Injectable Depot Formulation for Sustained Tolvaptan Release

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Solution Overview

Problem

Current oral administration of tolvaptan for polycystic kidney disease results in rapid disappearance, requiring high doses and frequent administration, leading to excessive diuretic effects and reduced quality of life for patients, as it fails to maintain a therapeutically effective blood concentration for an extended period.

Innovation Solution

Development of an injectable depot formulation containing optically active tolvaptan, specifically R-form or S-form, combined with a pharmaceutically acceptable carrier for intramuscular or subcutaneous administration, which maintains a therapeutically effective blood concentration for longer durations, reducing the frequency of dosing and minimizing side effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If oral administration of tolvaptan is used, then the drug can be easily administered, but the blood concentration disappears rapidly requiring frequent dosing

Engineering Contradiction:

Improveease of administrationVSAvoidduration of therapeutic effect

Core Design Contradiction:

Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent changes the physical and chemical parameters of tolvaptan by converting it from oral tablet form to injectable depot formulation. This involves altering the dosage form, route of administration, and release characteristics to achieve sustained blood concentration over 4 weeks or longer, resolving the contradiction between ease of administration and duration of action.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a depot formulation as an intermediary system that stores tolvaptan and releases it gradually into the bloodstream. This intermediary mechanism allows the drug to maintain therapeutic blood concentration for extended periods while still being administered conveniently as a single injection.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If high dose oral administration is used to maintain therapeutic effect, then the therapeutic effect can be maintained, but excessive diuretic effects and side effects occur

Engineering Contradiction:

Improvetherapeutic effect reliabilityVSAvoidexcessive diuretic effect

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements periodic action through controlled release mechanism where tolvaptan is released gradually from the depot formulation over 4 weeks or longer. This maintains blood concentration within the therapeutic window, avoiding the peaks that cause excessive diuretic effects while ensuring continuous therapeutic coverage.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the pharmacokinetic parameters by switching from oral to parenteral administration and using depot formulation. This alters the absorption profile to achieve sustained release, maintaining reliable therapeutic effect without the harmful side effects associated with high peak concentrations from oral dosing.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If frequent oral administration is used, then the therapeutic effect can be maintained, but patient quality of life and adherence decrease

Engineering Contradiction:

Improvetherapeutic effect maintenanceVSAvoidpatient time burden

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent achieves continuity of useful action through the depot formulation that provides sustained release of tolvaptan over 4 weeks or longer. This eliminates the need for frequent dosing while maintaining continuous therapeutic blood concentration, thereby improving patient quality of life and adherence without compromising therapeutic reliability.

Inventive Principle:

Principle #20Continuity of useful action

4Ease of manufacture

If racemic tolvaptan is used, then the formulation is simpler to produce, but the metabolic stability and efficacy are lower compared to optically active forms

Engineering Contradiction:

Improveformulation simplicityVSAvoidmetabolic stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies the extraction principle by separating the racemic mixture into individual optically active isomers (R-form or S-form). This removes the less effective or potentially harmful enantiomer, resulting in improved metabolic stability and efficacy while maintaining manufacturability through established chiral separation or asymmetric synthesis techniques.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP2941242B1Injectable depot formulation comprising optically active tolvaptan and process of producing the same

Publication Date: 2017.02.01 OTSUKA PHARM CO LTD

AI summary

This invention provides an injectable formulation to be administered intramuscularly or subcutaneously that is used for the prevention or treatment of polycystic kidney disease, and that can maintain a therapeutically effective blood concentration of tolvaptan for a long period of time; and a process for producing the same. More specifically, this invention relates to an injectable depot formulation comprising (1) a particle containing optically active tolvaptan as an active ingredient and (2) a pharmaceutically acceptable carrier for injection, and a process for producing the same.