TLC-densitometric Method Research Articles

Simultaneous measurement of duloxetine hydrochloride and avanafil at dual-wavelength using novel ecologically friendly TLC-densitometric method: application to synthetic mixture and spiked human plasma with evaluation of greenness and blueness

The simultaneous assay of duloxetine hydrochloride (DLX) and avanafil (AVN) in their pure forms, synthetic mixtures, and spiked human plasma was achieved using a novel, eco-friendly, sensitive, and specific HPTLC methodology that have been established and validated. Measuring the levels of co-administered antidepressants and sexual stimulants in biological fluids is an important step for individuals with depression and sexual problems. Separation was performed successfully using pre-coated silica gel 60-F254 as a stationary phase and a mobile phase composed of methanol, acetone, and 33% ammonia (8:2:0.05, v/v/v). Compact bands were produced by the optimized mobile phase that was chosen for development (Rf values were 0.23 and 0.75 for DLX and AVN, individually) after dual-wavelength detection for DLX and AVN at 232 and 253 nm, respectively. The results of polynomial regression analysis were exceptional (r = 0.9999 for both medicines) over concentration ranges of 5-800 and 10-800ng/spot for DLX and AVN, respectively. The quantitation limits were 4.69 and 9.53 ng/spot (0.31 and 0.94 µg/mL), whereas the detection limits were 1.55 and 3.15 ng/spot (0.63 and 1.91 µg/mL), for DLX and AVN, respectively. The International Council for Harmonization (ICH) criteria served as the basis for validating the established approach. Moreover, the proposed technique was evaluated in terms of greenness using four contemporary ecological metrics: The Analytical Greenness software (AGREE), the Green Analytical Procedure Index (GAPI), Eco-Scale, and the National Environmental Method Index (NEMI). Additionally, the Blue Applicability Grade Index (BAGI), a newly developed tool for evaluating the practicality (blueness) of procedures, was taken into consideration when evaluating the sustainability levels of the established approach.

Sensitive and Cost-Effective TLC-Densitometric Method for Determination of Metronidazole and Tinidazole in Tablets

A sensitive, easy-to-use, fast, and cost-effective TLC-densitometric method was developed for the separation of metronidazole, secnidazole, ornidazole, tinidazole, and 2-methyl-5-nitroimidazole and for the determination of metronidazole and tinidazole in Metronidazole Polpharma and Tinidazolum Polpharma tablets. Analyses were performed on chromatographic plates precoated with silica gel 60F254 using chloroform + methanol + diethylamine in a volume ratio of 9:1:1 as the optimal mobile phase. The method has been validated. The intraday and interday precision values for the three different concentrations ranged from 0.99% to 1.48% and 0.89% to 1.76%, and the precision values ranged from 1.13% to 2.48% and 0.95% to 2.49% for metronidazole and tinidazole, respectively. The limit of quantification (LOQ) was 0.036 and 0.066 µg/spot for metronidazole and tinidazole, respectively. The mean recovery was 103.1% and 100.6% for metronidazole and tinidazole, respectively. The content of metronidazole and tinidazole in tablets in relation to the content declared by the manufacturer was 101.3% and 99.8%, respectively. The obtained results were verified using the pharmacopeial method. The presented method is fast, sensitive, precise, selective, accurate, and robust. It allows for the analysis of several samples on one chromatography plate at the same time.

AQbD TLC-densitometric method approach along with green fingerprint and whiteness assessment for quantifying two combined antihypertensive agents and their impurities.

