{"id":8759,"date":"2025-10-25T05:48:59","date_gmt":"2025-10-25T00:18:59","guid":{"rendered":"https:\/\/chiralpedia.com\/blog\/?p=8759"},"modified":"2025-10-26T10:40:12","modified_gmt":"2025-10-26T05:10:12","slug":"the-hidden-chirality-in-drug-metabolites-a-metabolic-blind-spot","status":"publish","type":"post","link":"https:\/\/chiralpedia.com\/blog\/the-hidden-chirality-in-drug-metabolites-a-metabolic-blind-spot\/","title":{"rendered":"The Hidden Chirality in Drug Metabolites: A metabolic blind spot"},"content":{"rendered":"\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0);color:#cf2e2e\" class=\"has-inline-color\">\u201cChirality isn\u2019t hidden \u2014 we just stopped looking closely enough\u201d<\/mark><\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-e4c43020e1642f956e55451fd06994af\"><strong>The Unseen Journey After the Dose<\/strong>: <\/h2>\n\n\n\n<p>\ud83d\udc8a <strong>When a patient swallows a drug, the journey is far from over.<\/strong><em><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\"> Sometimes, the real chiral story begins after the dose.<\/mark> <\/em>The drug molecule meets a series of enzymes \u2014 oxidases, reductases, transferases \u2014 each capable of transforming it into one or more metabolites. We often assume these are simply inactive breakdown products, but chemistry rarely plays it that straight.<\/p>\n\n\n\n<p>In the chiral world, metabolism can do something extraordinary \u2014 it can <strong>invert, create, or amplify chirality<\/strong>. What starts as a single enantiomer may emerge as multiple stereoisomeric metabolites, each with its own pharmacological identity. Yet, most drug development programs and even regulatory documents remain silent on this stereochemical evolution.<\/p>\n\n\n\n<p>This silence represents a <strong>metabolic blind spot<\/strong> \u2014 one that can affect everything from drug safety to efficacy, and yet, remains overlooked in pharmacological discourse.<\/p>\n\n\n\n<h2 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-f416ef779c5585bf539c906cbb8d7474\"><strong>How Metabolism Makes New Chirality<\/strong><\/h2>\n\n\n\n<p>Drug metabolism doesn\u2019t merely deactivate molecules; it remodels them.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Phase I reactions<\/strong> (oxidation, reduction, hydrolysis) can introduce new chiral centers, for instance, by hydroxylating prochiral carbons.<\/li>\n\n\n\n<li><strong>Phase II reactions<\/strong> (such as conjugation with glucuronic acid or sulfate) may also yield diastereomeric conjugates.<\/li>\n<\/ul>\n\n\n\n<p>These transformations are <strong>stereoselective<\/strong>, often governed by the chiral nature of metabolic enzymes themselves. Cytochrome P450 isoforms, for example, display enantioselectivity \u2014 preferring one enantiomer over another, or acting differently on each.<\/p>\n\n\n\n<p>As a result, the body may process the left-handed and right-handed versions of a chiral molecule differently, yielding distinct pharmacokinetic and pharmacodynamic outcomes. Selected live examples are presented below for illustration.<\/p>\n\n\n\n<h1 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-2a092dd77502c780afb5538a7e9aba74\"><strong>The Case of Ibuprofen \u2014 A Metabolic Twist in Action<\/strong><\/h1>\n\n\n\n<p>Among over-the-counter drugs, <strong>ibuprofen<\/strong> is perhaps the best-known case of chiral metabolism. It is marketed as a <strong>racemate<\/strong>, but only the <strong>S-(+)-enantiomer<\/strong> inhibits cyclooxygenase (COX) enzymes and relieves pain.<\/p>\n\n\n\n<p>Here\u2019s the twist: in the body, the supposedly inactive <strong>R-(-)-enantiomer<\/strong> undergoes <strong>metabolic inversion<\/strong> \u2014 converted enzymatically into the active S-form. This chiral inversion is catalyzed by <strong>acyl-CoA synthetase<\/strong> and <strong>2-arylpropionyl-CoA epimerase<\/strong>, mainly in the liver.