{"id":7232,"date":"2025-06-01T13:35:00","date_gmt":"2025-06-01T08:05:00","guid":{"rendered":"https:\/\/chiralpedia.com\/blog\/?p=7232"},"modified":"2025-06-01T14:32:06","modified_gmt":"2025-06-01T09:02:06","slug":"episode-6-the-rise-of-the-chiral-switch-strategy-or-science","status":"publish","type":"post","link":"https:\/\/chiralpedia.com\/blog\/episode-6-the-rise-of-the-chiral-switch-strategy-or-science\/","title":{"rendered":"Episode 6: The Rise of the Chiral Switch: Strategy or Science?"},"content":{"rendered":"\n<p class=\"has-vivid-red-color has-text-color has-link-color wp-elements-e88c05e581b7fe8c5ca49714cc4fc066\"><em>&#8220;<strong><mark style=\"background-color:rgba(0, 0, 0, 0);color:#d92727\" class=\"has-inline-color\">When a drug transforms from a blend to a single hand, is it innovation -or a clever commercial sleight of hand?<\/mark><\/strong>&#8220;<\/em><\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-81c47aea2e5cee11d71e578c65a2be9b\"><strong>Introduction<\/strong><\/p>\n\n\n\n<p>The regulatory awakening around chiral drugs enabled not just better science but also a new strategic tool for the pharmaceutical industry: the <strong>chiral switch<\/strong>. This phenomenon -developing a single-enantiomer version of an already marketed racemate -became both a scientific opportunity and a commercial strategy. While some switches were genuine innovations that improved patient outcomes, others sparked ethical debates about <strong>evergreening<\/strong>, <strong>market exclusivity<\/strong>, and <strong>value to patients<\/strong>.<br>This episode explores the regulatory, scientific, ethical, and commercial dimensions of chiral switches, through notable case studies like <strong>esomeprazole<\/strong>, <strong>levocetirizine<\/strong>, and <strong>dexmethylphenidate<\/strong>.<\/p>\n\n\n\n<p><strong>What is a Chiral Switch?<\/strong><\/p>\n\n\n\n<p><strong>Definition<\/strong>: A chiral switch refers to the development and marketing of a <strong>single-enantiomer version<\/strong> of an <strong>already approved racemic drug<\/strong>.<\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-3a6aeb0bb7e0743b854555b9fcf8b6b6\"><strong>Motivations for Chiral Switches<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Enhance therapeutic profile (e.g., potency, safety).<\/li>\n\n\n\n<li>Reduce dose and side effects.<\/li>\n\n\n\n<li>Achieve more predictable pharmacokinetics.<\/li>\n\n\n\n<li>Extend patent life and commercial exclusivity (Agranat, Caner, &amp; Caldwell, 2002).<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"864\" height=\"474\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-01-visual-selection-1.png\" alt=\"\" class=\"wp-image-7500\" style=\"width:702px;height:auto\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-01-visual-selection-1.png 864w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-01-visual-selection-1-300x165.png 300w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-01-visual-selection-1-768x421.png 768w\" sizes=\"auto, (max-width: 864px) 100vw, 864px\" \/><\/figure>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-7f70b5121c06d65b44dfcccef6082d0b\"><strong>Regulatory Expectations for Chiral Switches<\/strong><\/p>\n\n\n\n<p>Agencies like FDA, EMA, PMDA, and TGA have laid down clear expectations when it comes to chiral switches:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>New molecular entity (NME) status<\/strong>: A single-enantiomer product derived from a racemate is typically treated as an NME.<\/li>\n\n\n\n<li><strong>Full NDA\/MAA submission<\/strong>: Not a simple supplemental application -full nonclinical, clinical, and CMC packages are expected.<\/li>\n\n\n\n<li><strong>Clinical superiority demonstration<\/strong>: Companies must demonstrate that the single enantiomer provides <strong>clinically meaningful advantages<\/strong> -not just chemical purity (FDA, 1992).<\/li>\n\n\n\n<li><strong>Bioequivalence considerations<\/strong>: Comparative pharmacokinetic studies must establish how the single enantiomer differs from the racemate.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"662\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-1.1-visual-selection-1024x662.png\" alt=\"\" class=\"wp-image-7545\" style=\"width:678px;height:auto\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-1.1-visual-selection-1024x662.png 1024w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-1.1-visual-selection-300x194.png 300w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-1.1-visual-selection-768x496.png 768w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-1.1-visual-selection.png 1034w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Failure to prove clear advantages can lead to regulatory challenges or market skepticism.