A Novel Validated RP-HPLC-DAD Method for the Simultaneous Estimation of Metformin Hydrochloride and Canagliflozin in Bulk and Pharmaceutical Tablet Dosage form with Forced Degradation Studies

Smart spectrophotometric methods for the simultaneous determination of newly co-formulated hypoglycemic drugs in binary mixtures

Achieving good glycemic control in patients with type II diabetes mellitus is essential for preventing both microvascular and macrovascular complications. Combination therapy represents the principle strategy for successful long term control of type II diabetes mellitus with minimal complications. Two sensitive, precise and non-destructive spectroscopic methods were developed for the simultaneous estimation of two new co-formulated hypoglycemic drugs; canagliflozin/metformin (CAG/MEF) and empagliflozin/linagliptin (EMG/LIG) in tablets with no need of previous separation. The first method was amplitude modulation (a normalized spectra-based UV spectrophotometric method) for the analysis of (CAG/MEF) binary mixture. The amplitude of the constant at the plateau region at (264-310 nm) on the ratio spectrum was measured and used for the determination of CAG concentration in the mixture. On the other hand, MEF was estimated by subtracting the previously obtained amplitude from the total amplitude of CAG and MEF at the isosbestic point (λ_iso) at 250 nm. The second method was chemometric-assisted FTIR spectrophotometric method for the determination of (EMG/LIG) binary mixture. (EMG/LIG) mixture in chloroform was analyzed using FTIR in the region 4000-400 cm^-1. The spectral region 3900-2900 cm^-1 was selected for (EMG/LIG) determination using principal component regression and partial least squares chemometric methods. The methods were validated according to ICH guidelines. The studied drugs were successfully determined in tablets applying the developed methods. Validation parameters were in agreement with acceptance limits, ensuring methods accuracy and selectivity. Besides, no significant difference was obtained by statistically comparing the obtained results with the reported one.

Validated Liquid Chromatographic Method for the Determination of (Canagliflozin, Dapagliflozin or Empagliflozin) and Metformin in the Presence of (1-Cyanoguanidine)

A simple and accurate liquid chromatographic method has been developed and validated for the determination of either canagliflozin, dapagliflozin propandiol monohydrate or empagliflozin and metformin in presence of metformin major degradation product;1-cyanoguanidine. The Liquid Chromatographic (LC) method was based on isocratic elution on Prontosil (Lichrosorb 100-5-NH2) column using a mobile phase consisting of NaH2PO4 buffer (10 mM, pH 2.8):acetonitrile (18.5:81.5, v/v), at a flow rate of 2 mL/min-1. Quantitation was achieved with UV detection at 225 nm. The validation of the method was assessed according to International Conference on Harmonization (ICH) guidelines. Linearity, accuracy and precision were satisfactory over the concentration ranges of 12.5-100, 3.75-30, 0.3075-2.46, and 0.3125-2.5 μg/mL for metformin HCl, canagliflozin, dapagliflozin propandiol monohydrate and empagliflozin, respectively. Limits of detection and quantitation were found to be 0.068, 0.135, 0.077 and 0.069 μg/mL and 0.206, 0.410, 0.233 and 0.210 μg/mL for metformin HCl, canagliflozin, dapagliflozin propandiol monohydrate and empagliflozin, respectively. The developed method is suitable for the quality control and routine analysis of the cited drugs separately or in combinations.

Different resolution techniques for management of overlapped spectra: Application for the determination of novel co-formulated hypoglycemic drugs in their combined pharmaceutical dosage form

To maintain intensive glucose control early in the type II diabetes mellitus process, novel combinations of canagliflozin/metformin (CAG/MEF) and empagliflozin/linagliptin (EMG/LIG) offer particular treatment benefits. In this study, sensitive and precise spectrophotometric methods were developed for the determination of such hypoglycemic drug combinations in bulk powder and in pharmaceutical dosage form without prior separation. The first method was ratio difference coupled with modified isosbestic point technique where the amplitude difference between 239 and 291 nm on the ratio spectrum of CAG obtained using 4 μg/ml of MEF as divisor was used for determination of CAG. On the other hand, MEF was estimated using a modified isosbestic spectrophotometric method, where the total concentration of CAG and MEF in mixture could be calculated at 250 nm (isosbestic point) after multiplication by a correction factor. Then concentration of MEF could be calculated by subtraction. The second method was ratio subtraction coupled with extended ratio subtraction, where EMG was determined at 225 nm by subtraction of plateau values from the ratio spectrum followed by multiplication with the spectrum of 6.5 μg/ml of LIG (divisor). Then, an extension of the normal ratio subtraction method was performed in order to determine LIG at 226 nm. Linearity was obtained over 5-30, 2.5-16, 2.5-16 and 1.25-8 μg/ml for CAG, MEF, EMG and LIG, respectively. The developed methods were successfully applied for the determination of studied drugs in tablets. Validation parameters were found to be within acceptance limits, thus confirming methods accuracy and selectivity. The obtained results were statistically compared with the reported one showing no significant difference in terms of accuracy and precision. The methods could be applied for routine analysis of the cited drugs in quality control laboratories.

Characterization of forced degradation products of canagliflozine by liquid chromatography/quadrupole time-of-flight tandem mass spectrometry and in silico toxicity predictions

RATIONALE

Forced degradation studies are useful for better understanding of the stability of active pharmaceutical ingredients and drugs and to generate information about drug degradation pathways and formation of degradation products (DPs). Identification of DPs plays a vital role in establishing the safety and therapeutic benefit of a drug.

