Transdermal delivery of cyclodextrin-solubilized curcumin.

The purpose of the present investigation was to explore the effect of cyclodextrin (CD) as permeation enhancer through rat skin in the form of a valuable and stable transdermal drug delivery system by exploiting its favorable properties. Phase-solubility studies demonstrated that the CD:drug ratio 1:2 was employed in complexation. Solid-state characterizations of complexes was performed by differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared, nuclear magnetic resonance spectrophotometry analysis, and scanning electron micrograph. The HP-ß-CD by virtue of its greater stability than the pure curcumin (CMN), allowed greater transdermal flux of CMN indicative of enhanced permeation via CMN-2-hydroxy propyl ß cyclodextrins (HP-ß-CD). Permeability studies of drug, complex, and with various penetration enhancers (PEs), were performed through rat skin, highlighted a favorable effect of CDs on drug permeation rate, due to its solubilizing action; in contrast with unpredictably poor skin permeation of pure drug. The complexes were found to cause relatively less irritation as compared to the pure drug and drug with PEs in skin irritation studies. The anti-inflammatory activity using paw odema model showed that the formulations of CMNCur-HP-ß-CD complex exhibited significant (p < 0.001) decrease in paw edema volume than its pure CMN gel demonstrating enhanced biological activity.

Polypropylene imine dendrimer mediated solubility enhancement: effect of pH and functional groups of hydrophobes.

Dendrimers today are known for their three dimensional, monodispersed, highly branched, macromolecular nano-scopic architecture with number of reactive end groups. Dendrimers have been reported to act as solubilizing agents to host both hydrophilic and hydrophobic drugs. The present study was performed to investigate the effect of pH on poly(propylene) imine dendrimers (5.0G) mediated solubility enhancement of hydrophobes differing in functional groups (pKa). Weakly basic, (famotidine, -NH2 functional group; pKa 7.1), weakly acidic (indomethacin, -COOH functional group; pKa 4.5) and amphoteric (amphotericin B, -COOH and -NH2 functional groups; pKa 5.7 and 10.0) hydrophobes were selected for the study. The experiment was carried out at pH 4.0, 7.4 and 10.0. The solubility of all the drugs was enhanced at pH 7.4 and 10.0 but not at pH 4.0. The drug-dendrimer complexes followed 1:1 stoichiometry (AL type of curve) and were characterized for stability of complex, complexation efficiency and thermodynamic properties. Thermodynamic properties were utilized to elucidate the mechanism behind dendrimer mediated solubility enhancement. The data suggested that hydrophobic and electrostatic interactions were responsible for solubility enhancement. Conclusively, PPI dendrimers were found useful in solubility enhancement of not only acidic and basic but also amphoteric drugs, their solubilization ability was clearly regulated by pH and chemical nature of drug.

Dendrimers: novel polymeric nanoarchitectures for solubility enhancement.

Poor solubility and hydrophobicity of drugs/bioactives limit their possible applications in drug delivery and formulation development. Apart from conventional methods of solubility enhancement, there are some novel methods which can be used in solubilization. Dendrimers represent a novel type of polymeric material that has generated much interest in many diverse areas due to their unique structure and properties. Dendrimer-mediated solubility enhancement mainly depends on factors such as generation size, dendrimer concentration, pH, core, temperature, and terminal functionality. Added advantage in solubilization can be achieved considering these factors. Available literature suggests that ionic interaction, hydrogen bonding, and hydrophobic interactions are the possible mechanisms by which a dendrimer exerts its solubilizing property. This review presents various mechanisms and reports relating to solubility enhancement using dendrimers. Also, micellar behavior and future possibilities in relation to solubilization via dendrimers are included.

A review of in vitro-in vivo investigations on dendrimers: the novel nanoscopic drug carriers.

Dendrimers have emerged as one of the most interesting themes for researchers as a result of their unique architecture and macromolecular characteristics. Several groups are involved in exploring their potential as versatile carriers in drug delivery. The use of dendrimers in drug delivery has been reviewed extensively. The increasing relevance of the potential of dendrimers in drug delivery emphasizes the need to explore the routes by which they can be administered. The present review focuses on dendrimer-mediated drug delivery based on various routes of administration, a topic that has received little attention in the available literature. With this focus in mind, we present a comprehensive exploration of the recent advances in the investigational aspects of these nanoscopic polymeric devices. Also included are some in vitro studies that present data suggestive of their possible application in different routes of administration.