Separation of alogliptin enantiomers in cyclodextrin-modified capillary electrophoresis: a validated method

Electrospun PVA nanofiber mat for topical Deflazacort delivery: accentuated anti-inflammatory efficacy for wound healing

PURPOSE

Asses the wound healing activity of Polyvinyl alcohol - Deflazacort (PVA-DEF) nanofibers mats synthesized by electrospinning technology.

METHODS

PVA-DEF nanofiber mats were created with various PVA polymer concentrations using an electrospinning process. The morphological features and diameter of the electrospun nanofibrous mats were investigated using scanning electron microscopy (SEM). The in vitro DEF release rate from PVA electrospun nanofibrous mats was evaluated. In addition to assessing wound healing activity in vivo, histological, and immunochemical tests were conducted.

RESULTS

Results revealed a uniform and smooth surface of the fiber with an average diameter of the selected fibers of 533.9 nm ± 45.83. Also, PVA electrospun nanofiber mats showed an initial burst release of more than 50% of the DEF in 1 h, and the rest of the DEF was released gradually for up to 480 min. Fickian diffusion is the main DEF release mechanism from PVA electrospun nanofiber mats. In male Wistar albino rats with 1 cm2 excision wounds, in vivo studies revealed a significant improvement in wound healing rate via modulation of tumor necrosis factor-alpha (TNF-α) and vascular endothelial growth factor (VEGF) expression.

CONCLUSION

PVA-DEF nanofiber mats can be used effectively for improving wound healing.

Using of eosin Y as a facile fluorescence probe in alogliptin estimation: Application to tablet dosage forms and content uniformity testing

New simple sensitive and reliable spectrofluorimetric approach was established for the determination of the antidiabetic drug; Alogliptin (ALG) in its pure and tablet forms. The developed approach is depended on the suppressive action of ALG on the eosin Y native fluorescence. The quenching action of ALG on the eosin Y native fluorescence was measured at acidic medium pH: 3.5, emission wavelength 541 nm (λ_ex. 260 nm). The relative fluorescence intensity (RFI) was measured, and it was directly proportional to ALG concentration in the concentration range of (15-110) μg/mL. The developed and optimized approach was entirely validated regarding to ICH guidelines. The developed method application was successfully extended for ALG content uniformity test (CU). The distribution fraction (DF), rate constants (K), and free energy changes (ΔG°) were calculated. The results obtained were compared to that of the published spectrophotometric one.

Hantzsch Condensation Reaction as a Spectrofluorometric Method for Determination of Alogliptin, an Anti-diabetic Drug, in Pure, Tablet, Human, and rat plasma

To analyze alogliptin in its pharmaceutical dosage forms and human plasma, a sensitive, inexpensive, simple, and precise spectrofluorimetric method was developed and tested. Also, this method was used to investigate the drug pharmacokinetic behavior in the blood of rats. It is based on the Hantzsch reaction, which produces yellowish luminous products that can be detected spectrofluorometrically at 480 and 415 nm, emission, and excitation, respectively, when the primary amine group in the examined drug reacts with acetylacetone and formaldehyde. Several experimental parameters that affect the reaction product's development and stability were explored and improved. The curve of fluorescence and concentration for alogliptin was linear in the concentration range of 0.05-3.60 μg ml^-1 . According to ICH criteria, the proposed approach was validated. The method was successfully utilized to evaluate the examined drug in dose formulations and spiked human plasma with high accuracy.

Different chromatographic methods for determination of alogliptin benzoate, metformin hydrochloride, and metformin impurity in bulk and pharmaceutical dosage form

Two simple, sensitive, and reproducible methods were developed for the determination of alogliptin and metformin hydrochloride in presence of metformin impurity "melamin" in pure form and in pharmaceutical formulation. Method (A) was a thin layer chromatographic method in which separation was achieved using ethyl acetate-methanol-formic acid (6:3.8:0.2, by volume) as a developing system followed by densitometric scanning at 230 nm. Method (B) was a high-performance liquid chromatography method; separation was achieved on C₁₈ column, the mobile phase consisted of a mixture of sodium lauryl sulfate buffer 0.1% w/v, pH 3: methanol in the ratio 70:30, v/v and measurement was done at 220 nm. System suitability testing parameters were calculated to ascertain the quality performance of the developed chromatographic methods. The proposed methods have been validated regarding accuracy, precision, and selectivity, moreover they have been successfully applied to Westirizide tablets containing both alogliptin and metformin hydrochloride, results indicate that there was no interference from additives. No significance difference was found when these methods were compared to the reported one.