<\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-810bab98ffe26cb214049593b5da4257\"><strong>Scientific Justifications for Chiral Switches<\/strong><\/p>\n\n\n\n<p>Switches are scientifically justifiable if:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Only one enantiomer is pharmacologically active<\/strong>.<\/li>\n\n\n\n<li><strong>The other enantiomer contributes adverse effects<\/strong>.<\/li>\n\n\n\n<li><strong>The racemate shows stereoselective metabolism leading to variable efficacy<\/strong>.<\/li>\n\n\n\n<li><strong>Simplified dosing or better safety margins<\/strong> are possible.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"672\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-02-visual-selection.png\" alt=\"\" class=\"wp-image-7502\" style=\"width:582px;height:auto\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-02-visual-selection.png 768w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-02-visual-selection-300x263.png 300w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/figure>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color wp-elements-f4abc55b195e158e54376d19fa0ff01a\"><strong>Without one or more of these justifications, regulators -and increasingly, payers and clinicians -question the rationale for the switch<\/strong> (Agranat &amp; Wainschtein, 2010).<\/p>\n\n\n\n<p class=\"has-vivid-red-color has-text-color has-link-color wp-elements-1d65b87b873725912549bcf04eca22c7\"><strong>Case Study 1: Esomeprazole  vs. Omeprazole<\/strong><\/p>\n\n\n\n<p><strong>Background<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Omeprazole was introduced in 1989 as a racemate for treating acid reflux.<\/li>\n\n\n\n<li>Esomeprazole, the S-enantiomer, was launched in 2001.<\/li>\n<\/ul>\n\n\n\n<p><strong>Scientific Rationale<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Omeprazole exhibits stereoselective metabolism: the R-form is more extensively metabolized by CYP2C19, leading to variability.<\/li>\n\n\n\n<li>Esomeprazole (S-form) has more consistent exposure across patients, offering better acid control.<\/li>\n<\/ul>\n\n\n\n<p><strong>Clinical Outcomes<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Studies demonstrated higher healing rates of erosive esophagitis and better symptom relief (Andersson, 2001).<\/li>\n<\/ul>\n\n\n\n<p><strong>Regulatory Response<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Approved as a new drug by the FDA after comprehensive clinical data submission.<\/li>\n<\/ul>\n\n\n\n<p><strong>Commercial Impact<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Esomeprazole became one of AstraZeneca\u2019s best-selling products, extending the commercial life of the omeprazole franchise well beyond patent expiry.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"450\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Caser-Study-1-Omeprazole-Edited-1024x450.png\" alt=\"\" class=\"wp-image-7708\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Caser-Study-1-Omeprazole-Edited-1024x450.png 1024w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Caser-Study-1-Omeprazole-Edited-300x132.png 300w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Caser-Study-1-Omeprazole-Edited-768x337.png 768w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Caser-Study-1-Omeprazole-Edited-1536x675.png 1536w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Caser-Study-1-Omeprazole-Edited.png 1748w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><mark style=\"background-color:rgba(0, 0, 0, 0);color:#da1919\" class=\"has-inline-color\">Regulatory and scientific success.<\/mark><\/figcaption><\/figure>\n\n\n\n<p class=\"has-vivid-red-color has-text-color has-link-color wp-elements-ced24d517a919eb8ba0510936a69a1f4\">&nbsp;<strong>Case Study 2: Levocetirizine vs. Cetirizine<\/strong><\/p>\n\n\n\n<p><strong>Background<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Cetirizine was marketed as a racemate for allergic rhinitis.<\/li>\n\n\n\n<li>Levocetirizine, the R-enantiomer, was launched in the early 2000s.<\/li>\n<\/ul>\n\n\n\n<p><strong>Scientific Rationale<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>R-enantiomer responsible for most H1-antihistamine activity.<\/li>\n\n\n\n<li>Reduced sedation potential compared to the racemate (Simons, 2004).<\/li>\n<\/ul>\n\n\n\n<p><strong>Clinical Outcomes<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Comparable efficacy but slightly improved tolerability.