Application of Design of Experiments® Approach-Driven Artificial Intelligence and Machine Learning for Systematic Optimization of Reverse Phase High Performance Liquid Chromatography Method to Analyze Simultaneously Two Drugs (Cyclosporin A and Etodolac) in Solution, Human Plasma, Nanocapsules, and Emulsions.

The objectives of current investigation are (1) to find out wavelength of maximum absorbance (λmax) for combined cyclosporin A and etodolac solution followed by selection of mobile phase suitable for the RP-HPLC method, (2) to define analytical target profile and critical analytical attributes (CAAs) for the analytical quality by design, (3) to screen critical method parameters with the help of full factorial design followed by optimization with face-centered central composite design (CCD) approach-driven artificial neural network (ANN)-linked with the Levenberg-Marquardt (LM) algorithm for finding the RP-HPLC conditions, (4) to perform validation of analytical procedures (trueness, linearity, precision, robustness, specificity and sensitivity) using combined drug solution, and (5) to determine drug entrapment efficiency value in dual drug-loaded nanocapsules/emulsions, percentage recovery value in human plasma spiked with two drugs and solution state stability analysis at different stress conditions for substantiating the double-stage systematically optimized RP-HPLC method conditions. Through isobestic point and scouting step, 205 nm and ACN:H2O mixture (74:26) were selected respectively as the λmax and mobile phase. The ANN topology (3:10:4) indicating the input, hidden and output layers were generated by taking the 20 trials produced from the face-centered CCD model. The ANN-linked LM model produced minimal differences between predicted and observed values of output parameters (or CAAs), low mean squared error and higher correlation coefficient values in comparison to the respective values produced by face-centered CCD model. The optimized RP-HPLC method could be applied to analyze two drugs concurrently in different formulations, human plasma and solution state stability checking.

Liquid chromatographic methods for separation, determination, and bioassay of enantiomers of etodolac: A review.

The control of enantiomeric purity and determination of individual enantiomeric drug molecules remains the subject of importance for clinical, analytical, and regulatory purposes and to facilitate an accurate evaluation of the risks posed by them to human health. A large number of pharmaceuticals are marketed and administered as racemates. Etodolac is among such nonsteroidal anti-inflammatory drugs. Overall literature reports on its enantioseparation are scanty. Liquid chromatography (LC) methods of enantioseparation of (±)-etodolac, including certain unconventional ones, are well covered and discussed in this paper. Methods of direct approach without using chiral columns or chiral thin-layer chromatography plate and of indirect approach using certain chiral derivatizing agents such as (S)-naproxen and (S)-levofloxacin are described. Most interesting aspects include establishment of structure and molecular asymmetry of chemically different types of diastereomeric derivatives using liquid chromatography with mass spectrometry (LC-MS), 1 H NMR spectroscopy and by drawing conformations in three dimensional views by using certain software. The methods provide chirality recognition even in the absence of pure enantiomers. Besides, recovery of pure enantiomers by detagging or via solubility difference of chiral inducing reagent and the analyte, without racemization at any stage, has been achieved. The limits of detection and quantification are much lower than the industry benchmarks.

Liquid chromatographic enantioseparation of (RS)-etodolac using (S)-levofloxacin and determination of absolute configuration of the diastereomeric derivatives.

(RS)-Etodolac was isolated from commercial tablets and was purified and characterized to be used as racemic standard. A pair of diastereomeric derivatives was synthesized using (S)-levofloxacin as a chiral derivatizing reagent. The derivatization reaction was carried out under conditions of stirring at room temperature (30°C for 1.5 h) as well as under microwave irradiation; the derivatives obtained by the two methods were compared. Reaction conditions for derivatization were optimized with respect to mole ratio of chiral derivatizing reagent and (RS)-etodolac. No racemization was observed throughout the study. Separation of diastereomeric derivatives was successful using C18 column and a binary mixture of methanol and triethyl ammonium phosphate buffer of pH 4.5 (80:20, v/v) as mobile phase at a flow rate of 1 mL min-1 and UV detection at 223 nm. An efficient approach for recognizing chirality and determining the absolute configuration of the diastereomeric derivatives of (RS)-etodolac is described, which in turn is a measure of the enantiomeric purity of (RS)-etodolac since the diastereomeric derivatives were separated and isolated using preparative thin-layer chromatography.

Quantitative analysis of anti-inflammatory drugs using FTIR-ATR spectrometry.

