A comparative study of the dissolubility of pure and silicon substituted hydroxyapatite from density functional theory calculations.

Introduction of silicon into hydroxyapatite (HA) is one of the effective ways to modulate the bioactivity of HA-based biomaterials. The bulk and surface structures of silicate-substituted HA (Si-HA) were characterized by using density functional theory calculations. The energetically favorable structures were identified from a number of candidate structures. Particular attention was paid to the surface structures of Si-HA, whose bioactivity is closely relevant to their surface atoms. Compared to the surface of pure HA, the Si-HA surface has similar surface energy but different charge distribution. Under the implicit solvent model, the exposed calcium/oxygen atoms become more positive/negative in net charge, resulting in a considerable change in the surface electrostatic potential at van der Waals distances. However, changes in the dissolution of surface calcium ions are not remarkable, as depicted by their activation energy leaving from the surface. Our calculations reveal that the surface structures and properties of HA were changed to some extent by silicate substitution, which provides some hints for understanding the experimentally observed changes in bioactivity and biodegradability of Si-HA that still remain controversial in many aspects.

Kinetics and dissolution of intratracheally administered nickel oxide nanomaterials in rats.

BACKGROUND: The toxicokinetics of nanomaterials are an important factor in toxicity, which may be affected by slow clearance and/or distribution in the body. METHODS: Four types of nickel oxide (NiO) nanoparticles were single-administered intratracheally to male F344 rats at three doses of 0.67-6.0 mg/kg body weight. The rats were sacrificed under anesthesia and the lung, thoracic lymph nodes, bronchoalveolar lavage fluid, liver, and other organs were sampled for Ni burden measurement 3, 28, and 91 days post-administration; Ni excretion was measured 6 and 24 h after administration. Solubility of NiO nanoparticles was determined using artificial lysosomal fluid, artificial interstitial fluid, hydrogen peroxide solution, pure water, and saline. In addition, macrophage migration to trachea and phagosome-lysosome-fusion rate constants were estimated using pulmonary clearance and dissolution rate constants. RESULTS: The wire-like NiO nanoparticles were 100% dissolved by 24 h when mixed with artificial lysosomal fluid (dissolution rate coefficient: 0.18/h); spherical NiO nanoparticles were 12% and 35% dissolved after 216 h when mixed with artificial lysosomal fluid (1.4 × 10-3 and 4.9 × 10-3/h). The largest irregular-shaped NiO nanoparticles hardly dissolved in any solution, including artificial lysosomal fluid (7.8 × 10-5/h). Pulmonary clearance rate constants, estimated using a one-compartment model, were much higher for the NiO nanoparticles with a wire-shape (0.069-0.078/day) than for the spherical and irregular-shaped NiO nanoparticles (0-0.012/day). Pulmonary clearance rate constants of the largest irregular-shaped NiO nanoparticles showed an inverse correlation with dose. Translocation of NiO from the lungs to the thoracic lymph nodes increased in a time- and dose-dependent manner for three spherical and irregular-shaped NiO nanoparticles, but not for the wire-like NiO nanoparticles. Thirty-five percent of the wire-like NiO nanoparticles were excreted in the first 24 h after administration; excretion was 0.33-3.6% in that time frame for the spherical and irregular-shaped NiO nanoparticles. CONCLUSION: These findings suggest that nanomaterial solubility differences can result in variations in their pulmonary clearance. Nanoparticles with moderate lysosomal solubility may induce persistent pulmonary inflammation.

Improvement of Forming Process of Jingning Particle / 中国药师

Objective:To improve the forming process of Jingning particle according to the influencing factors in its effectiveness, such as low yield, high moisture absorption and difficult dissolubility during oral administration. Methods:A new technology that im-mediate granulation after the extract was well mixed with lactose and dextrin and dried. The appearance, dissolubility, hygroscopicity and pellet formation rate ( granularity) were compared between the new technology and the old one, and the difference in critical rela-tive humidity was also studied. Results:The appearance, dissolubility and pellet formation rate of the new technology were all better than those of the old one, and the moisture absorption rate was reduced with the critical relative humidity up to 70%(25℃), which enhanced the granule stability. Conclusion:The pellet formation rate is improved by the new technology, which effectively solves the problems such as high moisture absorption and poor dissolubility, and the granule quality is improved.

