• Nuclear Engineering and Technology
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• 제48권2호
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• pp.554-558
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• 2016

The solubility of nickel ferrite in an aqueous solution of boric acid was studied by varying the pH at the temperatures ranging from $25^{\circ}C$ to $320^{\circ}C$. A flow-through autoclave system was specially designed and fabricated to measure the solubility of Fe in hydrothermal solutions under high temperature and pressure. The performance of this flow-through system was directly compared with the conventional static state technique using a batch-type autoclave system. The stability of fluid velocity for the flow-through autoclave system was verified prior to the solubility measurement. The influence of chemical additives, such as boric acid and $H_2$, on the solubility of nickel ferrite was also evaluated.

• Journal of Pharmaceutical Investigation
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• 제28권2호
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• pp.121-126
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• 1998

The solubility and physicochemical stability of caroverine hydrochloride (CRV), an antispasmodic, in buffered aqueous solutions were studied using a reverse phase high performance liquid chromatography. The solubilty of the drug at pH 2.76-5.40 was similar at the range 31.9-36.2 mg/ml $(34^{circ}C)$, but, at the pH higher than 6.0, markedly decreased. The use of polyethylene glycol 400 as a cosolvent did not increase the solubility at any compositions examined. Moreover. increasing molar concentration of aqueous phosphate buffer from 0 to 0.5 M remarkably decreased the solubility. The degradation of CRY followed the apparent first-order kinetics. The degradation was accelerated with decreasing pH and increasing storage temperature. The half-lives for the degradation of CRY (1.0 mg/ml) at pH 1.28. 4.01 and 5.93 $(45^{\circ}C)$ were 2.8, 31.4 and 124 hr. respectively. The pHs of incubated solutions were to some extent lowered perhaps due to the formation of acidic degradation products. The addition of disodium edetate (0.01%) to the CRY solution (pH 4.95) retarded 2.5 times the degradation rate at $45^{\circ}C$, but the use of sodium bisulfite (0.1%) accelerated 2.9 times the rate. The activation energy for the CRY solution (20 mg/ml. pH 5.4) containing 0.01% EDTA was calculated to be 5.98 kcal/mole. When the solution was stored under nitrogen displacement in ampoule, there was no significant degradation even after 3 months at $40^{\circ}C$, indicating that protection from oxidation by air (oxygen) is essential for the complete stabilization of CRY solution.

• 약학회지
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• 제50권1호
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• pp.1-7
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• 2006

The purpose of the present study was to formulate the aqueous solution of 1-cyclopent-3-enylmethyl-6(3,5-dimethyl-benzoyl)-5-ethyl-1H-pyrimidine-2,4-dione (CPD), a novel antivirus compound containing pirimidine structure. For this purpose, the effects of various solubilization agents such as cosolvents [ethanol, propylene glycol (PG), polyethylene glycol 300 (PEG 300), polyethylene glycol 400 (PEG 400), glycerin], surfactants (Tween 80, Cremophor$^{(R)}$ RH40, Cremophor$^{(R)}$ EL, Poloxamer 407, Poloxamer 188) and a complexation agent [hydroxypropyl-${\beta}$-cyclodextrin (HPBCD)] , on the solubility of CPD in aqueous solution were evaluated. The solubility of CPD in water was under $1\;{\mu}g/ml$ at $20^{\circ}C$. Cosolvents such as ethanol, PG, PEG 300, PEG 400 and glycerin did not enhance the solubility of CPD at the $0{\sim}40\%$ concentration range. The solubility of CPD was significantly elevated by the addition of cosolvents over the $80\%$ concentration range. On the other hand, tween 80, Cremophor$^{(R)}$ L, Cremophor$^{(R)}$ RH40, and HPBCD showed enhanced effects on the solubility of CPD. The enhanced effects of Poloxamer 407 or Poloxamer 188 on the CPD solubility were less pronounced compared with tween 80, Cremophor$^{(R)}$ L or Cremophor$^{(R)}$ RH40. As a results, tween 80 aqueous solution was selected as an optimum solvent system. The aqueous solutions containing $20\%$ tween 80 were formulated as a dosing solution containing CPD for its intraperitoneal and intrahypodermic administration, respectively, The formular showed physical stability after stored for 7 days at $4^{\circ}C$.

