Tabriz University of Medical Sciences Advanced Pharmaceutical Bulletin 2228-5881 11 3 2021 06 08 Colon Targeted Protein Nanoparticles Loaded Suppositories : Effective against Intestinal Parasites 490 496 10.34172/apb.2021.056 EN Swati Chauhan https://orcid.org/0000-0001-7815-5270 Neha Jain Shilani Sharma Shagun Mehra Upendra Nagaich https://orcid.org/0000-0003-0076-6885 Journal Article 10.34172/apb.2021.056 2019 08 02 2020 07 15 Purpose: The aim of the present investigation was to formulate protein nanoparticles (PNPs) loaded suppositories for colon targeting of metronidazole (MZ), to achieve sustain release effect. Methods: PNPs were formulated via desolvation technique by utilizing 23 factorial design which results into eight formulations. The synthesized PNPs were characterized for different physicochemical and in vitro parameters viz. particle size, surface morphology, entrapment efficiency and zeta potential, drug- excipients compatibility studies. Results: The formulated PNPs were found to be spherical in shape and have an average size in the range of 300.7 nm to 504.8 nm. Based on the results obtained, F7 was found to be the optimized formulation that was loaded into the suppository base. Furthermore, suppositories were also characterized for several parameters like content uniformity, weight variation and liquefaction time. Conclusion: Resultant, suppositories were free from pits, fissures and cracks. The in-vitro release data of MZ-PNPs loaded suppositories were compared with the suppositories loaded with active ingredient only i.e. MZ. Screening against Pheretima posthuma was also conducted. The results of in vitro drug release testing proved that protein nanoparticle loaded suppositories is a better approach, compared to pure MZ loaded suppositories. Release kinetic study concluded that the formulation follows Higuchi’s equation i.e. having a biphasic release pattern. The efficiency of the formulated dosage form was evaluated using Indian earthworms, P. posthuma.