Prosecution Insights
Last updated: April 19, 2026
Application No. 18/010,063

METHOD FOR PREPARING LANTHANUM CARBONATE TETRAHYDRATE AND PRODUCT THEREOF

Non-Final OA §103§112
Filed
Dec 13, 2022
Examiner
SPEER, JOSHUA MAXWELL
Art Unit
1736
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Nanjing Cavendish Bio-Engineering Technology Co. Ltd.
OA Round
1 (Non-Final)
87%
Grant Probability
Favorable
1-2
OA Rounds
3y 3m
To Grant
79%
With Interview

Examiner Intelligence

Grants 87% — above average
87%
Career Allow Rate
53 granted / 61 resolved
+21.9% vs TC avg
Minimal -8% lift
Without
With
+-8.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
32 currently pending
Career history
93
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
39.7%
-0.3% vs TC avg
§102
29.0%
-11.0% vs TC avg
§112
29.3%
-10.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 61 resolved cases

Office Action

§103 §112
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Election/Restrictions Applicant’s election of claims 1-6 in the 10/22/25 reply is acknowledged. Notwithstanding applicant’s statement that the election is being made with traverse, since applicant did not distinctly and specifically point out the/any supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)). It is noted that Claims 8-11 have been amended to be process claims rather than product claims and are being examined as part of the elected group. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 2-6, 8-9 and 11 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claims 2-6 all similarly list a broad range followed by “preferably” and then a narrow range. When two ranges for the same limitation are both presented within a single claim the scope of that claim becomes unclear. Applicant may amend to require either the narrow or the broad range, however for the purpose of this Office Action the claims are interpreted to require only the broad range to be consistent with a broadest reasonable interpretation. Claims 8-9 refer to Figs. 3-4, respectively. It is noted that claim language referring to spectra detailed in the Drawings is viewed as an incorporation by reference, which “is a necessity doctrine, not for applicant’s convenience.” See MPEP 2173.05(s), citing Ex parte Fressola, 27 USPQ2d 1608, 1609 (BPAI 1993) (citations omitted). To the extent that applicant could have claimed the spectral peaks explicitly without resorting to incorporation by reference, claims 8-9 are rejected under 35 U.S.C. 112(b)/2nd par. as indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 8 recites “the X-ray powder diffraction (XRPD) pattern”, Claim 9 recites “the thermogravimetric analysis graph”, and Claim 11 recites “the terahertz spectrum”. All of these phrases lack proper antecedent bases. Applicant may amend by changing “the” to “a”. Claim 11 recites “no characteristic spectral peak between 1.0 THz and 3.0 THz … characteristic spectral peaks between 3.0 THz and 3.9 THz”. The phrase “characteristic spectral peak” is indefinite because it is unclear if the mere presence (or absence) of a peak is required or if the peaks must have some character (size, shape, etc.) that is not disclosed by the specification. Applicant may amend by removing the phrase “characteristic” if the intended meaning is that a peak must be present within the range 3.0 - 3.9 THz and absent within the range 1.0 - 3.0 THz. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claim(s) 1-4, 6, and 8-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 5968976 A Murrer et al. in view of CN 1931788 A Shi in further view of American Elements to show a state of fact. Claim 1 requires “A preparation method of lanthanum carbonate tetrahydrate”. Murrer et al. discloses “According to a further aspect, the present invention is lanthanum carbonate of the formula La₂(CO3)3.xH₂O where x has a value from 3 to 6.” [Col. 2, lines 16-19]. Claim 1 further requires “comprising the following steps: (1) reacting lanthanum oxide with acetic acid to obtain lanthanum acetate”. Murrer et al. discloses “(i) reacting lanthanum oxide with an acid which gives a soluble salt of lanthanum” [Col. 2, lines 4-5]. It is noted that the solvent is water and lanthanum acetate is a water soluble salt of lanthanum, as evidenced by American Elements (“Lanthanum Acetate is a moderately water soluble crystalline Lanthanum source”). Claim 1 further requires “(2) reacting the lanthanum acetate obtained in step (1) with potassium carbonate or potassium bicarbonate or ammonium bicarbonate to obtain lanthanum carbonate octahydrate”. Murrer et al. discloses “(ii) reacting a solution of the thus obtained lanthanum salt with an alkali metal carbonate to produce a wet cake of lanthanum carbonate octahydrate” [Col. 2, lines 6-8]. It is noted that K2CO3 is an alkali metal carbonate. Claim 1 further requires “(3) drying the lanthanum carbonate octahydrate obtained in step (2) to obtain lanthanum