A validated RP-HPLC method for simultaneous determination of Metformin HCl and Vildagliptin in pharmaceutical formulation

A selective and sensitive reverse phase high performance liquid chromatographic (RP-HPLC) method has been developed for the separation and quantification of metformin HCl (MET) and vildagliptin (VILD) in tablet dosage form. The determination was carried out using phenomenax C18 column (4.6150 mm) as a stationary phase and mobile phase comprised of phosphate buffer (pH6.0): methanol (65:35v/v). The pH of phosphate buffer is adjusted to 6.0 by using orthophosphoric acid. The flow rate was maintained at 1.0ml/min and the eluent was monitored at 255nm.The retention time of MET and VILD were 1.503 min and 5.530 min respectively. The method was validated in terms of linearity, precision, accuracy, ruggedness, specificity and robustness. The method was linear over the range 50-150 g/ml for both MET (r = 0.999) and VILD (0.998). For precision studies; RSD for MET and VILD were 0.24 and 0.14 respectively. The percentage recoveries for both drugs from their tablets were 100.16 and 99.98 respectively. Inter-day; intra-day RSD for both drugs were found be 0.27 and 0.26, 0.13 and 0.29 respectively

Immunomodulatory Activity of the Methanol Extract of <i>Amorphophallus campanulatus</i> (Araceae) Tuber

Purpose: Traditionally, Amorphophallus campanulatus tuber is used for the treatment of enlarged spleen, rheumatism and tumour. Therefore, this study was designed to evaluate the immunomodulatory activity of the plant material. Method: The effect of the methanol extract (ME) of Amorphophallus campanulatus tuber on immunological function in mice was studied using charcoal clearance, spleen index and delayed-type hypersensitivity (DTH) response models. The extract was administered orally at doses of 250 and 500 mg/kg. Results: The extract exhibited immunomodulatory activity by causing a significant decrease in charcoal clearance, spleen index and delayed-type hypersensitivity (DTH) response. Conclusion: Amorphophallus campanulatus caused decreases in the charcoal clearance rate and cellular immunity by facilitating the footpad thickness response to sheep red blood cell (RBC) in sensitized mice

Immunomodulatory Activity of the Methanol Extract of Amorphophallus campanulatus (Araceae) Tuber

Purpose: Traditionally, Amorphophallus campanulatus tuber is used for the treatment of enlarged spleen, rheumatism and tumour. Therefore, this study was designed to evaluate the immunomodulatory activity of the plant material. Method: The effect of the methanol extract (ME) of Amorphophallus campanulatus tuber on immunological function in mice was studied using charcoal clearance, spleen index and delayed-type hypersensitivity (DTH) response models. The extract was administered orally at doses of 250 and 500 mg/kg. Results: The extract exhibited immunomodulatory activity by causing a significant decrease in charcoal clearance, spleen index and delayed-type hypersensitivity (DTH) response. Conclusion: Amorphophallus campanulatus caused decreases in the charcoal clearance rate and cellular immunity by facilitating the footpad thickness response to sheep red blood cell (RBC) in sensitized mice

Optically transparent frequency selective surfaces on flexible thin plastic substrates

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers

Endoscopic fine needle aspiration cytology in the diagnosis of gastro-oesophageal and colorectal malignancies.

In a prospective study we compared the diagnostic accuracy of endoscopic fine needle aspiration cytology with that of brush cytology and forceps biopsy in relation to gross tumour pattern and site in 265 confirmed consecutive cases of malignancy of the oesophagus, stomach, colon, and rectum. Aspiration cytology gave the highest diagnostic accuracy (94%), which was significantly better than that of brush cytology (84.9%) and biopsy (87.2%) (p less than 0.005). The difference was mainly related to tumour pattern. When compared to brush cytology and biopsy aspiration cytology was significantly better in submucosal tumours (92.9% v 7.1% and 14.3%, p less than 0.001); in infiltrative malignancies (95.8% v 90.1% and 78.9%, p less than 0.01), and in ulceronecrotic malignancies (90.9% v 36.4% and 45.4%, p less than 0.05). In polypoid malignancies there was a significant trend (p less than 0.05) in favour of forceps biopsy, with a diagnostic yield of 100% compared with 95% for aspiration cytology and 93.3% for brush cytology. The accuracy of the different techniques was not significantly related to the site of the tumour. The cumulative accuracy of aspiration cytology and biopsy was significantly better than that of biopsy and brush cytology (98.5% v 90.9%, p less than 0.005). Aspiration cytology was diagnostic in 21 of 24 lesions that were negative with both brush cytology and biopsy. There were no false positive cytology or histology results. We conclude that aspiration cytology is a simple, safe, and reliable technique with a high diagnostic yield and is of particular value in submucosal, infiltrative, and ulceronecrotic tumours