Induced mathematical filtration as an innovative strategy for discrimination and estimation of glycemic control drugs in fixed dose combination

An innovative strategy was developed for the estimation of a fixed dose combination containing Alogliptin (ALO) and pioglitazone (PIO) using induced concept for resolving the overlapped spectra, lacking isoabsorptive point. This strategy is based on coupling factors as numerical values or ratios as spectrum form with the recorded signals leading to induced mathematical filtration of the drug of interest and complete elimination of the interfering one in the combination without prior physical separation. The calculated factors were factor of equality in induced dual wavelength (IDW) or absorptivity factor in induced concentration subtraction method (ICS) while absorptivity ratio spectrum for induced amplitude modulation method (IAM). The calibration curves displayed linearity within 1.0–16.0 μg/mL for ALO and 2.0–22.0 μg/mL for PIO with good correlation coefficients. The induced methods specificity was also assured through the assaying different synthetic mixtures prepared to contain the two drugs in ratios approaching the ratio actually found in the marketed dosage form. The methods were applicable and suitable for estimating ALO and PIO in both bulk form and their fixed dose combination. Induced methods have been extensively validated in accordance with ICH guidelines and results demonstrated the accuracy and reproducibility in comparison to the reported method.

Spectrofluorometric determination of alogliptin an antidiabetic drug in pure and tablet form using fluorescamine, a fluorogenic agent: application to content uniformity test

Alogliptin is an antidiabetic drug that belongs to a group called dipeptidyl peptidase-4 enzyme inhibitors. As the drug contains a primary amino group in its structure, it readily reacts with fluorescamine in slightly alkaline medium (borate buffer, pH 8.8) to form a highly fluorescent product. Emission of this product was measured at 477 nm (λ_ex = 387 nm). The linear range between the fluorescence intensity and the drug concentration was 0.1-0.5 μg ml^-1 with a good correlation coefficient (0.9986). Limits of detection and quantitation were 22 and 72 ng ml^-1 , respectively. Guidelines of the International Conference for Harmonisation were followed to validate the developed method with acceptable results. Alogliptin content was determined successfully in its commercial dosage form using the fluorescamine method with good recovery (98.60-101.26%). The method has excellent levels of accuracy and precision compared with the reported method as assessed using Student's t-test and Fisher's exact test. The method was applied successfully for the content uniformity test with high recovery and low relative standard deviation.

Enantiomeric Determination of Drugs in Pharmaceutical Formulations and Biological Samples by Electrokinetic Chromatography

Chirality is a relevant issue in the pharmaceutical field due to the different biological activity that enantiomers of a chiral drug can show. In fact, the desired biological or pharmaceutical activity might be present in only one of the enantiomers, while the other enantiomer(s) may have different biological activity, be inactive or even toxic. This has motivated in recent years the development of drugs marketed as pure enantiomers to avoid exposing the organism to the action of enantiomers that may not be active or even harmful to health. Thus, it is of high interest to develop enantioselective analytical methodologies to control the presence of enantiomeric impurities and to understand the enantioselective metabolism of chiral drugs. This review gives an overview about the analytical strategies developed by electrokinetic chromatography (EKC) from 2010 to June 2019 for the enantiomeric determination of drugs in both pharmaceutical formulations and biological samples. The types of chiral selectors used, the migration order of enantiomers, their resolution, the detection technique employed and the sensitivity achieved are revised and compared. Also, applications to assess the enantiomeric purity control of pharmaceutical formulations and to determine chiral drugs in biological samples to study their metabolism are included. Advantages and limitations of the chiral methods developed by EKC are also discussed.

