• KSBB Journal
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• v.31 no.4
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• pp.219-227
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• 2016

Valsartan, a drug for the treatment of cardiovascular disease, exhibited low bioavailability which was caused by, at least in part, limited solubility at low pH. Present investigation deals with the preparation and characterization of gastro-retentive drug delivery system (GRDDS) using valsartan solid dispersion. We prepared solid dispersion using surfactants (Poloxamer 407) and alkalizer ($Na_2CO_3$) which may to be useful for improving solubility of valsartan at low pH and evaluated by saturated solubility of valsartan in distilled water. Valsartan gastro-retentive (GR) tablets containing solid dispersion prepared and evaluated by weight variation, floating time and dissolution rate. Compression at lower pressures resulted in the tablets floating over simulated gastric fluid (pH 1.2) for more than 17 h. In vitro release of valsartan from GR tablet was dependent on the amount of poloxamer 407 and hydroxypropyl methylcellulose. On the basis of evaluation parameter, formulation E-3 was selected as a final formulation. Therefore, it can be concluded that the GR tablets containing solid dispersion may be exploited successfully for the delivery of poorly drug such as valsartan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.397-404
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• 2016

The objective of this study is to determine the physical characteristics of the gel mass of vegetable soft capsules and to maintain their rheological stability for improving manufacturability. The effect of each capsule shell component on the viscosity of the gel mass was studied for 6 hours, and the effects of adding an alkalizer or electrolytes to neutralize the sulfate groups on the carrageenan molecule were also investigated. Carrageenan was identified as a major component that affects the viscosity of the gel mass, and it showed unstable properties with age. The viscosity and stability of the gel mass were remarkably improved when an alkalizer or electrolytes were added at 3.0% relative to the carrageenan. 3.6 M KCl showed the highest effect on increasing the viscosity. A stable gel mass composition for vegetable soft capsules was successfully developed, which can be considered to increase the application of the capsules in the pharmaceutical and food industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3494-3499
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• 2009

The stability of omeprazole in the aqueous solutions containing loxoprofen or Sodium bicarbonate was examined at room temperature. Loxoprofen or Sodium bicarbonate (60 mg) was added to omeprazole (600 ${\mu}g$/ml) solution to check the stability profile. Then, the solution was kept at room temperature for 80 hours. The concentration was assayed at each concentration by stability-indicating High performance liquid chromatography (HPLC) method. Aliquots of the solution were withdrawn at specified time intervals and assayed by chromatographic analysis for intact omeprazole. The relation between omeprazole concentration and peak area was linear from 5 to 160 ${\mu}g$/ml. The analysis method was precise with relative standard deviation (% RSD) no greater than 3.05 %. The remaining percentage-time curves revealed that omeprazole was degraded rapidly as functions of time and temperature following pseudo first-order kinetics. In conclusion, the stability of omeprazole was significantly affected by liquid solutions mixed with alkalizer (Sodium carbonate) or the NSAIDs (loxoprofen).

• Journal of Pharmaceutical Investigation
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• v.40 no.6
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• pp.367-372
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• 2010

Rabeprazole sodium (RPN) is known to be very unstable at acidic condition or some acidic pharmaceutical excipients such as acrylic acid polymer (carbomer 934) with carboxylic acids. Thus, degradation mechanism of binary blends of rabeprazole with pharmaceutical excipients in a solid state without using solvents at three different ratios (3:1, 1:1 and 1:3) was investigated using Fourier transform infrad (FTIR) spectroscopy. Alkalizer (MgO), neutral hydroxypropymethylcellulose (HPMC 4000) were also tested for comparison. The binary blends were stored under accelerated conditions ($40^{\circ}C$/75% relative humidity) for two weeks. The concentration of thioether rabeprazole from the binary blends with acidic carbomer 934 increased as the rabeprazole concentration decreased. In addition, the degradation half-life of rabeprazole as well as the relative peak area ratios obtained from FTIR spectra of S=O stretching at $1094.1\;cm^{-1}$ decreased consistently as the fraction of carbomer 934 increased due to its sensitivity between the basic benzimidazole nitrogen and carboxylic acid group of carbomer 934. The physical appearance also turned into strong brown color in the presence of carbomer 934. In contrast, there were no significant changes in the degradation kinetics of rabeprazole with MgO and HPMC 4000 in a solid state. This present study demonstrated that the solid-state compatibility test with the aid of HPLC chromatographic and FTIR spectral analyses could offer a valuable methodology to select suitable pharmaceutical excipients and to elucidate the degradation mechanism of RPN for drug formulations at the early formulation stages.