• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1725-1733
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• 2016

Recent findings have shown that microbial nitrogen flow and digestible energy of diets are increased when urea is combined with a slow-release urea (SRU) in diets with a starch to acid detergent fibre ratio (S:F) 4:1. This affect is attributable to enhanced synchrony between ruminal N availability for microbial growth and carbohydrate degradation. To verify the magnitude of this effects on lamb performance, an experiment was conducted to evaluate the effects of combining urea and a SRU in diets containing S:F ratios of 3:1, 4:1, or 5:1 on performance, dietary energetics and carcass characteristics of finishing lambs. For that, 40 Pelibuey${\times}$Katahdin lambs ($36.65{\pm}3kg$) were assigned to one of five weight groupings in 20 pens (5 repetition/treatments). The S:F ratio in the diet was manipulated by partially replacing the corn grain and dried distiller's grain with solubles by forage (wheat straw) and soybean meal to reach S:F ratios of 3:1, 4:1 or 5:1. An additional treatment of 4:1 S:F ratio with 0.8% urea as the sole source of non-protein nitrogen was used as a reference for comparing the effect of urea combination vs. conventional urea at the same S:F ratio. There were no treatment effects on dry matter intake (DMI). Compared the urea combination vs urea at the same S:F ratio, urea combination increased (p<0.01) average daily gain (ADG, 18.3%), gain for feed (G:F, 9.5%), and apparent energy retention per unit DMI (8.2%). Irrespective of the S:F ratio, the urea combination improved the observed-to-expected dietary ratio and apparent retention per unit DMI was maximal (quadratic effect, $p{\leq}0.03$) at an S:F ratio of 4:1, while the conventional urea treatment did not modify the observed-to-expected net energy ratio nor the apparent retention per unit DMI at 4:1 S:F ratio. Urea combination group tended (3.8%, p = 0.08) to have heavier carcasses with no effects on the rest of carcass characteristics. As S:F ratio increased, ADG, G:F, dietary net energy, carcass weight, dressing percentage and longissimus thoracis (LM) area increased linearly ($p{\leq}0.02$). Combining urea and a slow-release urea product results in positive effects on growth performance and dietary energetics, but the best responses are apparently observed when there is a certain proportion (S:F ratio = 4:1) of starch to acid detergent fibre in the diet.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.21-27
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• 2019

Analysis of water quality distribution is very important for river water quality management. Recently, various studies have been conducted on the analysis of water quality distribution according to reduction methods of nonpoint pollutant. The objective of this study was to select the probability distributions of water quality constituents (T-N, T-P, COD, SS) according to the farming forms (control, slow release fertilizer, water depth control) during non-storm period in the paddy fields. The field monitoring was conducted monitoring site located in Baeksan-myun, Buan-gun, Jeollabuk-do, Korea during non-storm period from May to September in 2016. Our results showed that there were no differences in water quality among three different farming forms, except for SS of control and water depth control. K-S method was used to analyzed the probability distributions of T-N, T-P, COD and SS concentrations discharged from paddy fields. As a results of the fitness analysis, T-N was not suitable for the normal probability distribution in the slow release fertilizer treatment, and the log-normal probability distribution was not suitable for the T-P in control treatment. The gamma probability distribution showed that T-N and T-P in control and slow release fertilizer treatment were not suitable. The Weibull probability distribution was found to be suitable for all water quality constituents of control, slow release fertilizer, and water depth control treatments. However, our results presented some differences from previous studies. Therefore, it is necessary to analyze the characteristics of pollutants flowing out in difference periods according to various farming types. The result of this study can help to understand the water quality characteristics of the river.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.751-765
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• 1997

Periodontal disease is a bacterially causal by disease, To remove plaque and bacteria, it has been necessary to prescribe chemical drug to patient to subjugate therapeutic unvalue by mechanical scaling. As a patient on a high dosage of the antibiotics to maintain the effective concentration may produce unfavorable side effects, this decase demands the Slow-release local drug delivery system. The object of the experiment is to study on the slow-release local drug delivery effects of calcium sulfate compounded with tetracycline that mainly used in periodontal disease. Experimental groups were divided into four classes as follow: Group 1 10% tetracycline compounded modified calcium sulfate paste. Group 2 : compounded and hardened 10% tetracycline and calcium sulfate. Group 3 : compounded 10% tetracycline and calcium sulfate, used Just before hardened. Group 4 : tetracycline-ethylene vinyl acetate fiber. In the four groups, release concentration, it's durability and the period of absorption by times are observed and concluded as follow: 1. An effective concentration($4{\mu}g/ml$) remained until 5 weeks in group 1, 9 days in group 2, 7 days in group 3, 15 days in group 4. 2. It was fully fused at 11.8 days average in group 2 and 14.8 days average in group 3. . There were no statistically significant results in tetracycline concentration until a week in group 2 and 3(p<0.05) These results suggest that tetracycline loaded calcium sulfate release sufficient tetracycline and fused in $11{\sim}14$ days, so calcium sulfate is useful carrier as slow release local drug delivery system.

