Solid state mechanochemical simultaneous activation of the constituents of the Silybum marianum phytocomplex with crosslinked polymers

Simultaneous improvement of solubilization kinetics of main flavolignans of Silybum marianum extract was obtained cogrinding with two crosslinked polymers: micronized crospovidone, PVP-CL(R) and sodium carboxymethylcellulose, Ac-Di-Sol(R) in the 1:3 active-to-polymer weight ratio. By this process it was assessed that the main extract components lost its crystalline structure, and the powder surface area was increased by 2.1- and 1.7-fold in the coground products with Ac-Di-Sol(R) and PVP-CL(R), respectively. This activated status of the dry extract remained stable over a period of 2 years. Solubilization kinetics resulted ameliorated both in terms of entire dry extract and in terms of single components. When the 1/3 coground systems with PVP-CL(R) and Ac-Di-Sol(R) were dissolved in saturated conditions they gave a concentration improvement compared to the native product of 8 and 31 times of silybin A, 7 and 27 times of silybin B, whereas in the case of silychristin a double concentration was obtained only using Ac-Di-Sol(R). The in vivo studies on rats confirmed that this solubilization improvement corresponded to an effective oral bioavailability enhancement. The highest bioavailability improvement was obtained with Ac-Di-Sol(R), with a relative bioavailability of 88.6, 17.96, and 16.4 compared to the extract for silybin A, silybine B, and silychristine, respectively.

Pharmacokinetics and immunomodulatory effects of phytotherapeutic lozenges (bonbons) with Echinacea purpurea extract

The relative bioavailability of the major alkamides, dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides, from Echinacea purpurea phytotherapeutic lozenges at three different dose levels (0.07, 0.21 and 0.9 mg) was evaluated in a pharmacokinetic study in humans and the possible effects on the immunological system were measured. Alkamides were found to be rapidly absorbed and measurable in plasma 10 min after administration of 0.21 and 0.9 mg lozenges and remained detectable for 3h for the 0.21 mg lozenges and for more then 3h for the 0.9 mg lozenges; 0.07 mg lozenges were measurable 20 min after administration and remained detectable for only 2h after the administration. A significant dose-independent down-regulation of the pro-inflammatory cytokines IL-12p70, IL-8, IL-6, IL-10 and TNF was observed 24h after oral administration. The results of non-compartmental pharmacokinetic analysis revealed that a C(max) of (0.65+/-0.41 ng/ml) was reached at 32 min with the 0.07 mg lozenges, (1.00+/-0.21ng/ml) at 25 min with the 0.21 mg lozenges and (8.88+/-5.89 ng/ml) at 19 with the 0.9mg lozenges. As evidenced by the dose-exposure relationship, no significant departure from dose proportionality was observed, indicating linearity in pharmacokinetics. To get a further insight in pharmacokinetics of dodeca-2E,4E,8Z,10E/Z-tetraenoic isobutylamides a compartmental population pharmacokinetic model was developed applying mixed effect modelling procedure. The results demonstrate that within the dose range studied pharmacokinetics of dodeca-2E,4E,8Z,10E/Z-tetraenoic isobutylamides are linear and that absorption is very rapid (t(1/2)=6 min) with apparently no lag time, thus indicating the possibility that a fraction of the drug is absorbed through the oral mucosa.