A simple reverse phase liquid chromatographic method has been developed and subsequently validated for simultaneous determination of ceftriaxone and sulbactam in parenteral preparation. The separation was carried out using a mobile phase consisting of phosphate buffer pH 3.5 adjusted with ortho phosphoric acid and acetonitrile (35:65). The column used was Kromasil C(8), 5 mu, 15 cm x 4.6 mm id with flow rate of 1 mL/min using PDA detection at 215 nm. The described method was linear over a concentration range of 50-250 and 100-500 mu g/mL for the assay of sulbactam and ceftriaxone, respectively. Ibuprofen (50 mu g/mL) was used as internal standard. The retention times of sulbactam, ceftriaxone and ibuprofen were found to be 2.3, 4.2 and 5.1 min, respectively. Results of analysis were validated statistically and by recovery studies. The limit of quantification (LOQ) for ceftriaxone and sulbactam were found to be 20 and 10 mu g/mL, respectively. The results of the study showed that the proposed RP-HPLC method is simple, rapid, precise and accurate, which is useful for the routine determination of ceftriaxone and sulbactam bulk drug and in its pharmaceutical dosage form.

A simple, fast, precise and accurate liquid chromatographic method was developed for the simultaneous estimation of paracetamol, methocarbamol and diclofenac potassium in tablets. Drugs were chromatographed on a reverse phase Hypersil C18 column using a mobile phase, 25 mM phosphate buffer (pH adjusted to 7.0±0.1) and acetonitrile in the ratio of 65:35 v/v. The flow rate was 1.2 ml/min and the effluent was detected at 225 nm. Chlormezanone was used as an internal standard. The retention time of paracetamol, methocarbamol and diclofenac potassium were 2.74, 3.82 and 6.05 min, respectively. The method was linear (correlation co-efficient was more than 0.999), precise (percentage residual standard deviation for 0.15 for paracetamol, 0.17 for methocarbamol and 0.16 for diclofenac potassium), accurate (overall mean average recovery yields: 99.9% for paracetamol, 100% for methocarbamol and 101% for diclofenac potassium) and selective. Due to its simplicity and accuracy, the method was suitable for routine quality control analysis of these drugs in combined dosage form.

A simple, precise and accurate high performance liquid chromatography (HPLC) method was developed for the simultaneous estimation of metformin with gliclazide and glipizide present in multicomponent dosage forms. The method was carried out on Inertsil® C18 column. A mobile phase composed of acetonitrile–water containing camphor sulphonic acid (adjusted to pH 7 using 0.1 N sodium hydroxide; 75 mM) at a flow rate of 1 ml min−1 was used for the separation. Detection was carried out at 225 nm. Tolbutamide was used as internal standard. Validation of the developed HPLC method was carried out.

A simple, precise and accurate HPLC method was developed for the simultaneous estimation of phenyl-propanolamine HCl, guaiphenesin and diphenylpyraline HCl in syrup. The method was carried out on a Shimpak C8 column with a mobile phase consisting of acetonitrile-triethylamine (pH adjusted to 3.5 using orthophosphoric acid; 0.5%), (35:65, v/v) at a flow rate of 1.2 ml min(-1). Detection was carried out at 210 nm. Diphenhydramine was used as internal standard. The validation of the method was also carried out.

A simple and precise reversed phase HPLC method was developed for the simultaneous estimation of acetaminophen, dextropropoxyphene and oxyphenbutazone in tablet formulations. The method was carried out on a Kromasil C18 (25 cm x 4.6 mm i.d., 5 I¼) column with a mobile phase consisting of acetonitrile:0.5% triethylamine (adjusted to pH 3.5 using orthophosphoric acid), (45:55 v/v) at a flow rate of 1.2 ml/min. Detection was carried out at 220 nm. Chlormezanone was used as internal standard. The retention time of acetaminophen, dextropropoxyphene, chlormezanone and oxyphenbutazone was 2.26, 3.72, 4.96 and 10.67 min, respectively. The validation of the proposed method was also carried out. The proposed method can be used for the estimation of these drugs in combined dosage forms.

Three accurate and simple methods for the simultaneous estimation of tinidazole and furazolidone in tablet formulations have been developed. The methods employ first derivative spectrophotometry, simultaneous equations and the multicomponent mode of UV-160A Shimadzu spectrophotometer. Both the drugs obey Beer's law in the concentrations employed for these methods. The results of the analysis have been validated statistically and by recovery studies.

A simple, precise and rapid reversed-phase HPLC method was developed for the simultaneous estimation of acetaminophen, ibuprofen and chlorzoxazone in formulations. The method was carried out on a Kromasil(R) C(8) column using a mixture of 0.2% triethylamine:acetonitrile (adjusted to pH 3.2 using dilute orthophosphoric acid), and detection was carried out at 215 nm using ketoprofen as internal standard. All these drugs showed linearity in the range of 2-10 mug ml(-1), and limits of quantification was found to be 10, 50 and 20 ng ml(-1) for acetaminophen, ibuprofen and chlorzoxazone, respectively.

A Simple, precise and rapid reversed phase HPLC method was developed for the simultaneous determination of atenolol and amoldipine from pharmaceutical formulations. The recovery and statistical validations were also carried out to find its applicability in routine quality control.

The concentric Mohr circles of modified apparent strain, true strain and stress permit quick visualisation and calculation of true strains and stresses from readings of gauges with known cross‐sensitivities.

The characteristics of continued displacement along constant specified directions of the common joint of a pin-jointed plane truss with members arranged symmetrically or unsymmetrically and made of elastic strain-hardening or elastic perfectly plastic material are compared.

A simple Reverse phase liquid chromatographic method has been developed and subsequently validated for simultaneous determination of Ofloxacin and Tinidazole in combination. The separation was carried out using a mobile phase consisting of 0.5%v/v Triethylamine buffer of pH 3.0 and Acetonitrile in the ratio of 73: 27. The column used was Kromasil C8, 5µ, 15 cm × 4.6 mm id with flow rate of 1.2 ml / min using PDA detection at 303 nm. The described method was linear over a concentration range of 10-50 µg/ml and 30-150 µg/ml for the assay of Ofloxacin and Tinidazole respectively. Ambroxol (50 µg/ml) was used as internal standard. The retention times of Ofloxacin, Tinidazole and Ambroxol were found to be 2.3, 4.1 and 5.1min respectively. Results of analysis were validated statistically and by recovery studies. The limit of quantification (LOQ) for Ofloxacin and Tinidazole were found to be 10 and 30 µg/ml respectively. The results of the study showed that the proposed RP-HPLC method is simple, rapid, precise and accurate, which is useful for the routine determination of Ofloxacin and Tinidazole bulk drug and in its pharmaceutical dosage form..