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"548\" height=\"248\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/10\/Ibuprofen-enantiomers.png\" alt=\"\" class=\"wp-image-8819\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/10\/Ibuprofen-enantiomers.png 548w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/10\/Ibuprofen-enantiomers-300x136.png 300w\" sizes=\"auto, (max-width: 548px) 100vw, 548px\" \/><figcaption class=\"wp-element-caption\"><em>The therapeutically active form of the drug, Ibuprofen, is the (S)-enantiomer. The inactive (R)-isomer, however, doesn\u2019t remain idle \u2014 it undergoes a one-way metabolic conversion in the body to form the active (S)-enantiomer. In other words, when the racemic mixture is administered, the distomer is transformed in vivo into the eutomer, while the latter remains unchanged<\/em><\/figcaption><\/figure>\n\n\n\n<p>Thus, both enantiomers ultimately contribute to therapeutic activity, but through different routes \u2014 one directly, one metabolically. This raises a profound question: when a drug\u2019s efficacy depends on metabolic inversion, should we still treat it as a racemate (1:1 ratio) or a chiral mixture?<\/p>\n\n\n\n<p><strong>Note: <\/strong><em>A chiral mixture is a broader term that can refer to any combination of chiral molecules, including a racemate (1:1 ratio), an enantioenriched mixture with an excess of one enantiomer.<\/em><\/p>\n\n\n\n<h1 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-3bf6101dd373e470e5e2a3908484ccc5\"><strong>Thalidomide \u2014 The Classic Cautionary Tale, Revisited<\/strong><\/h1>\n\n\n\n<p>No discussion on chiral metabolism can escape <strong>thalidomide<\/strong> \u2014 the molecule that taught the world how dangerous stereochemical indifference can be.<\/p>\n\n\n\n<p>When first marketed in the 1950s as a racemate, one enantiomer was sedative and antiemetic, while the other was teratogenic. In theory, producing only the \u201csafe\u201d enantiomer should have prevented harm. But metabolism defied that logic.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img decoding=\"async\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2022\/08\/Thalidomide-enantiomers-2-resize-2.png\" alt=\"\" style=\"width:751px;height:auto\"\/><figcaption class=\"wp-element-caption\"><em>In vivo studies showed that <strong>thalidomide undergoes rapid racemization<\/strong> \u2014 interconversion between its enantiomers in physiological conditions. The \u201cgood\u201d and \u201cbad\u201d forms equilibrate in the bloodstream, making it impossible to isolate safety by chirality alone. Under biological conditions, the enantiomers interconvert [<strong><em>bidirectional chiral inversion<\/em><\/strong>&nbsp;<em>\u2013 indicated by curved arrows<\/em>; (R)- to (S)- and vice versa].&nbsp;<br>This realization shattered the illusion that a single enantiomer guarantees purity of effect. It also emphasized the <strong>metabolic fluidity of chirality<\/strong> \u2014 how biological systems can blur the lines chemists try to draw.<\/em><\/figcaption><\/figure>\n\n\n\n<p>The <strong>Thalidomide tragedy<\/strong> (see &lt;<a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/21507989\/\">https:\/\/pubmed.ncbi.nlm.nih.gov\/21507989\/<\/a>&gt;) led to profound and lasting shifts in toxicity-testing protocols, regulatory oversight, and how chemists view chiral molecules. Today, when it comes to chiral drugs, each enantiomer is treated as a separate chemical entity\u2014almost as though one drug were two distinct therapies.<\/p>\n\n\n\n<h1 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-5c8dbdd962dc06ccb69dba5d660db6dc\"><strong>Propranolol and Citalopram \u2014 When Metabolites Rewrite Pharmacology<\/strong><\/h1>\n\n\n\n<p>The story repeats across many therapeutic classes.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Propranolol<\/strong>, a \u03b2-blocker used in cardiac therapy, exhibits enantioselective metabolism: the S-(\u2013)-form is more potent pharmacologically, but both enantiomers produce metabolites with differing receptor affinities and elimination rates.<\/li>\n\n\n\n<li><strong>Citalopram<\/strong>, an antidepressant, also demonstrates chiral complexity. The S-enantiomer (escitalopram) is the active component, yet the R-form and its metabolites can antagonize the S-form\u2019s serotonin transporter binding \u2014 subtly modulating efficacy.