Bhavesh H. Patel

HPLC Analysis for Simultaneous Determination of Rabeprazole and Domperidone in Pharmaceutical Formulation

Abstract A simple and sensitive reversed phase high performance liquid chromatographic (RP‐HPLC) method has been developed for the quantitative estimation of rabeprazole and domperidone in their combined dosage forms. Rabeprazole and domperidone were chromatographed using 0.01 M, pH 6.5 ammonium acetate buffer:methanol:acetonitrile (40:30:30 v/v, pH 7.44) as the mobile phase at a flow rate of 1.0 mL min−1 at ambient temperature and detected at 287 nm. The retention time (RT) of rabeprazole and domperidone were found to be 6.13±0.01 and 8.38±0.02, respectively. The linearities of rabeprazole and domperidone were in the range of 200–2000 ng/mL and 300–3000 ng/mL, respectively. The limit of detection was found to be 65.67 ng/mL for rabeprazole and 98.33 ng/mL for domperidone. The proposed method was applied for the determination of rabeprazole and domperidone in combined dosage forms.

Simultaneous Determination of Omeprazole and Domperidone in Capsules by RP‐HPLC and Densitometric HPTLC

Abstract A rapid, simple, and sensitive HPLC and a densitometric HPTLC method for the determination of omeprazole and domperidone in capsule formulations were developed and validated. For HPLC, the separation of components was achieved on a Phenomenex Rp‐C18 column. Isocratic elution with a mobile phase consisting of 0.01 M pH 6.5, ammonium acetate buffer: methanol:acetonitrile (40:30:30 v/v, pH 7.44±0.02), at a flow rate 1.0 mL/min was employed. Rabeprazole was used as the internal standard. In densitometric HPTLC, separation was achieved on aluminum sheets of silica gel 60F254 using ethyl acetate:methanol:benzene (40:20:40 v/v) as mobile phase. Linear concentration range of HPLC and HPTLC methods were between 400–2000 ng/mL and 120–360 ng/spot for both the drugs, respectively. In HPLC, the detection limit was 131.27 ng/mL for omeprazole and 131.20 ng/mL for domperidone, the mean analytical recovery in determination of omeprazole and domperidone capsules was 99.14±1.81 for omeprazole and 99.63±1.68 for domperidone. Whereas, the detection limit was 40.83 ng/spot for omeprazole and 40.53 ng/spot for domperidone, the mean analytical recovery in determination of omeprazole and domperidone capsules was 99.51±0.91 and 99.48±1.15, respectively, in HPTLC. The components were detected by UV detection at 295 nm. Thus, the proposed method is applicable for routine determination of omeprazole and domperidone in pharmaceutical formulations.

In vitro metabolism, disposition, preclinical pharmacokinetics and prediction of human pharmacokinetics of DNDI-VL-2098, a potential oral treatment for Visceral Leishmaniasis

The in vitro metabolism and in vivo pharmacokinetic (PK) properties of DNDI-VL-2098, a potential oral agent for Visceral Leishmaniasis (VL) were studied and used to predict its human pharmacokinetics. DNDI-VL-2098 showed a low solubility (10μM) and was highly permeable (>200nm/s) in the Caco-2 model. It was stable in vitro in liver microsomes and hepatocytes and no metabolite was detectable in circulating plasma from dosed animals suggesting very slow, if any, metabolism of the compound. DNDI-VL-2098 was moderate to highly bound to plasma proteins across the species tested (94-98%). DNDI-VL-2098 showed satisfactory PK properties in mouse, hamster, rat and dog with a low blood clearance (<15% of hepatic blood flow except hamster), a volume of distribution of about 3 times total body water, acceptable half-life (1-6h across the species) and good oral bioavailability (37-100%). Allometric scaling of the preclinical PK data to human gave a blood half-life of approximately 20h suggesting that the compound could be a once-a-day drug. Based on the above assumptions, the minimum efficacious dose predicted for a 50kg human was 150mg and 300mg, using efficacy results in the mouse and hamster, respectively.

A simple and sensitive HPTLC method for quantitative analysis of pitavastatin calcium in tablets

A quantitative high-performance thin-layer chromatographic method for determination of pitavastatin calcium in pharmaceutical preparations has been established and validated. Pitavastatin calcium from the formulations was separated and identified on silica gel 60F254 HPTLC plates with toluene-methanol-glacial acetic acid 7.6:2.36:0.04 (v/v) as mobile phase. The plates were developed to a distance of 8 cm and well resolved bands were obtained for pitavastatin calcium. Quantification was performed at 238 nm. The method was validated for specificity, precision, robustness, and accuracy. The calibration plot for pitavastatin calcium standard was linear in the range 40-250 ng per band with r = 0.9992, slope = 8.2415, and intercept = 203.2359. The limits of detection and quantification were 6.6 and 20.0 ng per band, respectively. The method is selective, sensitive, and specific with potential application in pharmaceutical analysis.