Synthesis and characterization of tannin grafted polycaprolactone.

Tannin and biodegradable polyester have attracted increasing interest for biomedical applications. To improve their compatibility, a novel tannin grafted polycaprolactone (TA-g-PCL) has been synthesized via ring-opening polymerization reaction. The structure of the product is characterized with FTIR, (1)H NMR and GPC. GPC results show that the experimental molecular weight is far less than the theoretical due to complicated stereo structure and large steric hindrance of tannic molecule, but the polydispersity of the product is narrow. At 115.76:1 of molar ratio of CL to tannin, molecular weight of the product reaches the maximum. Thermodynamics properties and dissolubility of TA-g-PCL are closely related to its molecular weight. With PCL molecular chain grows, TA-g-PCL changes from amorphous form to crystalline structure, and its dissolubility in chloroform is also enhanced significantly.

Preparation of slowly released microspheres of dextro-ketoprofen-?-cyclodextrin inclusion / 第三军医大学学报

Objective To prepare microspheres of dextro ketoprofen ? cyclodextrin (S KP ? CD) for prolonging the drug releasing time in vitro . Methods Microspheres containing S KP ? CD were prepared by complex coacervation method with gelatin and acacia. Trap efficiency, drug loading, and drug content were determined. The dissolubility of S KP in the intestinal liquid was compared with that in the gastric liquid. Results In comparison with S KP, microspheres of S KP ? CD possessed slow releasing property. Conclusion Drug microspheres prepared by this simple, easy, and accurate method are of slow releasing property.

Effects of Carbon Dioxide Pneumoperitoneum on Serum Levels of IL-1,IL-6,and CD11a/CD18 and CD11b/CD18 Expression and Pancreatic Pathology in Severe Acute Pancreatitis / 中国普外基础与临床杂志

Objective To examine the effects of carbon dioxide (CO2) pneumoperitoneum on local pancreas pathological changes,serum levels of amylase,IL-1,IL-6,and the positive rate of dissolubility adhesion molecule (CD11a/CD18 and CD11b/CD18) expression in rats with severe acute pancreatitis (SAP). Methods Fifty healthy male Sprague-Dawley (SD) rats were randomly divided into 3 groups:CO2 pneumoperitoneum group (n=20):SAP was induced by injecting 5% sodium taurocholate through retrogradely common biliopancreatic ducts via duodenal papilla,and then CO2 pneumoperitoneum was established at a pressure of 12 mm Hg (1 mm Hg=0.133 kPa) for 30 min; SAP group (n=20):The rats were treated as same as CO2 pneumoperitoneum group,except CO2 pneumoperitoneum; Simple operation group (n=10):Laparotomy was performed and nothing was done to duodenum and pancreas except for moving them softly. The blood samples were collected for examining serum levels of amylase,IL-1,IL-6,and the positive rates of CD11a/CD18 and CD11b/CD18 expression,and histopathologic examination of pancreas was performed. Results Compared with simple operation group,the pancreatic pathologic histology score,serum levels of amylase,IL-1,IL-6,and the positive rates of CD11a/CD18 and CD11b/CD18 expression were significantly higher in CO2 pneumoperitoneum group and SAP group (P=0.000). The levels of IL-1 and IL-6 were significantly lower in CO2 pneumoperitoneum group as compared to SAP group (P=0.000). There was no significant difference between CO2 pneumoperitoneum group and SAP group in pancreatic pathologic histology score (P=0.294),the level of serum amylase (P=0.073),the positive rates of CD11a/CD18 (P=0.155) and CD11b/CD18 expression (P=0.201). Conclusion CO2 pneumoperitoneum has inhibitory effect on the levels of IL-1 and IL-6,rather than the positive rates of CD11a/CD18 and CD11b/CD18 expression in SD rats with SAP.

