Stability of Tetracycline Hydrochloride in Reverse Micelles

Kim, Hyun-Joo,Lee, Hwa-Jeong,Sah, Hong-Kee The Korean Society of Pharmaceutical Sciences and 2005 Journal of Pharmaceutical Investigation Vol.35 No.5

The objective of this study was to investigate the stability of tetracycline HCl on encapsulation into and inside reverse micelles. To do so, tetracycline HCl was first mixed with cetyltrimethylammonium bromide, water and ethyl formate to make reverse micelles. The degradation kinetics of tetracycline HCl inside the reverse micelles was then assessed by scrutinizing its stability data. Under our experimental conditions, the reverse micelles formed spontaneously in absence of any mixing devices. During the preparation of the reverse micelles, however, considerable portions of tetracycline HCl underwent a chemical reaction (e.g., epimerization). For instance, $51.4{\pm}0.6%$ of an initial concentration of tetracycline HCl was transformed into a degradation product. Once dissolved inside the reverse micelles, the degradation of tetracycline HCl followed an exponential decay pattern. The plot of log{the degradation rate of tetracycline HCl} versus log{tetracycline HCl concentration} made it possible to determine the order of degradation reaction and rate constant. It was proven that the degradation of tetracycline HCl inside the reverse micelles followed a first order kinetics with a rate constant of 0.0027 $hour^{-1}$. Meriting further investigation might be formulation studies to stabilize tetracycline HCl on encapsulation into and inside the reverse micelles.

Thermal Deactivation Kinetics of Pseudomonas fluorescens Lipase Entrapped in AOT/Isooctane Reverse Micelles

Park, Kyung Min,Kwon, Chang Woo,Choi, Seung Jun,Son, Young-Hwan,Lim, Seokwon,Yoo, YoonJung,Chang, Pahn-Shick American Chemical Society 2013 Journal of agricultural and food chemistry Vol.61 No.39

<P>Thermostability of the lipase (EC 3.1.1.3) was found to be increased by the enzyme-entrapment in 50 mM AOT/isooctane reverse micelles. The half-life (15.75 h) of Pseudomonas fluorescens lipase entrapped in reverse micelles at 70 °C was 9.72- and 11.41-fold longer than those solubilized in a glycerol pool or in 10 mM phosphate buffer (pH 8.0), respectively. The enzyme deactivation model considering a two-step series-type was employed, and deactivation constants for the second step (<I>k</I><SUB>2</SUB>) at all temperatures were drastically decreased after the lipase was entrapped in reverse micelles. In particular, <I>k</I><SUB>2</SUB> (0.0354 h<SUP>–1</SUP>) at 70 °C in reverse micelles was 12.33- and 13.14-fold lower than in a glycerol pool or in the phosphate buffer, respectively. The deactivation energies (from <I>k</I><SUB>1</SUB>, <I>k</I><SUB>2</SUB>) for the lipase entrapped in the reverse micelles, solubilized in a glycerol pool, or in the aqueous buffer were 7.51, 26.35 kcal/mol, 5.93, 21.08 kcal/mol, and 5.53, 17.57 kcal/mol, respectively.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2013/jafcau.2013.61.issue-39/jf402539m/production/images/medium/jf-2013-02539m_0007.gif'></P>

Development of New Reverse Micellar Microencapsulation Technique to Load Water-Soluble Drug into PLGA Microspheres

Hyunjoo Kim,Mihyun Cho,사홍기 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.3

The objective of this study was to develop a new reverse micelle-based microencapsulation technique to load tetracycline hydrochloride into PLGA microspheres. To do so, a reverse micellar system was formulated to dissolve tetracycline hydrochloride and water in ethyl formate with the aid of cetyltrimethylammonium bromide. The resultant micellar solution was used to dissolve 0.3 to 0.75 g of PLGA, and microspheres were prepared following a modified solvent quenching technique. As a control experiment, the drug was encapsulated into PLGA microspheres via a conventional methylene chloride-based emulsion procedure. The microspheres were then characterized with regard to drug loading efficiency, their size distribution and morphology. The reverse micellar procedure led to the formation of free-flowing, spherical microspheres with the size mode of 88 µm. When PLGA microspheres were prepared following the conventional methylene chloride-based procedure, most of tetracycline hydrochloride leached to the aqueous external phase: A maximal loading efficiency observed our experimental conditions was below 5%. Their surfaces had numerous pores, while their internal architecture was honey-combed. In sharp contrast, the new reverse micellar encapsulation technique permitted the attainment of a maximal loading efficiency of 63.19 ± 0.64%. Also, the microspheres had smooth and pore-free surfaces, and hollow cavities were absent from their internal matrices. The results of this study demonstrated that PLGA microspheres could be successfully prepared following the new reverse micellar encapsulation technique.