carbonate tetrahydrate”. Murrer et al. discloses “(iii) controlled drying of the wet cake of lanthanum carbonate octahydrate so as to obtain a lanthanum carbonate with 3 to 6 molecules of water of crystallisation.” [Col. 2, lines 9-12]. Regarding the selection of acetic acid as the acid for forming a water soluble salt and this represents obvious selections of known chemicals. Additionally Shi discloses “20g of lanthanum oxide was dissolved in acetic acid to obtain a lanthanum acetate solution with a concentration of 1.0 mol/L.” [0027]. It would have been obvious for one of ordinary skill in the art to have used acetic acid as the acid in the process of Murrer et al. because it is disclosed by Shi as effective. Alternatively a rejection of Claim 1 over Shi in view of Murrer et al. is presented as well. Shi teaches steps 1 and 2 of Claim 1 “20g of lanthanum oxide was dissolved in acetic acid to obtain a lanthanum acetate solution with a concentration of 1.0 mol/L. 45g of ammonium bicarbonate was weighed and dissolved in 300ml of deionized water. The ammonium bicarbonate solution was heated to 100℃ and slowly poured into the solution while stirring at 250 rpm.” [0027]. Shi does not disclose that the lanthanum carbonate formed in step 2 is in the form of the octahydrate, however as understood by the examiner the fully hydrated form is the result of aqueous precipitation and drying is required to get the less hydrated forms. Shi does not disclose drying the lanthanum carbonate to form lanthanum carbonate tetrahydrate. It would have been obvious to one of ordinary skill in the art to have dried the lanthanum carbonate of Shi by the method of Murrer et al. to obtain lanthanum carbonate tetrahydrate. The motivation to do so would have been to form a useful medicinal product. Claim 2 requires “the weight ratio of lanthanum oxide to acetic acid in step (1) is 1: 1 to 1: 1.3, preferably 1: 1.1 to 1: 1.2.”. Murrer et al. does not explicitly disclose using acetic acid, however in Example 1 nitric acid is used (“Lanthanum oxide (1.5 kg, 4.58 mol) was suspended in water (5.5 litres) in a 20 litre flask. Nitric acid (Analar grade, 69%, SG 1.42, 1.88 litres, 29.23 mol) was added” [Col. 3, lines 59-61]). Had the same amount (29.23 mol) of acetic been used instead its mass would have been 1.75 kg (29.23 mol * 60.0527 g/mol * 0.001 kg/g) which is a weight ratio of lanthanum oxide to acetic acid of 1:1.17 which falls within both ranges presented. Claim 3 requires “the reaction temperature in step (1) is 40 °C to 100 °C preferably 60 °C to 80 °C; the reaction time is 0.1 h to 2 h, preferably 0.5 h to 1 h.”. Murrer et al. discloses “Lanthanum oxide (1.5 kg, 4.58 mol) was suspended in water (5.5 litres) in a 20 litre flask. Nitric acid (Analar grade, 69%, SG 1.42, 1.88 litres, 29.23 mol) was added to the stirred solution over 1.5 hours at such a rate as to keep the temperature between 60-80° C.” [Col 3, lines 59-63]. Claim 4 requires “the weight ratio of lanthanum acetate to potassium carbonate or potassium bicarbonate or ammonium bicarbonate in step (2) is 1: 1.2 to 1: 1.8, preferably 1: 1.4 to 1: 1.5.”. Murrer et al. discloses “Lanthanum oxide (1.5 kg, 4.58 mol) … A solution of sodium carbonate (1.65 kg, 15.57 mol) in water (7.75 litres) was added to the stirred lanthanum nitrate solution over 45 minutes.” [Col. 3, lines 59-67]. Had acetic acid been used in Example 1 it would have generated 4.58 mol of lanthanum acetate (1.45 kg) and had potassium carbonate been used in the same amount (15.57 mol) it would have weighted 2.15 kg (15.57 mol * 138.206 g/mol * 0.001 kg/g). This is a weight ratio of lanthanum acetate to potassium carbonate of 1:1.48 which falls within both ranges presented. Claim 6 requires “the temperature for the drying in step (3) is 60 °C to 90 °C, preferably 70 °C to 80 °C.”. Murrer et al. discloses “The dishes were then placed in a fan oven at 80° C.” [Col. 4, lines 10-11]. Claim 8 requires “the X-ray powder diffraction (XRPD) pattern of the lanthanum carbonate tetrahydrate is substantially as shown in Fig. 3.” (reproduced below). PNG media_image1.png 237 786 media_image1.png Greyscale Murrer et al. discloses an XRD pattern for lanthanum carbonate tetrahydrate in Fig. 3 (reproduced below). PNG media_image2.png 339 609 media_image2.png Greyscale To better visualize the similarity between the PXRD of the instant invention and the XRD of Murrer et al. a composite image with the x-axis properly scaled is presented below. PNG media_image3.png 550 777 media_image3.png Greyscale As can be seen above, these patterns are substantially the same, and any small differences are attributed to the differences between measuring devices as well as the difference between a powder XRD (XRPD) and a crystal XRD (XRD). Alternatively, to whatever extent the PXRD of the instant invention and the XRD of the prior art are not comparable (no such concession is given) it is