• 한국식품조리과학회지
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• 제9권4호
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• pp.278-283
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• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with protease on functional properties. The selected functional properties were solubility, emulsifying activity (EA), emulsion stability(ES), foam expansion(FE), and foam stability(FS). These properties were measu-red from pH 3.0 to pH 8.0. The proteases used in this study were iaolated from Meju(fermemted soybean) and had specific activity of 250 units/㎎ protein at pH 7.0, 1600 units of pretense was used for 1gr. of skim milk protein. Skim milk showed 30.5％ degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Solubility of native skim milk, control, 1 hr. and 3.5 hrs. groups were 3.37, 3.64, 10.21, 14.34％o at pH 4.0 respcetively. The emulsifying activity of native skim milk, control, 1 hr. and 3.5 hrs. groups were 38.8,42.0,43.0,46.7ft at pH 4.0, respectively. Enzymatic modification resulted in the increase of solubility and emulsifying activity at pH 4.0. However at pH 5.0 emulsifying activity of 1 hr. and 3.5 hr. group were lower than native skim milk and control groups. 1 hr. protease treatment was found to be most effective way of increasing foam expansion at pH 4.0 to 6.0. It was supported that, protease treated skim milk can be used to improve solubility, emulsifying activity, foam expansion at acid pH. meju protease. skim milk, solubility, emulsion, foam.

• Journal of Pharmaceutical Investigation
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• 제34권5호
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• pp.385-391
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• 2004

The purpose of the present study was to formulate the aqueous solution of $20-O-{\beta}-D-glucopyranosyl-20(S)-protopanaxadiol\;(IH-901)$, an intestinal bacterial metabolic derivative from Ginseng protopanaxadiol saponin. For this purpose, the effects of various solubilization agents such as cosolvents [ethanol, propylene glycol (PG), polyethylene glycol 300 (PEG 300), polyethylene glycol 400 (PEG 400), glycerin], surfactants $(Tween\;80,\;Cremophor^{\circledR}\;RH40,\;Cremophor^{\circledR}\;EL,\;Poloxamer\;407,\;Poloxamer\;188)$ and a complexation agent $[hydroxypropyl-{\beta}-cyclodextrin\;(HPBCD)]$, on the solubility of IH-90l in aqueous solution were evaluated. The solubility of IH-901 in water was under $1\;{\mu}g/ml\;at\;20^{\circ}C$. Cosolvents such as ethanol, PG, PEG 300, PEG 400 and glycerin did not enhance the solubility of IH-901 at the 0 - 40% concentration range. The solubility of IH-901 was significantly elevated by the addition of cosolvents over the 80% concentration range. On the other hand, tween 80, $Cremophor^{\circledR}\;EL,\;Cremophor^{\circledR}\;RH40$ and HPBCD showed enhanced effects on the solubility of IH-901. The enhanced effects of Poloxamer 407 or Poloxamer 188 on the IH-901 solubility were less pronounced compared with $Cremophor^{\circledR}\;EL\;or\;Cremophor^{\circledR}\;RH40$. As a results, $Cremophor^{\circledR}$ aqueous solution was selected as an optimum solvent system. The aqueous solutions containing 10% $Cremophor^{\circledR}\;EL$ and 7% $Cremophor^{\circledR}\;RH40$ were formulated as dosing solutions containing 5.0 mg/ml of IH-901 for its intravenous and oral administration, respectively. The formular showed physical stability after stored for 7 days at $4^{\circ}C$.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.560-565
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• 1997

The physicochemical properties of melatonin (MT) in propylene glycol (PG) and 2-hydroxypropyl-.betha.-cyclodextrin $(2-HP{\beta}CD)$ vehicles were characterized. MT was endothermally decomposed as determined by differential scanning calorimetry (DSC). Melting point and heat of fusion obtained were $116.9{\pm}0.24^{\circ}C $.and $7249{\pm}217 cal/mol$., respectively. MT as received from a manufacture was very pure, at least 99.9%. The solubility of MT in PG solution increased slowly until reaching 40% PG and then steeply increased. Solubility of MT increased linearly as concentration of $2-HP{\beta}CD$ without PG INCREASED$(R^2=0.993)$. MT solubility in the mixtures of pg and $2-HP{\beta}CD$ also increased linearly but was less than the sum of its solubility in $2-HP{\beta}CD$ and PG individually. The MT solubility was low in water, simulated gastric or intestinal fluid but the highest in the mixture of PG(40v/v%) and $2-HP{\beta}CD$ (30w/v%) although efficiency of MT solubilization in $2-HP{\beta}CD$ decreased as the concentration of PG increased. MT was degraded in a fashion of the first order kinetics $(r^2>0.90)$. MT was unstable in strong acidic solution (HCl-NaCl buffer, pH 1.4) but relatively stable in other pH values of 4-10 at $70^{\circ}C$. In HCl-NaCl buffer, MT in 10% PG was more quickly degraded and then slowed dpwm at a higher concentration. However, the degradation rate constant of MT in 2-HP.betha.CD was not changed significantly when compared to the water. The current studies can be applied to the dosage formulations for the purpose of enhancing percutaneous absorption or bioavailability of MT.

