• Journal of Pharmaceutical Investigation
• /
• v.37 no.3
• /
• pp.159-166
• /
• 2007

In order to develop an optimum formulation for iontophoretic delivery of vitamine C-2-phosphate (VCP) from Carbopol hydrogel, we have investigated various factors which can affect the iontophoretic flux through skin. Such factors as drug concentration, current density, current profile, current duration, ionic strength, pH and percutaneous enhancers (ethanol, glycerine, propylene glycerol, sorbitol, urea) were studied. Compared to the flux by passive or anodal delivery, the flux by cathodal delivery increased markedly, and thus, only cathodal delivery was used in the rest of the flux experiments. Flux increased linearly as the drug concentration and current density increased. As the duration of current application increased from 30 min to 120 min, flux increased linearly, however the AUC was not directly proportional to the applied amount of current. Flux also increased as the pH increased, possibly due to the increase in ionization of phosphate group. As the ionic strength increased, flux decreased. No significant increase in flux was observed after enhancer application, indicating that the effect of current on flux is dominating over the effect of percutaneous enhancers (P>0.05). These results provide important informations that are needed for optimal formulation of iontophortic delivery for VCP.

• YAKHAK HOEJI
• /
• v.40 no.4
• /
• pp.411-417
• /
• 1996

Epidermal growth factor(EGF), a potential healing agent for wounds and burns, has been formulated to topical gels with the hydrophilic polymers, Carbopol 934P. Physicochemical c haracteristics of the aqueous gels were evaluated by rheological properties and pH changes on storage. The gels were relatively stable at $4^{\circ}C$ and room temperature showing no changes in pH for two weeks, and revealed the rheogram of shear thinning plastic flow with the yield values in the range of 40 to 70dyne/$cm^2$. In vivo healing effects of different gel formulations have been compared with water-soluble and oleaginous ointments in full-thickness wound mouse model. The gel systems resulted in better wound healing effects than the other ointments. Furthermore, liposomal Carbopol gel has been developed by the addition of EGF-containing liposomal suspension into the Carbopol gel. The enhanced wound healing effects have been observed in the liposomal gel system, compared to the other gels and conventional ointments.

• Journal of Pharmaceutical Investigation
• /
• v.23 no.1
• /
• pp.55-59
• /
• 1993

Dissolution of mucosal adhesive tablets prepared with two polymers using hydroxypropylcellulose-H (HPC) and carbopol 934 (CP) was tested. Adhesive tablets containing HPC/CP and brilliant blue FCF (BB) were prepared from direct compression. Three factors of polymer ratio (HPC:CP), BB content and compression force were chosen as important factors of preparation and factorial analysis for these factors was carried out. Eight kinds of formulations from different combinations of three factors were prepared and dissolution test in pH 6.8 phosphate buffer solution was performed. Dissolution rate was significantly affected by HPC:CP ratio and BB content, but was not affected by compression force.

• Journal of Pharmaceutical Investigation
• /
• v.28 no.2
• /
• pp.87-92
• /
• 1998

Kojic acid (KA) is an antimelanogenic agent which has been widely used in cosmetics to whiten the skin color. However, it has the drawbacks of the skin irritancy and the instability against the pH, temperature, and light. In order to overcome these problems, various topical gels and multiple emulsion creams which can control the release of active ingredient, KA, were formulated employing cream bases of mineral oil with caprylic capric triglyceride and hydrophilic polymers such as chitosan, carbopol. and pluronics. Using Franz diffusion cells mounted with a synthetic cellulose membrane (MWCO 12,000), drug release characteristics of the formulations were evaluated by the HPLC assay of KA concentration in the receptor compartment of pH 7.4 phosphate buffered saline solution. Drug release from chitosan-based gels (ChitoGel) obeyed to the first order kinetics with a rapid release especially in the initial period. However, pluronic-based gels (PluGel) and carbopol-based gels (CarboGel) revealed controlled release of drug to some extent, followed by the square root-time kinetics. Moreover, the release of KA was further controlled with the W/O/W multiple emulsion creams (MultiCream), showing the apparent zero order release kinetics by virtue of dynamic ratecontrolling membrane of the oil layer. The flux $(J,\;{\mu}g/cm^2/hr)$ of ChitoGel. CarboGel. PluGel. and MultiCream in the initial period of 6hr were 73.30, 28.67. 24.04 and 7.72, respectively. On the other hand, the skin irritancy score of ChitoGel and MultiCream were observed as 2.5 and 2.3 respectively, in the rabbit skin irritation test. Although there were insignificant differences at p<0.05 between those formulations, it was possible to conclude that the W/O/W multiple emulsion creams containing KA might be a good candidate for an antimelanogenic drug delivery system due to the controlled release of acidic drug molecules.

