Study of Dissolution Kinetics of Mefenamic Acid Solid Dispersion with Polyvinylpyrrolidone

2021 ◽  
pp. 79-95
Author(s):  
R. Alrouhayya ◽  
T.F. Sheshko ◽  
E.B. Markova ◽  
V.S. Boldyrev ◽  
A.A. Razvodova ◽  
...  
Keyword(s):  
Therapeutic Effect ◽  
Active Substance ◽  
Mefenamic Acid ◽  
Active Component ◽  
Solid Dispersions ◽  
Dissolution Kinetics ◽  
Biologically Active ◽  
Hydrophobic Nature ◽  
Kinetics Of ◽  
Low Solubility

The low solubility of a biologically active substance in an aqueous medium is often the main reason for the reduced therapeutic effect of drugs. The most common approach to solve this problem is to obtain a watersoluble salt of the active substance and an appropriate preparatory formulation based on it. In this case, the solubility of the obtained compound in hydrophobic systems decreases dramatically, which decreases the rate of transmembrane transport and changes the pharmacokinetic laws of the process. In practice, not only the dependence of the therapeutic effect on the salt compound properties, but also a complete loss of the drug active ingredient activity can be observed. The use of biologically active compound solid dispersions in watersoluble polymers is the most promising approach to increase the therapeutic effect of drugs while maintaining the hydrophobic nature of the active component, to reduce the dose load on the patient’s body and obtain prolonged action. In experiments we obtained solid dispersions of mefenamic acid in polyvinylpyrrolidone and studied kinetic regularities of solubility of this promising drug form in aqueous solution of phosphate buffer. By means of mathematical modelling it was found that the phenomenon under study is well described by Ritger --- Peppas model, which considers diffusion of biologically active component into solution according to Fick's law with possible influence on mass transfer at swelling and degradation of polymer matrix

scholarly journals Evaluation of the Release Kinetics of a Pharmacologically Active Substance from Model Intra-Articular Implants Replacing the Cruciate Ligaments of the Knee

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1202 ◽  
Author(s):  
Dorota Wojcik-Pastuszka ◽  
Justyna Krzak ◽  
Bartosz Macikowski ◽  
Ryszard Berkowski ◽  
Bogdan Osiński ◽  
...  
Keyword(s):  
Drug Release ◽  
Active Substance ◽  
Rate Constants ◽  
Incubation Temperature ◽  
Release Kinetics ◽  
Dissolution Kinetics ◽  
Second Order ◽  
Prolonged Release ◽  
Pharmacologically Active ◽  
Kinetics Of

Implants are readily applied as a convenient method of therapy. There is great interest in the prolonged release of active substances from implants. The objective of this work was to evaluate the dissolution kinetics of steroidal anti-inflammatory preparation (SAP) released from novel implants, and to test the influence of the technology on SAP release kinetics. The proposed long-acting preparations may overcome difficulties resulting from repeated injections and often visits to ambulatory clinic, as the stabilizing function of the artificial ligament would be enriched with pharmacological activity. The potential advantages provided by the new coatings of knee implants include the continuous, sustained, and prolonged release of an active substance. The study was carried out using a modified United States Pharmacopoeia (USP) apparatus 4. The amount of SAP was measured spectroscopically. It was revealed that the transport of the drug was mainly a diffusion process. The drug release kinetics was analyzed using zero-, first-, and second-order kinetics as well as Korsmeyer-Peppas, Higuchi, and Hixon-Crowell models. The highest values of the release rate constants were k0 = (7.49 ± 0.05) × 10−5 mg × min−1, k1 = (6.93 ± 0.05) × 10−6 min−1, and k2 = (7.70 ± 0.05) × 10−7 mg−1 × min−1 as calculated according to zero-, first-, and second-order kinetics equations, respectively. The values of the rate constants obtained for the slowest process were k0 = (3.63 ± 0.06) × 10−5 mg × min−1, k1 = (2.50 ± 0.03) × 10−6 min−1, and k2 = (2.80 ± 0.03) × 10−7 mg−1 × min−1. They may suggest the possibility of sustained release of betamethasone from the system. Due to the statistical analysis, differences were observed between most of the studied implants. Incubation, temperature, time of stabilization of layers, and the method of SAP deposition on the matrix affected the drug release.

scholarly journals Alternative Methods for Dissolution Profile Comparison in the Dissolution Test

