Naproxen-loaded poly(lactic acid) microspheres: electrospray preparation and properties

Naproxen (NPX) is widely used to treat pain and inflammation but also causes gastrointestinal upset and ulcers. It is believed that further improvements in extendedrelease technology can mitigate these issues. Toward this end, we used electrospray to prepare NPX-loaded poly(lactic acid) (PLA) microspheres. The effects of NPX content on PLA/NPX composites were evaluated by characterization methods: infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Drug-releasing behaviors of pure NPX and NPXloaded PLA microspheres were explored by ultraviolet-visible spectroscopy. The microspheres were smooth and well dispersed based on SEM analysis. NPX was molecularly dispersed and incorporated into the PLA matrix, as evidenced by the XRD, FTIR DSC, and TGA results. An in vitro study suggested that compared to pure NPX, the initial burst of NPX release was reduced in the first 8 h, followed by a sustained release. For PLA/NPX microspheres, as the content of NPX increased, the release amount of NPX from PLA/NPX composites increased. The release behavior of PLA/NPX microspheres with 10% NPX content reached 29.1% at the end of 24h. PLA/NPX electrospray microspheres have potential utility for drug delivery.