Four simple, accurate, sensitive and economic Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopic (ATR-FTIR) methods have been developed for the quantitative estimation of some non-steroidal anti-inflammatory drugs. The first method involves the determination of Etodolac by direct measurement of the absorbance at 1716cm-1. In the second method, the second derivative of the IR spectra of Tolfenamic acid and its reported degradation product (2-chlorobenzoic acid) was used and the amplitudes were measured at 1084.27cm-1 and 1056.02cm-1 for Tolfenamic acid and 2-chlorobenzoic acid, respectively. The third method used the first derivative of the IR spectra of Bumadizone and its reported degradation product, N,N-diphenylhydrazine and the amplitudes were measured at 2874.98cm-1 and 2160.32cm-1 for Bumadizone and N,N-diphenylhydrazine, respectively. The fourth method depends on measuring the amplitude of Diacerein at 1059.18cm-1 and of rhein, its reported degradation product, at 1079.32cm-1 in their first derivative spectra. The four methods were successfully applied on the pharmaceutical formulations by extracting the active constituent in chloroform and the extract was directly measured in liquid phase mode using a specific cell. Moreover, validation of these methods was carried out following International Conference of Harmonisation (ICH) guidelines.

Pharmacological and toxicological investigations of etodolac loaded gum katira microspheres prepared by W1/O/W2 emulsion solvent evaporation technique in rats

ABSTRACT Etodolac is a non-steroidal anti-inflammatory drug (NSAID) and approved by USFDA as a COX2 inhibitor. Although etodolac therapy provides clinical benefits, it is associated with upper gastrointestinal (GI) tract complications also. Etodolac loaded gum Katira microsphere (ELGKM) was prepared by W1/O/W2 emulsion solvent evaporation technique. The gastric irritation properties of orally administered pure etodolac, ELGKM and blank microspheres (without etodolac) were evaluated in experimental rats treated for 6 days. The stomach examination and biochemical investigation of stomach tissue of treated rats indicated that ELGKM formulation remarkably reduced ulcerogenecity as compared to pure etodolac. The anti-inflammatory activities of pure etodolac and ELGKMs were ascertained by the implantation of cotton pellets in rats for 6 days. Based on the results, ELGKMs showed significant anti-inflammatory activities (P<0.01) as compared to control group. The cotton pellets test suggested that ELGKM formulation retained more anti-inflammatory properties among the groups. The hematological changes, biochemical analysis and histopathological studies of subacute toxicity in rats revealed that ELGKM were the effective sustained release formulation in the treatment of chronic pain and inflammation. In conclusion, the physicochemical characterization, pharmacological and toxicological studies suggest that ELGKMs may represent as a potential candidate for sustained drug delivery (10-12 hours) in chronic joint pain related diseases with remarkably diminished gastrointestinal side effects.

Enantioselective HPLC-DAD method for the determination of etodolac enantiomers in tablets, human plasma and application to comparative pharmacokinetic study of both enantiomers after a single oral dose to twelve healthy volunteers.

An enantioselective high performance liquid chromatographic method with diode array detection (HPLC-DAD) was developed and validated for the determination of etodolac enantiomers in tablets and human plasma. Enantiomeric separation was achieved on a Kromasil Cellucoat chiral column (250 mm × 4.6mm i.d., 5 µm particle size) using a mobile phase consisting of hexane: isopropanol: triflouroacetic acid (90:10:0.1 v/v/v) at a flow rate of 1.0 mL min(-1). The chromatographic system enables the separation of the two enantiomers and the internal standard within a cycle time of 8 min. The resolution between the two enantiomers was 4.25 and the resolution between each enantiomer and the internal standard was more than 2.0. Detection was carried out at 274 nm, and the purity assessment was performed using a photodiode array detector. Solid phase extraction technique using C-18 cartridge was applied to extract the analytes from the plasma samples, and the percentage recovery was more than 95% for the lower quantification limit. The method has been validated with respect to selectivity, linearity, accuracy and precision, robustness, limit of detection and limit of quantification. The validation acceptance criteria were met in all cases. The linearity range for the determination of each enantiomer in human plasma was 0.4-30.0 µg mL(-1) and the limits of quantification of R-etodolac and S-etodolac were 0.20 and 0.19 µg mL(-1), respectively. The validated method was successfully applied to the determination of etodolac enantiomers in tablets and to a comparative pharmacokinetic study of the two enantiomers after the administration of 300 mg single oral dose etodolac racemate tablets to twelve healthy volunteers.

