Leuprolide acetate which is a highly active agonist of luteinizing hormone–releasing hormone (LH-RH) potently inhibits their secretion in the pituitary gland and it is useful in the treatment of hormone-dependent diseases in males and females. To eliminate the inconvenience of daily injection, Leuprolide acetate is available in the market, in the form of its depot for 1 month, 3 months, and 6 months, and depending upon the requirement of the patients, it is given as a parenteral solution.
To make this depot, one of the major and responsible ingredients required is Bioresorbable PLGA (Poly Lactic co glycolic acid) polymer, which is used to make microspheres of Leuprolide acetate along with this PLGA Polymer.
The higher level of free acid content in PLGA polymer causes an increase in the initial burst. If the free acid content is less than 0.1%, then the initial burst is less than 10%. These water-soluble acid fractions designated as free acid is ranging from heptamer to monomer/oligomer of lactic acid. These oligomers are assumed to interfere with the formation of the hydrophilic barrier by the arrangement of the polymer around the drug domains and increase the number of aqueous channels through the polymer barrier resulting in enhancement of the initial burst – called “tunnel effect”.
In order to have the quality of polymer i.e. free acid value in control, among all available in the market, Nomisma Healthcare Pvt. Ltd has produced PLGA polymers with optimum low-level free acid content value to control initial burst.