Influence of Manufacturing Parameters on Development of Contraceptive Steroid Loaded Injectable Microspheres

The main objective of this work was to develop a system consisting of polymeric microspheres loaded with
steroid drugs. The drugs were encapsulated using biodegradable poly(lactide-co-glycolide) (PLG) and poly(e
caprolactone) (PCL) by double emulsion solvent evaporation method. The lipophilic drugs, levonorgestrel and
ethinylestradiol were made soluble by adding ethanol/water mixture. The effects of parameters like polymer con
centration and stabilizer concentration were studied on the size, size distribution, surface properties and loading
efficiencies of microspheres. The formulated microspheres were smooth, spherical and uniform in shape and size.
Fourier transformed infrared spectroscopy and differential scanning calorimetry studies seemed to confirm the
absence of chemical interaction between the drugs and the polymers, while the drugs were dispersed in the poly
mer. The increase in polymer concentrations increased the size as well as the loading efficiency of microspheres.
Data obtained in this study demonstrated that the PLG/PCL microspheres may be a suitable polymeric carrier
for long acting injectable drug delivery.