Comparison of Dissolubilities of Different Products of Ambroxol Hydrochloride Tablets / 中国药房

OBJECTIVE:To compare the dissolubility of ambroxol hydrochloride tablets from four different manufacturers METHODS:To determine the dissolubility of ambroxol hydrochloride tablets according to Chinese WS-430(X-370)-2000 RESULTS:The accumulative dissolving quantity of all preparations exceeded 80% in 45 minutes The comparison of Weibull parameters,m,T50 and Td,showed significant differences(P

Preparation of Rapid-disintegrated Lozenge / 中国药房

OBJECTIVE:To prepare a rapid-disintegrated lozenge METHODS:The formula and technology were decided by taking the disintegrating time and dissolubility as standard RESULTS:The lozenge could completely disintegrate in 20s and the accumnlated dissolubility of the model drug was 99% after 5 minutes in phosphate buffer(pH=6 80) CONCLUSION:Using now available equipment,suitable excipients and workmanship can prepare a rapid-disintegrated lozenge

Comparison of Dissolubility Between Different Products of Isosorbide-5-mononitrate Capsules / 中国药房

B The 45-minute dissolubilities of all the 5-ISMN capsules were higher than 85%,but the dissolubility parameters,m,T50,Td,had significant differences among them

Comparison of the Dissolubility of Chlorphenamine Maleate Tablets Produced by 4 Different Factories / 中国药房

OBJECTIVE:To compare the in vitro dissolubility of four kinds of commercial chlorphenamine maleate tablets. METHODS: To determine the dissolubility of four kinds of domestic commercial chlorphenamine meleate tablets by paddle method and to analyse the dissolution parameters, T50, Td, m, by variance analysis method. RESULTS: The dissolution parame- ters of the different tablets were T50(30. 3 197, 17. 3 695, 20. 1038, l4. 3 651), Td(34. 6 088, 26. 7 162, 28. 0 514, 22. 1 593)and m (2. 7 676, 0. 8 505, 1. 0 992, 0. 8 448). CONCLUSION: The statistical results indicated that there were significant differences between them(P

Study on the Dissolubility of Gonglaoquhuo Tablets / 中国药房

OBJECTIVE:The dissolution rates of baicalin in Gonglaoquhuo tablets were determined to provide a basis for evaluating and controlling the drug quality METHODS:The dissolution rates of Gonglaoquhuo tablets with different batch num_bers were determined by HPLC,using water as dissolution medium RESULTS:The T50 of Gonglaoquhuo tablets was 106min～220min and there were significant differences in dissolution parameters(T50,Td,m) between the tablets tested(P

Experimental Study on the Factors Affecting in Vitro Dissolubility of Total Puerariae Flavones Bioadhesive Tablets / 中国药房

OBJECTIVE:To study the main factors affecting in vitro dissolubility of total puerariae flavones(TPF)bioad?hesive tablets.METHODS:Using HPMC,Carbopol(CP934NP)as bioadhesive and base materials,lactose as porogenic agent to prepare bioadhesive tablets;Basket-rotating method was adopted to determine the dissolubility while0.1mol/L HCl was used as dissolution medium,Rotational speed was100r/min.The accumulated dissolution was detected and the influence of the amount of HPMC,CP,kind of porogenic agent,amount of lactose,size of granules in pressed tablets and medium pH on dissolubility was observed.RESULTS&CONCLUSION:The amount of HPMC,CP and lactose,kind of porogenic agent,size of granules in tablets and medium pH can affect the dissolubility of bioadhesive tablets.

Study on the Dissolubilities of Nimodipine Tablets Produced by Different Factories / 中国药房

OBJECTIVE:To compare the dissolubilities among nimodipine tablets produced by5different factories.METHODS:Measuring the dissolubilities of nimodipine tablets from different factories by HPLC and making the dissolu?tion curves according to Chinese WS-(X)-100-2000Z.Calculating T 50 、T d 、m,the data obtained were detected with t test. RESULTS:There were differences in the T 50 、T d and m(P

Comparison of Dissolubility Among Six Kinds of Nimodipine Tablets / 中国药房

OBJECTIVE:To compare the qualities of six kinds of Nimodipine tablet in terms of dissolubility METHODS:According to Appendix of Chp(2000),the dissolubilities of six kinds of Nimodipine tablet in ethanol,artificial gastric juice and artificial intestinal juice were determined respectively RESULTS:The dissolubility of domestic dispersion tablets was not as good as that of imported products but was obviously superior to that of other domestic products CONCLUSION:Owing to the use of advanced solid dispersion technic,Nidaer tablet is better than other domestic Nimodipine tablets in quality and its price is lower than that of similar imported product

