The rheology properties of common hydrophilic gel excipients / 药学学报

To investigate theological properties of common hydrophilic gel excipients such as Carbopol based on viscosity, the viscosity was determined by rotation method and falling-ball method. Linear regression was made between ln(eta) and concentration, the slope of which was used to explore the relation between viscosity and concentration of different excipients. The viscosity flow active energy (E(eta)) was calculated according to Arrhenius equation and was used to investigate the relation between viscosity and temperature of different excipients. The results showed that viscosities measured by two methods were consistent. Concentration of guargum (GG) and hydroxypropylmethyl cellulose (HPMC) solution had a great influence on the viscosity, k > 5; while concentration of polyvinylpyrrolidone-K30 (PVP-K30) and polyethylene glycol 6000 (PEG6000) exerted a less effect on viscosity, k < 0.2; viscosity flow active energy of different excipients were close, which ranged from 30 to 40 kJ x mol(-1). Therefore, theological properties study could provide the basis for application of excipients and establish a foundation for the research of relation between excipients structure, property and function.

Ketoconazole ion-exchange fiber complex: a novel method to reduce the individual difference of bioavailability in oral administration caused by gastric anacidity.

Water insoluble faintly alkaline drugs often have potential absorption problem in gastrointestinal tract in oral administration for patients with gastric anacidity. The purpose of the present study is to develop a novel method to improve the absorption of the water insoluble faintly alkaline drug in peroral administration. This method is based on ion exchange of ion-exchange fibers. Water-insoluble faintly alkaline drug ketoconazole was used as a model drug. Ketoconazole and the active groups of the ion-exchange fibers combined into ion pairs based on the acid-base reaction. This drug carrier did not release drugs in deionized water, but in water solution containing other ions it would release the drugs into the solution by ion exchange. Confirmed by the X-ray diffraction and the differential scanning calorimetry (DSC), the ketoconazole combined onto the ion-exchange fibers was in a highly molecular level dispersed state. The improved dissolution of ketoconazole ion-exchange fiber complexes is likely to originate from this ketoconazole's highly dispersed state. Furthermore, due to this ketoconazole's highly dispersed state, ketoconazole ion-exchange fiber complexes significantly decreased the individual difference of absorption in oral administration of ketoconazole caused by the fluctuation of the acid degree in the gastric fluid.

A novel method to enhance the efficiency of drug transdermal iontophoresis delivery by using complexes of drug and ion-exchange fibers.

The main reason for generally low efficiency of the transdermal iontophoretic drug delivery is that the fraction of the total current contributed by the drug ions is very small. The objective of this study was to find a method to increase the fraction of the total current contributed by the drug ions so as to enhance the drug's iontophoretic delivery. Iontophoretic transport of diclofenac solution and diclofenac assisted by ion exchange materials, including ion-exchange resin, ion-exchange membrane and ion-exchange fiber, across the rat skin were investigated. Both in vitro and in vivo iontophoretic transport experiments showed the amount of diclofenac permeated across rat skin from the diclofenac-fibers was highest among those from the diclofenac simple solutions and ion exchange materials complexes. The results of this study suggested that there is an enhancement of drug across rat skin by ion-exchange fibers in ion-exchange fibers assisted iontophoresis. The present study has demonstrated the potential of a new approach using ion-exchange fibers to enhance transdermal iontophoretic transport of an ionizable drug.

The preparation and kinetic study on enzymatically-controlled drug release of isotretinoin/amylose inclusion complex / 药学学报

The inclusion complex of isotretinoin was prepared by sealed-control temperature method and amylose was used as carrier. The formation of inclusion complex was confirmed by powder X-ray diffraction and DSC. The equation of enzymatically-controlled drug release was established by kinetic theory, and the release characteristic of drug was confirmed by using the kinetic equation. The results show that the drug release was attributed to first order reaction without alpha-amylase. However, with alpha-amylase, the drug release was an acceleration process by the effect of both dissociation and enzymatic hydrolysis simultaneously. The research indicates that drug release from the inclusion complex was modulated by the addition of alpha-amylase.