An gradient HPLC-DAD determination of phenylepherine, paracetamol, ambroxol and levocetrizine in pharmaceutical formulation

The development, validation and application of a simple and reliable gradient high-performance liquid chromatography–diode array detection (HPLC–DAD) procedure for the analysis of a complex mixture containing phenylephrine (PHE), paracetamol (PAR), ambroxol (AMB) and Levocetirizine (LEV) has been carried out . Chromatographic separation of PHE, PAR, AMB and LEV is achieved using a Phenomenex Ultracarb ODS-C18 (4.6×150 mm, 5 µ) column with gradient elution of the mobile phase composed of 10 mM phosphate buffer pH 3.3 and acetonitrile. A three step gradient program has been developed with step-1 elution starting with 2% (by volume) acetonitrile which ramped up linearly to 50% in 10 min, in step-2 reverting back to 20% in 5 min and in step-3 ended to achieve initial concentration of 2% in next 5 min thus contributing a total run time of 20 min. Flow rate maintained throughout the experiment is 1 mL/min. The Diode array detector (DAD) is set at 220 nm for quantification of the analytes based on measuring their peak areas. The retention times for PHE, PAR, AMB and LEV are approximately 4.4, 10.1, 14.00 and 17.90 min respectively. The proposed HPLC procedure is statistically validated with respect to linearity, ranges, precision, accuracy, selectivity and robustness. Calibration curves are found to be linear in 50 to 150% of target analyte in formulation with correlation coefficients &gt; 0.9996. The validated HPLC method is applied successfully with good recoveries of analytes from tablet dosage; no interfering peaks were encountered from the inactive ingredients

An gradient HPLC-DAD determination of phenylepherine, paracetamol, ambroxol and levocetrizine in pharmaceutical formulation

419-424The development, validation and application of a simple and reliable gradient high-performance liquid chromatography–diode array detection (HPLC–DAD) procedure for the analysis of a complex mixture containing phenylephrine (PHE), paracetamol (PAR), ambroxol (AMB) and Levocetirizine (LEV) has been carried out . Chromatographic separation of PHE, PAR, AMB and LEV is achieved using a Phenomenex Ultracarb ODS-C18 (4.6×150 mm, 5 µ) column with gradient elution of the mobile phase composed of 10 mM phosphate buffer pH 3.3 and acetonitrile. A three step gradient program has been developed with step-1 elution starting with 2% (by volume) acetonitrile which ramped up linearly to 50% in 10 min, in step-2 reverting back to 20% in 5 min and in step-3 ended to achieve initial concentration of 2% in next 5 min thus contributing a total run time of 20 min. Flow rate maintained throughout the experiment is 1 mL/min. The Diode array detector (DAD) is set at 220 nm for quantification of the analytes based on measuring their peak areas. The retention times for PHE, PAR, AMB and LEV are approximately 4.4, 10.1, 14.00 and 17.90 min respectively. The proposed HPLC procedure is statistically validated with respect to linearity, ranges, precision, accuracy, selectivity and robustness. Calibration curves are found to be linear in 50 to 150% of target analyte in formulation with correlation coefficients > 0.9996. The validated HPLC method is applied successfully with good recoveries of analytes from tablet dosage; no interfering peaks were encountered from the inactive ingredients

Stability indicating HPLC method for the simultaneous analysis of Gatifloxacin and Loteprednol in eyedrop formulation using design of experiment approach

187-197Design of experiment (DOE) assisted simple, rapid, precise and accurate stability indicating HPLC method has been developed for simultaneous estimation of Gatifloxacin (GTF) and Loteprednol (LOT) along with their forced degradation products. The developed method has been optimized and developed by using central composite design (CCD) in response surface methodology (RSM). Trails have been undertaken and ratio of phosphate buffer in mobile phase, pH of buffer and flow rate are selected as factors. Resolution, tailing factor (GTF) and tailing factor (LOTE) are selected for determining the system response in the process of method optimization. The responses have been optimized using the Derringer’s desirability function. The effective separation is achieved on Phenomenex EVO-C18 column (250 mm x 4.6 mm i.d, 5 μm particle size) with mobile composed of 10 mM phosphate buffer, pH 3.5 and organic phase composed of mixture of acetonitrile and methanol 60:40 % v/v, the flow rate was 1.0 mL/min, the signals were detected at 267 nm. The developed method was validated for linearity, accuracy, precision, and robustness. The method was applied successfully for stability samples