Lobna M. Abdel-Aziz

QUANTITATIVE DETERMINATION OF FOUR ANGIOTENSIN-II-RECEPTOR ANTAGONISTS IN PRESENCE OF HYDROCHLOROTHIAZIDE BY A GRADIENT TECHNIQUE HPLC IN THEIR PHARMACEUTICAL PREPARATIONS

Losartan potassium, Valsartan, Telmisartan, and Irbesartan are angiotensin-II-receptor antagonists (ARA II) group, which used in treatment of hypertension alone or in combination with other drugs mainly Hydrochlorothiazide. A gradient HPLC method was developed for the assay of several ARAII in presence of Hydrochlorothiazide. The method was performed by reversed phase high performance liquid chromatography using a mobile phase 0.025 M potassium dihydrogen phosphate (pH 6.0): acetonitrile = 80:20% with detection at 220 nm on an ACE C18 column (250 mm × 4.6 mm, 5 µm) at flow rate 1.5 mL/min in a gradient manner. The proposed method was validated in terms of linearity, accuracy, precision, and limits of detection and quantitation.

Development and Validation of HPLC Method for SimultaneousEstimation of Brimonidine Tartrate and Timolol Maleate in Bulk andPharmaceutical Dosage Form

Brimonidine tartrate and Timolol Maleate are used in treatment of glaucoma by decreasing intra ocular pressure. A validated HPLC method was developed for the assay of them. The method was performed on BDS HYPERSIL Cyano column (250×4.6 mm, 5 μ) and the mobile phase consisted of Ammonium acetate (pH 5.0, 0.01 M) - Methanol (40:60, V/V) which pumped at a flow rate equals to 1.5 ml/min at ambient temperature. 20 μl of drugs sample solutions were monitored at two fixed wavelengths (lambda=254.0 nm for Brimonidine Tartrate and 300.0 nm for Timolol Maleate). The proposed method was validated in terms of linearity, accuracy, precision and limits of detection and quantitation according to ICH.

Development of a Stability-Indicating HPLC Method for Simultaneous Determination of Amlodipine Besylate and Atorvastatin Calcium in Bulk and Pharmaceutical Dosage Form

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QUANTITATIVE DETERMINATION OF TELMISARTAN, RAMIPRIL, AMLODIPINE BESYLATE, AND ATORVASTATIN CALCIUM BY HPLC

Telmisartan is angiotensin-II-receptor antagonist (ARA II), which is used in treatment of hypertension alone or in combination with other antihypertensive drugs such as Ramipril and Amlodipine besylate or in combination with antihyperlipidemic agent such as Atorvastatin calcium. The RP- HPLC method was developed for the assay of Telmisartan, Ramipril, Amlodipine besylate, and Atorvastatin calcium. The method was performed by reversed phase high performance liquid chromatography using a mobile phase consisting of 0.025 M potassium dihydrogen phosphate (pH 6.0):acetonitrile = 60:40, v/v, with detection at 205 nm on a BDS Hypersil C18 (250 × 4.6 mm, 5 µm i.d) at a flow rate of 1.5 mL/min in an isocratic manner. Analytical run time was 8 min. Method exhibited good linear relationship in concentration ranges (10–60, 16–96, 10–60, 10–60 µg/mL); recovery percentages (100.06, 100.85, 99.54, 100.8%); LOD (0.58, 0.16, 0.72, 0.3 µg/mL); and LOQ (1.92 0.55, 2.4, 0.98 µg/mL) for Ramipril, Telmisartan, Amlodipine besylate, and Atorvastatin calcium, respectively. Method validation was developed following the recommendations for analytical method validation of International Conference on Harmonization (ICH) and Food and Drug Administration (FDA) organizations.

Quantitative Determination of Amlodipine Besylate, Losartan Potassium, Valsartan and Atorvastatin Calcium by HPLC in their Pharmaceutical

Amlodipine besylate is a calcium channel blocker which is used in treatment of hypertension alone or in combination with other antihypertensive drugs like angiotensin-II-receptor antagonists (ARA II) group (Losartan potassium and Valsartan) or in combination with anti hyperlipidemic agent like Atorvastatin calcium. RP- HPLC method was developed for the assay of these drugs. The method was performed by reversed phase high performance liquid chromatography using a mobile phase 0.01 M ammonium acetate buffer (pH 5.5): acetonitrile with detection at 240 nm on a spherical monomeric C18 column (250 mm × 4.6 mm, 5 μm) at flow rate of 1.5 ml/min. The proposed method was validated in terms of linearity ranged between [(2-12, 10-60, 16-96, 4-24 μg/ml) corresponding levels of 20-120% w/w of the nominal analytical concentration] with linear regression equations were [{y=64.627x – 3.6383 (r= 0.9998), y=75.385x – 8.3856 (r= 0.9997), y=64.492x – 25.981 (r= 0.9998), y=70.964x – 28.505 (r= 0.9998}], accuracy [100.18 ± 1.38, 100.79 ± 0.59, 100.45 ± 0.58 and 100.8 ± 1.69%], precision [99.29, 99.33, 99.30 and 99.30%], limits of detection [0.03, 0.18, 0.15, 0.007 μg/ml] and limits of quantitation [0.1, 0.54, 0.45, 0.024 μg/ml] for Amlodipine besylate, Losartan potassium, Valsartan and Atorvastatin calcium respectively. Method validation was developed following the recommendations for analytical method validation of International Conference on Harmonization (ICH) and Food and Drug Administration (FDA) organizations.

