Objective: To determine if ET-105 (lamotrigine for oral suspension) can be effectively administered through gastrostomy feeding tubes (g-tube). Background: Patients with epilepsy who have difficulty swallowing may require surgical implantation of a feeding tube. As accurate dose delivery of antiepileptic medications in these patients is important to maintain seizure control, there must be minimal aggregation, clogging, or adherence of drug to the tube and syringe. Lamotrigine is a broad spectrum antiepileptic for the treatment of seizures in adults and children, although currently only available in tablet form starting at 5 mg. ET-105, a new formulation of lamotrigine for oral suspension, eliminates the need for tablet crushing and may simplify dose preparation prior to g-tube administration. Design/Methods: This in vitro feeding tube study evaluated the accuracy of ET-105 dose delivery from 3 g-tubes of 2 different sizes: 5 cm/18 Fr or 0.8cm/12 Fr (2 manufacturers). Using the provided feeding tube kit syringe, 5 or 6 mL of reconstituted ET-105 suspension (10 mg/mL) was passed through each g-tube, followed by 2 mL of water to washout residue. The solution was diluted and filtered through a 0.45 μm filter. Recovery was analyzed using the verified method MOA0701 Assay of suspension by high performance liquid chromatography. Results: A total of 12 samples were tested per g-tube. The mean recovery of ET-105 solution was ≥100% using each of the 3 g-tubes and the percent relative standard deviation (% RSD) ranged from 2.2% to 2.4%. All individual samples met the protocol-defined acceptance criteria of ≥85% recovery and % RSD of ≤5%. There was no aggregation, clogging, or adherence observed. Conclusions: ET-105, lamotrigine for oral suspension, can be delivered accurately through g-tubes down to at least a minimum diameter of 0.8 cm/12 Fr. Disclosure: Dr. Shah has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eton Pharmaceuticals. Dr. Boyce has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Friends of FACES (NYU FACES epilepsy nonprofit), on-call/PT employment with Johns Hopkins, contract (database work) with Cancer Support Community. Dr. Boyce has received research support from small amount of funding to (#7) pay for research administrations from the Gould Syndrome Foundation and Dravet Syndrome Foundation (unsure if they are considered a "commercial entity"). Dr. Patel has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with employee of Aucta Pharmaceuticals, Inc.. Dr. Gong has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Aucta Pharmaceuticals, Inc. Dr. Lu has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with employee of Aucta Pharmaceuticals, Inc.. Dr. Li has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with employee of Aucta Pharmaceuticals, Inc..