1. INTRODUCTION
Non-alcoholic steatohepatitis (NASH) is a progressive form of metabolic fatty liver infection affecting 1.5%–6.5% globally (25 million in the United States alone) and drives progressive liver damage leading to hepatocellular carcinoma and cirrhosis, with 10%–15% developing cirrhosis within a decade and liver-related mortality 10–12 times higher than the simple fatty liver [1–3]. Meanwhile, primary biliary cholangitis (PBC), an autoimmune bile duct disorder predominantly affecting women (9:1 ratio), causes cholestatic liver injury where 30%–50% progress to cirrhosis within 10–15 years without treatment, with 25% requiring transplantation [4–10].
Recently, in 2024, the US FDA approved elafibranor (ELB) for treating PBC in adults, in combination with ursodeoxycholic acid (UDCA) [11]. ELB is an investigational, orally administered small molecule medication that functions as a dual agonist of PPAR-α/δ (peroxisome proliferator-activated receptors alpha and delta) [12–17]. Initially developed to address NASH, ELB has also shown significant promise in treating PBC, a rare autoimmune liver disease categorized by bile duct demolition and progressive cholestasis [18-21]. ELB exerts its therapeutic effects by selectively activating PPAR-α and PPAR-δ, two key regulators of metabolic and anti-inflammatory pathways [22–24]. Together, these mechanisms contribute to the reduction of hepatic steatosis (fatty liver), improvement in insulin resistance (beneficial for metabolic syndrome and type 2 diabetes), and anti-inflammatory and anti-fibrotic effects (critical in preventing liver disease progression) [25–27].
ELB has demonstrated remarkable efficacy in PBC, particularly in patients with an inadequate response to first-line therapy with UDCA [28–30]. The ELATIVE Phase 3 trial (2023) reported significant reductions in alkaline phosphatase, a key biomarker of PBC progression. In clinical trials, ELB exhibited a good safety profile, with predominantly mild-to-moderate adverse reactions observed (e.g., pruritus, headache, and gastrointestinal disturbances) [31,32]. Unlike older PPAR-γ agonists (e.g., thiazolidinediones), it does not appear to cause significant weight gain or cardiac risks, enhancing its therapeutic appeal [33]. ELB represents a substantial advancement in the treatment of liver and metabolic diseases, particularly for PBC patients with limited therapeutic options. Its development underscores the importance of targeting PPAR pathways in chronic diseases [34,35].
Stability studies of drug substances and products are required to ensure drug quality, efficacy, and safety as per ICH guidelines. Stability studies on ELB were conducted per ICH guidelines due to their importance for new drug substances or products. The degradation products were successfully separated and quantified using the Ultra Performance Liquid Chromatography method, and their identification was performed using a high-resolution mass spectrometer (HRMS). Structural confirmation was achieved by proposing a fragmentation pattern based on the HRMS data. So far, no stability studies or Liquid Chromatography - Tandem mass spectrometry method development have been conducted for ELB. The structure of ELB is shown in Figure 2.
2. MATERIALS AND METHODS
2.1. Chemicals and reagents
The API (ELB) was obtained as a complimentary sample from a respected pharmaceutical company. All chemicals and solvents, including hydrochloric acid (HCl), sodium hydroxide (NaOH), hydrogen peroxide (H2O2), acetonitrile (ACN), and formic acid (FA), were procured from Merck in Mumbai, India. Milli-Q water, used for the entire analysis, was obtained from the Merck Milli-Q Millipore system in Darmstadt, Germany.