Dyeing Wool Knitted Fabric in Nano-scale Reverse Micelle with Reactive Dyes - A Computer Colour Matching Study

Cheng-hao Lee,Yanming Wang,Yiu-lun Tang,Chi-wai Kan 한국섬유공학회 2021 Fibers and polymers Vol.22 No.5

The colour quality assessment of reverse micelle-based (in octane or nonane medium) and conventional waterbaseddyed wool knitted fabric has been investigated using computer colour matching (CCM) approach. Both water-basedand non-aqueous based dyeing methods exhibited no chromatic shift from the reflectance curves and established goodlinearity in the construction of calibration curves. The linearity of both calibration curves in terms of R2 value played a criticalrole in CCM. The colour yield obtained from reverse micellar dyed fabric samples was higher than the colour yield valuesfrom wool knitted fabrics dyed in water bath under different dye percentages. The CCM predicted concentrations were ingood agreement to theoretical concentrations for both dyeing systems. To conclude, the results showed that reverse micellardyeing in octane and nonane is capable of generating reliable colour recipes. The relative unlevelness indices (RUI) obtainedfrom dyed wool knitted fabrics using reverse micellar approach reveal good to excellent levelness, which fulfills therequirements of the textile processing industry. TEM picture illustrated that reverse micelles are in nano-scale and this couldenhance the dyeing effect of wool with reactive dyes.

Hexagonal to Cubic Phase Transition in the $D_2O$-Induced Reverse Micellar Solution of a PEO-b-PPO-b-PEO Block Copolymer

Kim, Do-Hyun,Ko, Yoon-Soo,Kwon, Yong-Ku The Polymer Society of Korea 2008 Macromolecular Research Vol.16 No.1

The morphology of the $D_2O$-induced reverse micellar structure of an amphiphilic block copolymer of poly( ethylene oxide )-b-poly(propylene oxide )-b-poly( ethylene oxide )($EO_{76}PO_{29}EO_{76}$) was investigated in hydrophobic media by small angle neutron scattering (SANS). Increasing $D_2O$ in the styrene/divinylbenzene solution of $EO_{76}PO_{29}EO_{76}$ led to a change in morphology of the reverse micelles from a short range ordered molecular aggregate to a hexagonally arranged micelle, and further to a spherical micelle.

Reverse Micelle법을 이용한 Nanometer 크기의 단일(Au, Ag) 및 합금(Au/Ag) Cluster의 합성과 특성 연구

김정수,유은아,나혜진 성신여자대학교기초과학연구소 2000 基礎科學硏究誌 Vol.18 No.-

Single metal(Ag, Au) and alloy(Ag/Au) clusters in the nanometer range were prepared in the reverse micelle solutions of sodium bis(2-ethylhexyl)-sulfosuccinate via reduction with hydrazine. The size and shape of metallic particles are controlled by the molar ratio of usrfactant and water. The change in the shape and size is followed by UV-visible spectroscopy, TEM, EDAX and ICP-AES. The peaks of surface plasmon of Ag and Au are showed in 420nm and 520nm respectively. The red shift in the surface plasmon peak is observed when the size of metallic particles increased. The size distribution of metallic particles is ranged from 1nm to 30nm with spherical shapes. This reverse micelle method is not properly applied to the synthesis of the Ag/Au alloy clusters.

