Self-association of Verapamil in Aqueous Electrolyte Solution

Taboada, Pablo; Pérez-Rodrı́guez, Martı́n; Attwood, David; Varela, Luis M.; Ruso, Juan M.; Mosquera, Vı́ctor

doi:10.1006/jcis.2001.7738

Cited by 6 publications

(2 citation statements)

References 28 publications

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“…From our studies we determined that for pure water the number of monomers participating in the aggregates is low (around two). This result is in agreement with reported aggregation numbers of several non-peptide surface active drugs in water, whose aggregation numbers vary from 3 to 12 [27, 28]. …”

Section: Discussionsupporting

confidence: 92%

Investigation on the self-association of an inorganic coordination compound with biological activity (Casiopeína III-ia) in aqueous solution

Marín-Medina

García‐Ramos

Ruíz-Azuara

et al. 2016

Chemistry Central Journal

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From studies using different experimental techniques employed to determine the presence of aggregates e.g. isothermal titration calorimetry, surface tension, electrical conductivity, UV–Vis spectrophotometry, dynamic and static light scattering, it is clearly demonstrated that the compound [Cu(4, 4′-dimethyl-2, 2′-bipyridine)(acetylacetonato)H2O]NO3 (Casiopeína III-ia), promising member of a family of new generation compounds for cancer treatment, is able to auto associate in aqueous media. Physicochemical properties associated with the formation of the aggregates were determined in pure water and in phosphate buffer media in order to simulate physiological conditions. From isothermal titration calorimetry and electrical conductivity measurements we calculated the dissociation constant of the aggregates, K D. For pure water the values obtained in both techniques are 2.73 × 10−4 and 5.93 × 10−4 M respectively while for the buffer media we obtained 4.61 × 10−4 and 1.57 × 10−3 M. The enthalpy of dissociation, ∆H D, calculated from the calorimetric data shows that the presence of the phosphate ions has an energetic effect on the aggregate stability since in pure water a value of 18.79 kJ mol−1 was obtained in comparison with the buffer media where a value 4 times bigger was found (70.48 kJ mol−1). With the data collected from these techniques the number of monomers calculated which participate in the formation of the aggregates is around two. From our surface tension, electrical conductivity and UV–Vis spectrophotometry measurements the critical aggregate concentration, cac, was determined. For each technique specific concentration ranges were obtained but we can summarize that the cac in pure water is between 3 and 3.5 mM and for the buffer media is between 3.5 and 4 mM. Dynamic light scattering measurements provide us with the hydrodynamic diameter of the aggregates and from static light scattering measurements we determined the molecular weight of the Casiopeína III-ia aggregates to be of 1000.015 g mol−1 which is two times the molecular weight of the Casiopeína III-ia molecule. This value is in agreement with the number of monomers which participate in the formation of the aggregates obtained from isothermal titration calorimetry and electrical conductivity data analysis.

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Section: Discussionsupporting

confidence: 92%

Investigation on the self-association of an inorganic coordination compound with biological activity (Casiopeína III-ia) in aqueous solution

Marín-Medina

García‐Ramos

Ruíz-Azuara

et al. 2016

Chemistry Central Journal

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“…47 For chlorpheniramine maleate, venlafaxine hydrochloride, and verapamil hydrochloride, calculated SRE was 1.20, 1.68, and 2.40. 47 These three drugs form micelles, and their cmc is 0.054, 50 0.028, 51 and 0.013 mol/L 52 for chlorpheniramine, venlafaxine, and verapamil, respectively. The SRE was larger for drugs with a smaller cmc in this study.…”

Section: Resultsmentioning

confidence: 99%

Drug Extended-Release System Utilizing Micelle Formation of Highly Water-Soluble Drugs and a Counter Polymer

Kojima,

Yoshida,

Kondo

et al. 2023

Mol. Pharmaceutics

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The objective of this study is to clarify the mechanism of extending release of highly water-soluble drugs via counter polymer (CP) utilization in poly(ethylene oxide) (PEO)/polyethylene glycol (PEG) matrix tablets. Carbomer, poly(acrylic acid), was used as a CP, which has the opposite charges to the drugs. The in vitro release of several highly water-soluble drugs from PEO/PEG tablet with or without CP were tested, the relationship between the sustained release effect by a CP (SRE) and the physicochemical properties of the drugs was investigated. The results demonstrated that the utilization of CP can extend the release of some highly water-soluble drugs by effectively controlling the drug diffusion through matrices. On the other hand, the effectiveness of CP was different depending on the drugs applied. There were not statistical correlations between SRE and physicochemical properties such as solubility, molecular weight, and charge intensity of the drugs, while a micelle forming property of the drugs played an important role in SRE by CP. It was concluded that CP, Carbomer, having negative charges could effectively interact with opposite charges on the surface of stable drug micelles, which could result in a significant decrease in drug diffusion leading to extended drug release. It is considered that the system utilizing CP is a promising approach to achieve extended release of highly water-soluble drugs with a reasonable tablet size, especially in the case of large drug loading.

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Molecular interactions, internal structure and drug release kinetics of rationally developed polymer–lipid hybrid nanoparticles

Wong

Shuhendler

et al. 2008

Journal of Controlled Release

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Self-association of Verapamil in Aqueous Electrolyte Solution

Cited by 6 publications

References 28 publications

Investigation on the self-association of an inorganic coordination compound with biological activity (Casiopeína III-ia) in aqueous solution

Investigation on the self-association of an inorganic coordination compound with biological activity (Casiopeína III-ia) in aqueous solution

Drug Extended-Release System Utilizing Micelle Formation of Highly Water-Soluble Drugs and a Counter Polymer

Molecular interactions, internal structure and drug release kinetics of rationally developed polymer–lipid hybrid nanoparticles

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