2.2. Instrumentation
A reverse-phase HPLC method was developed utilizing a Waters Arc HPLC (Milford, MA) with binary gradient pumps and a photodiode array (PDA) detector. Chromatographic isolation was performed on an XBridge BEH C18 column (diameter 150 × 4.6 mm, particle size 3.5 µ), and data were processed using Empower-II software. This study used a hot air circulation oven from Oswald Scientific Pvt Ltd, India, for thermal stability experiments. Photo degradation studies were conducted in a photostability test chamber (Oswald OPSH-G-16-GMP model, Oswald Scientific Pvt Ltd, India) equipped with a dual light source system of Ultraviolet and fluorescent light, which was configured strictly under ICH Q1B guidelines and could achieve precise control of temperature ±2°C and relative humidity ±5% Relative Humidity. The structural characterization of ELB and its degradation products was completed using HRMS (HRMS-Q-TOF 6530, Agilent Technologies, USA) coupled to an Agilent LC-1200 series liquid chromatography system, with data acquisition and processing achieved using Mass Hunter software (B.07.00). Mass spectrometry analysis was conducted using positive ion electrospray ionization (ESI+) mode, and low concentration tuning standards were used for system calibration. The optimized parameters for mass spectrometry included a full scan mass range of 50 to 1,500 m/z and a secondary mass spectrometry scan range of 50 to 1,000 m/z. The ion source parameters were as follows: nebulizer gas temperature set at 300°C, ion source temperature at 350°C, drying gas (N2) flow rate of 12 l/min, and nebulizer pressure at 55 psi. The voltage parameters included a capillary voltage of 3,500 V, fragmentation voltage of 175 V, octopole RF voltage of 750 V, and skimmer voltage of 65 V. Additionally, the collision energy was set between 10 and 30 eV.
 | Figure 1. Graphical abstract for ELB and its degradation products. [Click here to view] |
 | Figure 2. Structure of ELB. [Click here to view] |
2.3. Chromatographic conditions
Separation of ELB and its degradation impurities was achieved employing the following HPLC chromatographic conditions. The separation was accomplished on a Waters C18 column X-Bridge BEH (particle size 3.5 µ, length 150 × 4.6 mm), using FA (0.1%) in water as mobile phase A (MP-A) and ACN as MP-B. A gradient program was established by varying the percentage of MP-B over time [(Tmi/% ACN): 0/20, 3/20, 10/75, 15/95, 18/95, 18.1/20, and 20/20]. A PDA detector was utilized to identify the ELB and its degradation impurities. Operating conditions included maintaining the column at 40°C, setting the flow rate to 1.0 ml/min, and using a 10 µl injection volume.
2.4. Forced degradation studies
Stability studies of the ELB were performed in accordance with ICH guidelines Q1A (R2) and Q1B. The ELB was assessed under various stress conditions, including hydrolysis (acidic, basic, and neutral), thermal, oxidative, and photolytic conditions. The studies utilized an ELB concentration of 1 mg/ml. ELB was added to a 1.0 N HCl solution for acidic hydrolysis and refluxed at 60°C for 48 hours. Basic hydrolysis involved adding ELB to a 1.0 N NaOH solution and refluxing at 60°C for 8 hours. Neutral hydrolysis stability studies were conducted by adding ELB to milli-Q water (pH 6.8 ± 0.05, at room temperature) and stirring continuously at 60°C for 48 hours. In the thermal stability study, the ELB was subjected to exposure at 100°C for 48 hours. Oxidative conditions were simulated by subjecting the ELB to 10% H2O2 at room temperature for 24 hours. For the photolytic stability study, ELB was exposed to 200 Wh/m² UV light and 1.2 million lux hours of fluorescent light, with a control sample placed alongside the light-induced sample. The control sample was protected from light penetration by covering it with aluminum foil. The resulting degradation products were identified and quantified using HPLC and LC-MS analysis. Blank, stressed samples, and the control sample were injected, and degradation products were quantified by comparing the peak areas against those of the control and blank samples. The resulting HPLC chromatograms are depicted in Figure 3. The results of the forced degradation study of ELB are shown in Table 1
 | Figure 3. HPLC chromatographic peaks obtained from ELB and its degradation products: (a) blank chromatogram, (b) standard ELB API chromatogram, (c) alkaline hydrolysis stress chromatogram, (d) oxidative stress condition chromatogram, and (e) photolytic stress condition chromatogram. [Click here to view] |
Table 1. Results of the forced degradation study of ELB.