• YAKHAK HOEJI
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• v.41 no.1
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• pp.48-59
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• 1997

Sustained release matrix tablets, pellets, and coated pellets for the delivery of sulindac were prepared using cellulose derivatives at various ratios, and evaluated for the dis solution pattern. The release of sulindac, from matrix tablets prepared with low viscosity HPMC was relatively fast, and especially the tablets made of Metolose SM released all of sulindac within 1 hr. The release of drug from tablets made of other HPMC derivatives were retarded in the order of the following: Pharmacoat 645>Pharmacoat 606>Pharrnacoat 606+HPC-L>HPC-L. The most sustained release pattern was observed with the preparation of high viscous polymer. Metolose 90 SH. While release of sulindac, from matrix type pellet containing 10mg/cap of Metolose 90 SH or 60 SH was completed within 1 hr, a prolonged release formulation (30% in 1 hr) was obtained by the inclusion of EC. Pellets coated with HPMC showed a fast release pattern (${\geq}$ 80% within 2 hrs), whereas pellets coated with HPMC and EC (molar ratio 1 : 1) showed a sustained release pattern (${\geq}$ 80% in 12 hrs), vath the release from EC pellets being the most sustained. Fast (naked) and slow release pellets coated with EC, Metolose 60SH 50cps and propylene glycol. and enteric pellets coated with HPMCP 55 and Myvacet$^{\circledR}$ were prepared, and combined at various ratios for the assessment of dissolution pattern. The result indicates the possibility that the development of 24 hr sustained release delivery systems containing sulindac for oral administration could be achieved by means of combining sustained and fast release pellets at a proper portion.

• Archives of Pharmacal Research
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• v.15 no.2
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• pp.162-168
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• 1992

Release characteristics of five different types of hydrophilic albumin microspheres (HAM) containing different ratios of methotrexate-albumin (MTX-HSA) conjugates to free MTX: 1 : 0 (HAMC), 3 :1 (HAMC 3F), 1 :1 (HAMCF), 1:3 (HAMCF3) and 0 : 1 (HAMF) were investigated in the absence or presence of protease using dissolution tester. In all the HAMs studied except HAMC, the MTX was released bi-exponentially in the absence of protease; an initial fast release period up to approximately 6h, and thereafter the release rate was very much slower. The fast release of MTX from the HAMs (such as HAMC3F, HAMCF, HAMCF3 and HAMF) at the initial phase in probably due to the release of "physically associated" MTX from the core of the HAMs. The initial rate constants were 7.2, 8.7, 8.5 and 5.9 times greater than the second rate constants for HAMF, HAMCF3, HAMCF and HAMC3F, respectively. MTX release from HAMC was very slow and mono-phasic. It was at most 2.2% of the total entrapped amount by 24 h. The protease accelerated the release of MTX from the HAMs. The percentages of MTX released from HAMs up to 24 h were 100, 89.0, 75.0, 66.0 and 61.0% for HAMF, HAMCF3, HAMCF, HAMC3F and HAMC, respectively in the presence of protease and the corresponding values in the absence of protease were 30.2 19.0, 10.0, 6.5 and 2.2%, respectively. In vitro release of MTX in the presence of protease varied according to the ratios of MTX-HSA conjugates to MTX; the data set from HAMF, HAMCF3 and HAMCF fits better to monophasic first-order profile more adequately than to zero-order profile, that of HAMC3 monophasic first-order, and that of HAMC to bi-phasic zero-order. Above results suggested that zero-order release rate can be achieved by adjusting the ratio of MTX-HSA conjugates to MTX in the preparation of HAMs such as HAMC3F.as HAMC3F.

• Journal of Pharmaceutical Investigation
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• v.35 no.6
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• pp.453-460
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• 2005

4-Aminopyridine (AP) is a potassium channel blocker used in the treatment of neurological disorders such as multiple sclerosis and Alzheimer disease. AP‘s window of therapeutic effect appears to correlate with its plasma halflife (3.5 hours). It demonstrates pH-dependent solubility because of a weakly basic drug. In addition, the resulting release from conventional matrix tablets decreases with increasing pH-milieu of the gastrointestinal tract. The aim of this study is to design sustained release matrix tablet containing AP, overcoming this problem. $Eudragit^{\circledR}$ L 100 (EuL) and sodium alginate were used in an effort to achieve pH independent drug release. The effect of sodium alginate and EuL on drug release from matrix tablet was investigated. The drug release behavior from the different tablets was analyzed by $t_{20%},\;t_{40%},\;t_{60%}$, The exponential diffusion coefficient n, kinetic constant K were calculated according to the Korsmeyer-Peppas equation. The drug release from matrix tablets prepared with sodium alginate was decreased with increasing the content of sodium alginate in pH 7.4 while there is no significant difference in pH 1.2. The exponent n values were determined to be approximately 0.5 and 0.8 respectively, in both pH 1.2 and 7.4. These values indicate diffusion-based anomalous mechanism and erosion-based anomalous mechanism, respectively. The drug release from sodium alginate matrix tablets prepared with solid dispersion of EuL containing drug showed a slow drug release in an acidic medium and a more fast drug release in phosphate medium, compared with sodium alginate matrix tablets prepared with physical mixture. These results may be attributed to the gel forming ability of sodium alginate and pH dependent solubility of EuL. Therefore, sustained-release AP matrix tablets using sodium alginate and EuL were successfully prepared.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.148-149
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• 2000

• Journal of Periodontal and Implant Science
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• v.21 no.1
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• pp.175.1-175.1
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• 1991

• Proceedings of the Korean Society of Crop Science Conference
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• 1999.05a
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• pp.73-74
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• 1999

• Proceedings of the Turfgrass Society of Korea Conference
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• 2005.04a
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• pp.26-27
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• 2005