Prior art

The most relevant prior art for US patent 11623920B2, based on the provided patent text, is identified and analyzed below. The patent's independent Claim 1 covers a crystalline form of pitolisant hydrochloride sesquihydrate, characterized by specific PXRD peaks.

Most Relevant Prior Art for US11623920B2

The patent US11623920B2 explicitly discusses several prior art references in its "BACKGROUND" section. Among these, some directly relate to the preparation and forms of pitolisant and its salts.

1. Meier et al.

• Full Citation: The patent text refers to "Meier" disclosing a process for preparing pitolisant hydrochloride. While a specific patent number for Meier is not provided directly in the background text, it describes a "three step process for preparing pitolisant hydrochloride starting with piperidine and 3-chloropropanol... to give pitolisant (1) which is finally reacted with gaseous hydrochloric acid to obtain pitolisant hydrochloride".
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Meier's process describes the chemical synthesis of pitolisant, followed by its conversion to pitolisant hydrochloride using gaseous hydrochloric acid. This process is noted to utilize sodium hydride (NaH), a hazardous reagent.
• Potential Anticipation (35 U.S.C. § 102): Meier's disclosure describes the preparation of pitolisant hydrochloride. However, it does not explicitly mention or characterize the specific crystalline sesquihydrate form defined by the unique PXRD peaks in Claim 1 of US11623920B2. Therefore, while it anticipates the compound pitolisant hydrochloride, it does not appear to anticipate the specific crystalline sesquihydrate solid-state form as claimed in Claim 1, which is defined by its PXRD pattern.

2. Raga et al.

• Full Citation: The patent states, "Raga discloses a crystalline form of pitolisant monohydrochloride having a moisture content of 2.7 to 6.5% and its preparation thereof." A specific patent number for Raga is not provided in the background text.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Raga discloses a crystalline form of pitolisant monohydrochloride with a specified moisture content range (2.7 to 6.5%).
• Potential Anticipation (35 U.S.C. § 102): Raga describes a crystalline form of pitolisant monohydrochloride. However, Claim 1 of US11623920B2 specifically claims a sesquihydrate form (x=1.5, implying a water content of about 7.7% w/w as described in the patent) characterized by distinct PXRD peaks. The moisture content range disclosed by Raga (2.7 to 6.5%) is different from the sesquihydrate's water content (approx. 7.7% w/w). Additionally, Raga does not provide the specific PXRD peaks that characterize the crystalline form of Claim 1 (5.3, 7.3, 10.0, 11.8, and 26.1 ±0.2° two-theta). Therefore, Raga's disclosure does not appear to anticipate the specific pitolisant hydrochloride sesquihydrate form of Claim 1.

3. Sallarés et al.

• Full Citation: The patent states, "Sallarés discloses a process for preparing pitolisant (1) by forming the sodium salt of 3-(piperidin-1-yl)propan-1-ol (2) by reaction with sodium hydride (NaH), and then reacting the sodium salt with 3-(4-chlorophenyl)propyl methanesulfonate (3)". A specific patent number for Sallarés is not provided in the background text.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Sallarés describes a process for preparing pitolisant (the free base), also utilizing sodium hydride.
• Potential Anticipation (35 U.S.C. § 102): Similar to Meier, Sallarés focuses on the synthesis of pitolisant free base using a hazardous reagent (NaH). It does not disclose the conversion to pitolisant hydrochloride, let alone the specific sesquihydrate crystalline form claimed in US11623920B2, nor any specific PXRD characteristics. Thus, it does not anticipate Claim 1.

4. Colombano et al.

• Full Citation: The patent states, "Colombano discloses a process for preparing pitolisant (1) by reacting 4-azaspiro[3.5]nonan-4-ium bromide (4) with 3-(4-chlorophenyl)propan-1-ol (5)." A specific patent number for Colombano is not provided in the background text.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Colombano describes another process for preparing pitolisant free base.
• Potential Anticipation (35 U.S.C. § 102): Colombano describes a different route to pitolisant free base and does not disclose the hydrochloride salt or any specific crystalline forms of it. Therefore, it does not anticipate Claim 1.

5. Sefinovic et al. (EP 3 239 138 A1)

• Full Citation: EP 3 239 138 A1, "Hydrogen fumarate salt of 1-[3-[3-(4-chlorophenyl)propoxy]propyl]-piperidine, published on Nov. 1, 2017 to Stefinovic et al. of Sandoz AG (“Sefinovic”)."
• Publication/Filing Date: Published on November 1, 2017.
• Brief Description: Sefinovic discloses a hydrogen fumarate salt of pitolisant and a process for its preparation.
• Potential Anticipation (35 U.S.C. § 102): Sefinovic specifically discloses a fumarate salt of pitolisant, not the hydrochloride salt and certainly not the sesquihydrate crystalline form defined in Claim 1 of US11623920B2 by its specific PXRD pattern. Therefore, it does not anticipate Claim 1.

