Effects of source difference of sodium carboxymethyl starch on its properties and function / 药学学报

During the process of consistency evaluation, it was found that the consistency of drug release between generic and original brands in vitro was not sufficient to demonstrate their same release in vivo. The disintegration of tablets, as a premise for the release of tablet drugs, greatly affects the release of drugs, depending on the structure and properties of disintegrants. Hence the systematic research on disintegrants would be very important for the evaluation of generic consistency. In this experiment, the physicochemical properties and application of 11 different sodium carboxymethyl starch (CMS-Na) from 9 manufacturers were investigated. This provides the reference for selection of excipients for consistency evaluation. The particle morphology of CMS-Na was observed by scanning electron microscope. The particle size distribution was determined by dry particle size analyzer. The determination of pH and loss on drying was carried out according to the 2015 edition of Chinese pharmacopoeia method. The powder fluidity was evaluated with Carr's index, Hausner ratio and angle of repose. The disintegration performance of CMS-Na was evaluated through determining the water absorption and swelling. The disintegration effect of CMS-Na tablets was studied using lactose and microcrystalline cellulose as fillers. The results showed that pH values and weight loss on drying of all samples met the requirements, whereas the particle morphology, fluidity, water swell-ability and disintegration time had a large variation, which leads to the large differences the properties of CMS-Na depending on the sources. Therefore in order to ensure that the reproducibility of generic drugs from their name brand, our studies indicate that only a sizable choice of disintegrants could ensure good inter batch reproducibility.

Solubilization and protection of curcumin by mixed surfactants / 药学学报

The solubilization and protection of curcumin (Cur) by mixed surfactants were studied through the determination about the critical micellar concentration (CMC) of the mixed surfactants of Tween 80 and dodecyl trimethyl ammonium bromide (DTAB), molar solubilization ratio (MSR), degradation rate (k) of Cur in pH 13 solution and mixed surfactant solutions prepared at pH 13. The results showed that when Tween 80 was used alone, it exhibited high solubilization ability but poor stability. DTAB was used alone, it showed strong stability but poor solubilization ability. When DTAB was mixed with Tween 80 at different mole fractions, the stability of Cur was enhanced, and the best stability was observed when the mole fraction of DTAB was 0.4, although the solubilization ability was not the best at this mole fraction, but MSR was increased by 1.7 times compared to DTAB used alone. Mixed surfactant not only increased the solubility but also improved the stability of Cur. In addition, mixed surfactant has the advantages of less dosage and low toxicity, which is worth popularizing in application.

Rheological properties of compound carrageenan / 药学学报

The rheological properties of six compound gels that consists of kappa carrageenan (KC) and another excipient such as konjac gum were explored through comparison of their viscosity measured by the rotation method. The gel fluid type was dependent on the rheological curve fitted by the power-law equation. The effect of concentration on the viscosity of different compound gels was investigated by establishing the linear equation between their viscosity and concentration, the slope of which was used to determine the relation between viscosity and concentration of different compound gels. The viscous flow activation energy (Eη) was calculated by the Arrhenius equation, which was able to investigate the effect of temperature on their viscosity. The interaction between monomer and compound gels was also studied by measuring their viscosity. The results showed that six compound gels were pseudoplastic fluid. Among all compound gels, the KC-xanthan gum (KC-XG) solution exhibited the most obvious shear thinning, the strongest pseudoplasticity, while the smallest Eη, resulting in the best thermal stability of viscosity. Furthermore, the concentration of KC-sodium hyaluronate (KC-HA-Na) solution affected its viscosity significantly. The viscosity of six compound gels was greater than the summation of the two kinds of monomer gels, which suggests that there is a synergistic-viscosity interaction between KC and another excipient.