Spectrofluorimetric determination of etodolac, moxepril HCl and fexofenadine HCl using europium sensitized fluorescence in bulk and pharmaceutical preparations.

A simple, selective and sensitive luminescence method has been developed for the assay of etodolac (I), moxepril HCl (II) and fexofenadine HCl (III) in bulk drug and pharmaceutical formulations. The method is based on the luminescence sensitization of europium (Eu(3+)) by complexation with the studied drugs. The fluorescence intensities of the products were measured at 667 nm for (I) and at 615 for (II) and (III) while exciting at 276 for all the studied drugs. The fluorescence intensity was directly proportional to the concentration over the range (20-280), (40-240) and (30-80) ng/ml with limits of detection (LOD) = 0.93, 0.92 and 0.95 µg/ml for drugs I, II and III respectively. Optimum conditions for the formation of the complex in methanol were carefully studied. The proposed method was successfully applied for the assay of the studied drugs in pharmaceutical formulations with excellent recovery.

Separation of etodolac enantiomers by capillary electrophoresis. Validation and application of the chiral method to the analysis of commercial formulations.

Separation of etodolac enantiomers, which exhibit different biological activity and pharmacokinetic profiles, has been achieved using the randomly substituted (2-hydroxy)propyl-beta-cyclodextrin (HP-beta-CD) as chiral selector in capillary electrophoresis. The selection of this CD was made after screening of different CD derivatives of neutral and anionic nature. The effect on the enantioresolution of the buffer concentration and of the degree of substitution (DS) and concentration of the CD as well as of instrumental parameters, such as the capillary temperature and the separation voltage, were studied. The highest resolution of etodolac enantiomers was around 2.5 using 100 mM phosphate buffer (pH 7.0) with 20 mM HP-beta-CD (DS approximately 4.2) and UV detection at 225 (10) nm with a reference wavelength at 360 (50) nm. Validation of the chiral method in terms of selectivity, linearity, precision (instrumental repeatability, method repeatability, intermediate precision), and the limits of detection and quantitation allowed to evaluate its quality to the analysis of etodolac enantiomers in different pharmaceutical preparations containing racemic etodolac.

Enhanced release of solid dispersions of etodolac in polyethylene glycol.

This work examines the release of etodolac from various molecular weight fractions of polyethylene glycol (PEG) solid dispersions. Solid dispersions of etodolac were prepared in different molar ratios of drug/carrier by using solvent and melting methods. The release rate of etodolac from the resulting complexes was determined from dissolution studies by use of USP dissolution apparatus 2 (paddle method). The physical state and drug:PEG interaction of solid dispersions and physical mixtures were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and differential scanning calorimetry (DSC). The dissolution rate of etodolac is increased in all of the solid dispersion systems compared to that of the pure drug and physical mixtures. The solid dispersion compound prepared in the molar ratio of 1:5 by the solvent method was found to have the fastest dissolution profile. The physical properties did not change after 9 months storage in normal conditions.

Spectrophotometric and spectrofluorimetric determination of etodolac and aceclofenac.

Two simple, sensitive and reproducible spectrophotometric and spectrofluorimetric methods were adopted for the analysis of the anti-inflammatory drugs, etodolac and aceclofenac. The first method is based on the formation of coloured complexes between the drugs and p-dimethylaminobenzaldehyde reagent (PDAB) in the presence of sulfuric acid and ferric chloride. Measurement of the absorbances was carried out at 591.5 and 545.5 nm for etodolac and aceclofenac, respectively. Regression analysis of Beer's plots showed good correlation in the concentration ranges 10-80 and 8-55 microg ml(-1), respectively. The second was the spectrofluorimetric method in which samples of etodolac in ethanol showed native fluorescence at a lambda = 345 nm when excitation was at 235 nm and samples of aceclofenac in the phosphate buffer pH 8 showed native fluorescence at lambda = 355 nm when excitation was at 250 nm. The calibration graph was rectilinear from 96 to 640 ng ml(-1) for etodolac and from 2 to 8 microg ml(-1) for aceclofenac. The proposed methods are applied successfully for the determination of the two drugs in bulk powder with a mean accuracy of 100.48+/-0.85 and 100.03+/-0.38 in the PDAB method and of 100.61+/-0.79 and 99.88+/-0.45 in the spectrofluorimetric method. Applicability of the proposed methods was examined by analysing dosage forms of the investigated drugs. Recoveries were 98.77-101.46 and 98.65-102.10% for the two methods, respectively and RSD values were 0.6-0.7 and 0.35-1.06% respectively.