Preserving the environment, reducing the amount of waste resulting from chemical trials, and reducing the amount of energy consumed have currently become a pivotal global trend. An analytical quality by design (AQbD) based eco-friendly TLC-densitometric method was implemented for quantifying two antihypertensive agents, captopril (CPL) and hydrochlorothiazide (HCZ), along with their impurities; captopril disulphide (CDS), chlorothiazide (CTZ) and salamide (SMD). The analytical target profile (ATP) was first identified, followed by selecting the critical analytical attributes (CAAs), such as retardation factors and resolution between the separated peaks. Critical method parameters (CMPs) that may have a crucial influence on CAAs were identified and emanated through the quality risk assessment phase. A literature survey-based preliminary studies were performed, followed by optimization of the selected CMPs through a custom experimental design to attain the highest resolution with optimum retardation factors. Moreover, method robustness was also tested by testing the design space. Complete separation of the drugs and their impurities was achieved using ethyl acetate: glacial acetic acid (6: 0.6, v/v) as a developing system applied to a 12cm length TLC plate at room temperature with UV scanning at 215nm. Calibration graphs were found to be linear in the ranges of (0.70-6.00), (0.10-2.00), (0.20-1.00), (0.07-1.50) and (0.05-1.00) µg/band corresponding to CPL, HCZ, CDS, CTZ, and SMD, respectively. Four different green metric tools were used to evaluate the greenness profile of the proposed method, and results showed that it is greener than the reported HPLC method. Method whiteness assessment was also conducted. Moreover, the method performance was evaluated following the ICH guidelines, and the outcomes fell within the acceptable limits. The developed method could be approved for routine assay of the cited components in their pharmaceutical formulations and bulk powder without interference from the reported impurities. The issue of concern is saving money, especially in developing countries.

Determination of the Active Pharmaceutical Ingredients in Saridon Tablets Using an Economical and Sensitive Thin Layer Chromatography Method Combined with Densitometry

A new TLC–densitometric method has been developed for the identification and quantification of paracetamol (PA), propyphenazone (PP) and caffeine (C) in Saridon tablets using the NP-TLC technique combined with densitometry. This method allows for the simultaneous determination of PA, PP, and C in the same sample. Among all the tested chromatographic conditions, the mixture consisting of chloroform + toluene + ethyl acetate + ethanol + acetic acid (18:18:7.5:5.0:0.3, v/v/v/v/v) and a silica gel 60F254 plate proved to be the most effective for the separation of the three tested active pharmaceutical ingredients (APIs) and substances related to paracetamol. The full validation of the proposed NP-TLC method proved that it is specific, precise, accurate, robust and sensitive. The percentage content in relation to the content declared by the manufacturer was for propyphenazone 99.8%, paracetamol 101.6% and caffeine 100.8%, which was in accordance with pharmacopoeial requirements. The results presented indicate the possibility of using the developed method in the routine control of pharmaceutical preparations containing these APIs. The proposed method is economical and more sensitive compared to the previously proposed planar methods for the simultaneous determination of APIs. What is more, the presented method may be an excellent economical alternative when the HPLC method is unavailable for such a determination.

Green chromatographic methods for determination of co-formulated lidocaine hydrochloride and miconazole nitrate along with an endocrine disruptor preservative and potential impurity

Recently, green analytical chemistry (GAC) is a key issue towards the idea of sustainability, the analytical community is focused on developing analytical methods that incorporate green chemistry principles to minimize adverse impacts on the environment and humans. Herein, we present 2 sustainable, selective, and validated chromatographic methods. Initially, lidocaine hydrochloride (LDC) and miconazole nitrate (MIC) with two preservatives; methyl paraben (MTP) and saccharin sodium (SAC) were chromatographed via TLC–densitometric method which employed ethyl acetate: methanol: formic acid (9:1:0.1, by volume) as the mobile phase with UV detection at 220.0 nm, good correlation was obtained in the range of 0.3–3.0 µg/band for MIC and LDC. Following that, RP-HPLC was successfully applied for separating quinary mixture of LDC, MIC, MTP, SAC along with LDC impurity; dimethyl aniline (DMA) using C18 column, and a gradient green mobile phase composed of methanol and phosphate buffer (pH 6.0) in different ratios with a flow rate 1.5 mL/min and UV detection at 210.0 nm, linearity ranges from 1.00 to 100.00 µg/mL for MIC, 2.00–100.00 µg/mL for LDC and 1.00–-20.00 µg/mL for MTP and DMA. No records to date regarding the determination of the two drugs, besides MTP and DMA. The proposed methods were validated according to the ICH guidelines and applied successfully to the analysis of the compounds. The methods' results were statistically compared to those obtained by applying the reported one, indicating no significant difference regarding both accuracy and precision. The methods' greenness profiles have been assessed and compared with those of the reported method using different assessment tools.Graphical

Development of the paper-based colorimetric sensor for simple and fast determination of quercetin in guava leaf extract.