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"687\" height=\"280\" src=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/10\/Citaloptam-enantiomers.png\" alt=\"\" class=\"wp-image-8814\" srcset=\"https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/10\/Citaloptam-enantiomers.png 687w, https:\/\/chiralpedia.com\/blog\/wp-content\/uploads\/2025\/10\/Citaloptam-enantiomers-300x122.png 300w\" sizes=\"auto, (max-width: 687px) 100vw, 687px\" \/><figcaption class=\"wp-element-caption\"><strong>Citalopram: Chiral twins<\/strong><br><em>Citalopram is a chiral antidepressant made up of two mirror-image forms, or enantiomers \u2014 (S)-citalopram (better known as escitalopram) and (R)-citalopram. Among the two, it\u2019s the (S)-enantiomer that truly drives the drug\u2019s antidepressant power. It acts as a highly selective serotonin reuptake inhibitor (SSRI), enhancing serotonin levels in the brain. The (R)-enantiomer, on the other hand, is about 20 times less potent at blocking serotonin reuptake and can even interfere with the beneficial action of its (S)-counterpart. In other words, one enantiomer heals, while the other hinders.<\/em><\/figcaption><\/figure>\n\n\n\n<p>In both cases, metabolism not only modifies the molecule \u2014 it <strong>modifies the message<\/strong>. The metabolites can reinforce, compete with, or counteract the parent compound\u2019s action.<\/p>\n\n\n\n<h2 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-32d91a8b9a2b6919f63d4c613c50b3bf\"><strong>Analytical Blindness \u2014 The Technical Bottleneck<\/strong><\/h2>\n\n\n\n<p>One reason chirality in metabolites remains challenging lies in <strong>analytical limitations<\/strong>. Detecting and quantifying enantiomeric metabolites in biological fluids is a difficult task.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Chiral chromatography<\/strong> requires highly specialized stationary phases and careful method validation.<\/li>\n\n\n\n<li><strong>Mass spectrometry<\/strong> alone cannot distinguish enantiomers \u2014 it sees only mass, not handedness.<\/li>\n\n\n\n<li><strong>NMR and circular dichroism<\/strong> can help, but demand pure isolates and sophisticated interpretation.<\/li>\n<\/ul>\n\n\n\n<p>Because of these challenges, many pharmacokinetic studies still report \u201ctotal metabolite\u201d concentrations without resolving enantiomeric forms. What\u2019s lost in that averaging is often pharmacologically critical.<\/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-415eff74fae29e28532596f91d124339\"><strong>The Regulatory Silence<\/strong><\/p>\n\n\n\n<p>The <strong>U.S. FDA\u2019s 1992 \u201cDevelopment of New Stereoisomeric Drugs\u201d guidance<\/strong> was a milestone, urging that enantiomers be characterized separately for pharmacology, pharmacokinetics, and toxicology. However, that guidance remains <strong>non-binding<\/strong>, and it focuses primarily on the parent drug. There is still no regulatory requirement to study the stereochemistry of metabolites \u2014 even though the guidance itself acknowledges that \u201cstereoisomeric metabolites may contribute to drug action or toxicity.\u201d<\/p>\n\n\n\n<p>This creates an uneven landscape: the chirality of the starting material is scrutinized, but the chirality of its metabolic products often slips through unexamined.<\/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-adc1e5538c4ebaa9d51d4ad38ae725bd\"><strong>Why This Blind Spot Matters<\/strong><\/p>\n\n\n\n<p>Ignoring chirality at the metabolite level can have serious implications:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Misjudged potency:<\/strong> Active enantiomeric metabolites can lead to underestimated efficacy.<\/li>\n\n\n\n<li><strong>Unexpected toxicity:<\/strong> One enantiomeric metabolite may bind unintended receptors or accumulate selectively.<\/li>\n\n\n\n<li><strong>Variable pharmacokinetics:<\/strong> Stereoselective metabolism can differ among individuals or ethnic groups, affecting dosing precision.<\/li>\n<\/ul>\n\n\n\n<p>In the era of personalized medicine, such oversights run counter to our goal of <strong>precision pharmacotherapy<\/strong>. Understanding metabolic chirality isn\u2019t academic \u2014 it\u2019s essential.<\/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-f1c72c9368f09b63d685501b13ea7e12\"><strong>A Call for Chiral Literacy<\/strong><\/p>\n\n\n\n<p>If chemistry teaches us anything, it\u2019s that symmetry hides complexity. In pharmacology, the mirror image of a molecule can mean the mirror image of an outcome. Chiralpedia\u2019s mission is to illuminate these hidden corners \u2014 where regulatory documents, AI models, or metabolic pathways lose sight of stereochemistry. The overlooked  chirality of metabolites is one such corner, rich with both scientific challenge and clinical consequence.