Modulating drug loading and release profile of beta-cyclodextrin polymers by means of cross-linked degree / 药学学报

The purpose of the present study is to use beta-cyclodextrin polymers (beta-CDP) with different cross-linked degree (CLD) to form inclusion complexes with ibuprofen and examine the effects of structural and compositional factors of beta-CDP on its drug loading and release behaviors. A series of beta-CDP with different CLD were synthesized and characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and 13C NMR spectrum. The beta-CDP was systemically characterized for the relation between the CLD of beta-CDP and the drug loading and release as well. The results of FT-IR and 13C NMR showed that similar peak-shaped vibration of beta-CDP and beta-CD implies that the polymer keeps the original characteristic structure of beta-CD. The CLD of the beta-CDP played a critical role in the drug loading and release, increasing the CLD resulted in reduction of drug loading, but increase in drug release.

Kinetic study on dissociation of amylose/salicylic acid compound using non-isothermal method / 药学学报

The inclusion compound of amylose and salicylic acid (SA) was prepared by a sealed temperature control method, and the formation of the inclusion compound was confirmed by IR spectrum and powder X-ray diffraction. The kinetic parameters of dissociation of amylose/SA compound were studied by the nonisothermal method which was defined as a relationship between the dissociation ratio and time. The values of activation energy (Ea) and frequency factors (InA) were calculated by a nonlinear least-square method. In this study, the formation of the inclusion compound of amylose/SA was confirmed by IR spectrum powder X-ray diffraction. SA existed in a molecule form in the spiral stouction of amylose. The dissociation of amylose/SA compound was attributed to first order reaction. The values of Ea calculated by the nor-isothermal method were 21.71 and 22.41 kJ x mol(-1) at heating rate 5 and 10 degrees C x h(-1), respectively. The corresponding isothermal method value of Ea was 22.17 kJ x mol(-1); the calculated InA values were 9.32 and 10.08 at heating rate 5 and 10 degrees C x h(-1), respectively. The corresponding isothermal method lnA value was 9.26. The results were in good agreement with Ea values and lnA values by isothermal method. These results indicated that the non-isothermal method described in this study could be adequately used for the stability study of inclusion compound and was a rapid and accurate method for the determination of kinetic parameters.

Preparation of inclusion complex of paeonol and beta-cyclodextrin by sealed-control temperature method / 中国中药杂志

<p><b>OBJECTIVE</b>In the present study, using paeonol as model drug, a new sealed-control temperature method of preparing inclusion complex was developed, the effects of heating temperature, heating time, and crystallinity of beta-cyclodextrin (beta-CD) on formation of inclusion complex and release of the drug were investigated.</p><p><b>METHOD</b>A physical mixture of paeonol and beta-CD was sealed in a container, and heated at the desired temperature for the specified time. The inclusion complex of paeonol and beta-CD was confirmed by IR spectrum and powder X-ray diffraction.</p><p><b>RESULT</b>The results indicated that the inclusion complex formation of paeonol beta-CD by sealed-control temperature method was affected by heating temperature, heating time, and crystallinity of beta-CD. The inclusion complex was able to inhibit sublimation of paeonol, and dissolution rate of paeonol was increased when the paeonol was included by beta-CD.</p><p><b>CONCLUSION</b>Preparation of inclusion complex was simple and quick by sealed-control temperature method.</p>

Brief discussion on attitude of selecting point and posture of needling / 中国针灸

<p><b>OBJECTIVE</b>To promote the study on standardization of attitude of selecting point and posture of nee dling, so as to ensure safety of acupuncture and increase clinical therapeutic effect.</p><p><b>METHODS</b>Study, analyze and clinically test and verify on literature of past dynasties, and differentiate and analyze differences and significances of attitude of selecting point and posture of needling, indicate the reasonable parts of ancient and modern various theories, and relative contents should be purified, corrected in time, and put forward a proposal on the standardization.</p><p><b>CONCLUSION</b>Attitude of selecting point and posture of needling have close relation and have a certain difference; the experience of predecessors should be explored and systematized, and present confusion and out-of-date contents should be purified and relative standards should be established as early as possibly.</p>

On the needling depth of filiform needle at acupoints / 中国针灸

<p><b>OBJECTIVE</b>To promote the study on standardization of needling depth of acupoints, ensure safety of needling, and promote internationally academic exchanges of acupuncture and moxibustion.</p><p><b>METHODS</b>Study, analyze ancient and present literature of acupuncture and moxibustion, and compare the differences in needling depth, measure unit, description methods, and the causes and trend, and indicate confusion at present, and put forward a proposition for establishing standardization of needling depth.</p><p><b>CONCLUSION</b>There are a lot of confusions in needling depth of acupoints from the ancient times to the present, which produces severe unfavorable influence on standardization and international exchanges of acupuncture and moxibustion science, and it remains to be studied for the standardization as early as possibly.</p>