<\/li>\n<\/ul>\n\n\n\n<p><strong>Regulatory Response<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Approved as a separate drug in Europe and the U.S.<\/li>\n<\/ul>\n\n\n\n<p><strong>Commercial Impact<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Modest -although a scientific justification existed, the switch did not create dramatic clinical differentiation.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"489\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Study-2-Ceterezine-1024x489.png\" alt=\"\" class=\"wp-image-7518\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Study-2-Ceterezine-1024x489.png 1024w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Study-2-Ceterezine-300x143.png 300w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Study-2-Ceterezine-768x367.png 768w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Study-2-Ceterezine.png 1290w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">&nbsp;<mark style=\"background-color:rgba(0, 0, 0, 0);color:#df2727\" class=\"has-inline-color\">Scientific modest success; moderate commercial impact<\/mark><\/figcaption><\/figure>\n\n\n\n<p class=\"has-vivid-red-color has-text-color has-link-color wp-elements-317095df32f1a335378e781f0460196b\"><strong>Case Study 3: Dexmethylphenidate vs. Racemic Methylphenidate<\/strong><\/p>\n\n\n\n<p><strong>Background<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Methylphenidate (Ritalin\u00ae) was used for ADHD.<\/li>\n\n\n\n<li>Dexmethylphenidate, the d-threo-enantiomer, was introduced later.<\/li>\n<\/ul>\n\n\n\n<p><strong>Scientific Rationale<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The d-enantiomer is responsible for most CNS-stimulant effects.<\/li>\n\n\n\n<li>The l-enantiomer has negligible activity.<\/li>\n<\/ul>\n\n\n\n<p><strong>Clinical Outcomes<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Comparable efficacy at half the dose.<\/li>\n<\/ul>\n\n\n\n<p><strong>Regulatory Response<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Approved by the FDA with new clinical trials.<\/li>\n<\/ul>\n\n\n\n<p><strong>Commercial Impact<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Successful switch strategy by Novartis to sustain franchise life.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"407\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Studt-3-Methyphenidate-1024x407.png\" alt=\"\" class=\"wp-image-7526\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Studt-3-Methyphenidate-1024x407.png 1024w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Studt-3-Methyphenidate-300x119.png 300w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Studt-3-Methyphenidate-768x305.png 768w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/Case-Studt-3-Methyphenidate.png 1393w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><mark style=\"background-color:rgba(0, 0, 0, 0);color:#e12222\" class=\"has-inline-color\">&nbsp;Clear scientific and dosing advantage<\/mark><\/figcaption><\/figure>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-275439888d1914dace1583f337fa2dbf\"><strong>Ethical Challenges of Chiral Switches<\/strong><\/p>\n\n\n\n<p>While some chiral switches represent legitimate therapeutic innovation, others have attracted criticism:<\/p>\n\n\n\n<p><strong>Evergreening Concerns<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Critics argue that some switches are used primarily to <strong>extend patent life<\/strong> and <strong>stifle generic competition<\/strong> without offering meaningful clinical improvement (Hancu &amp; Modroiu, 2022).<\/li>\n<\/ul>\n\n\n\n<p><strong>Marginal Clinical Differences<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Some single-enantiomer versions show <strong>only modest advantages<\/strong>, insufficient to justify higher prices.<\/li>\n<\/ul>\n\n\n\n<p><strong>Regulatory Safeguards<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Agencies increasingly require <strong>head-to-head clinical trials<\/strong> against the racemate to demonstrate meaningful benefit.<\/li>\n\n\n\n<li>Ethical frameworks now push for transparency on the true value of a switch (EMA, 1994).