<\/p>\n\n\n\n<p>To move forward, we must integrate <strong>enantioselective metabolic studies<\/strong> into routine drug development, enhance <strong>analytical methods<\/strong> for metabolite chirality, and most importantly, foster <strong>chiral literacy<\/strong> among students and researchers alike.<\/p>\n\n\n\n<p>After all, the next time we design a \u201csingle-enantiomer\u201d drug, we should ask: <em>What will the body make of it \u2014 and what chiral stories will its metabolites tell?<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading has-ast-global-color-0-color has-text-color has-link-color has-medium-font-size wp-elements-a964435802ffd844462662777f59dc99\"><strong>References and Further Reading<\/strong><\/h2>\n\n\n\n<p><strong>Hutt, A. J., &amp; Caldwell, J. (1983).<\/strong> <em>The Metabolic Chiral Inversion of 2-Arylpropionic Acids \u2014 A Novel Route with Pharmacological Consequences.<\/em> <strong>Journal of Pharmacology and Experimental Therapeutics<\/strong>, 224(3), 658\u2013664. \u2014 Classic paper detailing metabolic inversion of (R)- to (S)-ibuprofen and other NSAIDs \u2014 the canonical example of in vivo chirality switch.<\/p>\n\n\n\n<p>Aboul-Enein HY, Kannappan V, Kanthiah S. Chiral Inversion of Pharmaceutical Drugs &#8211; Mini Review. Comb Chem High Throughput Screen. 2023;26(15):2577-2582. doi: &nbsp;<a href=\"https:\/\/doi.org\/10.2174\/1386207326666230102123655\" target=\"_blank\" rel=\"noreferrer noopener\">10.2174\/1386207326666230102123655<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/en.wikipedia.org\/wiki\/Chiral_inversion\">\u201cChiral inversion.\u201d <em>Wikipedia: The Free Encyclopedia<\/em>. Wikimedia Foundation, Inc. Accessed [24-10-2025]. <a href=\"https:\/\/en.wikipedia.org\/wiki\/Chiral_inversion?utm_source=chatgpt.com\">https:\/\/en.wikipedia.org\/wiki\/Chiral_inversion<\/a><\/a><\/p>\n\n\n\n<p><strong>Caldwell, J. (1995).<\/strong> <em>Pharmacological and Toxicological Implications of the Stereochemistry of Drug Metabolism.<\/em> <strong>Pharmacology &amp; Therapeutics<\/strong>, 45(3), 343\u2013395. \u2014 A comprehensive review of stereoselective oxidation, reduction, and conjugation reactions.<\/p>\n\n\n\n<p><strong>Ari\u00ebns, E. J. (1984).<\/strong> <em>Stereochemistry, a Basis for Sophisticated Nonsense in Pharmacokinetics and Clinical Pharmacology.<\/em> <strong>European Journal of Clinical Pharmacology<\/strong>, 26(6), 663\u2013668. \u2014 A witty yet insightful reminder of why neglecting stereochemistry distorts pharmacological interpretation.<\/p>\n\n\n\n<p><strong>Wsol, V., Skalova, L., &amp; Szotakova, B. (2004).<\/strong> <em>Enantioselectivity of Drug Metabolizing Enzymes.<\/em> <strong>Current Drug Metabolism<\/strong>, 5(6), 517\u2013533. \u2014 Discusses enantioselective metabolism by cytochrome P450s, esterases, and reductases across major drug classes.<\/p>\n\n\n\n<p><strong>Williams, K. M., et al. (1999).<\/strong> <em>Stereoselective Formation and Clearance of Omeprazole Metabolites in Humans.<\/em> <strong>Clinical Pharmacology &amp; Therapeutics<\/strong>, 66(5), 509\u2013517. \u2014 Demonstrates how P450 polymorphisms and chirality together modulate therapeutic outcome.<\/p>\n\n\n\n<p><strong>Kishimoto, W., et al. (2000).<\/strong> <em>Stereoselective Oxidation of Propranolol by Human CYP2D6 and CYP1A2.<\/em> <strong>Drug Metabolism and Disposition<\/strong>, 28(7), 848\u2013853. \u2014 A model case of enantioselective metabolism leading to pharmacodynamic asymmetry.<\/p>\n\n\n\n<p><strong>Jacquot C, et al., (2007).<\/strong>  Escitalopram et Citalopram: le r\u00f4le inattendu de l&#8217;\u00e9nantiom\u00e8re R [Escitalopram and citalopram: the unexpected role of the R-enantiomer]. Encephale. 33(2):179-87. French. doi: 10.1016\/s0013-7006(07)91548-1.<\/p>\n\n\n\n<p><strong>Tamura, H. O., et al. (1993).<\/strong> <em>Stereoselective Metabolism of Mefloquine and Its Implications for Antimalarial Efficacy and Toxicity.<\/em> <strong>Drug Metabolism Reviews<\/strong>, 25(2\u20133), 219\u2013244. \u2014 An instructive example of metabolic chirality influencing drug safety and duration.<\/p>\n\n\n\n<p><strong>Zhang, D., &amp; Zhu, M. (2019).<\/strong> <em>Drug Metabolism in Drug Design and Development (2nd Ed.).<\/em> Wiley. \u2014 Provides an integrated view of how stereoselective biotransformation shapes pharmacokinetics and toxicokinetics.<\/p>\n\n\n\n<p><strong>Darton, C. D., &amp; Yu, A. M. (2023).<\/strong> <em>Chiral Drug Metabolism: The Overlooked Dimension in Pharmacogenomics.