This present study aimed to develop a paper-based colorimetric sensor in the form of paper-microzone plates (PµZP), for simple and fast quercetin determination in guava leaf extract samples. Here, N-bromosuccinimide (NBS) solution was immobilized on the microzone as a sensing probe, where quercetin solution can be dropped on it to form red-purplish color adducts which can be seen by the naked eye or captured using a flatbed scanner. The color intensity of the microzone can be quantified against a blank solution and used as analytical data in scanometric assay. The sensor showed a response time of 8min, a linear interval of 1-10mM with a detection limit at 1.274mM toward quercetin, and exhibited good reproducibility (RSD < 1%) and accuracy (98-99% recovery). The quercetin level of guava leaf extract determined by the PµZP-scanometric method was found comparable with that of the TLC-densitometric method, suggesting its use as an alternative method for quercetin analysis in the guava leaf extract.

Green analytical chemistry and experimental design: a combined approach for the analysis of zonisamide

Green analytical chemistry principles, as well as experimental design, are a combined approach adopted to develop sensitive reproducible stability indicating HPLC method for Zonisamide (ZNS) determination. The optimal conditions for three chromatographic parameters were determined using a central composite design of the response surface. Kromasil C18 column (150 mm × 4.6 mm, 5 µm) was utilized with ethanol, H2O (30:70 v/v) as a mobile phase at a flow rate of 1 mL/min at 35 °C. Good reproducibility and high sensitivity were achieved along (0.5–10 µg/mL) concentration range. In contrast, the TLC-densitometric method was performed on aluminum plates precoated with silica gel 60F254 as a stationary phase and chloroform: methanol: acetic acid (8:1.5:0.5 by volume) as a developing system. Reproducible results were obtained in the range of (2–10 μg/band). The chromatograms of HPLC and TLC were scanned at 280 nm and 240 nm, respectively. The suggested methods have been validated following ICH guidelines, and no statistically significant differences were detected between the results of the current study and the official USP method. It was also found that using experimental design implements the green concept by reducing the environmental impact. Finally, Eco-Scale, GAPI and AGREE were used to assess the environmental impacts of the suggested methods.

Development of Different Separation Techniques for Impurity Profiling of Neostigmine Methylsulfate: A Comparative Study.

Different separation techniques have been employed to resolve mixtures of multicomponent preparations over the last few decades. They could be efficiently applied for impurity profiling of active drug substances. Impurity profiling has become a critical procedure in pharmaceutical companies to comply with numerous regulatory standards. Isolation and characterization of impurities are crucial for obtaining data that proves biological safety and efficacy. In this contribution, different HPLC, capillary electrophoresis (CE) and TLC-densitometric methods were developed for the determination of neostigmine methylsulfate (NEO) along with 3-hydroxyphenyltrimethyl ammonium methylsulfate (3-HPA) and 3-dimethylaminophenol (DAP) as its impurities in the presence of citric acid. The linearity for NEO was attained in the range of 5-120μg/mL and 10-60μg/mL for the HPLC and CE methods, respectively. Regarding the impurities, linearity was obtained over the range of 10-30μg/mL for 3-HPA and 5-30μg/mL for DAP in the two proposed methods. For the TLC method, NEO and DAP were determined within the range of 1-11μg/band, whereas 3-HPA was assayed over the range of 2-12μg/band. The suggested methods can be securely utilized for routine analysis of the cited components in quality control laboratories.

Two Stability Indicating Chromatographic Methods: TLC Densitometric versus HPLC Method for the Simultaneous Determination of Brinzolamide and Timolol Maleate in Ophthalmic Formulation in the Presence of Probable Carcinogenic Oxidative Degradation Product of Timolol Maleate