<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"780\" height=\"612\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-03-visual-selection.png\" alt=\"\" class=\"wp-image-7529\" style=\"width:600px;height:auto\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-03-visual-selection.png 780w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-03-visual-selection-300x235.png 300w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/04\/E6-03-visual-selection-768x603.png 768w\" sizes=\"auto, (max-width: 780px) 100vw, 780px\" \/><\/figure>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-07675b616f15b2a0a1542a331adefa16\"><strong>Payer and Prescriber Perspectives<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Insurance payers<\/strong> often require proof of significant therapeutic advantage before covering a more expensive single-enantiomer version.<\/li>\n\n\n\n<li><strong>Prescribers<\/strong> are cautious about switching patients from a well-tolerated racemate to a new enantiomer without clear reasons.<\/li>\n\n\n\n<li><strong>Patients<\/strong> are increasingly aware of chiral switch controversies, influencing public trust.<\/li>\n<\/ul>\n\n\n\n<p>Thus, even if regulators approve a chiral switch, <strong>market adoption<\/strong> is not guaranteed unless the clinical value proposition is clear.<\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-d03bffbfddea70e8e49e1a4cb27b9fa2\"><strong>Regulatory Trends: Tougher Standards for Switches<\/strong><\/p>\n\n\n\n<p>Modern regulatory expectations are more stringent:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>FDA and EMA<\/strong> now expect not only PK improvements but <strong>clear clinical benefit<\/strong>.<\/li>\n\n\n\n<li><strong>Comparative efficacy studies<\/strong> against the racemate are often needed.<\/li>\n\n\n\n<li><strong>Labeling<\/strong> must clearly explain differences in pharmacology, efficacy, and safety.<\/li>\n<\/ul>\n\n\n\n<p>Simply achieving better chiral purity without superior outcomes no longer suffices.<\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-f81d2bf8e5b10748e710282633bdb925\"><strong>Future of Chiral Switches<\/strong><\/p>\n\n\n\n<p>Looking forward:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>True chiral switches based on genuine clinical benefit will continue to be pursued.<\/li>\n\n\n\n<li>Regulatory scrutiny will ensure <strong>only scientifically justified switches<\/strong> succeed.<\/li>\n\n\n\n<li>Innovations in asymmetric synthesis and chiral drug design will favor <strong>initial single-enantiomer development<\/strong>, reducing the need for later switches.<\/li>\n<\/ul>\n\n\n\n<p>In short: <mark style=\"background-color:rgba(0, 0, 0, 0);color:#cf2e2e\" class=\"has-inline-color\"><strong><em>the bar for chiral switches is higher than ever -and rightly so.<\/em><\/strong><\/mark><\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-9e316c1999adbcade6b8c6749c3afcd7\"><strong>Conclusion<\/strong><\/p>\n\n\n\n<p>Chiral switches exemplify both the opportunities and challenges at the intersection of science, regulation, and commerce.<br>When grounded in genuine clinical benefit, they enhance therapy and serve public health.<br>When driven solely by commercial motivations, they risk undermining trust and value.<\/p>\n\n\n\n<p>Regulators today navigate this complex landscape with increasing vigilance, ensuring that when a drug switches from two hands to one, it does so for the right reasons.<\/p>\n\n\n\n<p>In the next episode, we will explore how regulators and scientists evaluate <strong>whether single enantiomers are truly superior<\/strong> -clinically, ethically, and economically.<\/p>\n\n\n\n<p class=\"has-vivid-red-color has-text-color has-link-color wp-elements-5e672955dd9f208527288b9716b0c9e7\"><strong>What is in the next episode?<\/strong><\/p>\n\n\n\n<p><em>&#8220;Is the better twin always truly better? Find out in <mark style=\"background-color:rgba(0, 0, 0, 0);color:#d92d2d\" class=\"has-inline-color\">Episode 7: <strong>Clinical Questions: Are Single Enantiomers Always Better?<\/strong>.<\/mark>&#8220;<\/em><\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-70f1e73667f2850b676b5e58240281c9\"><strong>References<\/strong><\/p>\n\n\n\n<p>Agranat, I., Caner, H., &amp; Caldwell, J. (2002). Putting chirality to work: The strategy of chiral switches. <em>Nature Reviews Drug Discovery, 1<\/em>(10), 753\u2013768.<\/p>\n\n\n\n<p>Agranat, I., &amp; Wainschtein, S. R. (2010). The strategy of enantiomer patents of drugs. <em>Drug Discovery Today, 15<\/em>(5-6), 163\u2013170.<\/p>\n\n\n\n<p>Andersson, T. (2001). Pharmacokinetics, metabolism and interactions of acid pump inhibitors: Focus on omeprazole, lansoprazole, pantoprazole, and rabeprazole. <em>Clinical Pharmacokinetics, 40<\/em>(7), 523\u2013538.<\/p>\n\n\n\n<p>European Medicines Agency (EMA). (1994). <em>Investigation of Chiral Active Substances<\/em> (CPMP Note for Guidance 3CC29a).