SIMULTANEOUS DETERMINATION OF METFORMIN HYDROCHLORIDE AND GLIPIZIDE IN TABLET FORMULATION BY HPTLC

Simultaneous determination of two antidiabetic drugs, metformin and glipizide, in pharmaceutical tablet formulations were investigated. Normal phase thin layer chromatography plate (silica gel 60 F254) was used as the stationary phase and water:methanol:0.5% w/v ammonium sulfate solution (6:3:1.5 v/v/v) as the mobile phase to determine two pharmaceutically active ingredients in formulations of Glynase-MF. This system gave a good resolution for metformin (Rf value of 0.22 ± 0.01) and glipizide (Rf value of 0.85 ± 0.01). The λmax was at 236 nm. The linear regression data for the calibration plot showed a good relationship with r = 0.9962 and 0.9930 for metformin and glipizide, respectively. The method was validated for precision and recovery. The limits of detection and quantification were 991.30 and 3003.95 ng/band for metformin and 9.57 and 29.01 ng/band for glipizide, respectively.

A Simple and Sensitive HPTLC Method for Simultaneous Determination of Metformin Hydrochloride and Sitagliptin Phosphate in Tablet Dosage Form

A simple, rapid, and precise high-performance thin-layer chromatographic (HPTLC) method for simultaneous estimation of two antidiabetic drugs, metformin hydrochloride and sitagliptin phosphate, in tablet dosage form has been developed and validated. Chromatography was performed on silica gel 60 F254 plates with butanol : water : glacial acetic acid (6 : 2 : 2, v/v/v) as mobile phase. This system gave a good resolution for metformin hydrochloride ( value of 0.35 ± 0.01) and sitagliptin phosphate ( value of 0.75 ± 0.01). Detection and quantification were carried out at 227 nm. The linear regression data for the calibration plot showed a good relationship with and 0.9991 for metformin hydrochloride and sitagliptin phosphate, respectively. The method was validated for precision and recovery. The limits of detection and quantification were 13.05 and 39.56 ng/μL for metformin hydrochloride and 2.65 and 8.03 ng/μL for sitagliptin phosphate, respectively. The amounts of the drugs in the marketed formulation were 99.86% and 98.91% for metformin hydrochloride and sitagliptin phosphate, respectively.

Determination of Escitalopram Oxalate and L-Methylfolate in Tablet by Spectrophotometric and Reverse Phase High-Performance Liquid Chromatographic Methods

Two new simple and selective assay methods have been presented for the analysis of Escitalopram Oxalate (ESC) and L-Methylfolate (L-MF) in pharmaceutical formulations. The ultraviolet (UV)-Spectrophotometric simultaneous equation method was based on the measurement of absorbance at 238 nm (ʎmax of ESC) and 284 nm (ʎmax of L-MF) in methanol. The assay was linear over the concentration ranges 0.5-12.0 μg/mL for ESC and 0.5-9.0 μg/mL for L-MF. The quantitation limits for ESC and L-MF were found to be 0.912 and 0.667 μg/mL; while the detection limits were 0.301 and 0.220 μg/mL for ESC and L-MF, respectively. The second method involved isocratic reversed-phase liquid chromatography using a mobile phase composed of methanol-0.02 M phosphate buffer (pH 5.5) (75:25, v/v), Hypersil BDS-C18 Column (5 µm, 250 mm × 4.6 mm i.d.) with detection at 270 nm. The linearity ranges were found to be 3.0-30.0 and 0.75-22.5 μg/mL for ESC and L-MF, respectively. The limits of detection were found to be 1.065 and 1.160 μg/mL for ESC and L-MF, respectively. The limits of quantitation were found to be 3.226 and 3.515 μg/mL for ESC and L-MF, respectively. The proposed methods were successfully applied to the determination of commercially available tablets with a high percentage of recovery, good accuracy and precision.

RAPID AND SENSITIVE SIMULTANEOUS ESTIMATION OF METFORMIN HYDROCHLORIDE AND PIOGLITAZONE HYDROCHLORIDE IN TABLET FORMULATION BY HPTLC METHOD

A rapid, simple, and sensitive HPTLC method for simultaneous estimation of two antidiabetic drugs, metformin hydrochloride and pioglitazone hydrochloride, in pharmaceutical tablet was developed and validated. Separation was achieved on aluminum sheets of silica gel 60 F254 using butanol:1, 4-dioxane:glacial acetic acid (5:3:2, v/v/v) as the mobile phase. This system gave a good resolution for metformin hydrochloride (R f value of 0.36 ± 0.01) and pioglitazone hydrochloride (R f value of 0.73 ± 0.01). Detection and quantification was carried out at 226 nm. Calibration plot was constructed in the range of 2000 to 20000 ng/band for metformin hydrochloride and 60 to 600 ng/band for pioglitazone hydrochloride. The linear regression data for the calibration plot showed a good relationship with r = 0.9960 and 0.9968 for metformin hydrochloride and pioglitazone hydrochloride, respectively. Assays for metformin hydrochloride and pioglitazone hydrochloride were 99.6% (RSD 0.618%) and 99.7% (RSD 0.511%), respectively, for the brand analyzed. The method was validated for precision and recovery. The limits of detection and quantification were 629.89 and 1908.76 ng/band for metformin hydrochloride and 8.51 and 25.77 ng/band for pioglitazone hydrochloride, respectively.