A comparative study between two stability-indicating chromatographic methods for the assay of brinzolamide and timolol maleate in the co-existence of the probable carcinogenic oxidative degradation product of timolol maleate in their ophthalmic formulation was demonstrated. The first method established the thin-layer chromatography coupled with the densitometric determination of the analyzed spots, using silica gel TLC aluminum plates F254 and a developing system of chloroform: methanol: ammonia (6:1:0.1, in volumes) at room temperature to give good separation for the three investigated components, where retardation factors for the oxidative degradation product of timolol maleate, brinzolamide and timolol maleate were (Rf 0.21), (Rf 0.46), and (Rf 0.55), respectively. The linear ranges were 2–10 and 3–16 μg/band for brinzolamide and timolol maleate, respectively. In the second method, high performance liquid chromatography (HPLC), photo diode array detection was used on a Eurospher 5 µm C18 100 Å (4.6 × 250 mm) column, using triethylamine pH 3.5, adjusted by glacial acetic acid: acetonitrile (20:80, v/v) at a rate of 0.5 mL per minute. An acceptable separation was achieved, where the retention times for timolol maleate, the oxidative degradation product of timolol maleate and brinzolamide, were (Rt 3.6), (Rt 4.7), and (Rt 5.6), respectively. Linearity covered a range of 20–120 μg/mL for both drugs. It has been proved previously that timolol maleate is liable to oxidation, giving a high-probability carcinogenic product in female mice. The validation for the new proposed stability-indicating methods was optimized in line with the ICH guidelines with good outcomes. It is worth noting that the HPLC-DAD method showed superior separation, economic and time-saving results, while TLC method was more sensitive.

TLC–Densitometric Analysis of Selected 5-Nitroimidazoles

Metronidazole, ornidazole, tinidazole, and secnidazole are 5-nitroimidazoles. The purpose of this work was to propose a new economical TLC–densitometric method to evaluate the chemical stability of metronidazole, secnidazole, ornidazole, and tinidazole under stress conditions. A forced degradation study was performed on silica gel and aqueous solutions at various pH values; the metronidazole, secnidazole, ornidazole, and tinidazole solutions were prepared in saline and in hydrogen peroxide, respectively. The samples of the 5-nitroimidazoles were heated. TLC analyses were performed on silica gel 60F254 using chloroform–methanol (9:1, v/v) as the mobile phase. As the TLC–densitometric method can effectively separate the metronidazole, secnidazole, ornidazole, and tinidazole from their degradation products which formed as a result of the stress studies, it is considered to can be a good alternative and important tool in the routine quality control and stability testing of metronidazole, secnidazole, ornidazole, and tinidazole in pharmaceutical formulations. The results indicate that the proposed TLC–densitometric method is cost-effective, rapid, specific, accurate, and precise; the TLC–densitometric method also realizes the criterion of the linearity. A major advantage of the proposed method is its low cost and ability to analyze the 5-nitroimidazole which was investigated and all its degradation products simultaneously.

Novel Stability-Indicating TLC-Densitometric Method for Quantification of Antazoline and Tetryzoline; Application to Pharmaceutical Formulation

Ophthalmic pharmaceutical preparation containing antazoline hydrochloride (ANT) and tetryzoline hydrochloride (TET) is prescribed widely as an over the counter (OTC) medication to treatment allergic conjunctivitis and their determination in presence of their degradation products is a major challenge. A novel sensitive, selective, and precise thin-layer chromatographic method established to determination both ANT and TET in both bulk drugs, formulation, and in presence of their degradation products with the elucidation of degradate's structures. Upon using silica gel plates and means of a developing system using ethyl acetate: ethanol: ammonia (8: 2: 0.1, by volume) the studied drugs separation was achieved, and scanning was carried out at 220.0 nm for the separated bands with a 0.2–18.0 µg/band concentration range for each of ANT and TET. Optimum separation was achieved with values Rf of 0.42 and 0.69, for TET and ANT, respectively. Additionally, the studied drugs' stock solutions were imperiled to different stress conditions. Both drugs were found to be vulnerable to alkaline hydrolysis as well as oxidative degradation showing well resolved degradation products' peaks. While they held out against acidic, thermal and photo degradation. Mass spectrometry was employed to elucidate the degradates' structures. Validity was applied for the proposed method with respect to all validation parameters. Effectively the method was applied to estimate the cited drugs' in marketed ophthalmic formulation.

Ecofriendly LC-MS/MS and TLC-densitometric methods for simultaneous quantitative assay and monitoring of BEGEV regimen, in vivo pharmacokinetic study application.