| Degradation condition | Exposure condition | Degradation (%) | Purity of API (%) |
|---|---|---|---|
| Unstressed sample | - | - | 99.63 |
| Neutral (Milli-Q-water) | 60°C for 48 hours | No degradation | 98.96 |
| Acidic (2.0 N HCl) | 60°C for 48 hours | No degradation | 99.03 |
| Basic (1.0 N NaOH) | 60°C for 8 hours | DP-1 (6.6) and DP-2 (4.67) | 87.21 |
| Oxidation (10% H2O2) | Room temperature for 24 hours | DP-3(11.42) and DP-4(6.43) | 81.32 |
| Photolytic [UV light (200 W m-2)] | Irradiation for 48 hours | DP-3(2.84) and DP-4(4.26) | 91.35 |
| Thermal | 100°C for 48 hours | No degradation | 99.03 |
3. RESULTS AND DISCUSSION
3.1. Method development
This research study primarily focused on identifying and quantifying the degradation products of ELB. A new HPLC method was developed to separate and quantify ELB along with its degradation products. During method development, several method conditions such as analytical column type, MP, column temperature, and MP gradient program, were optimized to achieve better resolution and peak shapes. Various C18 HPLC columns from brands such as YMC, Waters, Agilent, and Phenomenex were tested during this process. Among all the columns, the XBridge BEH C18 column (diameter 150 × 4.6 mm, particle size 3.5 µ) showed superior resolution and favorable peak shapes. Additionally, MP-A and B were optimized using 0.1% FA, 0.1% trifluoroacetic acid, and ammonium acetate (10 mM) buffers as MP-A, and ACN, MeOH, and a mixture of ACN and MeOH as MP-B. Of all the combinations, 0.1% FA as MP-A and ACN as MP-B proved to be optimal for obtaining good peak shapes and resolutions. The gradient program was optimized by varying the percentage of MP-B over time [(Tmin/% ACN): 0/20, 3/20, 10/75, 15/95, 18/95, 18.1/20, and 20/20]. The analytical column temperature was kept at 40°C, the flow rate was set at 1.0 ml/min, and an injection volume of 10 µl was utilized for this developed method.
3.2. Degradation behavior of ELB
In this study, we explored the stability properties of the ELB API by applying different forced degradation conditions using HPLC. The results indicated that ELB exhibited clear degradation patterns when exposed to alkaline hydrolysis (1.0N NaOH), oxidative conditions (10% H2O2). In addition, a noticeable degradation occurred under photolytic conditions. The summary of the mass balance results is shown in Table S1. The possible degradation pathways are proposed in Figure 4 [36]. In alkaline hydrolysis, the API drug was degraded into two degradation products (DP-1 and DP-2) in two ways. The first pathway involves alkaline hydrolysis of the α,β-unsaturated double bond present in the drug molecule, resulting in the cleavage of the unsaturated system. This hydrolysis produces two products: one is DP-1, which contains an aldehyde group, and the other is a product containing a keto group. This reaction proceeds via nucleophilic attack of hydroxide ions on the electrophilic β-carbon of the α,β-unsaturated carbonyl group, followed by bond cleavage. This type of reduction is analogous to a retro-aldol reaction and is commonly observed in compounds containing conjugated enone systems under basic conditions [37]. At the same time, it can be speculated that, in addition to the main pathway, an alternative degradation pathway unfolds via a 1,4-Michael addition reaction. In this process, the alkaline environment might promote the formation of an enolate ion from a ketone group that is one of its degradation intermediates. It is conceivable that this enolate then acts as a nucleophile and attaches to the β-carbon of another α,β-unsaturated carbonyl compound of the parent drug itself. This hypothetical addition may result in a product tentatively described as DP-2, which has an expanded carbon framework. This reaction may be particularly favorable under alkaline conditions because the base enhances enolate formation, thereby increasing the nucleophilicity of the attacking species. Under photolytic conditions and in the presence of air, the drug substance experienced oxidative degradation, leading to the formation of two degradation products, designated as DP-3 and DP-4. Oxygen plays a crucial role in this process by facilitating a free radical-mediated oxidation pathway. The degradation is further accelerated by photolysis, which provides the energy necessary for bond cleavage and the formation of radicals. The absence of degradation in acidic, neutral, and thermal conditions reflects the inherent stability of the molecule’s functional groups under those stresses. Specifically, the α,β-unsaturated carbonyl moiety is resistant to acid and heat but is susceptible to nucleophilic attack under basic conditions and to excitation under light, explaining the observed base- and photo-lability. The stability profile, therefore, reflects the selective reactivity of functional groups. In contrast, ELB exhibited good stability when exposed to thermal stress, neutral hydrolysis, and acidic hydrolysis stress conditions at 100°C. The optimized High-Performance Liquid Chromatography analytical method provided effective chromatographic separation of ELB API and its degradation products, and validation results confirmed that the method was suitable for assessing ELB stability.
