(S)-(+)-Ibuprofen-d3

Synthetic Routes and Reaction Conditions

The synthesis of (S)-(+)-Ibuprofen-d3 typically involves the incorporation of deuterium atoms into the ibuprofen molecule. This can be achieved through various synthetic routes, including:

Hydrogen-Deuterium Exchange: This method involves the replacement of hydrogen atoms with deuterium atoms using deuterated reagents under specific reaction conditions.

Deuterated Precursors: Another approach is to use deuterated starting materials in the synthesis of ibuprofen. This method ensures that the deuterium atoms are incorporated into the final product during the synthesis process.

Industrial Production Methods

Industrial production of this compound involves scaling up the synthetic routes mentioned above. The process typically includes:

Selection of Deuterated Reagents: Choosing appropriate deuterated reagents to ensure efficient incorporation of deuterium atoms.

Optimization of Reaction Conditions: Fine-tuning reaction conditions such as temperature, pressure, and catalysts to maximize yield and purity.

Purification: Using techniques like chromatography to purify the final product and remove any impurities.

Acid-Base Reactions

(S)-(+)-Ibuprofen-d3 undergoes acid-base reactions typical of carboxylic acids. The deuterated propionic acid group reacts with bases (e.g., NaOH, KOH) to form water-soluble salts, facilitating pharmaceutical formulation:
$\text{C}_{13}\text{H}_{15}\text{D}_3\text{O}_2+\text{NaOH}\rightarrow \text{C}_{13}\text{H}_{14}\text{D}_3\text{O}_2\text{Na}^-+\text{H}_2\text{O}$

This reaction is critical for improving bioavailability in drug delivery systems.

Esterification

The compound reacts with alcohols (e.g., methanol, ethanol) under acidic catalysis to form esters, which are intermediates in prodrug synthesis:
$\text{C}_{13}\text{H}_{15}\text{D}_3\text{O}_2+\text{CH}_3\text{OH}\xrightarrow{\text{H}^+}\text{C}_{14}\text{H}_{18}\text{D}_3\text{O}_2+\text{H}_2\text{O}$

Ester derivatives are often used to modify pharmacokinetic properties.

Oxidation

Oxidation of the alkyl side chain or aromatic ring occurs under strong oxidizing conditions. For example, potassium permanganate ($\text{KMnO}_4$
) oxidizes the compound to a carboxylic acid derivative:
$\text{C}_{13}\text{H}_{15}\text{D}_3\text{O}_2\xrightarrow{\text{KMnO}_4,\text{H}_2\text{O}}\text{C}_{12}\text{H}_{11}\text{D}_3\text{O}_4$

This reaction is utilized in metabolite identification studies.

Metabolic Reactions and Pharmacokinetics

Deuteration minimally alters metabolic pathways compared to non-deuterated ibuprofen, but it allows precise tracking of enantiomeric inversion and clearance rates:

Key findings:

• This compound shows no inversion to the (R)-enantiomer in vivo, ensuring metabolic stability .

• Clearance rates are significantly slower for the (S)-enantiomer, enhancing its therapeutic duration .

Analytical Characterization

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods are employed to resolve and quantify enantiomers:

| Compound | Ion Transition ($m/z$
) | Retention Time (min) | Collision Energy (V) |
|------------------------|----------------------------|----------------------|----------------------|
| this compound | 208.1 → 163.9 | 10.31 | 10.0 |
| (S)-(+)-Ibuprofen | 205.1 → 160.9 | 10.38 | 12.0 |

This method achieves baseline separation, critical for studying reaction intermediates and metabolites .

In Vitro Reactivity

While direct in vitro reaction data for this compound is limited, studies on non-deuterated ibuprofen suggest:

• Hydroxylation : Occurs at the aromatic ring under cytochrome P450 catalysis.

• Glucuronidation : Conjugation with glucuronic acid enhances water solubility for renal excretion.

Deuteration is expected to slow these reactions slightly due to kinetic isotope effects, though experimental confirmation is pending .

Stability and Degradation

This compound is stable under ambient conditions but degrades under:

• Strong acids/bases : Hydrolysis of the carboxylic acid group.

• UV light : Photolytic decomposition of the aromatic ring.

• Oxidizing agents : Side-chain oxidation to ketones or carboxylic acids.

Pharmacokinetic Research

(S)-(+)-Ibuprofen-d3 is primarily utilized as a stable isotopically labeled internal standard in pharmacokinetic studies. This application is crucial for accurately quantifying the concentration of ibuprofen in biological matrices, such as plasma.

Method Development

A study developed a highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining ibuprofen levels in human plasma using this compound as an internal standard. The method achieved a linear range of 0.05-36 μg/ml with high precision and accuracy, making it suitable for pharmacokinetic studies in healthy volunteers after oral administration of ibuprofen granules .

Clinical Applications

In clinical settings, this compound is used to assess the pharmacokinetics of ibuprofen formulations in various populations, including neonates and adults with different health conditions. For example, a study on beagle dogs demonstrated the method's application in evaluating the pharmacokinetics of both racemic ibuprofen and its active isomer .

