Spectrophotometric and HPLC determinations of anti-diabetic drugs, rosiglitazone maleate and metformin hydrochloride, in pure form and in pharmaceutical preparations

Biguanide Pharmaceutical Formulations and the Applications of Bile Acid-Based Nano Delivery in Chronic Medical Conditions

Biguanides, particularly the widely prescribed drug metformin, have been marketed for many decades and have well-established absorption profiles. They are commonly administered via the oral route and, despite variation in oral uptake, remain commonly prescribed for diabetes mellitus, typically type 2. Studies over the last decade have focused on the design and development of advanced oral delivery dosage forms using bio nano technologies and novel drug carrier systems. Such studies have demonstrated significantly enhanced delivery and safety of biguanides using nanocapsules. Enhanced delivery and safety have widened the potential applications of biguanides not only in diabetes but also in other disorders. Hence, this review aimed to explore biguanides’ pharmacokinetics, pharmacodynamics, and pharmaceutical applications in diabetes, as well as in other disorders.

Comparative Study of Different Derivative Spectrophotometric Techniques for the Analysis and Separation of Metformin, Empagliflozin, and Glimepiride

Background:

In some cases, lifestyle changes are not enough to keep type 2 diabetes under control, so there are several medications that may help. Metformin can lower your blood sugar levels, Glimepiride makes more insulin, whereas Empagliflozin prevents the kidneys from reabsorbing sugar into the blood and sending it out in the urine.

Methods:

Mean centering, double divisor, ratio spectra-zero crossing, and successive derivative were applied for the estimation of metformin, empagliflozin, and glimepiride respectively, in their prepared laboratory mixtures and in pharmaceutical tablets, without prior chemical separation. The absorption spectra of the mentioned drugs were recorded in the range of 200-400nm.

Results:

These methods were linear over concentration ranges of 1.0-10, 2.5-30, and 1.0-10 μgmL-1 of metformin, empagliflozin, and glimepiride respectively. Mean centering for metformin was measured at 234 and 248 nm, while empagliflozin and glimepiride had amplitude values at 276 and 262 nm, respectively. The derivative of double divisor was measured at 234, 278, and 288 nm for metformin, empagliflozin and glimepiride, respectively. The ratio of spectra-zero crossing was quantified at amplitude values of the analytical signal at 234 and 274 nm for metformin and empagliflozin, respectively, whereas glimepiride was determined at 242 and 286 nm. The successive ratio of metformin, empagliflozin, and glimepiride was determined at 284, 242, and 266 nm, respectively.

Conclusion:

The methods are validated according to the ICH guidelines where accuracy, precision and repeatability are found to be within the acceptable limit. The methods were studied and optimized. Upon validation linearity, precision, accuracy, LOD, LOQ and selectivity were proved to be operative for the analysis of specified drugs in pharmaceutical dosage configuration. Statistical illustration was done between the suggested methods with the reported methods with consideration to accuracy and precision. No significant difference was found by student’s t-test, F-test and one-way ANOVA.

Determination of levetiracetam in human plasma by online heart-cutting liquid chromatography: Application to therapeutic drug monitoring

Levetiracetam is an antiepileptic drug for the treatment of psychiatric patients. In this study, a selective, straightforward, and rapid online heart-cutting liquid chromatography method was developed for the therapeutic drug monitoring of levetiracetam. This method allows for the determination of levetiracetam in human plasma without complex sample preparation. The mobile phases consisted of 30 mM aq. orthophosphoric acid solution/methanol (70:30) at a flow rate of 1 mL/min for the first system and 10 mM aq. orthophosphoric acid solution/methanol (55:45) at a flow rate of 1 mL/min for the second system. The first separation was carried out on a GL Sciences Intersil ODS-3 column (4.6 mm × 150 mm, 3 µm) and the second separation was carried out on a Restek Ultra PFPP column (4.6 mm × 150 mm, 5 µm). The detection was carried out at 205 nm for both systems. The method was validated for selectivity and linearity, which were in the 6-60 µg/mL range. Intra- and interassay accuracies were <112.6%, and the intra- and interassay precisions were <6.4% for all quality control samples. The lower limit of quantitation was 6 µg/mL. The developed method was successfully applied for therapeutic drug monitoring of plasma samples from patients.

