• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.267-275
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• 2002

A self-microemulsifying drug delivery system (SMEDDS) was developed to increase the dissolution rate, solubility, and ultimately bioavailability of a poorly water soluble drug, lovastatin. SMEDDS was thε mixtures of oils, surfactants, and cosurfactants, which emulsify under conditions of gentle agitation, similar to those which would be encountered in the gastro-intestinal (GI) tract. Various types of self-emulsifying formulations were prepared using four types of oil (Capryol 90, Lauroglycol 90, Labrafil M 1944 CS and Labrafil M 2125), two surfactants (Cremophor EL and Tween 80), and three cosurfactants (Carbitol, PEG 400 and propylene glycol). Thε efficiency of emulsification was studied using a laser diffraction size analyzer to determine particle size distributions of the resultant emulsions. Optimized formulations selected for bioavailability assessment were Carpryol 90 (40%), Cremophor EL (30%) and Carbitol (30%). SMEDDS containing lovastatin (20 mg and 5 mg) were compared to a conventional lovastatin tablet $(Mevacor^{\circledR},\;20\;mg/tab)$ by the oral administration as prefilled hard gelatin capsules to fasted beagle dogs for in vivo study. The arεa under the serum concentration-time curve from time zero to the last measured time in serum, $AUC_{0{\rightarrow}24h}$, was significantly greater in SMEDDS, suggesting that bioavailability increase 130% and 192% by the SMEDDS, respectively. The self-emulsifying formulations of lovastatin afforded the improvement in absolute oral bioavailability relative to previous data of lovastatin tablet formulation. These data indicate the utility of dispersed self-emulsifying formulations for the oral delivery of lovastatin and potentially other poorly absorbed drugs.

• Polymer(Korea)
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• v.39 no.1
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• pp.33-39
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• 2015

Olmesartan affiliated to biopharmaceutics classification system class 2 is a poorly water soluble drug. For this reason, olmesartan showed a low bioavailability and a lot of difficulties in the process of designing the pharmaceutical formulation. We prepared the solid dispersions of olmesartan. We confirmed the dissolution rate of drug which was prepared by manufacturing. The pharmaceutical formulation of solid dispersions was designed by using PVP as water soluble polymer. We analyzed morphological feature of solid dispersion by employing a scanning electron microscope. Then, the crystalline property of solid dispersion was confirmed through X-ray diffraction and differential scanning calorimeter. Also, the chemical change of solid dispersion was confirmed by the Fourier transform infrared spectroscopy. In vitro dissolution test was used to analyze the dissolution rate of solid dispersion. The prepared solid dissolution olmesartan confirmed the dissolution rate in the pH 1.2. It was compared with olmetec and improved dissolution rate through solid dispersion.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.185-190
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• 2002

To improve the solubility of poorly water-soluble drug and to develop a sustained release tablets, the need for the technique, the formation of solid dispersion with polymeric materials that can potentially enhance the dissolution rate and extent of drug absorption was considered in this study. The 1:1, 1:4, and 1:5 solid dispersions were prepared by spray drying method using PVP K30, ethanol and methylene chloride. The dissolution test was carried out at in phosphate buffer solution at $37^{\circ}C$ in 100 rpm. Solid dispersed drugs were examined using differential scanning calorimetry and scanning electron microscopy, wherein it was found that felodipine is amorphous in the PVP K30 solid dispersion. Felodifine SR tablets were prepared by direct compressing the powder mixture composed of solid dispersed felodipine, lactose, Eudragit and magnesium stearate using a single punch press. In order to develop a sustained-release preparation containing solid dispersed felodipine, a comparative dissolution study was done using commercially existing product as control. The dissolution rate of intact felodipine, solid dispersed felodipine and its physical mixture, respectively, were compared by the dissolution rates for 30 minutes. The dissolution rates of felodipine for 30 minutes from 1:1, 1:4, 1:5 PVP K30 solid dispersion were 70%, 78% and 90%. However, dissolution rate offelodipine from the physical mixture was 5% of drug for 30 minutes. Our developed product Felodipine SR Tablet showed dissolution of 17%, 50% and 89% for 1, 4, and 7 hours. This designed oral delivery system is easy to manufacture, and drug releases behavior is highly reproducible and offers advantages over the existing commercial product. The dissolution rate of felodipine was significantly enhanced, following the formation of solid dispersion. The solid dispersion technique with water-soluble polymer could be used to develop a solid dispersed felodipine SR tablet.

