Biosynthesis and pharmacokinetics of Panax notoginseng enteric-coated soft capsules

To investigate the biosynthesis and pharmacokinetic course of enteric-coated soft capsules of Panax notoginseng saponins (PNS) in a beagle dog model.

To satisfy the enteric properties of soft capsules, the PNS enteric soft gelatin capsules were prepared by formaldehyde impregnation and orthogonal experimental design. The fluidity of gelatin and the disintegration time were selected as evaluation indexes; the soft gelatin capsule content was self-emulsifying, and the Km value and the optimal prescription were determined by making three-phase diagrams; in vivo pharmacokinetics studies were performed on six beagle dogs with 3 dogs in each group. Beagle dogs were divided into two groups randomly. One group was given PNS self-emulsifying enteric capsule and the other was given market conventional capsules. Plasma samples were collected at different times. After 1 week, the crossover experiment was carried out. The plasma concentration was detected by HPLC-MS (high performance liquid chromatography-mass spectrometry). Then the pharmacokinetic parameters were calculated by non-compartment model analysis.

The range and variance analysis of the orthogonal test determined that the best prescription of total saponins of Panax notoginseng enteric soft capsule was:gelatin:glycerol:water =1:1:2, Soak the films in 1% formaldehyde for 1 hour. The contents of the soft capsule self-microemulsion are prescribed as: IPM (isopropyl myristate):Cremophor RH40:PEG400 (polyethylene glycol 400) =1:4.5:4.5 (with suitable PNS); the pharmacokinetic parameters of PNS self-emulsified enteric capsules and conventional capsules in the market are as follows: Rb₁:C_max is (18.05±0.26) and (15.50±0.51) ng/mL, T_max is (2.00±0) and (3.00±0) h, AUC_0→t is 98.49±1.16 and 34.46±2.02 (ng/mL)·h, relative bioavailability is 196.2%; Rg₁: C_max is 4.16±0.25 and 3.88±0.28 ng/mL, T_max is 2.00±0 and 1.50±0 h, area under drug time curve (AUC)_0→t is 11.80±2.93 and 10.45±2.29 (ng/mL)·h, relative bioavailability is 77.2%; R₁:C_max is 1.84±0.25 and 1.48±0.21 ng/mL, T_max is 2.08±0.49 and 1.92±0.20 h, AUC_0→t is 7.06±2.07 and 7.16±2.59 (ng/mL)·h, relative bioavailability is 117.7%.

The experiment in vivo showed the higher relative bioavailability of PNS self-emulsifying enteric capsule compared with market conventional capsules. This will provide a potential application prospect for the clinical research and applications of PNS.