Current status and future prospects of drug eluting stents for restenosis.

Drug-eluting stents (DESs) prevail in the treatment of carotid artery diseases in the interventional cardiology world owing to their efficacy for significant reduction of restenosis. A current successful DES requires a polymer coating for drug delivery. Clinical trials examining several pharmaceutical agents have demonstrated marked reduction in restenosis following stenting. The development of DES is one of the major revolutions in the field of interventional cardiology. The ideal drug to prevent restenosis must have an anti-proliferative and anti-migratory effect on smooth muscle cells but, on the other hand, it must also enhance re-endothelialization in order to prevent late thrombosis. Additionally, it should effectively inhibit the anti-inflammatory response after balloon induced arterial injury. Although DES have significantly reduced the angiographic restenosis rate and have improved clinical outcomes, late thrombosis and restenosis remain an important subject of ongoing research.

Formulation of furosemide solid dispersion with micro crystalline cellulose for achieve rapid dissolution.

Furosemide, a weekly acidic, loop diuretic drug indicated for treatment of edema and hypertension having high permeability through stomach. It is practically insoluble in gastric fluid (0.006 mg/ mL) and having highly permeability through stomach but due to its solubility limitation it can't enter into systemic circulation. It was logically decided to design experiment, so as to achieve the set objectives. Attempt was made to prepare solid dispersion of furosemide with Poly ethylene glycol (PEG) 6000 containing microcrystalline cellulose (MCC) as adsorbent which would dissolve completely in less than 30 minutes (target selected by considering minimum gastric empting time). Microcrystalline cellulose converted sticky dispersion in to free flow powder hence increase surface area which responsible for dissolution improvement. Factorial design was applied to optimize formulation. Amount of poly ethylene glycol 6000 and microcrystalline cellulose were selected as an Independent variable while angle of repose and T(100%) were selected as dependent variable. Attempts for dissolution rate of furosemide improve bioavailability and consequently dose reduction would possible.

Stability-indicating reversed-phase liquid chromatographic method for simultaneous determination of simvastatin and ezetimibe from their combination drug products.

A simple, precise, and rapid stability-indicating reversed-phase column liquid chromatographic (RP-LC) method has been developed and subsequently validated for simultaneous estimation of simvastatin (SIM) and ezetimibe (EZE) from their combination drug product. The proposed RP-LC method utilizes a LiChrospher 100 C18, 5 microm, 250 x 4.0 mm id column at ambient temperature; optimum mobile phase consisting of acetonitrile-water-methanol (60 + 25 + 15, v/v/v) with apparent pH adjusted to 4.0 +/- 0.1; mobile phase flow rate of 1.5 mL/min; and ultraviolet detection at 238 nm. SIM, EZE, and their combination drug product were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. There were no other coeluting, interfering peaks from excipients, impurities, or degradation products due to variable stress conditions, and the method is specific for the estimation of SIM and EZE in the presence of degradation products. The described method was linear over the range of 1-80 and 3-80 microg/mL for SIM and EZE, respectively. The mean recoveries were 99.17 and 100.43% for SIM and EZE, respectively. The intermediate precision data were obtained under different experimental conditions, and the calculated value of the coefficient of variation was found to be less than the critical value. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.

Stability-indicating reversed-phase liquid chromatographic method for simultaneous determination of atorvastatin and ezetimibe from their combination drug products.

A simple, precise, and rapid stability-indicating reversed-phase column liquid chromatographic (RP-LC) method has been developed and subsequently validated for simultaneous estimation of atorvastatin (ATV) and ezetimibe (EZE) from their combination drug product. The proposed RP-LC method utilizes a LiChrospher 100 C18, 5 microm, 250 x 4.0 mm id column at ambient temperature; the optimum mobile phase consists of acetonitrile-water-methanol (45 + 40 + 15, v/v/v) with apparent pH adjusted to 4.0 +/- 0.1; mobile phase flow rate of 1.0 mL/min; and UV detection at 250 nm. ATV, EZE, and their combination drug product were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. There were no other coeluting, interfering peaks from excipients, impurities, or degradation products due to variable stress conditions, and the method is specific for the estimation of ATV and EZE in the presence of degradation products. The response was linear over the concentration range of 1-80 microg/mL for ATV and EZE. The mean recoveries were 99.27 and 98.5% for ATV and EZE, respectively. The intermediate precision data were obtained under different experimental conditions, and the calculated value of the coefficient of variation was found to be less than the critical value. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.

Simultaneous assay of olanzapine and fluoxetine in tablets by column high-performance liquid chromatography and high-performance thin-layer chromatography.

This paper describes validated high-performance liquid chromatographic (LC) and high-performance thin-layer chromatographic (TLC) methods for the simultaneous estimation of olanzapine and fluoxetine in pure powder and tablet formulations. The LC separation was achieved on a Lichrospher 100 RP-180, C18 column (250 mm, 4.0 mm id, 5 microm) using 0.05 M potassium dihydrogen phosphate buffer (pH 5.6 adjusted with o-phosphoric acid)-acetonitrile (50 + 50, v/v) as the mobile phase at a flow rate of 1 mL/min and ambient temperature. The TLC separation was achieved on aluminum sheets coated with silica gel 60F254 using methanol-toluene (40 + 20, v/v) as the mobile phase. Quantitation was achieved by measuring ultraviolet absorption at 233 nm over the concentration range of 10-70 and 40-280 microg/mL with mean recovery of 99.54 +/- 0.89 and 99.73 +/- 0.58% for olanzapine and fluoxetine, respectively, by the LC method. Quantitation was achieved by measuring ultraviolet absorption at 233 nm over the concentration range of 100-800 and 400-3200 ng/spot with mean recovery of 101.53 +/- 0.06 and 101.45 +/- 0.35% for olanzapine and fluoxetine, respectively, by the TLC method with densitometry. These methods are simple, precise, and sensitive, and they are applicable for simultaneous determination of olanzapine and fluoxetine in tablet formulations.