FDA Lists Patent for HemiClor 12.5 mg Chlorthalidone in Orange Book, Securing Formulation Protection Through 2045
核心洞察
PRM Pharma and Ingenus Pharmaceuticals announced the FDA Orange Book listing of U.S. Patent No. 12,667,554 B1 for HemiClor (搜索), the first and only FDA-approved 12.5 mg chlorthalidone tablet.
The patent protects the proprietary formulation technology through 2045, requiring future ANDA applicants to provide patent certifications during FDA review.
HemiClor (搜索) addresses guideline-recommended starting doses for hypertension (搜索) and eliminates the need for tablet splitting by delivering a commercially manufactured low-dose tablet.
PRM Pharma, LLC and Ingenus Pharmaceuticals, LLC announced on July 28, 2026, that the U.S. Food and Drug Administration has listed U.S. Patent No. 12,667,554 B1 in the FDA's Approved Drug Products with Therapeutic Equivalence Evaluations — commonly known as the Orange Book — for HemiClor (搜索) (chlorthalidone tablets, 12.5 mg). The listing secures intellectual property protection for the proprietary formulation technology through 2045, reinforcing the market position of the first and only FDA-approved 12.5 mg chlorthalidone tablet.
HemiClor (搜索) is indicated for the treatment of hypertension (搜索) in adults to lower blood pressure, a therapeutic goal that reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. The product is available by prescription through retail pharmacies nationwide.
Overcoming Formulation Barriers for a Decades-Old Molecule
Although chlorthalidone has been used clinically for decades, developing a 12.5 mg tablet that could meet FDA approval standards presented significant pharmaceutical challenges. According to the companies, these included difficulties related to dissolution, particle characteristics, stability, and manufacturability. The patented formulation technology enabled the development of a commercially manufactured 12.5 mg tablet that can be administered whole, eliminating the need for tablet splitting — a practice that can introduce dosing inaccuracies.
"Developing a commercially robust 12.5 mg chlorthalidone tablet required much more than reducing the dose," said Mukteeshwar Gande, M.S., R.Ph., Chief Scientific Officer of RiconPharma and inventor of the patented technology. "Our patented formulation technology addresses key pharmaceutical challenges while delivering a differentiated product designed to address an important clinical need."
Guideline Alignment and Clinical Rationale
HemiClor (搜索) was developed to provide healthcare professionals with a 12.5 mg dose that corresponds to the guideline-recommended starting dose for many adults initiating chlorthalidone therapy. Major hypertension (搜索) guidelines recognize chlorthalidone as a preferred thiazide-type diuretic because of its long duration of action and cardiovascular outcomes data. More recent guidelines also recommend optimizing chlorthalidone therapy as part of treatment strategies for resistant hypertension.
Joe McDevitt, President and CEO of PRM Pharma, noted that certain metabolic side effects associated with chlorthalidone are dose-related and may occur more frequently at higher doses. "HemiClor (搜索) demonstrates that meaningful innovation remains possible even for well-established medicines," McDevitt said. "HemiClor provides healthcare professionals with an FDA-approved 12.5 mg chlorthalidone treatment option that aligns with current hypertension (搜索) guidelines."
Orange Book Listing and Regulatory Implications
Under the Hatch-Waxman Act, the Orange Book listing carries significant regulatory weight. Any future applicant seeking approval through an Abbreviated New Drug Application (ANDA) for a generic equivalent must provide patent certifications addressing Orange Book-listed patents during the FDA review process. The patent protection extending through 2045 creates a substantial exclusivity period for HemiClor (搜索).
Safety Considerations
HemiClor (搜索) is contraindicated in patients with anuria or known hypersensitivity to chlorthalidone or sulfonamide-derived drugs. The most common adverse reactions include electrolyte imbalance, particularly hypokalemia, dizziness, and gastrointestinal discomfort. Periodic monitoring of serum electrolytes is recommended. Chlorthalidone may increase blood sugar levels, affect diabetes control, and may interact with lithium, antidiabetics, or NSAIDs.
PRM Pharma, LLC is a privately held specialty pharmaceutical company based in Pennsylvania focused on developing low-dose therapies to support clinical practice guidelines. Ingenus Pharmaceuticals, LLC, the patent owner and manufacturer of HemiClor (搜索), is a specialty pharmaceutical company focused on development, manufacturing, and lifecycle management of high-quality pharmaceutical products.