Pharmacokinetic and pharmacodynamic study of three products of epoetin alfa as single subcutaneous dose in healthy volunteers.

Hemax® is an epoetin alfa product developed by Biosidus S.A. in Argentina at the end of the 1980s and has been present in that market since 1991. The initial presentation was a lyophilized powder containing albumin as stabilizer, to best adapt to environmental conditions in developing countries; more recently, a prefilled syringe, albumin-free presentation was developed, since this presentation has become the preferred standard in many markets. The primary objective was to compare the pharmacokinetic profile of different formulations of epoetin alfa after a single subcutaneous administration to healthy volunteers of 40 000 IU of Eprex/Erypo® and Hemax® PFS. This clinical trial was conceived following an open-label, randomized, three-way three-period cross-over balanced, and sequential design. The study was conducted on 24 healthy volunteers. To analyze similarity between Hemax® PFS and the innovator product, Eprex®, area under the curve (AUC) and Cmax of both products have been compared. The 90% CI lower limit for the geometric mean ratios was higher than 80% for any comparisons, and the 90% CI upper limit for these geometric ratios was below 125% for all the comparisons made, thus demonstrating equivalence between both products. The comparison between Hemax® PFS and Eprex® resulted in similar 90% CI for Cmax , AUC(0-120 h) and AUC(0-inf) ratios, all of them within the 80-125% interval, with a power above 95% for each ratio. These findings suggest biosimilar patterns for absorption velocity (with Tmax close to 15 h), absorption extent, and elimination (with an elimination half-life close to 25-30 h for each formulation).

A prenylated flavanone from Dalea elegans inhibits rhodamine 6 G efflux and reverses fluconazole-resistance in Candida albicans.

In previous studies, 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin, a prenylated flavonoid isolated from Dalea elegans roots, showed activity against multiresistant Staphylococcus aureus and Candida albicans, as well as an uncoupling effect on mitochondria and antioxidant activity. The aim of this study was to evaluate the inhibitory effects of 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin and fluconazole on the efflux of rhodamine 6 G in azole-resistant C. albicans 12-99 that expresses multidrug transporters Cdr1p, Cdr2p, and Mdr1p. The effect of fluconazole and 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin on rhodamine 6 G efflux was assessed in both azole-sensitive and azole-resistant C. albicans. Between 1 and 1000 µM, 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin inhibited rhodamine 6 G efflux only in azole-resistant C. albicans 12-99 in a concentration-dependent manner (IC50 = 119 µM); a competitive effect was observed. It also showed selectivity of action in comparison with other flavanones (6-prenylpinocembrin, isolated from aerial parts of D. elegans, pinocembrin, naringenin, and hesperetin, all at 250 µM). To check the possible implications of the inhibition of azole efflux on cell growth, antifungal assays were conducted. Minimal inhibitory concentration values were 150 µM for 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin and higher than 400 µM for fluconazole. The combination of both compounds at either inhibitory or subinhibitory concentrations was significantly more effective than each compound separately. Minimal inhibitory concentration for fluconazole decreased by more than 400 times in the presence of 100 µM 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin, reversing azole resistance and giving values similar to those of azole-sensitive C. albicans. These data are consistent with a dual action of 2',4'-dihydroxy-5'-(1''',1'''-dimethylallyl)-6-prenylpinocembrin: direct antifungal effect on azole-resistant C. albicans 12-99 and inhibition of azole transporters, which results in reversion of fluconazole resistance.