Fexofenadine is a non-sedative and selective peripheral H 1 receptor antagonist prescribed for allergic rhinitis and chronic urticaria. This article deals with a simple, feasible, and sensitive isocratic reverse-phase highperformance liquid chromatographic method for the determination of fexofenadine hydrochloride in bulk drug, pharmaceutical dosage forms and in human serum. The chromatography was carried out at 20 ± 2°C using two different chromatographs and five different stationary phases. The isocratic mobile phase was phosphate buffer pH 7.4 and methanol (methanol-phosphate buffer, 35:65, v/v), detection was made at 218 nm and the mobile phase flowed at 1 ml min -1 . Validation parameters included linearity, accuracy, precision, specificity, limit of detection (LOD), limit of quantification (LOQ), and robustness over a linearity range 5-15 lg ml -1 according to the ICH guidelines (r [ 0.9999), the inter-and intra-day precisions were relative standard deviation (RSD) \ 0.8%. The system suitability was scrutinized by capacity factor, tailing factor, and number of theoretical plates (capacity factor [ 2.0, tailing factor B 2.0, and theoretical plates [ 2000). The retention time for five different stationary phases ranged from 3.78 to 4.15 min. The LOD and LOQ for the procedure were executed on samples containing very low concentrations of analytes on two different commercial brands of detectors.

Summary.A simple, rapid, and sensitive high-performance liquid chromatography method was developed and validated for the simultaneous determination and quantification of fusidic acid and steroids (prednisone, betamethasone valerate, hydrocortisone acetate, and dexamethasone sodium) from bulk drugs and human plasma. A RP-HPLC, operated at ambient temperature, was equipped with a UV detector for monitoring the effluents at 235 nm. The mobile phase consisted of methanol, acetonitrile, and 0.05 M phosphoric acid (10:60:30, v/v/v), and separation was achieved on a Medeterrane, C18 (5 µm, 12.5 x 0.46 mm) column at a flow rate of 1.7 mL min −1 . Calibration curves were linear over concentration range 0.625-10 μg mL −1 with correlation coefficient (r 2 ) greater than 0.9999. The coefficient of variation (CV) and relative error (RE) for intra-and interassay were <2% and <1%, respectively. Interference of other already administered common medicaments, such as aspirin, paracetamol, caffeine, nicotine, and other plasma components, were not found.

The fresh specimens of Champia compressa Harvey, Gelidium usmanghanii Afaq-Husain and M. Shameel, Gracilaria foliifera (Forsskål) Børgesen and Hypnea musciformis (Wulfen) J. V. Lamouroux, were collected from the coastal areas of Karachi (Pakistan) and their yield of agar was observed. With preextraction technique the percentage of algal yield was found to range from 13 to 28%. High quality gel strength was determined by modulus of elasticity i.e. (550 – 612g/cm2) and 1090 kPa and extraction time was 2 hrs. The structure of agar and agar contents were investigated by FT-IR spectroscopy for the first time from Pakistan. The results revealed some interesting characters (non sulphated β-D galacto pyranose residues, 3,6 anhydro galactose vibration), which were not reported earlier.

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