Casein/pectin nanocomplexes as potential oral delivery vehicles.

The object of this study was to enhance the solubility, dissolution rate, and oral bioavailability of rutin by complexation with 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD). The interaction of rutin with cyclodextrins (CyDs) was evaluated by the solubility, and ultraviolet (UV) and circular dichroism (CD) spectrophotometries. The chemical and enzymatic stability of rutin was examined in an alkaline buffer solution and in rat small intestinal homogenates, respectively. Dissolution rates of rutin and its CyD complexes were measured by the dispersed amount method. In vivo absorption studies of rutin after oral administration via conventional tablet containing rutin alone or its beta-CyD complexes was performed on beagle dogs. The stability constants calculated from the phase solubility method increased in the order of HP-gamma-CyD < G2-beta-CyD < beta-CyD < HP-beta-CyD. Spectroscopic studies also revealed that HP-beta-CyD and beta-CyD formed a relatively more stable inclusion complex with rutin. The dissolution rates of rutin increased by the complexation with CyDs in the order of rutin alone < HP-beta-CyD < or = beta-CyD. HP-beta-CyD inhibited the hydrolysis of rutin in the alkaline buffer solution and the small intestinal homogenates of rats, suggesting that HP-beta-CyD may stabilize rutin in a gastrointestinal tract after oral administration. When the tablet containing rutin or its beta-CyD complexes was administered to beagle dogs, the plasma levels of homovanillic acid (HVA) (a major stable metabolite of rutin) after oral administration of HP-beta-CyD complex were much higher than in either that of rutin alone or in its beta-CyD complex. The in vivo absorption study suggests that HP-beta-CyD increased the oral bioavailability of rutin from the gastrointestinal tracts of beagle dogs because of the increase in solubility, faster dissolution rate, and gastrointestinal stability. HP-beta-CyD has a significant advantage with respect to providing high aqueous solubility while maintaining a lack of toxicity in oral pharmaceutical preparations of rutin.

Improvement of Solubility and Oral Bioavailability of Rutin by Complexation with 2-Hydroxypropyl-β-cyclodextrin

Simultaneous spectrophotometric determination of rutin, quercetin and ascorbic acid in drugs using a Kalman Filter approach.

Preparation of starch nanoparticles loaded with quercetin using nanoprecipitation technique.

Quercetin encapsulation in modified silica nanoparticles: potential use against Cu(II)-induced oxidative stress in neurodegeneration

The fluorescence of solutions of reserpine under ultraviolet light is increased by heating with hydrogen peroxide, and is quantitatively related to its concentration. An assay procedure has been developed for tablet preparations containing reserpine alkaloid, and the results of the application of this method to a powdered extract of Rauwolfia serpentina is reported.

A Fluorometric Assay of Reserpine

A study of the decomposition of rutin and quercetin in alkaline solution has been made, and it has been found that rutin is more stable than quercetin under these conditions.

The relative stability of rutin and quercetin in alkaline solution.

The colorimetric determination of aluminum by means of morin (57,2′,4′-tetrahydroxy-flavonol) has furnished the basis for the colorimetric determination of flavonal compounds. A procedure based on this reaction has been developed for the determination of rutin in tablets. Paper partition chromatography has been employed to demonstrate the absence of any interfering flavonol compounds, such as quercetin, which might be present as breakdown products of rutin.

Earl B. Dechene

Papers

A Fluorometric Assay of Reserpine

The relative stability of rutin and quercetin in alkaline solution.

The determination of rutin in tablets.

A colorimetric method for the assay of diethylstilbestrol

A note on the extraction and fluorescence of some oxidation products of reserpine.