RESUMO
Therapeutic antisense oligonucleotides (ASOs) represent a diverse array of chemically modified singlestranded deoxyribonucleotides that work complementarily to affect their mRNA targets. They vastly differ from conventional small molecules. These newly developed therapeutic ASOs possess unique absorption, distribution, metabolism, and excretion (ADME) processes that ultimately determine their pharmacokinetic, efficacy and safety profiles. The ADME properties of ASOs and associated key factors have not been fully investigated. Therefore, thorough characterization and in-depth study of their ADME properties are critical to support drug discovery and development processes for safe and effective therapeutic ASOs. In this review, we discussed the main factors affecting the ADME characteristics of these novels and evolving therapies. The major changes to ASO backbone and sugar chemistry, conjugation approaches, sites and routes of administration, etc., are the principal determinants of ADME and PK profiles that consequentially impact their efficacy and safety profiles. In addition, species difference and DDI considerations are important in understanding ADME profile and PK translatability but are less studied for ASOs. We, therefore, have summarized these aspects based on current knowledge and provided discussions in this review. We also give an overview of the current tools, technologies, and approaches available to investigate key factors that influence the ADME of ASO drugs and provide future perspectives and knowledge gap analysis.
RESUMO
Gastroretentive drug delivery systems (GRDDS) are modified-release dosage forms designed to prolong their residence time in the upper gastrointestinal tract, where some drugs are preferentially absorbed, and increase the drug bioavailability. This work aimed the development of a novel GRDDS containing 60 mg of sildenafil citrate, and the evaluation of the feasibility of the proposed formulation for use in the treatment of pulmonary arterial hypertension (PAH), for once a day administration, by using in silico pharmacokinetic (PK) modeling and simulations using GastroPlusTM. The Model-Informed Drug Development (MIDD) approach was used in formulation design and pharmacokinetic exposure prospecting. A 22 factorial design with a central point was used for optimization of the formulation, which was produced by direct compression and characterized by some tests, including buoyancy test, assay, impurities, and in vitro dissolution. A compartmental PK model was built using the GatroPlusTM software for virtual bioequivalence of the proposed formulations in comparison with the defined target release profile provided by an immediate release (IR) tablet formulation containing 20 mg of sildenafil administered three times a day (TID). The results of the factorial design showed a direct correlation between the dissolution rate and the amount of hydroxypropyl methyl cellulose (HPMC) in the formulations. By comparing the PK parameters predicted by the virtual bioequivalence, the formulations F1, F2, F3 and F5 failed on bioequivalence. The F4 showed bioequivalence to the reference and was considered the viable formulation to substitute the IR. Thus, GRDDS could be a promising alternative for controlling the release of drugs with a pH-dependent solubility and narrow absorption window, specifically in the gastric environment, and an interesting way to reduce dose frequency and increase the drug bioavailability. The MIDD approach increases the level of information about the pharmaceutical product and guide the drug development for more assertive ways.