The swelling behavior of choline fenofibrate hydrogel matrix tablets using dynamic image analysis / 药学学报

The purpose of this study is to investigate the effects of formulation on the swelling behavior of choline fenofibrate hydrogel matrix tablets and reveal the relation between swelling property and release profile using dynamic image analysis. The volume swelling ratio (SR) and height/width (k) could evaluate the swelling behavior of matrix tablets well. The mount of hydroxypropyl methylcellulose (HPMC) and the ratio between K15M and K4M affected the volume swelling ratio, while PVP didn't. The three factors all impacted k, which was an indicator of the strength of the gel formed by HPMC. The accumulative release ratio and SR, the rate of swelling and the rate of release were compared. The proper model equations were established for the results with an excellent correlation. The results prove that there is a strong relevance between the swelling behavior and release property. This study provides a guideline in the study design for hydrogel matrix tablets.

Preparation and properties of thermosensitive in situ gel for ophthalmic formulation containing pearl hydrolyzate / 药学学报

The study was designed to generate an ophthalmic thermosensitive in situ gel with improved mechanical and mucoadhesive properties that may prolong the retention time to enhance the bioavalability of pearl hydrolyzate. The gene was comprised of poloxamer 407, poloxamer188 and Carbopol 934, which were optimized by central composite design and response surface methodology. The rheological properties, transcorneal permeability, retention time and in vitro release behaviors of the optimal gel formulation were investigated. The gel was Newtonian liquid at 25℃ and performed as a semisolid gel with non-Newtonian liquid property with a gelation time of 13 s at 35℃. Compared with a conventional eye drops, the ophthalmic in situ gel exhibited a sevenfold increase in retention with a sustained release behavior, which was observed with suitable permeability coefficient at 5.58 cm·s-1. In conclusion, the new gel of pearl hydrolyzate prolonged the release duration of drug, which may decrease the frequency of administration of pearl hydrolyzate. kilometers with ecological similarity between 20% and 40%, mainly in Yunnan, Guangxi, Guangdong, Guizhou, Hainan, Sichuan, Fujian and Chongqing. The climate factors mainly affecting the distribution of Panax notoginseng (Burk.) F. H. Chen were precipitation of warmest quarter, SD of temperature seasonality, altitude, isothermality, coefficient of variation of precipitation seasonality, mean temperature of monthly, precipitation of driest month, reference bulk density of soil and soil texture.

Determination of contact angle of pharmaceutical excipients and regulating effect of surfactants on their wettability / 药学学报

To study the effects of surfactants on wettability of excipients, the contact angles of six types of surfactants on the surface of two common excipients and mixture of three surfactants with excipients were measured using hypsometry method. The results demonstrated that contact angle of water on the surface of excipients was associated with hydrophilcity of excipients. Contact angle was lowered with increase in hydrophilic groups of excipient molecules. The sequence of contact angle from small to large was starch < sodium benzoate < polyvinylpyrrolidone < sodium carboxymethylcellulose < sodium alginate < chitosan < hydroxypropyl methyl cellulose <magnesium stearate. In addition, surfactants both in droplets and mixed in excipients significantly reduced the contact angle of excipients, and their abilities to lower contact angle varied. The results of the present study offer a guideline in the formulation design of tablets.

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.

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.

LC-MS/MS determination of budesonide in dog plasma / 药学学报

A liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of budesonide in dog plasma. Budesonide and the internal standard triamcinolone acetonide were separated from plasma by alkalinized liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a Capcell Pak C18 MG column with the mobile phase consisted of acetonitrile -5 mmol x L(-1) ammonium acetate (60:40, v/v) at a flow-rate of 0.50 mL x min(-1). A tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the negative ion mode. Quantification was performed using multiple reaction monitoring (MRM) of the transitions m/z 489 --> m/z 357 and m/z 493 --> m/z 413 for budesonide and the internal standard, respectively. The linear calibration curves were obtained in the concentration range of 25.0-2000 pg x mL(-1). The lower limit of quantification was 25.0 pg x mL(-1). The intra- and inter-day relative standard deviation over the entire concentration range was less than 15%. The accuracy was in the range of -8.1% to -1.7% in terms of relative error. The method was applied to a pharmacokinetic study of budesonide controlled-release capsules in Beagle dogs. Maximal budesonide plasma level was observed after (3.5 +/- 3.3) h and the Cmax was (786 +/- 498) pg x mL(-1) after a single oral administration of 9 mg budesonide capsules, Cmax was increased to (2142 +/- 1515) pg x mL(-1) after multiple oral administration (9 mg x 5 d) of budesonide capsules. This method was selective and rapid, and the sensitivity was sufficient for the purpose of the pharmacokinetic study of budesonide controlled-release formulation.