• KSBB Journal
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• v.22 no.5
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• pp.328-335
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• 2007

In this work ursolic acid (UA), a poorly water-soluble compound, was inclusion complexed with 2-hydroxypropyl-$\beta$-cyclodextrin (HP-$\beta$-CD) by various methods such as kneading, solvent evaporation and two types of supercritical fluid processes. The solubility and characteristics of these UA/HP-$\beta$-CD complexes were investigated by scanning electron microscopy, x-ray diffraction and HPLC. The water solubilities of the two complexes obtained from solvent evaporation and ASES processes were observed to increase up to 6$\sim$240 folds and 12$\sim$56 folds, respectively, compared with that of unprocessed UA. The stability of UA/HP-$\beta$-CD complex samples in cosmetic formulations was examined at various temperatures for one month. The UA/HP-$\beta$-CD complex prepared by solvent evaporation was found to be most stable among all the cosmetic formulations tested in our experiments.

• Journal of Practical Agriculture & Fisheries Research
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• v.5 no.1
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• pp.28-35
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• 2003

This study was conducted to investigate the nutrition status, growth and fruit quality of 'Campbell Early' grapes in Hwaseong area. Organic matter content of 3 vineyard soils was significantly lower than standard value. P₂O₅ and K contents of Y vineyard and P₂O₅ of C vineyard were very high. But there were no significant differences in contents of Ca, Mg and CEC. Compared to the standard value. T-N, Ca and Mg contents of petiole were adequate. P₂O₅ contents of Y and C vineyard and K contents of Y vineyard were significantly higher than standard value. Berry firmness, color and bloom occurrence on fruit skin showed no differences among 3 vineyard. Soluble solids content poorly, yield per tree and goods fruit of C vineyard decreased significantly compared to the fruit in Y and H vineyards. Russetted fruit of Y vineyard, colored fruit of H vineyard, and unfertilized fruit, cracked fruit, and bitter rot were observed frequently.

• Journal of Pharmaceutical Investigation
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• v.38 no.4
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• pp.249-254
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• 2008

Solid dispersions of poorly water-soluble drug, atorvastatin, were prepared with Eudragit L100 to improve the solubility by spray dryer. To investigate the correlation between physicochemical properties and dissolution rate of solid dispersions, the samples were characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and fourier transform infrared spectroscopy (FT-IR). SEM and DSC were found that atorvastatin is amorphous in the Eudragit L100 solid dispersion. FT-IR was used to analyze the salt formation by interaction between atorvastatin and Eudragit L100. The dissolution rate of solid dispersed atorvastatin was markedly increased compared to drug powder in stimulated intestinal juice (pH 6.8). Thus, the solid dispersed atorvastatin using the spray drying method with Eudragit L100 may be effective for the bioavailability.

• Applied Biological Chemistry
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• v.27
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• pp.56-67
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• 1984

As in many other country, the use of organic matter in Korea has long history. Farmers understand the value of organic matter as the source of plant nutrient and soil improving agent in general. Since 50 years ago, the sources of organic matter in paddy soils were compost, rice and barly straw, green manure, animal waste, fish and beancake, etc.. Application of green manures such as vetch and chinese milk vetch showed no significant effect on the yield of brown rice in paddy soil. On the other hand, the effects of compost and rice straw showed more significant on the yield of brown rice in paddy soil. Application of rice straw in rice cultivation is commonly made at different times between harvest, early spring and several weeks before transplanting. Considering the suitable paddy soil for application of rice straw under well to moderately well drained soil, the yield was pronounced more than poorly drained soil. Based on laboratory and field experimants, application of rice straw promoted the decrease of oxidation-reduction potential in well to moderately well drained soil. This results to be enhanced the release of some mineral nutrients,. such as potassium, calcium, silicon, and increase of availability of soil phosphorus. In the field experiments, results obtained from nitrogen fraction on the immobilization-mineralization of the tracer nitrogen applied in paddy soil,the amount and index of organic nitrogen incoporated in soil was more pronounced in rice straw application than control. Rice straw and its transformation products incoporated in the soil, provided the inflow of energy necessary to maintain heterotrophic microbes activities. Rice straw and its transformation products, especially soluble carbohydrate, enhanced the population of free-living heterotrophic $N_2$ - fixing microbes. Moreover, rice straw and its transformation products in paddy soil, enhanced the activities of soil enzymes such as dehydrogenase and urease.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1133-1133
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• 2001

