Formulation and evaluation of amorphous solid dispersion Boerhaavia diffusa methanolic root extract for improving dissolution properties

Boerhaavia diffusa is a perennial plant whose leaves and roots have historically been used to treat asthma, urinary disorders, rheumatism, and jaundice, among other ailments. Like many natural products, the poor solubility limited poor dissolution properties of Boerhaavia diffusa's alcoholic extract act as one of the major constraints in making an effective commercial oral formulation. The present investigation was aimed to prepare amorphous solid dispersion of methanolic extract of Boerhaavia diffusa root powder to improve its dissolution properties. Water-soluble polymers - HPMCAS-L, HPMC E−5, PVP K-30 were used to prepare stable amorphous solid dispersion. The pure extract and the polymers in varied ratios were dissolved in a suitable solvent which was subsequently evaporated using a rotary vacuum evaporator. The results of DSC and PXRD studies indicated complete conversion of semi-crystalline phytoconstituents to amorphous or molecularly dispersed form within polymer matrix (at 1:4 ratio). The results of FTIR studies proved the stability of phytoconstituents within the polymer matrix as there was no change in any characteristic peaks of pure extract. The result of in-vitro dissolution studies indicated significant improvement in the release of phytoconstituents from all the prepared batches compared to pure extract and physical mixture (f2 < 50). The stability studies indicated that all formulations with a 1:4 ratio (pure extract: polymer) were able to maintain the phytoconstituents in amorphous/molecularly dispersed form within the polymer matrix for 6 months at 25 °C/60 ± 5 RH.