The delivery mechanism of micro-porous osmotic pump tablets / 药学学报

To investigate the delivery mechanism of micro-porous osmotic pump tablets ( MPOP), taking tramadol hydrochloride ( TR) as the model drug, tramadol hydrochloride micro-porous osmotic pump tablets (TR MPOP) were prepared with compressible starch as diluent, cellulose acetate as coating material, polyethylene glycol 400 as pore-forming agents. The equilibrium solubility and osmolality of TR were determined. The effects of fillers in tablet cores, coating levels, and osmotic pressures of release media on expansion behavior of preparations were described. The influences of the category, osmolality, and pH value of release media, release methods, and release conditions on release curves of tablets were evaluated. Based on several models, the delivery pattern of TR MPOP was fitted. The equilibrium solubility in water and osmolality of TR were (775.8 +/- 17.7) g x L(-1) and 4.036 Osmol x kg(-1), respectively. During the drug-release period, it was observed that the tablets expanded markedly in response to the expansion characteristics of compressible starch and the osmotic pressure difference across the membrane. When osmotic pressure of release media increased, the significant change of the equilibrium solubility of TR was not found, but the release rates of TR MPOP decreased significantly. The delivery rate was not influenced by the pH of release mediums, dissolution methods and paddle stirring rates. The drug release profile conformed to the model of zero order in 8 h. The pore-forming agents were dissolved in release medium, which caused micro-pores. The expansion of tablets made the size of micropores bigger, and then the drug-releasing pores were obtained. It was proved that the drivers of drug delivering from TR MPOP were mainly the difference of osmotic pressure, and secondly the difference of solubility. TR MPOP were the controlled-release preparation.

Determination of salidroside and p-tyrosol in Hongjingtian for injection(freezing-dry) by SPE-HPLC / 中国中药杂志

<p><b>OBJECTIVE</b>To assay salidroside and p-tyrosol in Hongjingtian for injection (freezing-dry).</p><p><b>METHOD</b>Samples were purified by Sep-Pak C18 column and salidroside and p-tyrosol were determined by HPLC with Irregular-H C18 (4.6 mm x 250 mm, 5 microm), and eluted with a mobile phase of methanol-acenitonitrile -0.06% phosphate (10: 10:80). The flow rate was 1.0 mL x min(-1), the detection wavelength was set at 275 nm and the column temperature was maintained at 30 degrees C.</p><p><b>RESULT</b>The calibration curves were linear in the range of 2.24-22.4 microg for salidroside (0.999 7) and 0.856-8.56 microg for p-tyrosol (0.999 6), the average recovery was 101.3%, 99.8% respectively.</p><p><b>CONCLUSION</b>The method is convenient, rapid, accurate and reliable.</p>

Effect of solution viscosity on polymer precorneal residence time evaluated by in vitro method / 药学学报

<p><b>AIM</b>To evaluate how solution viscosity affects the precorneal residence of five water-soluble polymers with different properties.</p><p><b>METHODS</b>Captive bubble technique was used, with the consecutive change of contact angle interpreted as an indication of desorption process, to study the residence of those polymers in vitro on freshly enucleated rabbit eyes under physiological conditions.</p><p><b>RESULTS</b>Carbopol and sodium hyaluronate (HA), which adsorbed to isolated ocular surface more than 15 min, showed the optimum precorneal retentive capabilities. When the solution viscosity increased from 12 mPa.s to 50 mPa.s, the residence time of carbopol and HA were prolonged 10 min and 7 min, respectively, but that of sodium carboxymethylcellulose was not affected.</p><p><b>CONCLUSION</b>The result suggested that higher viscosity is beneficial to improve the ocular residence time of bio-adhesive polymers.</p>