 | Figure 4. Proposed pathways for the formation of degradation products from ELB. (a) Proposed pathways for the formation of DP-1, (b) Proposed pathways for the formation of DP-2, (c) Proposed pathways for the formation of DP-3, and (d) Proposed pathways for the formation of DP-4. [Click here to view] |
3.3. Determining the chemical structure of degradation products of ELB
Employing LC-MS/MS-ESI-QTOF, four different degradation compounds were identified and characterized; the details are shown in Table 2 and Figure 5. The Tandem mass spectrometry degradation models based on these products suggested the proposed degradation pathways and plausible structures of the degradation products.
 | Figure 5. MS/MS spectra for ELB degradation products: (A) MS/MS spectra for DP-1, (B) MS/MS spectrum for DP-2, (C) MS/MS spectrum for DP-3, and( D) MS/MS spectrum for DP-4. [Click here to view] |
Table 2. Mass spectrometry details for ELB and its degradation products.
| ELB and Degradation products | Chemical formula [M + H]+ | Calculated mass [M + H]+ | Observed mass [M + H]+ | Mass error (ppm) |
|---|---|---|---|---|
| ELB | C22H25O4S+ | 385.1468 | 385.1476 | 2.07 |
| DP-1 | C12H17O2+ | 193.1223 | 193.1231 | 4.14 |
| DP-2 | C31H35O5S2+ | 551.1920 | 551.1912 | −1.45 |
| DP-3 | C22H25O5S+ | 401.1417 | 401.1427 | 2.49 |
| DP-4 | C22H25O6S+ | 417.1366 | 417.1379 | 3.11 |
3.4. DP-1
In alkaline hydrolysis, the API drug degraded into two degradation products (DP-1 and DP-2), which were separated on HPLC with maximum retention times of 8.32 and 14.46 minutes, respectively. The DP-1 mass fragmentation pattern is shown in Figure 6. The resulting compound DP-1 was confirmed by mass spectrometry, exhibiting a molecular ion peak at m/z 237, which corresponds to its protonated form ([M + H]+). DP-1 lost a CO2 (44 Da) molecule after subsequent dissociation, forming a fragment ion at m/z 193. This fragment ion further fragmented into another new fragment ion at m/z 151 by losing a prop-1-ene (42 Da) moiety. The fragment ion (m/z 151) further dissociated into two new ions, at m/z 123 and 133, by losing a CO (28 Da) and a H2O (18 Da) molecule. Additionally, the fragment ion (m/z 133) further dissociated into the new fragment ion at m/z 105 by losing a CO molecule (28 Da). Finally, the fragment ion (m/z 105) further fragmented into a tropylium cation at m/z 91 by losing a methyl group (15 Da). Based on this mass fragmentation pattern, DP-1 was identified with the chemical name 2-(4-formyl-2,6-dimethylphenoxy)-2-methylpropanoic acid, and its formula is C13H16O4.
 | Figure 6. Proposed cleavage pattern for degradation product DP-1. [Click here to view] |
 | Figure 7. Proposed cleavage pattern for degradation product DP-2. [Click here to view] |
 | Figure 8. Proposed cleavage pattern for degradation product DP-3. [Click here to view] |
 | Figure 9. Proposed cleavage pattern for degradation product DP-4. [Click here to view] |
3.5. DP-2
The base hydrolysis of ELB leads to the emergence of another degradation impurity, DP-2. The resulting compound, DP-2, was confirmed by mass spectrometry, exhibiting a molecular ion peak at m/z 551, which corresponds to its protonated form ([M + H]+). DP-1 furthermore dissociated to generate three new fragments with m/z 507, 505, and 461, by losing CO2 (44 Da), methanethiol (46 Da), and CO2 (44 Da) plus methanethiol (46 Da) molecules, respectively. The fragment ion m/z 505 then fragmented into another ion, m/z 459, by losing the methanethiol (46 Da) moiety. Additionally, the fragment ion m/z 461 further dissociated into three ions, m/z 419, 357, and 403, by losing prop-1-ene (42 Da), acetone (58 Da) plus methanethiol (46 Da), and acetone (58 Da) molecules. Furthermore, the fragment ion m/z 357 additionally dissociated into fragment ion m/z 121 by losing a chemical moiety C17H16O (236 Da). Finally, the fragment ion m/z 403 fragmented into fragment ion m/z 167 by losing the chemical moiety C17H16O (236 Da). Based on this mass fragmentation pattern, DP-2 was identified with the chemical name 2-(4-(1,5-bis(4-(methylthio)phenyl)-1,5-dioxopentan-3-yl)-2,6-dimethylphenoxy)-2-methylpropanoic acid, and the formula is C31H34O5S2.
