Purpose: Micellar solubilization is a powerful alternative for dissolving hydrophobic drugs in aqueous environments. The application of micelles in drug delivery, in order to minimize drug degradation and loss, to prevent harmful side effects, and to increase drug bioavailability, is also presented.
DO surfactants increase solubility?
One important property of surfactants is the formation of colloidal-sized clusters in solutions, known as micelles, which have particular significance in pharmacy because of their ability to increase the solubility of sparingly soluble substances in water (1).
How DO micelles increase solubility?
The solubiliza- tion phenomenon is clearly related to the formation of micelles, since a sharp increase in solubility is observed when the cmc is attained. Once micelles are-formed, the solubility increases proportionally with in- crease in surfactant concentration.
What is meant by micellar solubilization?
Micellar solubilization (solubilization) is the process of incorporating the solubilizate (the component that undergoes solublization) into or onto micelles. Solublization may occur in a system consisting of a solvent, an association colloid (a colloid that forms micelles), and at least one other solubilizate.
What is the importance of solubilization in pharmacy?
Solubility, the phenomenon of dissolution of solute in solvent to give a homogenous system, is one of the important parameters to achieve desired concentration of drug in systemic circulation for desired (anticipated) pharmacological response.
Which agent is used in micellar solubilization?
The drug paclitaxel is highly lipophilic in nature and insoluble in water. Its current marketed form as an intravenous infusion paclitaxel is solubilized by using Cremophor EL, which is a nonionic surfactant and helps in the micellar solubilization.
How does surfactant affect solubility?
Surfactants, or surface-active agents, are amphiphilic molecules. Their heads are polar, or hydrophilic, and their tails hydrophobic. They are soluble in both organic solvent and water. The surfactant reduces the surface tension of water by adsorbing at the liquid–gas interface.
How does a surfactant affect the solubility of polar substance?
A surfactant is a molecule that has either an ionic or polar end called the head, which is soluble in polar solvents (hydrophilic) or a non-polar end called the tail, which is soluble in the non-polar solvent (hydrophobic.) This reduces the surface tension between the two solvents.
Which part of the micelle is soluble in water?
hydrophilic shell
2.3. Micelles are spherical amphiphilic structures that have a hydrophobic core and a hydrophilic shell. The hydrophilic shell makes the micelle water soluble that allows for intravenous delivery while the hydrophobic core carries a payload of drug for therapy.
How micelle affects the aqueous solubility of a pharmaceutical solutions?
The varying polarity in the micelles facilitates the incorporation of poorly water-soluble drug molecules, which results in solubilization, viz. in an increase in the apparent aqueous solubility of the drug. The micellar solubilization of drugs by surfactants is an exten- sively studied topic [6-19].
What do you understand by solubilization?
Solubilization is the formation of a thermodynamically stable, isotropic solution of a substance (the solubilizate), normally insoluble or slightly soluble in water, by the addition of a surfactant (the solublizer).
What is solubilization in biology?
Solubilization is the increase in solubility of a poorly water–soluble substance with surface-active agents. The mechanism involves entrapment (adsorbed or dissolved) of molecules in micelles and the tendency of surfactants to form colloidal aggregations at critical micelle concentration levels.
What is Micellar solubilization and how does it work?
PURPOSE: Micellar solubilization is a powerful alternative for dissolving hydrophobic drugs in aqueous environments. In this work, we provide an insight into this subject. METHODS: A concise review of surfactants and micelles applications in pharmacy was carried out.
How do surfactant micelles solubilize oil?
Literature distinguishes two major mechanisms of solubilization process of oil by surfactant micelles, affecting the kinetics of solubilization: surface reaction, i.e., by transient adsorption of micelles at the water-oil interface, and bulk reaction, whereby the surfactant micelles capture dissolved oil molecules.
How many micelles can be present in a micellar solution?
Usually, in a micellar solution the aggregation number is approximately constant for a broad total concentration range (up to about 100 times the cmc), with the number of micelles varying (21). However, at certain conditions micelles can grow with the aggregation number varying with the surfactant concentration. (22).
What is an anisotropic water distribution in micelle?
Micelles are known to have an anisotropic water distribution within their structure. In other words, the water concentration decreases from the surface towards the core of the micelle, with a completely hydrophobic (water-excluded) core.