Conclusion on Anticipation for Claim 1:

Based on the descriptions provided in US11623920B2 itself, none of the cited prior art explicitly discloses a crystalline form of pitolisant hydrochloride sesquihydrate characterized by the specific PXRD peaks (5.3, 7.3, 10.0, 11.8, and 26.1 ±0.2° two-theta) as defined in independent Claim 1. While Meier and Raga mention pitolisant hydrochloride or its crystalline forms, they do not provide the detailed characterization (specifically the PXRD data and precise hydration state) that would directly anticipate the claimed sesquihydrate form. The other references (Sallarés, Colombano, Sefinovic) describe different salts or processes for the free base, and thus are even less likely to anticipate the specific crystalline form of pitolisant hydrochloride sesquihydrate.### Most Relevant Prior Art for US11623920B2

The provided patent text for US11623920B2 details several prior art references, primarily focusing on the synthesis of pitolisant and its various salts. The most relevant prior art documents that discuss pitolisant hydrochloride or other solid forms are analyzed below, particularly in relation to independent Claim 1 of US11623920B2, which covers a crystalline form of pitolisant hydrochloride sesquihydrate characterized by specific PXRD peaks.

1. Meier et al.

• Full Citation: While a specific patent number is not provided in the background section, the patent refers to "Meier" disclosing a process for preparing pitolisant hydrochloride.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Meier's process involves a three-step synthesis, starting with piperidine and 3-chloropropanol, to yield 3-(piperidin-1-yl)propan-1-ol, which is then reacted with 3-(4-chlorophenyl)propyl methanesulfonate in the presence of sodium hydride (NaH) to give pitolisant. This pitolisant is then reacted with gaseous hydrochloric acid to obtain pitolisant hydrochloride.
• Potential Anticipation (35 U.S.C. § 102): Meier's disclosure anticipates the compound pitolisant hydrochloride itself. However, independent Claim 1 of US11623920B2 specifically claims a crystalline pitolisant hydrochloride sesquihydrate defined by a unique set of PXRD peaks (5.3, 7.3, 10.0, 11.8, and 26.1 ±0.2° two-theta). The Meier disclosure, as described, does not provide any characterization of a specific crystalline form, nor does it mention a sesquihydrate or its PXRD pattern. Therefore, it does not directly anticipate the specific crystalline form of Claim 1.

2. Raga et al.

• Full Citation: The patent refers to "Raga" disclosing a crystalline form of pitolisant monohydrochloride. A specific patent number for Raga is not provided in the background section.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Raga discloses a crystalline form of pitolisant monohydrochloride that has a moisture content ranging from 2.7 to 6.5%.
• Potential Anticipation (35 U.S.C. § 102): Raga describes a crystalline form of pitolisant monohydrochloride. However, Claim 1 of US11623920B2 claims a sesquihydrate (x=1.5), which has a water content of approximately 7.7% w/w according to the detailed description of US11623920B2. This moisture content differs from Raga's disclosed range of 2.7 to 6.5%. Furthermore, Raga's disclosure, as presented, does not provide the specific PXRD peaks that define the sesquihydrate form of Claim 1. Without this specific structural characterization, Raga does not directly anticipate the crystalline pitolisant hydrochloride sesquihydrate claimed in US11623920B2.

3. Sallarés et al.

• Full Citation: The patent refers to "Sallarés" disclosing a process for preparing pitolisant (1). A specific patent number for Sallarés is not provided in the background section.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Sallarés describes a process for preparing pitolisant (the free base) by forming the sodium salt of 3-(piperidin-1-yl)propan-1-ol with sodium hydride (NaH) and then reacting it with 3-(4-chlorophenyl)propyl methanesulfonate.
• Potential Anticipation (35 U.S.C. § 102): This reference describes the preparation of the pitolisant free base and does not mention its conversion to the hydrochloride salt, let alone a specific crystalline hydrate form. Therefore, it does not anticipate Claim 1.

4. Colombano et al.

• Full Citation: The patent refers to "Colombano" disclosing a process for preparing pitolisant (1). A specific patent number for Colombano is not provided in the background section.
• Publication/Filing Date: Not explicitly stated in the provided text.
• Brief Description: Colombano discloses a process for preparing pitolisant (the free base) by reacting 4-azaspiro[3.5]nonan-4-ium bromide with 3-(4-chlorophenyl)propan-1-ol.
• Potential Anticipation (35 U.S.C. § 102): Similar to Sallarés, this reference is directed to the synthesis of the pitolisant free base and does not disclose the hydrochloride salt or its specific crystalline forms. Therefore, it does not anticipate Claim 1.

5. Sefinovic et al.

• Full Citation: EP 3 239 138 A1, "Hydrogen fumarate salt of 1-[3-[3-(4-chlorophenyl)propoxy]propyl]-piperidine," published on November 1, 2017 to Stefinovic et al. of Sandoz AG.
• Publication/Filing Date: Published on November 1, 2017.
• Brief Description: Sefinovic discloses a hydrogen fumarate salt of pitolisant and a process for its preparation.
• Potential Anticipation (35 U.S.C. § 102): This reference describes a fumarate salt of pitolisant, which is a different chemical entity from the hydrochloride salt. It does not disclose pitolisant hydrochloride, nor its sesquihydrate form or associated PXRD data. Therefore, it does not anticipate Claim 1.

Summary of Anticipation for Claim 1:

While the prior art cited in US11623920B2's background discloses the general compound pitolisant hydrochloride or processes for making pitolisant free base, none of them explicitly describe or characterize the specific crystalline form of pitolisant hydrochloride sesquihydrate by its unique PXRD peaks (5.3, 7.3, 10.0, 11.8, and 26.1 ±0.2° two-theta) as defined in independent Claim 1. Therefore, based on the provided patent text, these prior art references do not appear to directly anticipate Claim 1 under 35 U.S.C. § 102.