• Journal of Pharmaceutical Investigation
• /
• v.24 no.3
• /
• pp.155-165
• /
• 1994

Some mucoadhesive polymers such as hydroxypropylcelluose (HPC) and carbopol-934 (CP) have been employed for the preparation of mucoadhesive polymeric systems, and their physical properties including mucoadhesion, swelling, and drug release were evaluated. A new simple experimental technique that can quantitatively measure the bioadhesive properties of various polymeric systems has been developed by the methods of detachment force test. As the polymeric systems, the discs of freeze-dried HPC/CP solid dispersions were prepared. The mucosa used in these tests were upper, middle, and lower parts of small intestine of male rats weighing $300{\sim}350\;g$. Detachment forces were increased as the mole fraction of CP increased in discs of HPC/CP solid dispersions. In the points of intestinal site dependence of mucoadhesion, the solid dispersions revealed non-specific mucoadhesion to the intestine. Swelling and drug release characteristics of mucoadhesive polymeric systems were studied extensively to find out the feasibility for the oral controlled delivery systems. Swelling ratio, expressed as the final height/initial height, has been determined in various pH buffer solutions. Hydrochlorothiazide (HCT) was employed as a model drug for release study. Apparent swelling and drug release rate constants, $K_s$ and $K_r$ respectively, were obtained from the square-root time plot of either swelling ratio or released amount of drug, particularly for the time periods before reaching the equilibrium. As a result, the swelling ratio of HPC/CP solid dispersions was increased as the weight percentage of CP increased. Similarly, the release of HCT from the solid dispersions was dependent on pH changes and CP contents, resulted in the slower release of HCT with the increases of pH and CP contents.

• Polymer(Korea)
• /
• v.36 no.2
• /
• pp.182-189
• /
• 2012

In this study, poloxamer hydrogels were prepared by electron beam irradiation and evaluated for potential application as a buccal mucoadhesive drug delivery system. Poloxamer, one of typical thermoresponsive polymers, was modified to have vinyl end groups for crosslinking reaction, and its hydrogels were fabricated by irradiation crosslinking reaction. Carbopol as a mucoadhesive polymeric additive was introduced to improve the mucoadhesive property of the hydrogels and its effect on the mucoadhesion and drug release properties was investigated. The results showed that the end group modification of poloxamer and the addition of carbopol improved mucoadhesive force and mechanical properties and led to a sustained drug release behavior.

• Polymer(Korea)
• /
• v.34 no.5
• /
• pp.459-463
• /
• 2010

Amphotericin B (AmB) is anti-fungal agent for the treatment of systemic fungal infections, but its poor solubility has limited clinical applications. In this study, a new gel formulation made up of L-arginine as solubilizer, thermosensitive Poloxamer 407 (P 407), and adhesive carbopol was designed for effective solubilization and delivery of AmB. The aqueous solubility of AmB was enhanced up to 2.6 mg/mL by addition of L-arginine. Aqueous P 407 solutions of more than 20% w/v showed thermo-induced sol-gel-sol phase transition. The phase transition behavior was affected by the presence of AmB and L-arginine, and the phase transition range was broadened by addition of carbopol. In vitro drug release was improved by the solubilizing effect of L-arginine, and the presence of mucoadhesive carbopol prolonged the release rate as a function of concentration.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1998.05a
• /
• pp.77-82
• /
• 1998