<\/p>\n\n\n\n<p>Food and Drug Administration (FDA). (1992). <em>Development of New Stereoisomeric Drugs<\/em> (Policy Statement). Federal Register, 57(88), 22249-22250.<\/p>\n\n\n\n<p>Hancu, G., &amp; Modroiu, A. (2022). Chiral switch: Between therapeutical benefit and marketing strategy. <em>Pharmaceuticals, 15<\/em>(2), 240.<\/p>\n\n\n\n<p>Simons, F. E. (2004). Advances in H1-antihistamines. <em>New England Journal of Medicine, 351<\/em>(21), 2203\u20132217.<\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-04467d121d4a3fe2d97a693c0133ceb1\"><strong>Further Reading<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-chiralpedia wp-block-embed-chiralpedia\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"kmrcMNlSQU\"><a href=\"https:\/\/chiralpedia.com\/blog\/chiral-drugs-a-twisted-tale-in-pharmaceuticals\/\">Chiral Drugs: A twisted tale in pharmaceuticals<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;Chiral Drugs: A twisted tale in pharmaceuticals&#8221; &#8212; Chiralpedia\" src=\"https:\/\/chiralpedia.com\/blog\/chiral-drugs-a-twisted-tale-in-pharmaceuticals\/embed\/#?secret=AXDLgR39EN#?secret=kmrcMNlSQU\" data-secret=\"kmrcMNlSQU\" width=\"500\" height=\"282\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-chiralpedia wp-block-embed-chiralpedia\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"BPeb8vI7Xk\"><a href=\"https:\/\/chiralpedia.com\/blog\/chiral-switch-unlocking-the-potential-of-single-enantiomers\/\">Chiral Switch: Unlocking the Potential of Single Enantiomers<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;Chiral Switch: Unlocking the Potential of Single Enantiomers&#8221; &#8212; Chiralpedia\" src=\"https:\/\/chiralpedia.com\/blog\/chiral-switch-unlocking-the-potential-of-single-enantiomers\/embed\/#?secret=QGXovo0QRl#?secret=BPeb8vI7Xk\" data-secret=\"BPeb8vI7Xk\" width=\"500\" height=\"282\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>&#8220;When a drug transforms from a blend to a single hand, is it innovation -or a clever commercial sleight of hand?&#8220; Introduction The regulatory awakening around chiral drugs enabled not just better science but also a new strategic tool for the pharmaceutical industry: the chiral switch. This phenomenon -developing a single-enantiomer version of an already marketed racemate -became both a scientific opportunity and a commercial strategy. While some switches were genuine innovations that improved patient &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/chiralpedia.com\/blog\/episode-6-the-rise-of-the-chiral-switch-strategy-or-science\/\"> <span class=\"screen-reader-text\">Episode 6: The Rise of the Chiral Switch: Strategy or Science?<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":7711,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-sidebar-layout":"","site-content-layout":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"categories":[7,43,116],"tags":[23,22],"ppma_author":[93,95],"class_list":["post-7232","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-chiral-science","category-chirality","category-regulatory-affairs","tag-chiral_drugs","tag-chirality"],"authors":[{"term_id":93,"user_id":1,"is_guest":0,"slug":"chiralusrblg","display_name":"Valliappan Kannappan","avatar_url":{"url":"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2024\/09\/vk.jpg","url2x":"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2024\/09\/vk.jpg"},"first_name":"","last_name":"","user_url":"https:\/\/chiralpedia.com\/blog\/","job_title":"Founder, chiralpedia.com","description":""},{"term_id":95,"user_id":2,"is_guest":0,"slug":"chandramouli-r","display_name":"Chandramouli R","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/dafe0b6a18e9248eb688088e3e993360328363d8d087bbd01648f0bddae05eb5?s=96&d=mm&r=g","first_name":"","last_name":"","user_url":"","job_title":"","description":""}],"_links":{"self":[{"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts\/7232","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/comments?post=7232"}],"version-history":[{"count":32,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts\/7232\/revisions"}],"predecessor-version":[{"id":7710,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts\/7232\/revisions\/7710"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/media\/7711"}],"wp:attachment":[{"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/media?parent=7232"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/categories?post=7232"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/tags?post=7232"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/ppma_author?post=7232"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}