Preparation of Fluconazole-?-Cyclodextrin Inclusion Complex / 中国药房

OBJECTIVE:To study the preparation technic and determination of the content and dissolubility of the fluconazole-?-cyclodextrin inclusion complex(FCIC) METHODS:The FCIC was prepared by coprecipitation method and ultr_asonic method The content and percentage of the accumulated dissolubility of FCIC were determined by UV-spectrophotometry RESULTS:Fluconazole and ?-cyclodextrin could form inclusion complex through either preparation technology The contents of fluconazole in the complex were(11 34?0 77)% and(11 23?0 24)% respectively The dissolubility met the standard in CP CONCLUSION:Stable complex could be formed between fluconazole and ?-cyclodextrin

Study on the Preparation and in Vitro Dissolubility of Ofloxacin Hollow Suppository / 中国药房

OBJECTIVE:To prepare ofloxacin hollow suppository(OHS) and to observe its in vitro dissolubility.METHODS:OHS was prepared with PEG 6000,PEG 400 and Carbopol-940 as wase material and wax as retardant.The content of ofloxacin in OHS was determined with the first order derivative UV-spectrophotometry.RESULTS:The wax,as a retardant,could retard the release of drug.The in vitro dissolution of OHS revealed the first order dissolution pattern:K0～1=27.81/h,indicating a speedy effect,K2～6=5.94/h,indicating sustained-release effect.CONCLUSION:This preparation is feasible in technology and controllabe in quality.The preparation of OHS extends the kinds of dose-form of ofloxacin

In Vitro Dissolubility of Diclofenac Potassium Double-layer Tablet and the Factors Affecting Its Dissolubility / 中国药房

OBJECTIVE:To investigate the characteristics of drug release and the factors affecting the in vitro dissolubility of diclofenac potassium double-layer tablets(DPD).METHODS:UV-spectrophotometry and rotating basket method in the pha-rmacopeia of China 2000 edition were used to determine the in vitro dissolubility of DPD and Higuchi equation was adopeted to simulate the in vitro drug release.The main parameters of dissolution were stastistically analysed.RESULTS:Dissolution parameters of DPD were as follows:T0.3=0.10h,Td=3.30h,T0.9=9.19h.Hardness of tablets did not affect the dissolution rate significantly;pH of dissolution media significantly influenced on the rate.Rotation speed had a significant effect on dissolution action only at the beginning of test.CONCLUSION:DPD has good properties of fast and sustained release.Proper media is the key of in vitro drug release test,however,the ultimate results should be based on in vivo trial.

Preparation and in Vitro Dissolution Characteristics of Famotidine Dispersible Tablets / 中国药房

OBJECTIVE:To study the preparation of famotidine dispersible tablets and to observe the dissolution characteristics in vitro METHODS:To optimize the conditions for preparation by orthogonal design RESULTS:The tablets could completely disintegrate within 1 min;In vitro dissolution test showed T50=0 56min CONCLUSION:In comparison with commercial famotidine tablets,the dispersible tablets prepared in optimum condition were rapid in disintegration and homogenous in dispersal

Investigation on the Dissolubilities of Tamoxifen Citrate Tablets Produced by Four Different Factories / 中国药房

OBJECTIVE:To compare the dissolubilities of Tamoxifen citrate tablets from four domestic pharmaceutical factories METHODS:Rotating basket method and paddle method were used,and Td were calculated by Weibull distribution RESULTS:Statistical analysis showed that there were significant differences in Td among the products from different factories,and the dissolubility of the same product detected by rotating basket was slower than that by paddle method CONCLUSION:The dissolubilities of Tamoxifen citrate tablets have significant differences among four different domestic products

Preparation of Xiao' er Jiere Hollow Type Suppository and Its in-vitro Dissolution / 中药新药与临床药理

Objective To establish the preparation method of Xiao' er Jiere hollow type suppository and determination method of the dissolubility.Methods Xiao' er Jiere hollow type suppository and ordinary suppository were prepared.With bacalin and chlorogenic acid as the standards,the in-vitro dissolution test and HPLC method were applied to determine the accumulated dissolution rate of bacalin and chlorogenic acid in two different types of suppository.Results The linearity of bacalin was in the range of 0.040 ? g～ 0.320 ? g(r=0.999 7)and that of chlorogenic acid was in the range of 0.064～ 0.512 ? g(r=0.999 8).The accumulated dissolution rate of the hollow type suppository was over 97 % in 30min.Conclusion Drug release rate of hollow type suppository is higher than the ordinary suppository.The method is stable and accurate.