현재 온실 난방에 주로 이용되고 있는 난방기는 대부분이 화석에너지를 연료로 사용하고 있다. 따라서 생산비의 가중이 불가피하며, 또한 연소 과정에서 발생하는 배기 가스로 인하여 환경 오염이 문제시되고 있다. 따라서 태양에너지를 보다 더 적극적으로 활용할 수 있는 기술의 개발이 요구된다. 태양에너지를 시설 농업에 적극적으로 이용하기 위해서는 주간에 밀도가 낮은 태양에너지를 고밀도로 축열하여 기온이 급강하하는 야간의 보온에 활용하여야 한다. 주간의 온실내 잉여 태양에너지를 축열할수 있는 상변화 온도 3$0^{\circ}C$ 수준의 잠열축열재를 개발하기 위하여 수행한 본 연구의 결과를 요약하면 다음과 같다. 1. SCD에 Borax를 0.0~5.0wt% 첨가하여 과냉도를 25.$0^{\circ}C$에서 $1.5^{\circ}C$ 이하로 조절하였으며, Borax의 적정 함량은 3.0wt%였다. 2. SCD에 Carbopol을 0.0~3.0wt% 첨가하여 상분리량을 70.0%에서 0.0%로 조절하였으며, Carbopol의 적정 함량은 1.5wt%였다.3. 축열재 내구성 검증을 위하여 0~1,500회의 상변화 사이클을 수행하였다. 이때 상변화 온도의 변화량이 $\pm$1.$0^{\circ}C$ 이하, 잠열량 변화가 $\pm$2.0 kacl/kg 이하로서 안정된 값을 보였다. 이상의 결과로 볼 때 축열재의 수명을 10년까지는 보장할 수 있는 것으로 판단되었다.

• Archives of Pharmacal Research
• /
• v.29 no.5
• /
• pp.412-417
• /
• 2006

Triamcinolone acetonide (TA) is a corticosteroid that is used in the systemic and topical treatment of many inflammatory diseases. In this study, a phonophoretic drug delivery system was designed to enhance the TA permeability and the influence of ultrasound was examined. In order to establish the transdermal delivery system for TA, a hydrophilic carbopol gel containing TA was prepared after adopting phonophoresis. A permeation study through mouse skin was performed at $37^{\circ}C$ using a Franz diffusion cell, and the ultrasound treatment was carried out for 10 h. The level of TA permeation through the skin was evaluated under various ultrasound conditions including the frequency (1.0, 3.0 MHz), intensity (1.0, $2.5W/cm^2 $), and duty cycle (continuous, pulse mode) using a 0.5% TA gel. The highest permeation was observed under the ultrasound treatment conditions of low frequency, high intensity, and in continuous mode.

• Korea-Australia Rheology Journal
• /
• v.21 no.4
• /
• pp.269-280
• /
• 2009

The drop formation dynamics of a shear thinning, elastic, yield stress ($\tau_o$) fluid (Carbopol 980 (poly(acrylic acid)) dispersions) in silicone oil has been investigated in a flow-focusing microfluidic channel. The rheological character of each solution investigated varied from Netwonian-like through to highly non-Newtonian and was varied by changing the degree of neutralization along the poly (acrylic acid) backbone. We have observed that the drop size of these non-Newtonian fluids (regardless of the degree of neutralisation) showed bimodal behaviour. At first we observed increases in drop size with increasing viscosity ratio (viscosity ratio=viscosity of dispersed phase (DP)/viscosity of continuous phase (CP)) at low flowrates of the continuous phases, and thereafter, decreasing drop sizes as the flow rate of the CP increases past a critical value. Only at the onset of pinching and during the high extensional deformation during pinch-off of a drop are any differences in the non-Newtonian characteristics of these fluids, that is extents of shear thinning, elasticity and yield stress ($\tau_o$), apparent. Changes in these break-off dynamics resulted in the observed differences in the number and size distribution of secondary drops during pinch-off for both fluid classes, Newtonian-like and non-Newtonian fluids. In the case of the Newtonian-like drops, a secondary drop was generated by the onset of necking and breakup at both ends of the filament, akin to end-pinching behavior. This pinch-off behavior was observed to be unaffected by changes in viscosity ratio, over the range explored. Meanwhile, in the case of the non-Newtonian solutions, discrete differences in behaviour were observed, believed to be attributable to each of the non-Newtonian properties of shear thinning, elasticity and yield stress. The presence of a yield stress ($\tau_o$), when coupled with slow flow rates or low viscosities of the CP, reduced the drop size compared to the Newtonian-like Carbopol dispersions of much lower viscosity. The presence of shear thinning resulted in a rapid necking event post onset, a decrease in primary droplet size and, in some cases, an increase in the rate of drop production. The presence of elasticity during the extensional flow imposed by the necking event allowed for the extended maintenance of the filament, as observed previously for dilute solutions of linear polymers during drop break-up.