To date no analytical method has been developed for the determination of the BEGEV regimen and no study has investigated the kinetic interaction between the drugs, to give us priorities for further clinical study, so two rapid, accurate, sensitive and ecofriendly chromatographic methods were developed for the simultaneous determination of bendamustine (BEN), gemcitabine (GEM) and vinorelbine (VIB) using sildenafil (SIL) as an internal standard (IS) for the purpose of an in vivo pharmacokinetics study in rats. Firstly, the LC-MS/MS method was performed using a mixture of methanol and a 0.1% aqueous solution of formic acid as the mobile phase on a ZORBAX Eclipse Plus C18 (4.6 mm × 150 mm, 5 μm) column as the stationary phase. BEN, GEM and VIB were ionized by positive ions and detected in the multi-reaction monitoring (MRM) mode using precursor → products of m/z 358.20 → 228.25 for BEN, m/z 264.05 → 112.15 for GEM, m/z 779.55 → 122.20 for VIB and m/z 475.00 → 58.35 for SIL. Secondly, TLC-densitometry was applied on TLC silica gel plates using methanol : ethyl acetate (8 : 2, v/v) as the developing system when the separated peaks were scanned at 280 nm. FDA guidelines were followed for validation of the proposed methods, which presented acceptable ranges; then they were applied for an in vivo study in rats with a quantitative determination of each drug after single or combined administration for an investigation of any suspected drug-drug interaction, and all pharmacokinetic parameters were calculated for therapeutic drug monitoring of those drugs. Green analytical chemistry principles were considered during all the procedural steps to ensure the greenness and the safety of the methods, which were evaluated using four assessment tools, eco-scale assessment, the national environmental method index (NEMI), the green analytical procedure index (GAPI) and the analytical greenness metric approach (AGREE), and the results were satisfactory.

FDA-Validated Ecofriendly Chromatographic Methods for Simultaneous Determination of Gemcitabine and Sorafenib: Applications to Pharmacokinetics

Combination therapy of gemcitabine and sorafenib is synergistically effective and well tolerated in patients with non-small cell lung cancer (NSCLC). In this study, the pharmacokinetic parameters of both gemcitabine and sorafenib were estimated after intra-peritoneal administration in rats using novel, green and sensitive RP-HPLC and TLC-densitometric methods where sildenafil used as an internal standard. Firstly, the developed RP-HPLC method achieved on ZORBAX Eclipse Plus C18 (4.6 mm × 150 mm, 5 μm) using a mixture of methanol: 40 mM ammonium acetate solution. On the other hand, the developed TLC-densitometric method was achieved on TLC plates using a developing system of methanol: ethyl acetate (3: 7, by volume) and scanning wave length at 260 nm. Additionally, the developed methods were validated according to FDA guidelines. Moreover, the developed methods were successfully used to study the pharmacokinetic parameters of both gemcitabine and sorafenib after administration of each drug alone and co-administration in rats. The results presented that drug–drug interaction between drugs happened when administrated together affecting the pharmacokinetic parameters of each other. The proposed methods, being ecofriendly, accurate, and sensitive, may become the corner stone for further clinical studies of the studied drugs determinations applied on humans.

Green validated chromatographic methods for simultaneous determination of co-formulated oxytetracycline HCl and flunixin meglumine in the presence of their impurities in different matrices

Green analytical chemistry is an important area of chemical sciences. So, developing competent eco-friendly analytical tools is a big challenge. This study devotes two chromatographic techniques for the simultaneous determination of a binary formulated mixture of oxytetracycline HCl (OXY) and flunixin meglumine (FLU), and their impurities tetracycline (TRC) and 2-chloronicotinic acid (CNA), respectively. Primarily, a TLC densitometric method is proposed and validated using TLC plates sprayed with 5% EDTA of pH 9 as a stationary phase and (acetonitrile/ distilled water/ ethanol 7:2:1, by volume) as a developing system. Well-separated spots are detected at 267 nm where linear relations have been achieved at 0.05–2 μg/band and 0.01–2 μg/band for OXY and FLU, respectively. The second developed and validated method is HPLC which is fulfilled on Hypersil BDS column-C18. A mobile phase of distilled water with 0.1%TFA/ acetonitrile in a ratio of 82: 18, v/v firstly then 70: 30, v/v after 9 min is used in a sequential isocratic elution at 210 nm for FLU and 267 nm for OXY, TRC, and CNA. Sensitive and wide linearity ranges are achieved at 0.05–200 μg/mL for both drugs. The two methods are applied successfully in cattle meat and milk for cited drugs determination. According to ICH guidelines, a validation study has been accomplished for the proposed methods. Statistical comparison has been carried out with official and reported methods. Eventually, the greenness of both procedures is evaluated using Eco-Scale which gives eco-friendly results.Graphical abstract

Antibacterial Activity and TLC-Densitometric Analysis of Secondary Metabolites in the Leaves of the Traditional Herb, Melastoma malabathricum L.