3.6. DP-3
Under photolysis and oxidative stress conditions, ELB leads to the formation of two degradation products (DP-3 and 4), which were separated on HPLC with maximum retention times of 8.76 and 10.72 minutes, respectively. The resulting compound, DP-3, was confirmed by mass spectrometry, exhibiting a parent ion peak at m/z 401, which corresponds to its protonated form ([M + H]+). DP-3 furthermore dissociated to produce four new fragments with m/z values of 357, 337, 233, and 169 by sequentially losing CO2 (44 Da), methanesulfenic acid (64 Da), another CO2 (44 Da), and 2-(4-ethynyl-2,6-dimethylphenoxy)-2-methylpropanoic acid (232 Da) molecules. The fragment ion m/z 337 then fragments into another ion, m/z 251, by losing a CO2 (44 Da) molecule. Additionally, the fragment ion m/z 233 further dissociated into fragment ion m/z 147 by losing prop-1-ene (42 Da) and CO2 (44 Da) molecules. Another fragment ion, m/z 169, further dissociated into fragment ion m/z 141 by losing a carbon monoxide (28 Da) molecule. Based on this mass fragmentation pattern, DP-3 was identified with the chemical name (E)-2-(2,6-dimethyl-4-(3-(4-(methylsulfinyl)phenyl)-3-oxoprop-1-en-1-yl)phenoxy)-2-methylpropanoic acid, and the formula is C22H24O5S.
3.7. DP-4
The compound DP-4 was confirmed through mass spectrometry, showing a parent ion peak at m/z 417, which corresponds to its protonated form ([M + H]+). DP-4 then dissociated to produce three fragment ions with m/z values of 402, 373, and 331 by losing a CH3 group (15 Da), CO2 (44 Da), and a combination of carbon dioxide (44 Da) and prop-1-ene (42 Da), respectively. The fragment (m/z 402) subsequently fragmented into another ion at m/z 358 by losing a CO2 molecule (44 Da). This fragment ion at m/z 358 further dissociated into m/z 316 by losing prop-1-ene (42 Da). Additionally, the fragment (m/z 316) further degraded into another ion at m/z 252 by losing a sulfur dioxide molecule (64 Da). The fragment (m/z 373) derived from DP-4 further dissociated into a fragment ion at m/z 183 by losing a chemical moiety of 2-isopropoxy-1,3-dimethyl-5-vinylbenzene (190 Da). The fragment ion at m/z 183 then dissociated into another fragment ion at m/z 155 by losing a carbon monoxide molecule (28 Da). Based on this mass fragmentation pattern, DP-4 was identified as (E)-2-(2,6-dimethyl-4-(3-(4-(methylsulfonyl)phenyl)-3-oxoprop-1-en-1-yl)phenoxy)-2-methylpropanoic acid, with the chemical formula C22H24O6S.
3.8. Method validation
This stability-indicating assay method has been validated according to ICH standards [38]. Specificity, accuracy, precision, linearity, robustness, and solution stability have all been thoroughly evaluated as validation parameters. Specificity was confirmed by demonstrating that the ELB peak did not show any interference from other peaks or degradation products. Furthermore, ELB’s specificity was verified through peak purity analysis of stressed materials using a PDA detector; a non-contaminating peak was established by a chromatogram displaying a purity threshold greater than the purity angle. Recovery experiments were conducted by preparing ELB solutions at three concentration levels (0.5, 1.0, and 1.5 mg/ml) and injecting each in triplicate to evaluate precision. Next, the percent relative standard deviation (% RSD) of peak areas was calculated. Repeatability and intermediate precision tests were employed to assess the method’s precision. Six different ELB preparations at 100% (1.0 mg/ml) concentration were analyzed for repeatability, and the % RSD of the peak areas was computed.