Effects of Stirring and Addition of Chemical Compounds on Glycerolysis of Triglyceride in Reversed Micelles

Chang, Pahn Shick,Rhee, Joon Shick 한국미생물 · 생명공학회 1991 Journal of microbiology and biotechnology Vol.1 No.3

Glycerolysis of triolein by lipase from Chromobacterium viscosum lipase was studied batchwise in AOT-isooctane reversed micelles. The reaction mixture was extracted with chloroform and the content of triolein, 1,2-diolein, 1,3-diolein, 1-monoolein, and free fatty acid in the condensed chloroform solution was determined using high performance liquid chromatography (HPLC). The effect of agitation speed on the initial rate of conversion was examined. As the speed of agitation increased up to 700 rpm, the reaction rate increased. However, above 700 rpm, the rate approached maximum and did not increase that much. The glycerolysis activity and the stability of the enzyme were affected by stirring and addition of histidine or copper. Addition of histidine and copper increased the rates of glycerolysis but they are detrimental to the operational stability in reversed micelles.

Spectroscopic Properties of Quercetin-3-O-rhamnoside and Quercetin-3-O-rutinoside in Aerosol-OT Reverse Micelles

박형련,Hai-Bo Liu,신성철,박종근,박기민 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.3

The anomalous spectroscopic properties of quercetin-3-O-rhamnoside (QCRM) and quercetin-3-O-rutinoside (QCRT) in AOT reverse micelle were studied. The excited state intramolecular proton transfer (ESIPT) occurs through the strong hydrogen bond between the –OH at position 5 and the carbonyl oxygen. Because the ESIPT can only happens in the S_1 state and the Franck-Condon factor involved in the S_2 → S-1 internal conversion is small, the S_2 → S_o emission alone appears. Because the molecular planarity is improved at the interior of the micelle, the excited state intramolecular charge transfer in the S1 state is extended, and the excited state is more tolerable for any quenching effects in the micelle. Therefore, an S_1 → S_o emission was newly discovered under this micelle microenvironment. For the S_2 → S_o emission, the quantum yields increase but the quantum yield of the S_1 → S_o emission approximately decreases as the water concentration in the micelle increases.

Spectroscopic Properties of Quercetin-3-O-rhamnoside and Quercetin-3-O-rutinoside in Aerosol-OT Reverse Micelles

Park, Hyoung-Ryun,Liu, Hai-Bo,Shin, Sung-Chul,Park, Jong-Keun,Bark, Ki-Min Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.3

The anomalous spectroscopic properties of quercetin-3-O-rhamnoside (QCRM) and quercetin-3-O-rutinoside (QCRT) in AOT reverse micelle were studied. The excited state intramolecular proton transfer (ESIPT) occurs through the strong hydrogen bond between the -OH at position 5 and the carbonyl oxygen. Because the ESIPT can only happens in the $S_1$ state and the Franck-Condon factor involved in the $S_2\;{\rightarrow}\;S_1$ internal conversion is small, the $S_2\;{\rightarrow}\;S_o$ emission alone appears. Because the molecular planarity is improved at the interior of the micelle, the excited state intramolecular charge transfer in the $S_1$ state is extended, and the excited state is more tolerable for any quenching effects in the micelle. Therefore, an $S_1\;{\rightarrow}\;S_o$ emission was newly discovered under this micelle microenvironment. For the $S_2\;{\rightarrow}\;S_o$ emission, the quantum yields increase but the quantum yield of the $S_1\;{\rightarrow}\;S_o$ emission approximately decreases as the water concentration in the micelle increases.

Spectroscopic Properties of Apigenin in Various Bulk Solutions and Aerosol-OT Reverse Micelles

박형련,서정자,박철호,Duan Yu,박기민 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.9

The fluorescence and ultraviolet (UV)/visible absorption spectra of apigenin (API) were measured and examined in bulk solutions and aerosol-OT (AOT) reverse micelles. The Stokes’ shift in micelles is very small due to the small dipole moment change upon excitation. Since the intermolecular interaction between API and H2O in micelles is weak, the fluorescence parameters are relatively insensitive to the change in water concentration compared with those in bulk solutions. Since the B ring can rotate freely, the dihedral angle between the A, C, and B rings can be changed easily by the influence of the solvent. The potential energy curves of the electronic states show a very shallow or no minimum. Although the change in electronic energy by intermolecular interaction will be very small, the point where emission occurs on the energy curve can be altered very sensitively. Due to these reasons, the fluorescence properties of API are very sensitive to changes in excitation wavelength and solvent.