Indonesia is rich in the biodiversity of medicinal plants used traditionally for healing several ailments. Melastoma malabathricum L. is one of the traditional herbs used to treat many diseases. A TLC-densitometric method was developed for determining secondary metabolites such as phenolic compounds and their related compounds, M. malabathricum leaves from Riau, Indonesia. This study investigated the secondary metabolites of M. malabathricum extract by spraying reagent: FeCl3, p-anisaldehyde, and cerium (IV) sulfate and followed by antibacterial assay through broth macro dilution method. Densitometric qualitative analysis of phenolic compounds and their related compounds was employed to examine peaks of the M. malabathricum extract through winCATS software. After spraying with particular reagents, the three extracts showed various spots/bands with several colors and exhibited peaks in TLC densitogram profiles. Three extracts were tested for antibacterial activity against Staphylococcus aureus and Escherichia coli. The result showed that ethyl acetate extract revealed excellent antibacterial activity against S. aureus and E. coli with MIC values of 3.125±0.6 mg/mL and 6.25±0.5 mg/mL, respectively. Owing to the presence of a wide variety of secondary metabolites, the leaf extract of M. malabathricum is expected to exhibit and help develop as a therapeutic agent.

Development of fingerprinting method for Siddha formulation Nilaavaarai chooranam: A HPTLC approach

Selective and efficient analytical methods are required not only for quality assurance but also for authentication of herbal formulations. Fingerprint method for Nilaavaarai Chooranam with TLC Densitometric Methods (HPTLC) using piperine as an internal standard was developed. The HPTLC estimation was carried out with three laboratory batches and one marketed formulation of Nilaavaarai Chooranam and crude drug containing piperine. The concentration of piperine present in raw material was found to be 2.9836±0.497w/w in Piper nigrum and in three identical laboratory batch of Nilaavaarai Chooranam NC-I, NC-II and N-III, was found to be 0.1761 ± 0.384, 0.1759 ± 0.534%, 0.1760 ± 0.019 w/w respectively. The piperine content in all the three different batches is found to be in close proximities with each other. The results were comparable to marketed formulations. Hence the present method is simple, sensitive, precise and accurate and can be adopted for routine fingerprinting method for quality control of Nilaavaarai Chooranam.

Formulation and Evaluation of Analytical Methods for Determination of Indacaterol

Abstract: Indacaterol is a novel class of β2 adrenoreceptor -agonist used to treat chronic obstructive pulmonary disease. Various analytical methods used for the estimation of Indacaterol have been reviewed in this project. These methods include Ultraviolet Spectrometric method, High Performance Liquid Chromatography method, Capillary electrophoretic method, TLC densitometric method for qualitative and quantitative estimation of Indacaterol in pharmaceutical formulation

Sustainable TLC-densitometric method for pharmacokinetic study of the concurrently used ibuprofen and metronidazole: Green metric assessment

Combination therapy with metronidazole has been demonstrated to be superior in surgical site infections and pain treatment protocols. Ibuprofen, on the other hand, is an effective and safe medication with long duration of action for patients with post-operative pain.In this investigation, in vivo estimation of metronidazole and ibuprofen was performed, followed by a pharmacokinetic study using an ecological TLC-densitometric approach. Separation of drugs and the internal standard, furosemide from plasma matrix was performed using ethyl acetate: ethanol: ammonium hydroxide solution 33% (5:5:0.1, by volume) on TLC silica gel 60 F254 plates and scanning at 220.0 nm and 310 nm. The method was sensitive for metronidazole and ibuprofen in the ranges of 0.1–2.5 and 0.1–3.0 µg/band, respectively.Furthermore, the devised method’s performance was evaluated by analyzing various samples obtained from volunteers at different time intervals who received either a single medication or a combination of drugs. The information gathered was utilized to investigate the pharmacokinetic properties of both medicines. According to the findings of the pharmacokinetic study, co-administration of metronidazole and ibuprofen increased their maximum plasma concentrations and time required to reach this concentration. It was also discovered that ibuprofen greatly influenced the bioavailability and distribution of metronidazole. Accordingly, care should be taken when both medications are used simultaneously, especially for metronidazole, which requires dose regulation. Furthermore, different novel Green analytical chemistry metrics were applied to assess the suggested method, including GABI, RGB colored tool, AGREE, and hexagon. The results revealed that the developed analytical approach had a negligible environmental impact.