Separations of antifungal compounds in capillary electrophoresis with two anionic cyclodextrins

CD-CZE methods were developed for complete stereoisomeric separations of a series of six γ-lactam analogues, of which some were neutral, or cationic depending on the background electrolyte nature. The tested cyclodextrin was the versatile sulfobutylether- β-CD, used either in a phosphate buffer using capillaries dynamically coated with polyethylene oxide or in a borate buffer using uncoated capillaries. Long-end and short-end modes and concentration variations of chiral selectors allowed finding conditions of complete separation of four out of the six derivatives (i.e., 1, 2, 3, and 4) in short run times, confirming their broad range of applications. To separate the two last compounds, the highly sulfated- γ-CD was examined as chiral selector in acidic phosphate conditions. The enantiomers of the γ-lactam analogues 5 and 6 were baseline resolved with 5.5 and 4%, respectively as concentration in the buffer.

Development and validation of a cyclodextrin-modified capillary electrophoresis method for the enantiomeric separation of vildagliptin enantiomers

The enantiomers of vildagliptin, an orally available and selective dipeptidyl-peptidase-4 inhibitor used for the treatment of type II diabetes, have been separated by CD-modified CZE, using uncoated fused-silica capillary. After screening 13 negatively charged CD derivatives as potential chiral selectors, sulfobutyl-ether-α-CD (SBE-α-CD) was selected for the enantioseparation. For the optimization, a factorial analysis study was performed by orthogonal experimental design. Six experimental factors were chosen as variable parameters: temperature, applied voltage, chiral selector and BGE concentrations, pH, and the parameters of the hydrodynamic injection. The optimized system still was not considered final as the second peak (S-enantiomer) migrated too close to the EOF, resulting in a potential inaccuracy during the determination of the chiral impurity. To fine-tune the method "one factor at a time" variation approach was applied. The final method (applying 15°C capillary temperature, 40 mbar × 4 s hydrodynamic injection, 25 kV voltage in 75 mM acetate-Tris buffer [pH 4.75] containing 20 mM SBE-α-CD as chiral selector) was validated according to the ICH guideline. RSD percentage of the resolution value, migration times, and corrected peak areas were below 5% during testing repeatability and intermediate precision. LOD and LOQ values were found to be 2.5 and 7.5 μg/mL, respectively. The method is considered linear in the 7.5-180 μg/mL range for the R-enantiomer. The robustness of the method was justified using Plackett-Burmann statistical experimental design.

Chiral separation of asenapine enantiomers by capillary electrophoresis and characterization of cyclodextrin complexes by NMR spectroscopy, mass spectrometry and molecular modeling

The enantiomers of asenapine maleate (ASN), a novel antipsychotic against schizophrenia and mania with bipolar I disorder have been separated by cyclodextrin (CD) modified capillary zone electrophoresis for the first time. 15 different CDs were screened as complexing agents and chiral selectors, investigating the stability of the inclusion complexes and their enantiodiscriminating capacities. Although initially, none of the applied chiral selectors gave baseline separation, β-CD proved to be the most effective chiral selector. In order to improve resolution, an orthogonal experimental design was employed, altering the concentration of background electrolyte, organic modifier, pH, capillary temperature and applied voltage in a multivariate manner. The developed method (160 mM TRIS-acetate buffer pH 3.5, 7 mM β-CD, at 20 °C, applying 15 kV) was successful for baseline separation of ASN enantiomers (R(s)=2.40±0.04). Our method was validated according to ICH guidelines and proved to be sensitive, linear, accurate and precise for the chiral separation of ASN. Properties of the inclusion complexes, such as stoichiometry, atomic level intermolecular host-guest connections are proposed on the basis of ROESY NMR measurement, ESI-MS spectrometry and molecular modeling studies. It was found that the ASN-β-CD complex is of 1:1 composition, and either of the aromatic rings can be accommodated in the β-CD cavity.