Table 3. Validation results of the developed HPLC method.
| Parameter | ELB |
|---|---|
| System suitability | |
| Retention time | 11.83 min |
| Theoretical plate count | 35484 |
| Tailing factor | 0.8 |
| %RSD | 0.46 |
| LOD (µg/ml) | 0.18 |
| LOQ (µg/ml) | 0.66 |
| Linearity | |
| R2 | 0.9999 |
| Accuracy (0.05 mg/ml)_50% (n = 3) | |
| %recovery | 99.2 |
| % RSD | 1.02 |
| Accuracy(0.1 mg/ml)_100% (n = 3) | |
| %recovery | 99.67 |
| % RSD | 0.82 |
| Accuracy(0.15 mg/ml)_150%(n = 3) | |
| %recovery | 99.86 |
| % RSD | 0.75 |
| Ruggedness (n = 6) % RS | 1.08 |
Analyzing 100% ELB samples from various analysts and on different days allowed the assessment of intermediate precision, again using % RSD for comparison. Five ELB concentrations of 50%, 75%, 100%, 125%, and 150% were tested in triplicate for linearity. A calibration curve was created by plotting concentrations against peak areas, followed by linear regression analysis to determine the coefficient of determination (R²). The method’s sensitivity was established through the signal-to-noise ratio, which was used to derive the limits of detection (LOD) and quantification (LOQ). The robustness test included intentional variations in mobile phase organic content (±5%), column temperature (40°C ± 4°C), and flow rate (0.8 ± 0.1 ml/min). A summary of the validation results is provided in Table 3.
4. CONCLUSION
This study primarily focused on investigating the stability properties of the ELB API by applying various forced degradation conditions, including hydrolysis (acidic, basic, and neutral), oxidative, thermal, and photolytic conditions. We found that the ELB exhibited significant degradation under alkaline hydrolysis, oxidation, and photolytic stress conditions, whereas it remained stable under neutral hydrolysis, acidic hydrolysis, and thermal conditions. The four new degradation impurities were formed, which have not been published before. Two degradation impurities (DP-1 and 2) were produced during alkaline degradation, whereas two other new degradation products (DP-3 and 4) were formed under oxidative and photolytic conditions. A newly developed HPLC method was employed to separate and quantify the resulting degradation products. These degradation products of the ELB were characterized using HPLC and LC-ESI-MS/MS techniques. The structures of the degradation products were established using mass spectral data, proposing a plausible degradation pattern. It can be emphasized that this study is a fundamental contribution to understanding the intrinsic stability of the drug ELB and supports the development of analytical methods that indicate stability without directly affecting formulation development.
5. AUTHOR CONTRIBUTIONS
All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work. All the authors are eligible to be author as per the International Committee of Medical Journal Editors (ICMJE) requirements/guidelines.
6. FUNDING
This research did not receive any specific grant or financial support from any public, commercial, or not-for-profit funding agencies. The organization had no role in the conduct of the study.
7. CONFLICTS OF INTEREST
The authors declare that there are no conflicts of interest associated with this manuscript. Although one of the authors, Babji Palakeeti, is affiliated with an industry organization (Analytical Discovery Chemistry, Aragen Life Sciences Pvt. Ltd., Hyderabad, India), this affiliation had no direct or indirect influence on the study design, experimental work, data interpretation, results, or manuscript preparation.
8. ETHICAL APPROVALS
This study does not involve experiments on animals or human subjects.
9. DATA AVAILABILITY
All the data is available with the authors and shall be provided upon request.
10. PUBLISHER’S NOTE
All claims expressed in this article are solely those of the authors and do not necessarily represent those of the publisher, the editors and the reviewers. This journal remains neutral with regard to jurisdictional claims in published institutional affiliation.
11. USE OF ARTIFICIAL INTELLIGENCE (AI)-ASSISTED TECHNOLOGY
The authors declare that they have not used artificial intelligence (AI)-tools for writing and editing of the manuscript, and no images were manipulated using AI.
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SUPPLEMENTARY MATERIAL
Table S1. Summary of mass balance results.
| Stress condition | Time (hours) | % Assay of ELB | Purity angle | Purity threshold | Total impurities (%) | Mass balance (%) (% Assay + % Total impurities ) |
|---|---|---|---|---|---|---|
| Base degradation (1N NaOH at 60°C) | 8 hour | 87.21 | 0.259 | 0.284 | 11.27 | 98.48 |
| Oxidation (30% H2O2 at room temperature) | 24 hour | 81.32 | 0.197 | 0.245 | 17.85 | 99.17 |
| Photolytic (UV light (200 W m−2) | Irradiation for 48 hour | 91.35 | 0.277 | 0.298 | 7.10 | 98.45 |