Fruit sweetness, as indexed by total soluble solids (TSS), and fruit acidity are key factors in the description of the fruit eating quality. Our group has been using short wave NIR spectroscopy (SW-NIR; 700-1100 nm) in combination with chemometric methods (PLS and MLR) for the non-invasive determination of the fruit eating quality (1,2). In order to further improve calibration performance, we have investigated SW-NIR spectra of sucrose and D-glucose. In previous reports on the band assignment for these sugars in the 1100-2500 nm spectral region (3-7), it has been established that change in concentration, temperature and physical state of sugars reflects on the shape and position of the spectral bands in the whole NIR region(5-7). The effect of change in concentration and temperature of individual sugar solutions and sugar spiked Juice samples was analysed using combined spectroscopic (derivative, difference, 2D spectroscopy) and linear regression chemometric (PLS, MLR) techniques. The results have been compared with the spectral data of a range of fruit types, varying in TSS content and temperature. In the 800-950 nm spectral region, the B-coefficients for apples, peaches and nectarines resemble those generated in a calibration of pure sucrose in water (Fig. 1). As expected, these fruits exhibit better calibration and prediction results than those in which the B-coefficients were poorly related to those for sugar.(Figure omitted).

• Journal of Pharmaceutical Investigation
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• v.33 no.1
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• pp.7-14
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• 2003

The PVP-based solid dispersion systems (SDs) containing lovastatin (LOS) and solubilizers (sodium lauryl sulfate, tween 80 and oleic acid) were prepared to enhance dissolution rate of practically water insoluble LOS using solvent evaporation method. Two different organic cosolvents either acetone/ethanol or acetonitrile/ethanol were used for the preparation of SDs. The LOS contents were highly decreased when acetone/ethanol cosolvents were used. The decrease of LOS contents was not caused by acetonitrile or acetone, based on HPLC data. The surface morphology as investigated by scanning electron microscope (SEM) and angle of repose as an index of flowability of SDs were highly dependent on the type and amount of solubilizers used. Based on differential scanning calorimetry (DSC) and X-ray powder diffraction data, the SDs made crystalline LOS into amorphous structure or partially eutectic mixtures. The simultaneous use of the solubilizers in SDs was also useful to increase dissolution rate of LOS in gastric or intestinal fluid. The SDs containing solubilizers reached 76% and 60% in gastric and intestinal fluid, respectively but the commercial tablet gave only less than 4%. These solubilizers in SDs could be also applicable for enhancing dissolution and bioavailability of poorly water-soluble drugs.

• Journal of Pharmaceutical Investigation
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• v.35 no.4
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• pp.233-241
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• 2005

Ursolic acid (UA), a bioactive triterpene acid, has been known to increase collagen content in human skin in addition to other actions such as anti-inflammatory, skin-tumor prevention and anti-invasion. However, it is poorly soluble in water. Therefore, we firstly prepared microemulsion system with benzyl alcohol, ethanol and Cremophor EL, RH 40 and Brij 35 as surfactant in order to increase solubility of UA and then prepared microemulsion was dispersed in o/w cream base for the topical delivery of UA in an effort to improve anti-wrinkle effect. The pseudo-ternary phase diagrams were developed and various microemulsion formulations were prepared using benzyl alcohol as an oil, Cremophor EL, RH 40 and Brij 35 as a surfactant. The droplet size of microemulsions was characterized by dynamic light scattering. The accumulation of VA in the skin from topical cream was evaluated in vitro using hairless mouse skins. The mean droplet size was $26.8{\pm}6.6$ nm for microemulsions II with Cremophor EL. All UA creams showed pseudoplastic flow and hysterisis loop in their rheogram, depending on the type of materials added in topical creams. The in vitro accumulation data demonstrated the UA topical cream prepared with the combination of Poloxamer 407 and Xanthan gum as a copolymer showed higher accumulation percentage than those prepared with either Poloxamer 407 or Xanthan gum. These results suggest that UA topical cream using microemulsion systems may be promising for the topical delivery of UA.