A Sensitive HPTLC Method for the Estimation of Glibenclamide, Rosiglitazone Maleate and Metformin Hydrochloride from a Multicomponent Dosage Form

A sensitive, rapid and cost-effective method based on HPTLC with UV detection was developed for the quantitation of Glibenclamide (GLIBEN), Rosiglitazone maleate (ROSI) and Metformin hydrochloride (MET) from a combined dosage form. Pre-coated RP-18 F254s aluminum sheets were used as the stationary phase. Methanol–tetrahydrofuran–water–glacial acetic acid (16: 3.6: 4: 0.4, v/v) used as the mobile phase, along with chamber saturation of 10 min offered an optimum migration (Rf = 0.54, 0.62 and 0.80 for GLIBEN, ROSI and MET, respectively). TLC Scanner 3 was used for densitometric evaluation of the chromatograms. DigiStore 2 Documentation System with winCATS software version 1.4.10 was used for the quantitation and photodocumentation. The LOD for GLIBEN, ROSI and MET was found to be 80 ng, 80 ng and 48 ng, respectively. Moreover, the LOQ was 200 ng, 200 ng and 120 ng for GLIBEN, ROSI and MET, respectively. The method was linear for GLIBEN (r = 0.9991), ROSI (r = 0.9993) and MET (r = 0.9988) within the tested range (200–1000, 200–1000 and 120–600 ng/band, respectively). The method was found to be precise and accurate for all the three drugs. The method was applied for the analysis of Triglucored tablets, and it proved to be a reliable quality control tool for the routine analysis of GLIBEN, ROSI and MET in a combined dosage form.

A Facile Colorimetric and Spectrophotometric Method for Sensitive Determination of Metformin in Human Serum Based on Citrate-Capped Gold Nanoparticles: Central Composite Design Optimization

For the determination of Metformin in human serum, a facile colorimetric and spectrophotometric sensor was designed based on citrate-capped gold nanoparticles (citrate-GNPs). In this probe, the addition of Metformin to GNP solution generates a naked-eye color change resulting from the aggregation of GNPs. Study of this color conversion and quantity analysis of analyte is operated by spectrophotometric instruments. The three factors pH, time, and GNP ratio were selected to examine their effects on sensing results and their values optimization. The optimization of parameters was done by means of central composite design and one-at-a-time methods. The sensing results proved the highly selective and sensitive performance of the sensor for Metformin in a linear range of 6.25-133.3 ppm with a detection limit of 1.79 ppm. The relative standard deviation (RSD) of the reported method is 2.53%.

Rapid Detection of Six Glucocorticoids Added Illegally to Dietary Supplements by Combining TLC with Spot-Concentrated Raman Scattering

The objective of this study was to establish a novel method for rapid detection of six glucocorticoids (prednisone, prednisone acetate, prednisolone, hydrocortisone, hydrocortisone acetate, and dexamethasone) added illegally in dietary supplements simultaneously by combining thin layer chromatography (TLC) with spot-concentrated Raman scattering (SCRS). The doping ingredients were separated by TLC, and viewed and located with UV light (254 nm), enriched by chromatography, then Raman spectra were directly detected by a Raman Imagine microscope with 780 nm laser source. This method had complementary advantages of TLC and Raman spectroscopy, which enhanced the specificity of the test results. The limit of detection (LOD) of the reference substances were 4 μg, 4 μg, 4 μg, 6 μg, 6 μg, and 4 μg, respectively. The method was used to study the six glucocorticoids added illegally in five dietary supplements. Fake drugs had been detected. The study showed that the TLC-SCRS method is simple, rapid, specific, sensitive, and reliable. The method could be used for effective separation and detection of six chemical components used in dietary supplement products, and would have good prospects for on-site qualitative screening of dietary supplement products for adulterants.

Preparation and in vitro evaluation of enteric-coated tablets of rosiglitazone sodium

The aim of this study was to prepare the rosiglitazone sodium enteric-coated tablets and investigate its release rate. The rosiglitazone sodium enteric-coated tablet was prepared by single punch tablet press using substituted hydroxypropyl cellulose and polyvinylpyrrolidone (PVP). The release rate from the enteric-coated tablet of rosiglitazone sodium was evaluated. The release rate study showed that few rosiglitazone sodium was released from enteric coated formulation within 2 h in simulated gastric juice, while it released more than 80% of the labeled amount in 30 min in simulated intestinal juice. The preparing method of rosiglitazone sodium enteric-coated tablets was simple and had a good reproducibility. The release condition and determined methods could be used for the routine determinations of rosiglitazone sodium enteric-coated tablets.

