(T1530-02-11) In Vivo Characterization and Bioequivalence Study of 3D Printed Tenofovir Disoproxil Fumarate Printlets

Purpose: 3D printing is an emerging technology that is capable of producing personalized medication. One of the common methods of 3D printing that is used to print solid dosage forms is Selective Laser Sintering (SLS) [1]. Its ease of use allows it to be utilized at point-of-care, such as pharmacies or hospitals, where physicians prescribe a medication that is tailored to the patient’s needs, which can later be printed by technicians. Characterization of the printlets plays a key role in ensuring the safety and quality of the medication. In addition to physiochemical characterization, iv-vivo characterization is also required. Bioequivalence testing is a crucial in-vivo study that compares the pharmacokinetic performance of a generic product to an already approved commercial product. Two products are considered bioequivalent when they are equal in the rate and extent of the drug’s bioavailability. The purpose of this study was to conduct an in-vitro characterization and bioequivalence test between SLS-printed tenofovir disoproxil fumarate and a commercially available product to prove that SLS-printed medication is bioequivalent to the commercial product.

Methods: The printlet formulation (F5, test) and commercial TDF tablet (generic of Viread®, reference) were used in the pharmacokinetic study. The study was performed in Sprague-Dawley Rats (n = 8/group, male: female 1:1) weighing 250-350 g, and suspension of the printlets and the tablets formulation in water was administered to the animals at 30 mg/Kg by oral gavage. Approximately 0.3 ml of blood was collected from the tail vein at 0, 0.5, 2, 4, 6, 8, 12, 24, 36, 48, and 72 h. The animals were anesthetized with isoflurane inhalation before sample collection. Plasma was separated by centrifuging the blood at 13300 rpm and 4°C for 15 minutes. TNF from the sample was extracted by the protein precipitation method. Briefly, an equal volume of 1 M trifluoracetic acid was added to the plasma followed by the addition of 100 μL of TNF-d6 as an internal standard (IS, 500 ng/ml), and 100 μL 0.1% formic acid solution, vortexed for 1 min, and centrifuged at 13300 rpm and 4 oC for 15 minutes. The supernatant was analyzed for IS and TNF by a validated UPLC-MS method.

Results: In-vivo performance of TDF was compared with the commercial tablets (generic tablets of Viread®). Pharmacokinetic profiles of the printlets (Test product, T) and commercial tablets (reference product, R) of TDF were superimposable. No statistical differences in pharmacokinetic parameters i.e., the area under the curve (AUC), time to reach maximum plasma concentration (Tmax), and maximum plasma concentration (Cmax) were observed between the two formulations (p >0.05). Tmax, Cmax, and AUC of the printlets and the tablets were 0.5±0.0 and 1.4±0.8 h, 855.1±146.4 and 1078.3±617.8 ng/ml, and 9387.7±3089.1 and 7913±1987 ng.h/ml, respectively. For bioequivalence comparison between two formulations, Cmax and AUC were logarithm transformed followed by calculation of geometric mean and 90% confidence interval (CI). 90% CI of Cmax and AUC was 0.973-1.032 and 0.979-1.023, respectively. The T/R ratio of the geometric mean of Cmax and AUC were 0.984 and 1.016, respectively. Thus, the values of the T/R ratio of Cmax and AUC fell within 90% CI. Therefore, two formulations can be considered bioequivalent in the test animal models.

Conclusion: In-vivo performance of the printed formulation was similar to the commercial product as pharmacokinetic profiles were superimposing, and parameter values were similar (Cmax, Tmax, and AUC). Two products met bioequivalence criteria. Thus, the dose-flexible formulation can be prepared with a 3D printing method with demonstrated quality and in-vivo performance instead of compounded products that are usually not thoroughly studied and characterized.

References: [1] Barakh Ali SF, Mohamed EM, Ozkan T, Kuttolamadom MA, Khan MA, Asadi A, et al. Understanding the effects of formulation and process variables on the printlets quality manufactured by selective laser sintering 3D printing. Int J Pharm. 2019;570:118651. doi: 10.1016/j.ijpharm.2019.118651.
[2] FDA: Guidance document- Bioequivalence Studies with Pharmacokinetic Endpoints for Drugs Submitted Under an ANDA Guidance for Industry. (2021). Accessed May 1, 2023.

Acknowledgements: This work was supported by National Institute of Health R56 grant #1R56HD106612-01. The study was performed as per protocol #IACUC 2021-0215 approved by Texas A&M's Institutional Animal Care and Use Committees. No conflict of interest.

Blood Plasma Concentration vs time profile of printlet and commercial product