<\/em> <strong>Frontiers in Pharmacology<\/strong>, 14, 1130782. \u2014 Recent discussion linking chirality to precision medicine and interindividual variability.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><\/li>\n<\/ol>\n\n\n\n<p><strong>Park, B. K., &amp; Kitteringham, N. R. (1994).<\/strong> <em>Drug Metabolism and Drug Toxicity \u2014 The Role of Reactive Intermediates.<\/em> <strong>Chemical Research in Toxicology<\/strong>, 7(3), 307\u2013319. \u2014 Many reactive metabolites are chiral; this paper connects metabolic asymmetry to idiosyncratic toxicity.<\/p>\n\n\n\n<p><strong>Liu, H., et al. (2015).<\/strong> <em>Chiral Metabolomics: Analytical Advances and Biological Implications.<\/em> <strong>TrAC Trends in Analytical Chemistry<\/strong>, 74, 141\u2013150. \u2014 Modern analytical methods for detecting enantiomeric metabolites in biological systems.<\/p>\n\n\n\n<p><strong>Fasinu, P. S., et al. (2019).<\/strong> <em>Enantioselective Metabolism of Chiral Drugs and Its Implications for Drug Safety and Efficacy.<\/em> <strong>Drug Metabolism Reviews<\/strong>, 51(3), 308\u2013323. \u2014 Bridges stereoselective biotransformation and clinical pharmacology.<\/p>\n\n\n\n<p><strong>FDA (1992).<\/strong> <em>Development of New Stereoisomeric Drugs: Guidance for Industry.<\/em> \u2014 Notes the importance of metabolite stereochemistry in safety evaluation.<\/p>\n\n\n\n<p><strong>EMA (2011).<\/strong> <em>Guideline on the Investigation of Drug Interactions.<\/em> \u2014 References stereoselective metabolic pathways in drug\u2013drug interaction assessment.<\/p>\n\n\n\n<p><strong>Kannappan, V. (2025).<\/strong> <em>When Labels Miss the Twist: Chirality and the Enantiomer Gap.<\/em> <strong>Chiralpedia Blog.<\/strong> \u2014 Explores the regulatory blind spot complementing the metabolic one.<\/p>\n\n\n\n<p><strong>ChiralMetDB (2024).<\/strong> <em>Database of Stereoselective Metabolic Reactions and Chiral Metabolites.<\/em> <a>https:\/\/chiralmetdb.org<\/a> \u2014 A growing resource cataloging chiral metabolites and their enzymatic origins.<\/p>\n\n\n\n<p><strong>Human Metabolome Database (HMDB).<\/strong> <a>https:\/\/hmdb.ca<\/a> \u2014 Provides stereochemical annotation for thousands of endogenous and xenobiotic metabolites.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u201cChirality isn\u2019t hidden \u2014 we just stopped looking closely enough\u201d The Unseen Journey After the Dose: \ud83d\udc8a When a patient swallows a drug, the journey is far from over. Sometimes, the real chiral story begins after the dose. The drug molecule meets a series of enzymes \u2014 oxidases, reductases, transferases \u2014 each capable of transforming it into one or more metabolites. We often assume these are simply inactive breakdown products, but chemistry rarely plays it &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/chiralpedia.com\/blog\/the-hidden-chirality-in-drug-metabolites-a-metabolic-blind-spot\/\"> <span class=\"screen-reader-text\">The Hidden Chirality in Drug Metabolites: A metabolic blind spot<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":8840,"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":[7,43,42],"tags":[115,23,136,22,67],"ppma_author":[93],"class_list":["post-8759","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-chiral-science","category-chirality","category-drug-stereochemistry","tag-chiral_analysis","tag-chiral_drugs","tag-chiral_metabolites","tag-chirality","tag-chiralpedia"],"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":""}],"_links":{"self":[{"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts\/8759","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=8759"}],"version-history":[{"count":35,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts\/8759\/revisions"}],"predecessor-version":[{"id":8847,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/posts\/8759\/revisions\/8847"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/media\/8840"}],"wp:attachment":[{"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/media?parent=8759"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/categories?post=8759"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/tags?post=8759"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/chiralpedia.com\/blog\/wp-json\/wp\/v2\/ppma_author?post=8759"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}