Influence of Chromatographic Conditions on LOD and LOQ of Fluoxetine and Sertraline Analyzed by TLC-Densitometric Method

This research introduces the analysis of fluoxetine and sertraline by means of the TLC-densitometric method. They provide information on LOD and LOQ under various chromatographic conditions. The study used adsorption (NPTLC) and partition (RPTLC) thin-layer chromatography in combination with a densitometric analysis. Four types of chromatographic plates precoated with: silica gel 60 F254, silica gel 60, silanized silica gel 60 F254 (RP-2), and a mixture of silica gel 60 and kieselguhr F254, as well as three mobile phases: chloroform + methanol + ammonia (9:1:0.4, v/v/v), chloroform + methanol + glacial acetic acid (5:4:1, v/v/v), and acetone + toluene + ammonia (10:9:1, v/v/v), were used in NPTLC. RP-18F254 and silanized silica gel 60 F254 (RP-2) plates and four mobile phases: methanol + water (10:0 and 9:1, v/v), acetone + water (10:0 and 9:1, v/v), were used in RPTLC. The lowest LOD and LOQ values for fluoxetine were obtained using a silanized silica gel 60 F254 (RP-2) with acetone + toluene + ammonia (10:9:1, v/v/v) in NPTLC, and with a silanized silica gel 60 F254 (RP-2) in combination with methanol + water (10:0, v/v) in RPTLC. The lowest LOD and LOQ values of sertraline were obtained using a silica gel 60 with acetone + toluene + ammonia (10:9:1; v/v/v) in NPTLC. The smallest amount of sertraline was detected on the silanized silica gel 60 F254 plate in combination with methanol + water (9:1, v/v) in RPTLC. The obtained results provide important information that can give a good basis and set the direction for further, more detailed research; the results can also benefit other researchers who analyze fluoxetine and sertraline with the TLC technique in model systems (testing standards) as well as in drug and biological samples.

A green TLC densitometric method for the simultaneous detection and quantification of naphazoline HCl, pheniramine maleate along with three official impurities

Impurity profiling of a pharmaceutical compound is now taking great attention during quality assessment of pharmaceuticals, as presence of small amount of impurities may affect safety and efficacy. In this work, a novel TLC chromatographic method coupled with densitometric detection was established for the simultaneous quantification of naphazoline HCl, pheniramine maleate and three of their official impurities, namely; naphazoline impurity B, pheniramine impurities; A & B. Chromatographic separation was carried out on TLC aluminum silica plates F254, as a stationary phase, using methanol: ethyl acetate: 33.0% ammonia (2.0: 8.0: 1.0, by volume), as a mobile phase. Plates were examined at 260.0 nm and International Council for Harmonisation (ICH) guidelines were followed for method’s validation. Important factors, such as; composition of mobile phase and detection wavelengths were optimized. Linearity was achieved over the ranges of 2.0–50.0 µg band−1 for naphazoline, 10.0–110.0 µg band−1 for pheniramine, 0.1–10.0 µg band−1 for naphazoline impurity B and 2.0–50.0 µg band−1 for both pheniramine impurities. The proposed method was assessed in terms of accuracy, precision and robustness where satisfactory results (recovery % ≈ 100% and RSD < 2) were obtained. The method was also applied for the simultaneous determination of naphazoline HCl and pheniramine maleate, in Naphcon-A® eye drops, with respective recoveries of 101.36% and 100.94%. Method greenness was evaluated and compared to the reported HPLC one via environmental, health and safety tool. The developed method has much potential over the reported one of being simple, selective, economic and time saving for the analysis of the five cited compounds.