Dissolution of Soap Scum by Surfactants. Part III. Effect of Chelant Type on Equilibrium Solubility and Dissolution Rate of Calcium and Magnesium Soap Scums in Various Surfactant Systems

2015 ◽  
Vol 18 (6) ◽  
pp. 925-932 ◽  
Author(s):  
Sawwalak Itsadanont ◽  
Prariyada Theptat ◽  
John F. Scamehorn ◽  
Sukhwan Soontravanich ◽  
David A. Sabatini ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Equilibrium Solubility ◽  
Soap Scum ◽  
Calcium And Magnesium ◽  
Surfactant Systems

scholarly journals The Effect of PVP Molecular Weight on Dissolution Behavior and Physicochemical Characterization of Glycyrrhetinic Acid Solid Dispersions

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xiaoyu Sui ◽  
Yan Chu ◽  
Jie Zhang ◽  
Honglian Zhang ◽  
Huiyu Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dissolution Rate ◽  
Solid Dispersions ◽  
Physicochemical Characterization ◽  
Dissolution Behavior ◽  
Enhancement Effect ◽  
Glycyrrhetic Acid ◽  
Equilibrium Solubility ◽  
Drug Molecules ◽  
Pvp K30

The effect of polyvinylpyrrolidone (PVP) as glycyrrhetic acid (GA) solid dispersions carrier at different molecular weights on the dissolution behavior and physicochemical properties was investigated. PVP-GA-SDs prepared with all four molecular weight PVPs displayed good enhancement of dissolution rate and equilibrium solubility compared with pure drug and corresponding physical mixtures. The results showed that the enhancement effect of molecular weight on dissolution rate and equilibrium solubility follows PVP   K 30 > PVP   K 60 > PVP   K 17 > PVP   K 15 . In addition, the dissolution rate and solubility of the SDs with a carrier-drug ratio of 8 : 1 were better than the samples of 4 : 1. The DSC and XRD patterns showed that the crystallization of GA in SDs prepared by PVP K30 and PVP K60 was significantly inhibited, and both were transformed to amorphous. Based on FTIR and Raman detection, a hydrogen-bond between PVP and drug molecules is formed. SEM results showed that there were no significant differences in the appearance of SDs prepared with four PVPs, and no crystalline morphology of GA was seen. In conclusion, the findings of this study demonstrated that the dissolution performance of the PVP-GA-SDs prepared by the solvent method is related to the molecular weight of PVP, and the change in the molecular weight of PVP does not cause a monotonic change in dissolution of GA. The samples with PVP K30 as the carrier have the best dissolution performance.

scholarly journals Application of experimental design in examination of the dissolution rate of carbamazepine from formulations: Characterization of the optimal formulation by DSC, TGA, FT-IR and PXRD analysis

2015 ◽  
Vol 80 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Marko Krstic ◽  
Slavica Razic ◽  
Dragana Vasiljevic ◽  
Djurdjija Spasojevic ◽  
Svetlana Ibric
Keyword(s):  
Experimental Design ◽  
Dissolution Rate ◽  
Analytical Techniques ◽  
Ambient Conditions ◽  
The Poor ◽  
Brij 35 ◽  
Ft Ir ◽  
Surfactant Systems ◽  
Selection Of

Poor solubility is one of the key reasons for the poor bioavailability of these drugs. This paper displays a formulation of a solid surfactant system with carbamazepine, in order to increase its dissolution rate. Solid state surfactant systems are formed by application of fractal experimental design. Poloxamer 237 and Poloxamer 338 were used as surfactants and Brij? 35 was used as the co-surfactant. The ratios of the excipients and carbamazepine were varied and their effects on the dissolution rate of carbamazepine were examined. Moreover, the effects of the addition of natural (diatomite) and a synthetic adsorbent carrier (Neusiline UFL2) on the dissolution rate of carbamazepine were also tested. The prepared surfactant systems were characterized and the influence of the excipients on possible changes of the polymorphous form of carbamazepine examined by application of analytical techniques (DSC, TGA, FT-IR, PXRD). It was determined that an appropriate selection of the excipient type and ratio could provide a significant increase in the carbamazepine dissolution rate. By application of analytical techniques, it was found that that the employed excipients induce a transition of carbamazepine into the amorphous form and that the selected sample was stable for three months, when kept under ambient conditions.

Equilibrium solubility measurement of compounds with low dissolution rate by Higuchi's Facilitated Dissolution Method. A validation study

2017 ◽  
Vol 106 ◽  
pp. 133-141 ◽  
Author(s):  
Krisztina Takács-Novák ◽  
Maria Urac ◽  
Péter Horváth ◽  
Gergely Völgyi ◽  
Bradley D. Anderson ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Validation Study ◽  
Equilibrium Solubility ◽  
Dissolution Method ◽  
Solubility Measurement

The Effect of Calcium and Magnesium on Rabbit Blood Platelet Aggregation in Vitro

1964 ◽  
Vol 12 (01) ◽  
pp. 179-200 ◽  
Author(s):  
Torstein Hovig
Keyword(s):  
Platelet Aggregation ◽  
Cation Exchange ◽  
Calcium Concentration ◽  
Blood Platelets ◽  
Blood Platelet ◽  
Rabbit Blood ◽  
Calcium And Magnesium ◽  
Induced Aggregation ◽  
Blood Platelet Aggregation

SummaryThe effect of calcium and magnesium on the aggregation of rabbit blood platelets in vitro was studied, with the following results:1. Platelet aggregation induced by ADP or collagen could be prevented by EGTA or EDTA. The aggregating effect was restored by recalcification. The effect was also restored by addition of magnesium in EDTA-PRP, but not in EGTA-PRP unless a surplus of calcium was present.2. Calcium remained in concentrations of the order of 0.15–0.25 mM after dialysis or cation exchange of plasma. Aggregation of washed platelets resuspended in such plasma could not be produced with ADP or collagen, unless the calcium concentration was increased or that magnesium was added.3. The adhesiveness of blood platelets to collagen was reduced in EGTA-PRP and EDTA-PRP. Release of ADP from platelets influenced by collagen could not be demonstrated either in EGTA-PRP (presence of magnesium) or in EDTA-PRP.4. It is concluded that calcium is a necessary factor both for the reaction leading to release of ADP and for the the aggregation produced by ADP.5. Thrombin induced aggregation of washed platelets suspended in tris-buffered saline in the presence of calcium. No effect of magnesium could be observed unless small quantities of calcium were present.

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.

Dissolution Rate of Copper in Lead and Aluminum Melts

1994 ◽  
Vol 80 (4) ◽  
pp. 294-299
Author(s):  
Katsumi MORI ◽  
Toshiro KITAHARA ◽  
Kunihiko NAKASHIMA
Keyword(s):  
Dissolution Rate
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