Spectrophotometric and HPLC methods for simultaneous estimation of amlodipine besilate, losartan potassium and hydrochlorothiazide in tablets.

Two UV-spectrophotometric and one reverse phase high performance liquid chromatography methods have been developed for the simultaneous estimation of amlodipine besilate, losartan potassium and hydrochlorothiazide in tablet dosage form. The first UV spectrophotometric method was a determination using the simultaneous equation method at 236.5, 254 and 271 nm over the concentration range 5-25, 10-50 and 5-25 mug/ml for amlodipine besilate, losartan potassium and hydrochlorothiazide, respectively. The second UV method was a determination using the area under curve method at 231.5-241.5, 249-259 and 266-276 nm over the concentration range of 5-25, 5-25 and 10-50 mug/ml for amlodipine besilate, hydrochlorothiazide and losartan potassium, respectively. In reverse phase high performance liquid chromatography analysis is carried out using 0.025 M phosphate buffer (pH 3.7):acetonitrile (57:43 v/v) as the mobile phase and Kromasil C18 (4.6 mm i.dx250 mm) column as stationery phase with detection wavelength of 232 nm linearity was obtained in the concentration range of 2-14, 20-140 and 5-40 mug/ml for amlodipine besilate, losartan potassium and hydrochlorothiazide, respectively. Both UV-spectrophotometric and reverse phase high performance liquid chromatography methods were statistically validated and can be used for analysis of combined dose tablet formulation containing amlodipine besilate, losartan potassium and hydrochlorothiazide.

Simultaneous estimation of amlodipine besilate and olmesartan medoxomil in pharmaceutical dosage form.

Two UV Spectrophotometric and one reverse phase high performance liquid chromatography methods have been developed for the simultaneous estimation of amlodipine besilate and olmesartan medoxomil in tablet dosage form. First UV spectrophotometric method was a determination using the simultaneous equation method at 237.5 nm and 255.5 nm over the concentration range 10-50 mug/ml and 10-50 mug/ml, for amlodipine besilate and olmesartan medoxomil with accuracy 100.09%, and 100.22% respectively. Second UV spectrophotometric method was a determination using the area under curve method at 242.5-232.5 nm and 260.5-250.5 nm over the concentration range of 10-50 mug/ml and 10-50 mug/ml, for amlodipine besilate and olmesartan medoxomil with accuracy 100.10%, and 100.48%, respectively. In reverse phase high performance liquid chromatography analysis carried out using 0.05M potassuim dihydrogen phosphate buffer:acetonitrile (50:50 v/v) as the mobile phase and Kromasil C18 (4.6 mm i.d.x250 mm) column as the stationery phase with detection wavelength of 238 nm. Flow rate was 1.0 ml/min. Retention time for amlodipine besilate and olmesartan medoxomil were 3.69 and 5.36 min, respectively. Linearity was obtained in the concentration range of 4-20 mug/ml and 10-50 mug/ml for amlodipine besilate and olmesartan medoxomil, respectively. Proposed methods can be used for the estimation of amlodipine besilate and olmesartan medoxomil in tablet dosage form provided all the validation parameters are met.

Changing patterns of airway accidents in intubated ICU patients.

OBJECTIVE: To document the changes in patterns of airway accidents in intubated patients. DESIGN: Prospective recording of all airway accidents over two periods: 1994-1997 and 1998-1999. PATIENTS: Ventilated patients (5,046) intubated for 9,289 days over 4 years (1994-1997) and 2,932 ventilated patients intubated for 6,339 days over 2 years (1998-1999). MEASUREMENTS: The incidence and pattern of airway accidents over a 2-year period were compared to an earlier similar analysis done in the previous 4 years. RESULTS: The total accident rate in the 1994-1997 period was 36 in 5,046 patients over 9,289 intubated-patient days. The total accident rate in the period 1998-1999 was 20 in 2,932 patients over 6,339 intubated-patient days. The frequency of blocked tracheal tube increased to equal that of unplanned extubation (UE) of endotracheal tube (ETT) as the commonest airway accident. There were nine episodes of blocked tracheal tube in the two current years compared to four in the previous 4 years and there were nine episodes of UE in the two current years compared to 15 in the previous 4 years. There were a total of 18 ETT accidents in 2,930 patients over 5,309 ETT days compared to a total of two tracheostomy accidents in 67 patients over 1,030 tracheostomy days. CONCLUSIONS: We noted a change of the pattern of airway accidents. We noted an increasing trend in the incidence of blocked tracheal tubes, associated with an increased duration of heat and moisture exchanger-filters use. We also noted that the incidence of tracheostomy tube accidents was similar to that of ETT accidents in the current study, unlike the earlier study where tracheostomy tube accidents were more frequent than ETT accidents. This was due to the elimination of tracheostomy tube displacements during the later study period. We associated this with the use of adjustable tracheostomy length tubes.