METHODS

Canagliflozin (CAN) was subjected to different stress conditions as per International Conference on Harmonization guidelines (Q1A R2). All the DPs and the drug were well separated on an Aquity CSH C₁₈ (100 × 2.1 mm, 1.7 μm) column using acetonitrile-methanol (70:30, v/v) and formic acid in gradient mode. The same UPLC method was employed for LC/HRMS for the characterization of DPs. In addition, in silico toxicity was predicted for all the DPs by using TOPKAT and DEREK software tools.

RESULTS

CAN was found to degrade under oxidative stress condition and formed DP1 and DP2. This is a typical case of degradation where co-solvents acetonitrile-water (50:50, v/v) and methanol-water (50:50, v/v) react with CAN under acid hydrolytic conditions leading to the formation of pseudo-DPs, DP3 and DP4, respectively. Among these, DP2 and DP3 showed ocular irritancy whereas DP1 showed skin sensitization.

CONCLUSIONS

The drug was labile under oxidative stress condition. CAN reacted with co-solvent under acid hydrolytic conditions and gave pseudo-DPs. All the DPs were separated using UPLC and characterized by LC/QTOF/MS/MS. Toxicity of DPs was evaluated using TOPKAT and DEREK software tools.

Different mathematical processing of absorption, ratio and derivative spectra for quantification of mixtures containing minor component: An application to the analysis of the recently co-formulated antidiabetic drugs; canagliflozin and metformin

In the presented work several spectrophotometric methods were performed for the quantification of canagliflozin (CGZ) and metformin hydrochloride (MTF) simultaneously in their binary mixture. Two of these methods; response correlation (RC) and advanced balance point-spectrum subtraction (ABP-SS) were developed and introduced for the first time in this work, where the latter method (ABP-SS) was performed on both the zero order and the first derivative spectra of the drugs. Besides, two recently established methods; advanced amplitude modulation (AAM) and advanced absorbance subtraction (AAS) were also accomplished. All the proposed methods were validated in accordance to the ICH guidelines, where all methods were proved to be accurate and precise. Additionally, the linearity range, limit of detection and limit of quantification were determined and the selectivity was examined through the analysis of laboratory prepared mixtures and the combined dosage form of the drugs. The proposed methods were capable of determining the two drugs in the ratio present in the pharmaceutical formulation CGZ:MTF (1:17) without the requirement of any preliminary separation, further dilution or standard spiking. The results obtained by the proposed methods were in compliance with the reported chromatographic method when compared statistically, proving the absence of any significant difference in accuracy and precision between the proposed and reported methods.

Comparative Liquid Chromatographic Study for Concurrent Determination of Canagliflozin and Metformin in Combined Tablets

New HPLC-UV method (method A), for simultaneous determination of metformin (MET) and canagliflozin (CANA), was developed and compared to another novel UPLC-UV method (method B) in their tablet combination. Concerning method A, isocratic separation was done by C18 column (100 mm × 2.1 mm, 3 μm) using methanol and 0.03 M phosphate buffer (75 : 25, v/v) at pH 3.2 as a mobile phase. Meanwhile, chromatographic separation in method B was achieved via Hypersil® gold (50 mm × 2.1 mm, 1.9 μm). Mobile phase was methanol and 0.03 M phosphate buffer at ratio of 80 : 20  v/v. In both, detection was done at wavelength of 240 nm. Method A showed satisfactory linearity results over 1-50 μg·mL^-1 and 0.5-100 μg·mL^-1, while method B linearity was at 0.1-50 μg·mL^-1 and 0.25-100 μg·mL^-1 for CANA and MET, respectively. In terms of accuracy and precision, method A accuracy was 99.81 ± 0.73 and 99.37 ± 0.54, while method B gave accuracy of 99.47 ± 1.03 and 99.73 ± 0.89 for CANA and MET, respectively. For precision, the % RSD was found to be less than 2% for three concentrations analyzed three times. The two methods are convenient for quality laboratories, yet the UPLC method offered the advantage of shorter run times and higher sensitivity.

Analytical tools for determination of new oral antidiabetic drugs, glitazones, gliptins, gliflozins and glinides, in bulk materials, pharmaceuticals and biological samples

The review presents analytical methods for determination of new oral drugs for the treatment of type 2 diabetes mellitus (T2DM), focusing on peroxisome proliferator-activated receptor gamma agonists (glitazones), dipeptidyl peptidase 4 inhibitors (gliptins) and sodium/glucose co-transporter 2 inhibitors (gliflozins). Drugs derived from prandial glucose regulators, such as glinides, are considered because they are present in some new therapeutic options. The review presents analytical procedures suitable for determination of the drugs in bulk substances, such as pharmaceuticals and biological samples, including HPLC-UV, HPLC/LC-MS, TLC/HPTLC, CE/CE-MS, spectrophotometric (UV/VIS), spectrofluorimetric and electrochemical methods, taken from the literature over the past ten years (2006-2016). Some new procedures for extraction, separation and detection of the drugs, including solid phase extraction with molecularly imprinted polymers (SPE-MIP), liquid phase microextraction using porous hollow fibers (HP-LPME), HILIC chromatography, micellar mobile phases, ion mobility spectrometry (IMS) and isotopically labeled internal standards, are discussed.