Simultaneous identification, confirmation and quantitation of illegal adulterated antidiabetics in herbal medicines and dietary supplements using high-resolution benchtop quadrupole-Orbitrap mass spectrometry

This paper presents an application of ultrahigh-performance liquid chromatography and quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HR MS) for the screening, confirmation and quantification of 11 antidiabetics in herbal medicines and dietary supplements. The mass spectrometer was operated in Full MS/dd-MS(2) (data-dependent MS(2)) mode. The full MS scan acquired data for identification and quantification, and dd-MS(2) scan obtained product ion spectra for confirmation. UHPLC-Q-Orbitrap MS quantification was achieved using matrix-matched standard calibration curves with phenacetin as internal standard. The method validation that included selectivity, sensitivity, calibration curve, accuracy and precision, recovery, matrix effect and stability was evaluated. The response showed good linear relationship with the concentrations of analytes over wide ranges (e.g., 0.0004-1 μg/g for metformin) with all the coefficients of correlation (r(2)) >0.9991. The detection limits (LODs) were in the range of 0.05-0.5 ng/g for different analytes. The recoveries yielded results higher than 74.3% for all compounds. The accuracy was in the range of -6.75 to 3.85%, while the intra- and inter-day precision ranged from 0.048 to 11.5%. Among 63 batches of herbal medicines and 34 batches of dietary supplements samples, 7 batches of dietary supplements were positive, while all the herbal medicines were negative. Overall, the novel UHPLC-Q-Orbitrap has demonstrated great performance for identification, confirmation and quantification of antidiabetics in herbal medicines and dietary supplements, ensuring food safety and public health.

Development and validation of spectrophotometric and HPTLC methods for simultaneous determination of rosiglitazone maleate and metformin hydrochloride in the presence of interfering matrix excipients

Two simple methods have been developed and validated for the simultaneous determination of rosiglitazone maleate (ROS) and metformin hydrochloride (MET) in synthetic mixtures and coated tablets in a ratio of 1:250 (ROS:MET). The first method was a spectrophotometric one. The minor component, ROS was determined by measuring the values of absorbance at λmax 312 nm and the D1 amplitudes at 331 nm where MET shows no absorption contribution. However, absorbance interferences from tablet excipients were successfully corrected by D1 at 331 nm zero-crossing technique. Study of spectral interference from tablet excipients was included in the text. Standard curves for Amax and D1 methods were in the concentration range 20.0-80.0 μg mL(-1). The major component, MET was determined both in binary mixtures and tablets by measuring its Amax at 236 nm. Extensive dilution eliminated any absorption contribution from the coexisting ROS or tablet matrix. Standard curves showed linearity in the concentration range 4.0-12.8 μg mL(-1). The second method was based on high performance thin layer chromatography (HPTLC) separation of the two drugs followed by densitometric measurements of their spots at 230 nm. The separation was carried out on Merck HPTLC aluminium sheets of silica gel 60 F254 using methanol:water:NH4Cl 1% w/v (5:4:1 v/v/v) as the mobile phase. Linear calibration graphs of peak area values were obtained versus concentrations in the range of 0.4-2.0 μg band(-1) and 20.0-100.0 μg band(-1) for ROS and MET, respectively. According to International Conference on Harmonisation (ICH) guidelines, different validation parameters were verified for the two methods and presented.

Stability-indicating HPTLC method for simultaneous determination of nateglinide and metformin hydrochloride in pharmaceutical dosage form

A stability indicating high performance thin layer chromatography (HPTLC) method was developed and validated for determination of two anti-diabetic drugs, nateglinide and metformin hydrochloride in co-formulations. Study was performed on pre-coated silica gel HPTLC plates using chloroform:ethyl acetate:acetic acid (4:6:0.1 v/v/v) as the mobile phase. A TLC scanner set at 216 nm was used for direct evaluation of the chromatograms in the reflectance/absorbance mode. Method was validated according to ICH guidelines. The correlation coefficients of calibration curves were found to be 0.996 and 0.995 in the concentration range of 200-2400 and 500-3000 ng band(-1) for nateglinide and metformin, respectively. The method had an accuracy of 99.72% for nateglinide and 100.08% for metformin hydrochloride. The method had the potential to determine these drugs simultaneously from dosage forms without any interference of the tablets excipients. Nateglinide and metformin hydrochloride were also subjected to acid, base, oxidation, wet, heat and photo-degradation studies. The degradation products obtained were well resolved from the pure drugs with significantly different Rf values. As the method could effectively separate the drugs from its degradation products, it can be used for stability-indicating analysis.