understood that the PXRD spectrum is a physical property of lanthanum carbonate tetrahydrate and that Murrer et al., being in possession of lanthanum carbonate tetrahydrate, would have obtained the same PXRD spectrum had they sampled their lanthanum carbonate tetrahydrate with a PXRD technique. Claim 9 requires “the thermogravimetric analysis graph of the lanthanum carbonate tetrahydrate is substantially as shown in Fig. 4.” It has been held that where claimed and prior art products are produced by identical or substantially similar methods, a prima facie case of anticipation or obviousness has been established. MPEP 2112.01, citing In re Best, 562 F.2d 1252, 1255 (CCPA 1977). In other words, if the prior art teaches or at least suggests the claims' positive method steps, it matters not whether the prior art also teaches or suggests the features of the intended result of performing said steps — it would not be reasonable to expect different results when performing identical or at least substantially similar steps. Accord, MPEP 2145 II, citing, e.g., In re Baxter Travenol Labs., 952 F.2d 388, 392 (Fed. Cir. 1991) (stating that “Mere recognition of latent properties in the prior art does not render nonobvious an otherwise known invention”). See also In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990) (stating the “general rule that merely discovering and claiming a new benefit of an old process cannot render the [old] process again patentable”) (emphasis in original). In other words it is not reasonable to expect that the lanthanum carbonate tetrahydrate of Murrer et al. would have had a thermogravimetric analysis graph showing anything other what is shown by Fig. 4. Claim 10 requires “the lanthanum carbonate tetrahydrate has a sodium content of less than 0.005 wt%.”. Murrer et al. does not explicitly disclose the sodium wt. % of the synthesized lanthanum carbonate however they do disclose a through 6 step washing procedure (“The suspension was left overnight, filtered (Buchner funnel, 540 paper) and dried on the filter in a current of air for 30 minutes. The solid was then re-suspended in water, stirred for 40 minutes and filtered. This procedure was repeated to give a total of six washes” [Col. 4, lines 1-5]) which is expected to essentially completely remove sodium. Additionally, Murrer et al. does not disclose a sodium content which reasonably suggests that the lanthanum carbonate is sodium free. Furthermore considering that the intended use is as medication given to people, it would have been obvious to one of ordinary skill in the art that the material should be as pure as possible including removing any sodium impurity that may remain. Claim 11 requires “the terahertz spectrum of the lanthanum carbonate tetrahydrate has no characteristic spectral peak between 1.0 THz and 3.0 THz and has characteristic spectral peaks between 3.0 THz and 3.9 THz.”. It has been held that where claimed and prior art products are produced by identical or substantially similar methods, a prima facie case of anticipation or obviousness has been established. MPEP 2112.01, citing In re Best, 562 F.2d 1252, 1255 (CCPA 1977). In other words, if the prior art teaches or at least suggests the claims' positive method steps, it matters not whether the prior art also teaches or suggests the features of the intended result of performing said steps — it would not be reasonable to expect different results when performing identical or at least substantially similar steps. Accord, MPEP 2145 II, citing, e.g., In re Baxter Travenol Labs., 952 F.2d 388, 392 (Fed. Cir. 1991) (stating that “Mere recognition of latent properties in the prior art does not render nonobvious an otherwise known invention”). See also In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990) (stating the “general rule that merely discovering and claiming a new benefit of an old process cannot render the [old] process again patentable”) (emphasis in original). In other words it is not reasonable to expect that the lanthanum carbonate tetrahydrate of Murrer et al. would have had a terahertz spectrum outside of the range claimed. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOSHUA MAXWELL SPEER whose telephone number is (703)756-5471. The examiner can normally be reached M-F 9am-5pm EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Anthony Zimmer can be reached at 571-270-3591. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /JOSHUA MAXWELL SPEER/ Examiner Art Unit 1736 /DANIEL BERNS/Primary Examiner, Art Unit 1736
Read full office action

Prosecution Timeline

Dec 13, 2022
Application Filed
Nov 24, 2025
Non-Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
87%
Grant Probability
79%
With Interview (-8.2%)
3y 3m
Median Time to Grant
Low
PTA Risk
Based on 61 resolved cases by this examiner. Grant probability derived from career allow rate.

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