Zhejiang Medicine has filed a patent for a method to prepare a nemonoxacin malate active pharmaceutical ingredient (API) with low combination impurities. The method involves dissolving nemonoxacin free base and D,L-malic acid in a C1-C3 alcohol/water mixed solvent, followed by cooling crystallization and solid-liquid separation to obtain the nemonoxacin malate API. The patent claims specific temperature, mole ratio, and solvent use amount parameters for the preparation process. GlobalData’s report on Zhejiang Medicine gives a 360-degree view of the company including its patenting strategy. Buy the report here.
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According to GlobalData’s company profile on Zhejiang Medicine, cancer treatment biomarkers was a key innovation area identified from patents. Zhejiang Medicine's grant share as of June 2023 was 1%. Grant share is based on the ratio of number of grants to total number of patents.
Method for preparing nemonoxacin malate active pharmaceutical ingredient
A recently filed patent (Publication Number: US20230201189A1) describes a method for preparing nemonoxacin malate API. The method involves several steps to obtain the desired product.
In the first step, a C1-C3 alcohol/water mixed solvent is provided, in which nemonoxacin free base and D,L-malic acid are dissolved. The temperature of the mixed solvent is maintained between 50°C and 65°C. The feeding mole ratio of D,L-malic acid to nemonoxacin free base is 0.95:1.0-1.2:1.0. The use amount of the mixed solvent is 8-14 times the weight of the nemonoxacin free base, and the weight ratio of water to alcohol is 0.4-0.7:1.
The second step involves cooling crystallization of the mixed solution obtained in the first step. After cooling, solid-liquid separation, washing, and drying are performed on the precipitated solid to obtain the nemonoxacin malate API.
The patent also provides additional variations and modifications to the method. For example, claim 2 specifies that the temperature of the mixed solvent can be between 55°C and 60°C. Claim 3 states that the use amount of the mixed solvent can be 10-12 times the weight of the nemonoxacin free base. Claim 4 mentions that the weight ratio of water to alcohol can be 0.5-0.6:1. Claim 5 suggests a specific feeding mole ratio of D,L-malic acid to nemonoxacin free base.
Furthermore, claim 6 introduces the use of activated carbon to decolorize the mixed solution before cooling crystallization. Claim 7 describes two methods of cooling crystallization: direct cooling crystallization and gradient cooling crystallization. The latter involves specific temperature ranges and steps for cooling, stirring, and filtering.
The patent also includes claims related to the resulting nemonoxacin malate API. Claim 9 states that the method results in a nemonoxacin malate API with low combination impurities. Claim 10 specifies that the sum of certain impurities in the API should not exceed 0.15 wt %.
Overall, this patent presents a detailed method for preparing nemonoxacin malate API, along with variations and specifications for the process and the resulting product.
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GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies
