_1734373309 20241216182149000 Editor editor.jddt@gmail.com Universal Journal of Pharmaceutical Research Universal Journal of Pharmaceutical Research Univ J Pharm Res 2456-8058 2831-5235 11 15 2024 Hesham Seary https://orcid.org/0009-0002-7656-7831 Elsaied Barakat https://orcid.org/0009-0001-6301-8449 Mohamed A. Raslan https://orcid.org/0009-0005-4331-4143 Ahmed M. Samy https://orcid.org/0000-0002-3220-2876 Objective: This study seeks to explore the solubility of an antidiabetic drug with poor water solubility, Repaglinide (RPG), in various media, and develop and optimize RPG-loaded spanlastic formulations. Methods: A 72-hours solubility study was conducted for RPG in different media, followed by UV spectrum analysis. Spanlastics containing RPG were prepared through the thin-film hydration (TFH) method combined with ultrasonication, incorporating varying concentrations ofthe lipophilic, non-ionic surfactant agents, Span 60 and Tween 80. Characterization was performed To assess particle size (PS), polydispersity index (PDI), zeta potential (ZP), and entrapment efficiency (EE%). Optimization was achieved by analysing characterization results and using a mixture design of Design Expert software which predicted the optimized formula. Results: RPG exhibited the highest solubility in phosphate buffer saline (PBS, pH 6.8) incorporating 0.5% Tween 20 (168.595 µg/mL), followed by PBS with 0.1% Tween 80 (80.355 µg/mL), PBS alone (56.163 µg/mL), and PBS with 0.1% sodium lauryl sulphate (SLS) (53.706 µg/mL). UV scanning in methanol revealed three characteristic absorption bands for RPG, with peak selection optimized for molar absorptivity in each medium. The RPG-loaded spanlastic formulations demonstrated nano-sized vesicles with uniform size distribution, high stability, and efficient drug encapsulation. Optimized spanlastics predicted a particle size 126.162 nm, PDI 0.416, ZP-43.258 mV, and EE% 77.753%. Conclusions: This research emphasizes the potential of optimized RPG-loaded spanlastics, developed through the thin-film hydration method, as a promising approach for improving the solubility and stability of poorly water-soluble drugs. RPG showed the highest solubility in PBS (pH 6.8) containing 0.5% Tween 20, and the formulation achieved desirable nanosize, uniformity, and high encapsulation efficiency.                         Peer Review History: Received 12 July 2024;   Reviewed 16 September 2024; Accepted 23 October; Available online 15 November 2024 Academic Editor: Dr. Asia Selman Abdullah, Pharmacy institute, University of Basrah, Iraq, asia_abdullah65@yahoo.com Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Antonio José de Jesus Evangelista, Federal University of Ceará, UFC, Brazil, tony_biomed@hotmail.com Asmaa Ahmed Mohamed Ahmed Khalifa, Pharos University, Alexandria, Egypt, asmaa.khalifa@pua.edu.eg 11 15 2024 http://creativecommons.org/licenses/by-nc/4.0 10.22270/ujpr.v9i5.1221 https://ujpronline.com/index.php/journal/article/view/1221 https://ujpronline.com/index.php/journal/article/download/1221/1753 https://ujpronline.com/index.php/journal/article/download/1221/1753 https://ujpronline.com/index.php/journal/article/download/1221/1754 https://ujpronline.com/index.php/journal/article/download/1221/1755