![]() The increased percutaneous drug permeability is due to the deformability of these colloidal carriers, which is provided by the presence in the carrier composition of ethanol, edge activators and liquid lipid components in the case of ethosomes, transfersomes and niosomes, respectively. #Sufficient velocity magna graecia skinIn principle, the percutaneous adsorption of active ingredients can be further enhanced using Poloxamer 407 hydrogel as a matrix for the dispersion of colloidal drug delivery systems, thus increasing the skin contact time of the colloidal carrier.įlexible colloidal drug carriers, such as ethosomes, transfersomes and niosomes, have many advantages in comparison with traditional topical dosage forms, thus showing the ability of overcoming the skin barrier and hence enhancing the drug permeability through the stratum corneum. The poloxamer 407 gel is well flowing on the skin and has the ability to increase topical permeation of drugs like ketoprofen and piroxicam. Moreover, its good adhesive property brings some advantage over other gelling agent, increasing the residence time on the skin. The topical use of Poloxamer 407 gels is encouraged because of its non-occlusive behavior at body temperature and its safety. However, the gelling temperature and rheological features of gels can be also influenced by other factors, such as presence of drugs, other excipients and other components as drug delivery systems. Topical Poloxamer 407 gel is of particular interest since concentrated solutions (>20% w/ w) of the copolymer are transformed from low viscosity transparent solutions to solid gels with a slight heating. For example, gels designed for topical use have to be prepared using high Poloxamer 407 concentrations thus obtaining a gel at room temperature. The T sol →gel is strongly influenced by the Poloxamer 407 concentration and hence the concentration is selected as a function of the use requirements. The thermogelling phenomenon is reversible and occurs at a specific sol-gel transition temperature (T sol →gel), namely the temperature increase favors the interaction between different segments of the copolymer, thus eliciting the aggregation of Poloxamer 407 molecules into micelles due to the dehydration of the hydrophobic Poloxamer 407 blocks and hence the sample gelation. Poloxamer 407, due to its thermo-gelling property, is used as a component of pharmaceutical dosage forms for rectal, nasal and oral applications, as well as for cosmetic use. Poloxamer 407 copolymer, also known as Pluronic F127 ®, is a non-toxic and non-irritable polymer which represents an excellent excipient, compatible with many different substances and useful for different purposes, for instance increasing the solubility of poorly water-soluble drugs. This study provide evidence that vesicular systems do not influence the rheological features of the gel, supporting the possibility to encapsulate an innovative system into a three-dimensional network. The advantages of the Rheolaser Master™ analyzer are: (i) its ability to determine viscoelastic parameter, without altering or destroying the sample and at rest (zero shear) (ii) possibility of aging analysis on the same sample. For this reason, the Rheolaser Master™, based on diffusing wave spectroscopy, and a Kinexus Rotational Rheometer were used to evaluate the influence of nanocarriers on the microrheological features of hydrogels. The evaluation of the interaction between colloidal carriers and the Poloxamer 407 hydrogel network is essential for a suitable design of an innovative topical dosage form. A strategic approach in topical therapeutic treatments may be the inclusion of drug delivery systems, such as ethosomes, transfersomes and niosomes, into hydrogel poloxamer formulation. Hydrogels made up of Poloxamer 407 are characterized by specific rheological features, which are affected by temperature, concentration and presence of other compounds. Its use has many advantages, such as bio-adhesion, enhanced solubilization of poorly water-soluble drugs and many applications fields like oral, rectal, topical, nasal drug administration. Poloxamer 407 copolymer is a versatile and widely used thermo-reversible material. ![]()
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