GnRH Antagonists with Nicotinoyl Substitution for Solubility
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Solution Overview
Problem
Current GnRH antagonists have limitations in water solubility, particularly at physiological pH, which affects their bioavailability and stability, and there is a need for compounds with higher antigonadotropic potency and reduced histamine release.
Innovation Solution
Development of GnRH antagonists with specific modifications, such as nicotinoyl substitution at position 5, which enhance water solubility and maintain or improve biological efficacy, including the use of formulations like microspheres with acid additives and biodegradable polymers for sustained release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If GnRH antagonists are designed with conventional structures, then they exhibit antigonadotropic activity, but their water solubility is limited particularly at physiological pH
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of GnRH antagonists through nicotinoyl substitution at position 5 instead of the conventional picolinoyl group. This chemical parameter change increases water solubility while maintaining physiological pH compatibility and biological efficacy, directly resolving the contradiction between solubility and stability
Solution Approach 2:
The patent employs composite materials by formulating GnRH antagonists with biodegradable polymers and acid additives to create sustained-release compositions. This composite approach enhances both solubility and stability by combining the antagonist with materials that improve dissolution characteristics while maintaining controlled release and physiological compatibility
2Reliability
If GnRH antagonists are administered frequently to maintain suppression, then therapeutic effectiveness is maintained, but treatment compliance and productivity decrease
Solution Approach 1:
The patent applies preliminary action by formulating GnRH antagonists in sustained-release compositions that pre-establish controlled release mechanisms. This allows the drug to be administered less frequently while maintaining therapeutic effectiveness, as the formulation itself ensures continuous suppression without requiring frequent patient intervention
Solution Approach 2:
The patent implements periodic action through sustained-release formulations that provide controlled, extended-release of the antagonist over multiple days or weeks. This periodic release pattern maintains consistent therapeutic suppression while reducing the frequency of administration from daily to less frequent intervals, improving compliance
3Reliability
If conventional GnRH antagonists are used, then gonadotropin suppression is achieved, but gelling issues and formulation instability occur
Solution Approach 1:
The patent uses intermediaries by incorporating acid additives and biodegradable polymers as mediating substances in the formulation. These intermediaries prevent gelling issues and improve formulation stability while allowing the GnRH antagonist to maintain its gonadotropin suppression activity, resolving the contradiction between efficacy and stability
Data Source
AI summary
Antagonistic peptides of GnRH having improved water solubility are disclosed. These peptides are capable of suppressing serum testosterone levels in vivo to chemical castration levels of ≦0.5 ng/ml. Stable, filter sterilizable, non-gelling solutions containing the GnRH antagonists at least at levels typically used in sustained release formulations also are disclosed, as is a method of increasing the solubility of GnRH antagonist in a polymer containing dispersed phase, which method comprises addition of an acid to the dispersed phase.