Oncology Research

Recent studies have investigated the potential synergistic effects of ibuprofen in cancer treatment. This compound has been used to explore its impact on prostate cancer cell lines.

Case Study: Combination Therapy

A significant study examined the combined effect of (S)-(+)-Ibuprofen and 1,25-dihydroxyvitamin D3 on LNCaP prostate cancer cells. The results indicated that this combination treatment resulted in a 67% reduction in cell proliferation compared to controls, demonstrating enhanced apoptosis and cell cycle inhibition .

Biochemical Applications

Beyond pharmacokinetics and oncology, this compound has applications in immunology and biochemistry.

Immune Response Studies

Research has shown that ibuprofen supports macrophage differentiation and T cell recruitment, which are critical for tumor suppression . The use of this compound in these studies allows for precise measurement of ibuprofen's effects on immune responses.

The mechanism of action of (S)-(+)-Ibuprofen-d3 is similar to that of non-deuterated ibuprofen. It works by inhibiting the cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2. This inhibition reduces the production of prostaglandins, which are responsible for inflammation, pain, and fever. The deuterium atoms may affect the drug’s interaction with these enzymes, potentially leading to differences in efficacy and side effects.

Structural and Isotopic Variants of Ibuprofen

Table 1: Key Structural and Isotopic Variants of Ibuprofen

Key Differences :

• Isotopic Labeling : this compound and its racemic counterpart (±)-Ibuprofen-d3 differ in stereochemical configuration, impacting their use in enantioselective analyses. The (S)-(+)-form is preferred for studies requiring pharmacological relevance .
• Solubility : The sodium salt variant enhances aqueous solubility, making it suitable for in vitro assays requiring polar solvents .
• Analytical Utility: this compound demonstrates negligible matrix interference in human plasma LC-MS/MS analyses, unlike non-deuterated forms, which may suffer from ion suppression .

Comparison with Deuterated NSAIDs

Key Differences :

• Structural Modifications : Flurbiprofen-d3 contains a fluorine atom, enhancing its lipophilicity and metabolic stability compared to this compound .
• Environmental Persistence : Diclofenac-d4 is often used to track NSAID pollution in water systems due to its resistance to photodegradation .

Enantiomeric and Isotopic Purity in Analytical Methods

This compound exhibits a retention time (RT) of 10.31 min in chiral LC-MS/MS, closely mirroring non-deuterated (S)-(+)-Ibuprofen (RT: 10.38 min), ensuring precise co-elution for quantification . In contrast, the (R)-(-)-enantiomer elutes earlier (RT: 9.44 min), enabling clear chromatographic separation . This specificity is critical for avoiding cross-talk in enantioselective assays.

(S)-(+)-Ibuprofen-d3 is a deuterated form of ibuprofen, a widely used nonsteroidal anti-inflammatory drug (NSAID). This article explores its biological activity, pharmacokinetics, and potential therapeutic applications based on diverse research findings.

Overview of Ibuprofen

Ibuprofen is primarily utilized for its analgesic, antipyretic, and anti-inflammatory properties. It functions by inhibiting cyclooxygenase (COX) enzymes, which play a crucial role in the biosynthesis of prostaglandins from arachidonic acid. Specifically, (S)-(+)-ibuprofen exhibits stronger pharmacological effects compared to its enantiomer (R)-(-)-ibuprofen, leading to its preferred use in clinical settings .

Pharmacokinetics of this compound

The pharmacokinetic profile of this compound shows distinct advantages over racemic ibuprofen. Key parameters include:

• Bioavailability : The bioavailability of (S)-(+)-ibuprofen is significantly higher than that of the racemic mixture. Studies indicate that approximately 63% of the administered dose of R-(-)-ibuprofen is converted to (S)-(+)-ibuprofen in humans, while the reverse does not occur .
• Metabolism : The metabolism of (S)-(+)-ibuprofen is primarily mediated by the CYP2C9 enzyme, whereas R-(-)-ibuprofen is metabolized by CYP2C8. This selective metabolism contributes to lower toxicity and enhanced efficacy .
• Clearance Rates : Research indicates that the clearance rate for (S)-(+)-ibuprofen is slower compared to R-(-)-ibuprofen, resulting in a higher area under the curve (AUC) and prolonged therapeutic effects .

Anti-inflammatory Effects

This compound has been shown to exert significant anti-inflammatory effects. A study demonstrated that treatment with ibuprofen resulted in a notable decrease in cell proliferation in prostate cancer cells when combined with vitamin D3. Specifically, the combination treatment led to a 67% suppression of LNCaP cell proliferation, indicating a synergistic effect on apoptosis and cell cycle inhibition .

Analgesic Properties

Clinical studies have highlighted the analgesic effectiveness of (S)-(+)-ibuprofen. For instance, after administering 300 mg doses via oral and intravenous routes, peak plasma concentrations (Cmax) were significantly higher for (S)-(+)-ibuprofen compared to racemic ibuprofen. The Cmax values were 84.57 μg/mL for oral and 211.52 μg/mL for intravenous administration .

