March-April 2019 Indian Journal of Pharmaceutical Sciences 234 Research Paper Currently, developing a novel type of drug delivery is a very important goal in pharmaceutical research, especially nanoparticle drug delivery. A drug can be packaged, dispersed or encapsulated as a nanoparticle, which acts as a drug delivery system for directing the drug to a specific target by recognizing specific ligands on target surface leading to increased penetration and efficacy. Manipulation of drug half-life, circulation time and bioavailability is possible through changing the size and surface characteristics of the nanoparticle [1] . It is worth noting that these manipulations not only improve drug absorption and therapeutic efficacy due to target specificity but also reduce dosing interval leading to decreased toxicity. Nanoparticles can be a nanopowder, nanoclusters or nanocrystals [2] . For pharmaceutical technology, nanoparticles used as drug delivery are defined as submicron particles whose range is less than 1 µm. The materials are different varieties including polymers, lipids (liposomes), magnetic, even inorganic or metallic compounds (iron, silica) and bacterial nanoparticles or minicells. Normally, drug releases from nanoparticles is by diffusion, erosion, swelling, and degradation after entering the body. However, there has been limited success due to several reasons that included, low drug loading in cell-carrier, untimely drug release instead of continuous release over time and limited drug administration because of its characteristics. As all of these problems had been reported in many nanoparticles, e.g. liposomes, micelles, nanospheres and nanofibers [1] , finding an ideal drug delivery system with an optimal size, shape and surface characteristics including the specific target binding size is still a challenge for the scientists. Minicell is described as a type of abnormal division in bacteria, which came from mutation or stress environment [3] , resulting in a small spherical bacterium whose diameter is less than 1 µm. Scientists suggested that this was a new term for nanocells, due to the fact that it has its diameter in the range of a nanometer. Studies on Tinidazole Delivery from Nano-sized Minicells Originated from Leuconostoc mesenteroides L. VU, D. NGUYEN 1 AND T. H. K. NGUYEN* School of Biotechnology, Department of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam, 1 Faculty of Natural Sciences, Thu Dau Mot University, Vietnam Vu et al.: Improvement of Absorption of Tinidazole by Nano-sized Minicells This study reported the ability of Leuconostoc mesenteroides VTCC B-871 to produce nano-sized minicells for the delivery of tinidazole to improve permeation through mice intestinal membrane. Using scanning electron microscope and transmission electron microscope, morphology of minicells while loading the drug was observed. Minicells did not change spherical shape and size (400 nm) over the time kept in buffered saline gelatin containing tinidazole. Based on Box-Behnken design, the optimal conditions were selected for actual encapsulation. Minicells could encapsulate tinidazole approximately to 90 % as determined by high performance liquid chromatographic analysis. Maximum concentration of tinidazole released from minicells was 70 % at pH 3.4 and 55 % at pH 7.2, respectively. Absorption of tinidazole from minicells was quantified in mice. Tinidazole could be absorbed faster from the minicells than tinidazole alone in fed mice upon oral administration. The study demonstrated that the absorption of water-insoluble tinidazole with food could be improved by Leuconostoc minicells. Key words: Tinidazole, Box-Behnken design, drug absorption in fed mice, drug release, Leuconostoc mesenteroides, minicells *Address for correspondence E-mail: nhktu@hcmiu.edu.vn This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms Accepted 20 January 2019 Revised 12 June 2018 Received 20 February 2017 Indian J Pharm Sci 2019;81(2):234-240