Patent on hydroxynorketamine modified‑release dosage form for the use in the treatment of depression – by ingredientpharm

Introduction

The development of a hydroxynorketamine modified-release dosage form marks a significant progression in neuropsychiatric therapeutics. Hydroxynorketamine (HNK), a metabolite of ketamine, exhibits rapid antidepressant activity via mechanisms distinct from the parent compound, notably allosteric modulation of α₇-nicotinic acetylcholine receptors and downstream activation of mTOR pathways. Such targeted activity suggests HNK is a promising active pharmaceutical ingredient (API) with a favorable safety profile—absent ketamine’s dissociative and addictive side effects. The formulation of a modified‑release form using CELLETS® —uniform spherical pellets—enhances therapeutic control, sustaining plasma concentration across time and improving patient adherence while potentially mitigating peak‑to‑trough fluctuations. In this context, inert cores may preferably have a particle size in the range of 100 to 500 μm and more preferably in the range of 200 to 400 μm, with the particle size range indicating the size range for 90% of the particles as determined by sieve analysis, such as CELLETS® 200 to name an example.

API Function and Patient Benefits

Hydroxynorketamine functions primarily by inhibiting α₇-nicotinic receptors to reduce intracellular Ca²⁺ and D‑serine levels, which attenuates excitotoxic NMDA receptor activity; simultaneously, it enhances mTOR signaling and AMPA receptor function. These combined effects accelerate synaptogenesis and yield antidepressant responses in both preclinical and emerging clinical contexts. For patients, this translates to rapid mood elevation without ketamine-associated side effects such as hallucinations or abuse potential. From a pharmacokinetic standpoint, a modified‑release dosage form improves therapeutic consistency, eases dosing schedules, and heightens tolerability.

Modified‑release dosage Formulation with CELLETS®

The incorporation of CELLETS® into the modified‑release formulation offers several advantages: their uniform size and high sphericity ensure reproducible drug coating and release kinetics; they also allow multiparticulate dosing, reducing variability and enabling tailored release profiles. In the context of HNK, CELLETS® can be engineered with specific polymeric coatings—such as ethylcellulose or Eudragit—that dissolve or erode at controlled rates, releasing the API steadily over prolonged intervals. This approach minimizes peak systemic concentrations, thus reducing potential side effects and sustaining efficacy. Importantly, CELLETS® support monolithic layering or reservoir systems, facilitating complex release profiles like initial burst followed by sustained delivery—desirable for achieving rapid onset followed by maintenance in depression treatments.

Key Findings on Hydroxynorketamine modified‑release dosage form

In the disclosed patent (US 2025 0177325 A1), researchers describe a multiparticulatе modified‑release system for administering hydroxynorketamine using CELLETS® as a core substrate. The CELLETS® are coated with successive polymer layers that modulate drug release, achieving an initial release phase followed by prolonged delivery. Pharmacokinetic modeling demonstrates a flattened plasma-concentration profile, attenuated maximum concentration (C_max), extended time to peak (T_max), and increased area under the curve (AUC), which collectively enable sustained therapeutic levels of HNK over time. This steady-state exposure is anticipated to mitigate rebound symptoms and reduce dosing frequency, thereby enhancing patient adherence and transforming treatment regimens toward once-daily or even less frequent administration.

Conclusion and Outlook

In conclusion, the Hydroxynorketamine modified‑release dosage form leveraging CELLETS® presents a compelling pharmaceutical strategy. It capitalizes on HNK’s distinct mechanism as a non-dissociative antidepressant, optimizing its clinical utility via controlled release. Cellet-based formulations promise improved pharmacokinetics, enhanced tolerability, and greater convenience—factors that could significantly benefit individuals with treatment-resistant depression. Looking forward, further development is warranted: in vitro−in vivo correlation studies, polymer selection optimization, and confirmatory clinical trials will be critical. This technology may pave the way for broader applications of HNK in other neuropsychiatric or neurodegenerative disorders, fulfilling unmet medical needs with a refined dosage form that aligns with both patient and therapeutic goals.

Patent Details

• Name or patent: Hydroxynorketamine for the use in the treatment of depression
• Patent number: US 20250177325 A1
• Year of patent: 2025
• Patent holder names and affiliation: (Names not specified in public abstract; likely the inventors assigned to their sponsoring institution or company as listed in patent document)

This summary underscores the innovative use of CELLETS® in creating a refined hydroxynorketamine modified-release dosage form that elevates both therapeutic performance and patient-centric outcomes.

Read more here

Source: ingredientpharm, website hydroxynorketamine modified-release dosage form – a new patent

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