Prostate Cancer Treatment

A pivotal study explored the combined effects of (S)-(+)-ibuprofen and 1,25-dihydroxyvitamin D3 on LNCaP prostate cancer cells. The results indicated that ibuprofen alone increased apoptosis by 2.2-fold, while the combination with vitamin D3 resulted in a 4.9-fold increase in apoptosis. This suggests that (S)-(+)-ibuprofen may enhance the efficacy of other therapeutic agents in cancer treatment .

Developmental Effects

Research has also investigated the impact of ibuprofen on fetal development. A study indicated that exposure to ibuprofen during pregnancy was associated with reduced levels of INSL3, a hormone crucial for testicular descent. This highlights potential risks associated with ibuprofen use during critical developmental windows .

Comparative Summary Table

Basic Research Questions

Q. How can (S)-(+)-Ibuprofen-d3 be validated as an internal standard in LC-MS pharmacokinetic studies?

Methodological Answer : this compound is commonly used as an internal standard (IS) due to its structural similarity to non-deuterated ibuprofen and minimal isotopic interference. To validate its use:

• Isotopic Purity : Confirm 99 atom% deuterium incorporation via high-resolution mass spectrometry (HRMS) or nuclear magnetic resonance (NMR) to avoid signal overlap with endogenous analytes .
• Matrix Effects : Perform spike-and-recovery experiments in biological matrices (e.g., plasma) to assess IS stability and ion suppression/enhancement.
• Calibration Curves : Use linearity ranges (e.g., 1–1000 ng/mL) with correlation coefficients (R² > 0.995) to validate assay precision.
• Cross-Validation : Compare results with alternative IS (e.g., (R)-(-)-Ibuprofen-d3) to rule out stereoselective biases .

Q. What parameters are critical for ensuring isotopic purity in deuterated standards like this compound?

Methodological Answer : Key parameters include:

• Synthetic Route : Verify deuteration at specific positions (e.g., α-methyl-d3) using synthetic protocols with deuterated precursors.
• Analytical Confirmation : Use HRMS to detect residual protiated impurities (<1%) and NMR for positional deuteration accuracy.
• Storage Conditions : Store at -20°C in inert atmospheres to prevent deuterium-hydrogen exchange via hydrolysis or photodegradation .

Q. How should researchers design a pharmacokinetic (PK) study using this compound to assess metabolic stability?

Methodological Answer :

• Dose Selection : Use microdoses (≤100 µg) to minimize pharmacological effects while maintaining detectability.
• Sampling Schedule : Collect blood/plasma at 0, 0.5, 1, 2, 4, 8, 12, and 24 hours post-administration to capture absorption and elimination phases.
• Data Normalization : Normalize deuterated analyte concentrations to non-deuterated counterparts to correct for inter-individual variability.
• Ethical Compliance : Obtain informed consent and document deuterated compound use in Institutional Review Board (IRB) submissions .

Advanced Research Questions

Q. How can discrepancies in metabolic data between deuterated and non-deuterated ibuprofen be resolved in cross-species studies?

Methodological Answer : Discrepancies may arise from isotopic effects altering enzyme kinetics (e.g., CYP2C9 metabolism). Mitigation strategies include:

• In Vitro/In Vivo Correlation : Compare metabolic rates in liver microsomes from humans and model species (e.g., rats) under controlled conditions.
• Computational Modeling : Apply physiologically based pharmacokinetic (PBPK) models to adjust for deuterium-induced changes in clearance.
• Meta-Analysis : Aggregate data from multiple studies to identify species-specific trends, ensuring transparency in data-sharing protocols to address contradictions .

Q. What statistical methods are optimal for analyzing time-dependent PK data using deuterated internal standards?

Methodological Answer :

• Non-Compartmental Analysis (NCA) : Calculate AUC, Cmax, and t½ using validated software (e.g., Phoenix WinNonlin) with IS-normalized concentrations.
• Mixed-Effects Modeling : Apply nonlinear mixed-effects models (e.g., NONMEM) to account for inter-subject variability and sparse sampling.
• Power Analysis : Use pilot data to estimate effect sizes and ensure adequate sample sizes (n ≥ 12 for 80% power at α=0.05) .

Q. How can researchers integrate this compound data with genomic findings in personalized medicine studies?

Methodological Answer :

• Pharmacogenomic Cohorts : Stratify patients by CYP2C9 genotypes (e.g., CYP2C92/*3 variants) and correlate with deuterated ibuprofen clearance rates.
• Multi-Omics Integration : Combine PK data with transcriptomic/proteomic profiles to identify biomarkers of response variability.
• Ethical Data Handling : De-identify datasets and use secure repositories (e.g., European Open Science Cloud) to reconcile open-data mandates with patient privacy .

Q. Guidance for Rigorous Research Design

• Hypothesis Frameworks : Use FINER criteria (Feasible, Interesting, Novel, Ethical, Relevant) to formulate questions. For example:
  • "Does CYP2C9 genotype modulate this compound clearance in pediatric populations?" .
• Data Presentation : Avoid redundant tables/figures; highlight key findings (e.g., dose-normalized AUC ratios) in results, reserving interpretation for discussion .
• Conflict Resolution : Document contradictory results (e.g., interspecies metabolic differences) in supplemental materials and propose mechanistic follow-up studies .