• 대한의용생체공학회:의공학회지
• /
• 제39권4호
• /
• pp.161-167
• /
• 2018

Polyvinyl alcohol/sodium carboxymethyl cellulose (PVA/NaCMC) hydrogels were prepared by physical crosslinking (cyclic freezing/thawing) and gamma (${\gamma}$)-ray irradiation to evaluate the effect of NaCMC concentration (2~8 wt%) on the mechanical properties and the biocompatibility of the PVA/NaCMC hydrogels. The swelling rate of PVA/NaCMC hydrogels regardless of irradiation rose with increasing NaCMC content from 2 wt% to 8 wt%, while the gelation rate was the reverse. As the NaCMC content increased from 2 wt% to 6 wt%, the compressive strength of the hydrogels increased dramatically from $8.5{\pm}2.0kPa$ to $52.7{\pm}2.5kPa$ before irradiation and from $13.5{\pm}2.9kPa$ to $65.5{\pm}8.7kPa$ after irradiation. When 8 wt% NaCMC was added afterwards, the compressive strength decreased however. The irradiated PVA/NaCMC hydrogels containing 6 wt% NaCMC exhibited the tailored properties of the swelling rate of $118{\pm}3.7%$, the gelation rate of $71.4{\pm}1.3%$, the strength of $65.5{\pm}8.7kPa$, respectively, and no cytotoxicity was observed.

• Journal of Pharmaceutical Investigation
• /
• 제40권1호
• /
• pp.23-31
• /
• 2010

In our previous work on levodopa delivery at pH 2.5 using iontophoresis, we found that cathodal delivery showed higher permeation than anodal delivery and electroosmosis plays more dominant role than electrorepulsion. In this work, we studied the transdermal transport of levodopa at very low pH (pH=1.0) where all levodopa molecules are cations, and evaluated some factors which affect the transdermal transport. The transport study at pH 2.5 was also conducted for comparison. The contribution of electrorepulsion and electroosmosis on flux was also evaluated. Using stable aqueous solution, the effect of electrode polarity, current density, current type and drug concentration on transport through skin were studied and the results were compared. We also investigated the iontophoretic flux from hydroxypropyl cellulose (HPC) hydrogel containing levodopa. In vitro flux study was performed at $33^{\circ}C$, using side-by-side diffusion cell. Full thickness hairless mouse skin were used. Current densities applied were 0.2, 0.4 or $0.6\;mA/cm^2$. Contrary to the pH 2.5 result, anodal delivery showed higher flux, indicating that electrorepulsion is the dominant force for the transport, overcoming the electroosmotic flow which is acting against the direction of electrorepulsion. Cumulative amount of levodopa transported was increased as the current density or drug concentration was increased. When amount of current dose was constant, continuous current was more beneficial than pulsed current in promoting levodopa permeation. Similar transport results were obtained when hydrogel was used as the donor phase. These results indicate that iontophoretic delivery of zwitterion such as levodopa is much complicated than that can be expected from small ionic molecules. The results also indicate that, only at very low pH like pH 1.0, electrorepulsion can be the dominant force over the electroosmosis in the levodopa transport.

• 융합정보논문지
• /
• 제9권6호
• /
• pp.233-241
• /
• 2019

본 연구는 수도권에 거주하는 20~30대 여성을 대상으로 마스크팩 인식 및 구매 행동에 대하여 설문지를 이용하여 조사하였다. 본 연구 결과, 연구 대상자들은 피부미용에 대한 관심이 높지만 마스크팩 타입에 따른 특징과 차별성 인식은 미흡한 것으로 조사되었다. 마스크팩을 사용한 후, 조사 대상자들의 51.1%가 효능 효과에 만족한 것으로 조사되었으나, 마스크팩 사용 시 대표적인 불편한 점으로는 시트형 마스크팩은 사용성, 크기, 밀착성 및 피부 자극으로 불만족스러웠으며, 하이드로 겔타입의 소재와 슬리밍 타입은 내용물, 흡수성에 대해 불만족스러운 것으로 확인되었다. 또한, 셀룰로오스 팩과 하이드로겔 타입의 팩은 동일하게 불쾌감을 가지는 것으로 확인되었다. 본 연구 결과를 통하여 마스크팩 시장의 기초 마케팅 자료로서 활용이 가능할 것으로 사료되어 진다.

• 폴리머
• /
• 제33권6호
• /
• pp.551-554
• /
• 2009

Poly(vinyl alcohol) (PVA)와 carboxymethyl cellulose sodium salt(CMC)는 우수한 생체적합성 및 수용성으로 인하여 생체의학 분야에서 주목하는 재료 중 하나이다. 본 연구에서는 PVA와 CMC를 동결/융해 과정과 감마선 조사에 의하여 인공연골로서 사용 가능한 수화젤을 제조하였다. 수화젤 제조시 PVA/CMC의 농도는 PVA는 7 wt%, CMC는 4 wt%로 고정시켰으며, 동결/융해 과정은 2회 반복하였으며, 감마선은 30 kGy조사하였다. 방사선 조사 전과 후의 겔화율은 눈에 띄는 차이는 보이지 않았으나 팽윤도는 조사 후에 감소하였으며, 겔강도는 증가하였다.CCK-8 assay에 의하여 세포독성이 없는 것으로 확인되었다. 제조된 PVA/CMC 수화젤은 체내에 삽입되는 인공연골 재료로서 사용가능성을 제시하였다.

• Korea-Australia Rheology Journal
• /
• 제14권4호
• /
• pp.189-201
• /
• 2002

The interaction between hydrophobically modified hydroxyethyl cellulose (hmHEC), containing approximately 1 wt% side-alkyl chains of $C_{16}$, and an anionic sodium dodecyl sulphate (SDS) surfactant was investigated. For a semi-dilute solution of 0.5 wt% hmHEC, the previously observed behaviour of a maximum in solution viscosity at intermediate SDS concentrations, followed by a drop at higher SDS concentrations, until above the cmc of surfactant when the solution resembles that of the unsubstituted polymer, was confirmed. Additionally, a two-phase region containing a hydrogel phase and a water-like supernatant was found at low SDS concentrations up to 0.2 wt%, a concentration which is akin to the critical association concentration, cac, of SDS in the presence of hmHEC. Above this concentration, SDS molecules bind strongly to form mixed micellar aggregates with the polymer alkyl side-chains, thus strengthening the network junctions, resulting in the observed increase in viscosity and elastic modulus of the solution. The shear behaviour of this polymer-surfactant complex during steady and step stress experiments was examined In great detail. Between SDS concentrations of 0.2 and 0.25 wt%, the shear viscosity of the hmHEC-polymer complex network undergoes shear-induced thickening, followed by a two-stage shear-induced fracture or break-up of the network. The thickening is thought to be due to structural rearrangement, causing the network of flexible polymers to expand, enabling some polymer hydrophobic groups to be converted from intra- to inter-chain associations. At higher applied stress, a partial local break-up of the network occurs, while at even higher stress, above the critical or network yield stress, a complete fracture of the network into small microgel-like units, Is believed to occur. This second network rupture is progressive with time of shear and no steady state in viscosity was observed even after 300 s. The structure which was reformed after the cessation of shear is found to be significantly different from the original state.