2021 ◽  
Vol 10 (4) ◽  
pp. 197-207
Author(s):  
D. P. Romodanovsky ◽  
D. V. Goryachev
Keyword(s):  
Active Substance ◽  
Dissolution Kinetics ◽  
Alternative Methods ◽  
Drug Dissolution ◽  
Dissolution Profile ◽  
Dissolution Test ◽  
Similarity Factor ◽  
Model Independent ◽  
Kinetics Of ◽  
Comparative Dissolution

Introduction. The article discusses the problem of assessing the similarity of the dissolution profiles of two batches of the nebivolol. The use of a generally accepted similarity factor for assessing equivalence is unacceptable in some cases, for example, for drugs with a high variability in the values of the release of the active substance from the formulation. At the same time, at present, there are no generally accepted approaches to comparing the profiles of the dissolution kinetics of drugs, with the exception of the method for assessing the comparability of profiles based on the mathematical calculation of the similarity factor f2, which has certain criteria that limit its application.Aim. To demonstrate alternative methods for assessing the similarity between the dissolution profiles of two drugs using a practical example.Materials and methods. The results of the comparative dissolution test of two series of nebivolol at a dosage of 5 mg. Five model-independent methods for assessing the equivalence of drug dissolution were used. Statistical data processing was performed using Microsoft Excel software.Results and discussion. The paper presents a practical example of using five alternative model-independent methods for assessing the equivalence of the dissolution profile. An example is used to illustrate the proposed equivalence limits and statistical methodology. Also, various approaches to determining the boundaries of equivalence have been proposed to assess the similarity of the dissolution profiles of an active substance.Conclusion. According to the results of the comparative dissolution test of two batches of nebivolol, it was shown that the use of the similarity factor as a criterion for assessing dissolution profiles led to a false positive result. In such cases, the possibility of using alternative methods for assessing the equivalence of dissolution profiles described in the article, or other methods presented in the scientific literature, should be considered, with a justification of their acceptability in each specific case.

Solubility Enhancement of Poorly Soluble Drug Simvastatin by Solid Dispersion Technique

2016 ◽  
Vol 2 (2) ◽  
pp. 91-95
Author(s):  
Neelima Rani T ◽  
Pavani A ◽  
Sobhita Rani P ◽  
Srilakshmi N
Keyword(s):  
Dissolution Rate ◽  
Drug Carrier ◽  
Solid Dispersions ◽  
Aqueous Solubility ◽  
Onset Of Action ◽  
Kneading Method ◽  
Wetting Property ◽  
Poorly Soluble ◽  
Dispersion Technique ◽  
Low Solubility

This study aims to formulate solid dispersions (SDs) of Simvastatin (SIM) to improve the aqueous solubility, dissolution rate and to facilitate faster onset of action. Simvastatin is a BCS class II drug having low solubility & therefore low oral bioavailability. In the present study, SDs of simvastatin different drug-carrier ratios were prepared by kneading method. The results showed that simvastatin solubility & dissolution rate enhanced with polymer SSG in the ratio 1:7 due to increase in wetting property or possibly may be due to change in crystallinity of the drug.

Preparation and Evaluation of Skeletal Cobalt-Molybdenum Hydrodesulfurization Catalysts

1995 ◽  
Vol 60 (4) ◽  
pp. 568-575
Author(s):  
Karel Sporka ◽  
Jiří Hanika ◽  
Vladimír Jůn
Keyword(s):  
Aqueous Solutions ◽  
Active Component ◽  
Catalyst Activity ◽  
Gas Oil ◽  
Gamma Alumina ◽  
Molybdenum Sulfides ◽  
Hydrodesulfurization Catalysts ◽  
Hds Catalysts ◽  
Kinetics Of ◽  
Preparation And Evaluation

Preparation of skeletal Co-Mo catalysts by controlled impregnation of aluminosilicate skeletons containing deposited gamma-alumina with aqueous solutions of active component precursors has been investigated. The activity of the laboratory catalysts in gas oil hydrodesulfurization has been determined. Kinetics of impregnation of skeletal supports, the effect of their type, and the dependence of catalyst activity on the content of cobalt and molybdenum sulfides are reported. HDS skeletal catalysts prepared were compared with the extruded types. It was found that skeletal HDS catalysts show the higher activity (related to the content of alumina and Co-Mo sulfides) than the extruded ones due to the less significant effect of internal diffusion. However, if the activity is related to the same volume of catalyst bed, the activity of skeletal catalysts is only one fourth of that of the extruded types.

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