Quantitative Determination of Four Angiotensin-II-Receptor Antagonistsin Presence of Hydrochlorothiazide by a Gradient Technique HPLC in their Pharmaceutical Preparations

Losartan potassium, Valsartan , Telmisartan and Irbesartan are angiotensin-II-receptor antagonists (ARA II) group which used in treatment of hypertension alone or in combination with other drugs mainly Hydrochlorothiazide. A gradient HPLC method was developed for the assay of several ARAII in presence of Hydrochlorothiazide. The method was performed by reversed phase high performance liquid chromatography using a mobile phase 0.025 M potassium dihydrogen phosphate (pH 6.0): acetonitrile =80:20% with detection at 220 nm on an ACE C18 column (250 mm × 4.6 mm, 5 μm) at flow rate 1.5 ml/min in a gradient manner. The proposed method was validated in terms of linearity, accuracy, precision and limits of detection and quantitation.

Stability Indicating HPLC Method for Simultaneous Determination of Several Angiotensin-II-Receptor Antagonists in Their Dosage Forms

A stability-indicating reversed-phase liquid chromatographic (RP-HPLC) method has been established for simultaneous determination of four angiotensin-II-receptor antagonists (Losartan potassium, Valsartan, Telmisartan and Irbesartan) in the presence of the degradation products generated in studies of forced decomposition. All drug substances were subjected to drastic condition of stress studies involving hydrolysis by acid and base, thermal decomposition by heat at 70°C, oxidation by hydrogen peroxide and photo degradation. Losartan potassium and Valsartan were degraded acidic conditions. Irbesartan was degraded basic conditions. Telmisartan showed good stability against all stress conditions. Successful separation of the drugs from the degradation products was achieved on ACE C18 column (250 mm×4.6 mm, 5 μm) with 65:35 % (v/v) potassium dihydrogen phosphate (0.025 M, pH 6.0): acetonitrile as a mobile phase at flow rate 1.5 ml/min with UV detection at 220 nm. The proposed method was validated in terms of linearity, accuracy, precision and limits of detection and quantitation. Statistical analysis proved the method enabled reproducible and selective quantification of these drugs as the bulk drug and in pharmaceutical dosage forms. Because the method effectively separates the drugs from their degradation products, it can be used as stability-indicating.

HPLC METHOD FOR DETERMINATION OF FLUOROMETHOLONE AND SODIUM CROMOGLYCATE IN BULK AND OPHTHALMIC SOLUTION

Fluorometholone and Sodium Cromoglycate are used in the treatment of allergic conjunctivitis. A validated HPLC method was developed for the assay of them. The method was performed on BDS HYPERSIL C18 column (250x4.6 mm, 5μ) and the mobile phase consisted of potassium dihydrogen phosphate (pH 4.5, 0.025M) - Acetonitrile (40:60, V/V) which pumped at a flow rate 1.0 ml/min at ambient temperature. 20 μl of drugs sample solutions were monitored at two fixed wavelengths (lambda = 240.0 nm for Sodium Cromoglycate and 330.0 nm for Fluorometholone). The proposed method was validated in terms of linearity, accuracy, precision and limits of detection and quantitation according to ICH

Spectrophotometric Determination of Atorvastatin Calcium and RosuvastatinCalcium in Bulk and Dosage Form Using P-Dimethylaminobenzaldehyde

A simple and sensitive spectrophotometric method is described for determination of atorvastatin calcium and rosuvastatin calcium in bulk and tablet forms. The method depends on the formation of colored chromogen between atorvastatin calcium and rosuvastatin calcium and p-dimethylaminobenzaldehyde (PDMAB) in acidic conditions and the reaction mixture exhibits maximum absorbance at λmax 540 and 570 nm for atorvastatin calcium and rosuvastatin calcium, respectively. Under the indicated conditions, this method was linear over the concentration range of 20-160 μg/ml and 2-16 μg/ml for atorvastatin calcium and rosuvastatin calcium, respectively. The method was statistically applied for the determination of drugs in both bulk and tablet forms. Results were compared with reference methods and no significant difference was obtained.

HPLC Determination of Carvedilol, Candesartan Cilexetil and Hydrochlorothiazide in Their Bulk and Tablet Dosage Forms

Abstract An isocratic HPLC method was developed for rapid simultaneous separation and determination of carvedilol, candesartan cilexetil and hydrochlorothiazide in pure and tablet dosage form. Separation was carried out on a Hypersil gold C18 (15 μm, 100 x 4.6 mm) column. Mobile phase composed of methanol, acetonitrile and 0.1% ortho-phosphoric acid in the ratio of (35:50:15, v/v/v). The flow rate was 0.8 ml/min and UV detection was measured at 215 nm. Linearity range was observed from 1–90 μg/ml for the three drugs. The proposed method was validated in terms of linearity, accuracy, precision and limits of detection and quantitation according to ICH. The obtained results were compared with reference methods.