Changes in morphology of in situ forming PLGA implant prepared by different polymer molecular weight and its effect on release behavior.

The effects of polymer molecular weight on drug release behavior would be more complicated from in situ forming implants (ISFIs) that change gradually from liquid to semi-solid or solid after injection. To investigate this phenomenon, three commercially available D,L-lactic acid-co-glycolic acid (PLGA) polymers with molecular weights of 12, 34, and 48 kDa were used to prepare ISFIs containing leuprolide acetate (LA) as a model peptide. The influence of polymer molecular weight on the membrane formation, morphology, and also on their in vitro drug release behavior over a period of 28 days was investigated.

Zinc-leuprolide complex: preparation, physicochemical characterization and release behaviour from in situ forming implant.

Leuprolide acetate (LA) has been accepted as treatment for prostatic cancer and is currently also being evaluated in phase II clinical trials for the treatment of Alzheimer's disease. In this study, the zinc complex of leuprolide was prepared and its structure determined by Fourier-transform infrared (FTIR), differential scanning calorimetry (DSC), UV, X-ray diffraction (XRD), atomic absorption spectroscopy, elemental analysis, and compared with these parameters for leuorolide acetate. Also, the in vitro release profile of leuprolide and its complex form in situ forming implant (ISFI) in comparison to a commercial formulation (Eligard) was investigated.

Solubilization of an amphiphilic drug by poly(ethylene oxide)-block-poly(ester) micelles.

The purpose of this study was to investigate the solubilization of an amphiphilic drug, i.e, amiodarone (AMI) in methoxy poly(ethylene oxide)-block-poly(ester) micelles of different core structure. The effect of core-forming block structure as well as molecular weight, applied drug to polymer ratios and assembly condition on AMI solubilization; stability of the solubilized formulation upon dilution in phosphate buffer and the hemolytic activity of solubilized AMI against rat red blood cells were assessed and compared to those parameters for the commercial intravenous formulation of AMI.