• Biomolecules & Therapeutics
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• 제8권4호
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• pp.332-337
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• 2000

Physicochemical properties of aspalatone (acetylsalicylic acid maltol ester, AM), which has been recently found to have an antithrombotic effect, were studied in terms of solubility, dissolution, partition coefficient (Pc) and stability. The solubility of AM at 37$^{\circ}C$ was about 1.2 mg/ml and the P$_{c}$ value for n-octanol/water and chloroform/water was 11.4 and 382.6, respectively. Dissolution rates of AM at pH 1.2 and 6.8 were more than 80% within 30 min. The degradation of AM followed apparent first-order kinetics, and was dependent on temperature, pH and ionic strength. From the pH-rate profile, the optimal pH was found to be at around 4.0. Half-lives at pH 1.2 and 6.8 were 33.5 and 44.4 hr, respectively. The degradation rate of AM at pH 1.2 was somewhat faster than that of aspirin, but at pH 7.0, the degradation rate of AM was slower than that of aspirin.n.

• 한국식품영양학회지
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• 제7권3호
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• pp.177-182
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• 1994

The effect of phosphate salt (NafHP04) and sodium citrate on the emulsion stability of soy protein isolate (SPI) in the presence of calcium was investigated in terms of salt concentration and addition order. Both phosphate and citrate salts decreased the solubility of SPI despite their pH enhancing effects. Addition of calcium chloride (CaCl2) significantly decreased ES, which showed nearly negligible at more than 3 mM CaCl2 concentration. When Na2HP04 were added in the presence of 5 mM Cac12, 55 greatly increased up to 20mM concentration, above which however ES decreased. It was found that the addition order of Na2HPO4 and CaCl2 affected ES. The addition of phosphate and subsequent CaCl2 exhibited the higher 55 than the reverse order. In both cases, the overall ES profile was found to be nearly similar to the solubility profile of SPI, indicating the positive relationship between solubility and emulsion stability of SPI in the presence of calcium. Similar trend to the phosphate effect on ES was also observed for sodium citrate in the presence of calcium.

• 대한화장품학회지
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• 제25권1호
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• pp.120-136
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• 1999

A newly synthesized polyhydroxy aromatic compound(LG 106w) has good skin lightening effect. Inclusion complexation of LG 106w with $\beta$-cyclodextrin and its hydroxypropyl and dimethyl derivatives was studied by the solubility method, scanning electron microscopy and differential thermal analysis. A relationship between host and guest was clearly reflected in the magnitude of the stability constant(DM-$\beta$> HP-$\beta$>$\beta$ -cyclodextrin). Formulation problems, which resulted from its very low solubility in aqueous solution, were resolved by the inclusion formation. LG 106W from inclusions is much more water-soluble than pure one. The improvement of pH and temperature stability correlated with the increased solubility was also observed. Inclusion complex of LG 106w had similar activity to pure LG 106w on the inhibition of melanin synthesis in B-16 melanoma cell but showed lower irritation on cultured cell test in vitro. According to the results, cyclodextrins might be one of the reliable candidates for improving the availability of LG 106w.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.940-947
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• 2022

Meta-heuristic algorithms have found their place in optimization problems. Henry gas solubility optimization (HGSO) is one of the newest population-based algorithms. This algorithm is inspired by Henry's law of physics. To evaluate the performance of a new algorithm, it must be used in various problems. On the other hand, the optimization of the proportional-integral-derivative (PID) gains for load-following of a nuclear power plant (NPP) is a good challenge to assess the performance of HGSO. Accordingly, the power control of a pressurized water reactor (PWR) is targeted, based on the point kinetics model with six groups of delayed-neutron precursors. In any optimization problem based on meta-heuristic algorithms, an efficient objective function is required. Therefore, the integral of the time-weighted square error (ITSE) performance index is utilized as the objective (cost) function of HGSO, which is constrained by a stability criterion in steady-state operations. A Lyapunov approach guarantees this stability. The results show that this method provides superior results compared to an empirically tuned PID controller with the least error. It also achieves good accuracy compared to an established GA-tuned PID controller.