Improved stability and oral bioavailability of Ganneng dropping pills following transforming lignans of herpetospermum caudigerum into nanosuspensions

Abstract

The present study was designed to improve storage stability and oral bioavailability of Ganneng dropping pills (GNDP) by transforming lignans of Herpetospermum caudigerum (HL) composed of herpetrione (HPE) and herpetin (HPN) into nanosuspen-sion (HL-NS), the main active ingredient of GNDP, HL-NS was prepared by high pressure homogenization and lyophilized to transform into solid nanoparticles (HL nanoparticles), and then the formulated HL nanoparticles were perfused into matrix to obtain NS-GNDP by melting method. For a period of 3 months, the content uniformity, storage stability and pharmacokinetics test in vivo of NS-GNDP were evaluated and compared with regular GNDP at room temperature. The results demonstrated that uniformity of dosage units of NS-GNDP was acceptable according to the criteria of Chinese Pharmacopoeia 2015J. Physical stability of NS-GNDP was investigated systemically using photon correlation spectroscopy (PCS), zeta potential measurement, and scanning electron microscopy (SEM). There was a slight increase in particles and PI of HL-NS re-dispersed from NS-GNDP after storage for 3 months, compared with new formulated NS-GNDP, which indicated a good redispersibility of the NS-GNDP containing HL-NS after storage. Besides, chemical stability of NS-GNDP was studied and the results revealed that HPE and HPN degradation was less when compared with that of GNDP, providing more than 99% of drug residue after storage for 3 months. In the dissolution test in vitro, NS-GNDP remarkably exhibited an increased dissolution velocity compared with GNDP and no distinct dissolution difference existed within 3 months. The pharmacokinetic study showed that HPE and HPN in NS-GNDP exhibited a significant increase in AUC 0-t , C max and decrease in T max when compared with regular GNDP. These results indicated that NS-GNDP possessed superiority with improved storage stability and increased dissolution rate and oral bioavailability.