Patent ID: 7566792

Claim:
A method for lactonisation of mevinolinic acid of formula II and isolation of Lovastatin of formula (I): which comprises the steps of: a) adjusting the pH of a fermentation broth containing mevinolinic acid(II) to 3.5±0.1 with a mineral acid, and optionally filtering the fermentation broth, b) adding a hydrophobic solvent to the aqueous fermentation broth or the mycelia cake and bubbling an inert gas into the biphasic mixture, c) heating the fermentation broth or the mycelia cake at 55±5° C., in the presence of a hydrophobic solvent, carrying out lactonisation of mevinolinic acid (II) and extracting Lovastatin(I) into a hydrophobic solvent, concurrently, in a time period between 12-19 hours, under constant nitrogen bubbling, d) isolating impure Lovastatin (I) from said hydrophobic solvent, e) purifying impure Lovastatin (I) by dissolving impure Lovastatin (I) in a chlorinated solvent followed by removal of suspended resinous impurities by filtration, adding a hydrophobic solvent, heating the mixture to 55±5° C., evaporating the chlorinated solvent followed by crystallization from a hydrophobic solvent to give pure Lovastatin (I) of purity≧98.70%, or by dissolving Lovastatin (I) in a mixture of a chlorinated solvent and a hydrophobic solvent, filtering the suspended impurities, and heating the mixture to 55±5° C., followed by evaporating the chlorinated solvent and crystallizing from the hydrophobic solvent to give pure Lovastatin (I) of purity≧98.70%, f) recrystallising Lovastatin (I), from a aliphatic alcohol, by heating Lovastatin (I) with an aliphatic alcohol between 65 to 75° C. for 30 minutes, cooling the mixture between −5 to +5° C. and filtering crystalline Lovastatin (I) followed by drying at 35-40° C. to give pure Lovastatin (I) of purity≧99.3%, substantially free from impurities and conforming to pharmacopoeial specification.