Drug targeting to macrophages using paromomycin-loaded albumin microspheres for treatment of visceral leishmaniasis: an in vitro evaluation

Purpose: Preparation and in vitro evaluation of PM loaded albumin microspheres (MS) (of size < a parts per thousand currency sign 5 mu A mu m) to target macrophages for treatment of visceral leishmaniasis. Methods: PM loaded MS were prepared by spray-drying method using albumin as a polymer matrix and stabilized using heat treatment. These MS were evaluated for product yield, encapsulation efficiency, particle size, size distribution, contact angle, drug--polymer interactions, and for in vitro drug release. Fluorescent labeling and in vitro uptake of these MS was assessed in RAW 264.7 cell line. Results: PM loaded albumin MS were prepared with a mean particle size approximate to a parts per thousand 3 mu A mu m. Free albumin content and contact angle study confirmed the stabilization of these MS. Release studies showed biphasic release pattern. Interaction studies ruled out any possibility of drug--polymer interaction. Uptake study in macrophage confirmed the suitability of prepared MS for macrophage targeting. Conclusion: The proposed drug-delivery system was found suitable for targeting macrophages in vitro and may serve as an optimum carrier to target macrophages where Leishmania parasite resides.