Investigation of hyperbranched Poly(glycerol esteramide) as potential drug carrier in solid dispersion for solubility enhancement of lovastatin

Hyperbranched poly(glycerol esteramide)s (HPGEA) with weight average molecular weight (M-w) ranging between 5000 and 12000 Da and degree of branching of 57-62% were employed as drug carriers in formulating lovastatin solid dispersions (LOV SD) through fusion-solvent method. SD 4 (LOV: HPGEA = 5%:95% w/w) illustrated substantial enhancement via in vitro dissolution and solubility studies in which it achieved 2-fold increment in cumulative drug release and 3.7-fold increment in solubility as compared to pure LOV. The performance of SD 4 (time required for 50% drug release, T-50% = 90 min; solubility = 38.27 mu g mL(-1)) was also found to be superior than the marketed product (Apo-Lovastatin) (T-50% = 300 min; solubility = 12.44 mu g mL(-1)). FTIR analysis revealed the formation of intermolecular hydrogen bonding between the OH group of LOV and C=0 ester group of HPGEA in the SD system. Meanwhile, a smooth-surfaced and homogenous amorphous form with no sharp crystals of LOV was observed in SEM image of SD 4. The XRD pattern of the SD 4 pre-formulation showed broad amorphous halo similar to HPGEA, depicting the amorphous nature of the SD 4. Stability study revealed that HPGEA did not undergo recrystallisation upon storage at room and accelerated conditions (40 degrees C/75% RH) for up to 3 months. In conclusion, the HPGEA demonstrated promising potential as a novel solubility and dissolution enhancer for LOV in SD.