◽  
Geometric Parameters ◽  
Thermal Design ◽  
Trial And Error ◽  
Heat Transfer Area ◽  
Compact Heat Exchangers ◽  
Minimization Technique ◽  
Combined Structure

It is a recognized hard task for the traditional thermal design of compact heat exchangers to obtain the optimal geometric parameters efficiently and effectively, owing to its complex trial-and-error process. In response to this issue, a simplified conjugate-gradient method (SCGM) combined with a sequential unconstrained minimization technique (SUMT) as a favorable optimization technique is incorporated with the traditional thermal design in this study, and then the key geometric parameters of fin-and-tube heat exchangers (FTHEs) are investigated and optimized successfully. In this method, the minimum total weight of FTHEs as the final objective is discussed, involving two geometric parameters, diameter of tube and height of shape as search variables. Aiming to minimize the objective function, SCGM is introduced to the SUMT to update the search variables continually with the fixed search steps and the search directions. Meanwhile, with the known geometric parameters from the SUMT, the log-mean temperature difference method (LMTD) is applied to determine the heat transfer area under the combined structure sizes for a given heat duty. Additionally, optimization results for three different heat duty is discussed in this work. The results show that it is effective to obtain the optimal sets of geometric parameters of FTHEs by the present method, and there are some guidance values for the thermal designs of compact heat exchangers.

Reliability Based Optimization of Submarine Pressure Hulls With Inelastic Interstiffener Buckling Failure

2006 ◽  
Author(s):  
P. Radha ◽  
K. Rajagopalan
Keyword(s):  
Unconstrained Minimization ◽  
Computer Code ◽  
Correction Method ◽  
Penalty Function Method ◽  
Simulation Design ◽  
Design Variables ◽  
Minimization Technique ◽  
Buckling Failure ◽  
Optimal Values ◽  
Reliability Based Optimization

Uncertainties that exist in modelling and simulation, design variables and parameters, manufacturing processes etc., may lead to large variations in the performance characteristics of the system. Optimized deterministic designs determined without considering uncertainties can be unreliable and may lead to catastrophic failure of the structure being designed. Reliability based optimization (RBO) is a methodology that addresses these problems. In this paper the reliability based optimization of submarine pressure hulls in which the failure gets governed by inelastic interstiffener buckling has been described. The problem has been formulated to minimize the ratio of weight of shell-stiffener geometry to the weight of liquid displaced, subjected to reliability based inelastic interstiffener buckling constraint. Since the methods of analysis of inelastic buckling failure of submarine pressure hulls are inadequate, in the present study the Johnson-Ostenfeld inelastic correction method has been adopted for formulating the constraint. By considering spacing of the stiffener, thickness of the plating and depth of the stiffener as the design variables, Sequential Unconstrained Minimization Technique (SUMT) has been used to solve the design problem. RBO has been carried out to get the optimal values of these design variables for a target reliability index using Interior Penalty Function Method for which an efficient computer code in C++ has been developed.

scholarly journals Solid dispersion of meloxicam: Factorially designed dosage form for geriatric population

2008 ◽  
Vol 58 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Deepa Pathak ◽  
Sunita Dahiya ◽  
Kamla Pathak
Keyword(s):  
Drug Release ◽  
Solid Dispersion ◽  
Dosage Form ◽  
Solid Dispersions ◽  
Methyl Cellulose ◽  
Water Soluble ◽  
Hydroxyethyl Cellulose ◽  
Scanning Calorimetry ◽  
Geriatric Population ◽  
Peg 4000

Solid dispersion of meloxicam: Factorially designed dosage form for geriatric populationThe objective of the present work was to improve the dissolution properties of the poorly water-soluble drug meloxicam by preparing solid dispersions with hydroxyethyl cellulose (HEC), mannitol and polyethylene glycol (PEG) 4000 and to develop a dosage form for geriatric population. Differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy were used to investigate the solid-state physical structure of the prepared solid dispersions. Higher invitrodissolution of solid dispersions was recorded compared to their corresponding physical mixtures and the pure drug. PEG 4000 in 1: 9 drug to carrier ratio exhibited the highest drug release (100.2%), followed by mannitol (98.2%) and HEC (89.5%) in the same ratio. Meloxicam-PEG 4000 solid dispersion was formulated into suspension and optimization was carried out by 23factorial design. Formulations containing higher levels of methyl cellulose and higher levels of either sodium citrate or Tween 80 exhibited the highest drug release.

scholarly journals Design expert assisted mathematical optimization of solubility and study of fast disintegrating tablets of Lercanidipine Hydrochloride

2019 ◽  
Vol 9 (1-s) ◽  
pp. 172-180
Author(s):  
Seema Saini ◽  
Rajeev Garg
Keyword(s):  
Dissolution Rate ◽  
Solid Dispersion ◽  
Solid Dispersions ◽  
Mathematical Optimization ◽  
Statistical Design ◽  
In Vivo Studies ◽  
Dissolution Profile ◽  
Fast Disintegrating Tablets ◽  
Lercanidipine Hydrochloride

90% of drugs being researched today, posses poor solubility setback which inturn renders  the drug with slower rate of absorption from the buccal route; hence dissolution is the rate limiting step for such lipophilic drugs. So, there is a need to keep a check on the dissolution profile of these drugs to ensure maximum therapeutic utilization. The dissolution rate therefore becomes a primary factor which governs the rate and extent of its absorption. Enormous work is being performed in the field of enhancement of solubility and dissolution behaviour of such drugs. Advancements and innovations have developed solid dispersion (SD) technique as the novel method for the solubility enhancement. Precision of dosing and patient's compliance is a crucial prerequisite for the management of chronic Antihypertensive treatment, So there arised a need to formulate a system which should resolve the difficulties associated with conventional tablets. This issue can be better tackled with the formulation of orally fast disintegrating tablets. The aim of the present study was to improve the solubility and dissolution rate of Lercanidipine hydrochloride (LRH) by formulating a solid dispersion with Polyvinyl pyrollidine (PVP-K30) and Guargum. Full Factorial designs are exploited to learn and research the effects of different variables on the quality determinant parameters. An appropriate statistical model was selected for the scrutiny of the enhanced dissolution pattern. Finally, these solid dispersions were incorporated into fast disintegrating tablets. Keywords: Lercanidipine Hydrochloride, Solid dispersion, Statistical design approach, Melt fusion method, Fast disintegrating tablet, In vivo studies

Design of Transverse-Plane Bulkheads in Tankers

1976 ◽  
Vol 20 (02) ◽  
pp. 67-78
Author(s):  
Carl Arne Carlsen ◽  
Dag Kavlie
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Unconstrained Minimization ◽  
Optimization Methods ◽  
Transverse Plane ◽  
Design Stage ◽  
Preliminary Design Stage ◽  
Minimization Technique ◽  
Institute Of Technology ◽  
Aided Design

A program system, INDETS, for computer-aided design of tanker structures has been developed. The system, which is the result of a joint effort of the Norwegian Institute of Technology, Trondheim, and the Aker Group, Oslo, is considered an effective tool for practical design. A design module of INDETS for tanker transverse-plane bulkheads is presented. The girder system is analyzed by a three-dimensional frame model including the surrounding structure as substructures. Two optimization methods, the Stress Ratio Technique and the Sequential Unconstrained Minimization Technique, are applied. A number of parametric variations on topology have been performed, and the depth and breadth have been varied to derive curves for estimating the weight of bulkheads at the preliminary design stage. As a conclusion, a simple-formula is presented.

Sign in / Sign up

Export Citation Format

Share Document