Ficaria verna Huds. extracts and their β-cyclodextrin supramolecular systems

<p>Abstract</p> <p>Background</p> <p>Obtaining new pharmaceutical materials with enhanced properties by using natural compounds and environment-friendly methods is a continuous goal for scientists. <it>Ficaria verna </it>Huds. is a widespread perennial plant with applications in the treat of haemorrhoids and to cure piles; it has also anti-inflammatory, astringent, and antibiotic properties. The goal of the present study is the obtaining and characterization of new <it>F. verna </it>extract/β-cyclodextrin complexes by using only natural compounds, solvents, and environment-friendly methods in order to increase the quality and acceptability versus toxicity indicator. Thus, the flavonoid content (as quercetin) of <it>Ficaria verna </it>Huds. flowers and leaves from the West side of Romania was determined and correlated with their antioxidant activity. Further, the possibility of obtaining β-cyclodextrin supramolecular systems was studied.</p> <p>Results</p> <p><it>F. verna </it>flowers and leaves extracts were obtained by semi-continuous solid-liquid extraction. The raw concentrated extract was spectrophotometrically analyzed in order to quantify the flavonoids from plant parts and to evaluate the antioxidant activity of these extracts. The <it>F. verna </it>extracts were used for obtaining β-cyclodextrin complexes; these were analyzed by scanning electron microscopy and Karl Fischer water titration; spectrophotometry was used in order to quantifying the flavonoids and evaluates the antioxidant activity. A higher concentration of flavonoids of 0.5% was determined in complexes obtained by crystallisation method, while only a half of this value was calculated for kneading method. The antioxidant activity of these complexes was correlated with the flavonoid content and this parameter reveals possible controlled release properties.</p> <p>Conclusions</p> <p>The flavonoid content of <it>F. verna </it>Huds. from the West side of Romania (Banat county) is approximately the same in flowers and leaves, being situated at a medium value among other studies. β-Cyclodextrin complexes of <it>F. verna </it>extracts are obtained with lower yields by crystallisation than kneading methods, but the flavonoids (as quercetin) are better encapsulated in the first case most probably due to the possibility to attain the <it>host</it>-<it>guest </it>equilibrium in the slower crystallisation process. <it>F. verna </it>extracts and their β-cyclodextrin complexes have antioxidant activity even at very low concentrations and could be used in proper and valuable pharmaceutical formulations with enhanced bioactivity.</p

Effect of pH and Hydroxylpropyl-b-Cyclodextrin on Solubility and Stability of Gliclazide

Purpose: Hydroxy propylated &#946 cyclodextrin (HP-&#946-CD) has been used to improve the aqueous solubility of a variety of pharmacological compounds. Through the complexation of HP-&#946-CD, it is possible to enhance the water solubility and hence the drug bioavailability after oral administration. The present study was undertaken to examine the effect of pH and concentration of HP-&#946-CD on the solubility of gliclazide as it shows pH dependent solubility and stability. Method: The equilibrium solubility of gliclazide in a series of solutions of varying pH (from 1.2 to 11) was determined and compared with the equilibrium solubility of gliclazide in the presence of 20% HP- &#946-CD at same pH values. Result: As the pH increases from 9.2 to 11 its solubility relatively constant (3.5 μg/ml ± 0.5). Addition of 20% HP--CD increased the solubility to about 9 times at pH 1.2 and 4; 15 times at pH 6.8; 40 times at pH 7.4; 58 times at pH 9.2 and 67 times at pH 11. It was observed that solubility of protonated form is more than neutral molecule. HP-&#946-CD resulted in increased solubility at all pH values. But inclusion of drug in the cavity of HP-&#946-CD might depend upon charged state of the molecule. Conclusion: The solubility of gliclazide can be increased either by the addition of HP-&#946-CD or by adding pH lowering agents. Keywords: pH, hydroxypropylated-&#946-cyclodextrin (HP-&#946-CD), gliclazide