Preparation and evaluation of risperidone-loaded microsphere/sucrose acetate isobutyrate in situ forming complex depot with double diffusion barriers / 药学学报

In the present study, a risperidone loaded microsphere/sucrose acetate isobutyrate (SAIB) in situ forming complex depot was designed to reduce the burst release of SAIB in situ forming depot and to continuously release risperidone for a long-term period without lagime. The model drug risperidone (Ris) was first encapsulated into microspheres and then the Ris-microspheres were embedded into SAIB depot to reduce the amount of dissolved drug in the depot. The effects of different types of microsphere matrix, including chitosan and poly(lactide-coglycolide) (PLGA), matrix/Ris ratios in microspheres and morphology of microspheres on the drug release behavior of complex depot were investigated. In comparison with the Ris-loaded SAIB depot (Ris-SAIB), the complex depot containing chitosan microspheres (in which chitosan/Ris = 1 : 1, w/w) (Ris-Cm-SAIB) decreased the burst release from 12.16% to 5.80%. However, increased drug release rate after 4 days was observed in Ris-Cm-SAIB, which was caused by the high penetration of the medium to Ris-Cm-SAIB due to the hydrophilie of chitosan. By encapsulation of risperidone in PLGA microspheres, most drugs can be prevented from dissolving in the depot and meanwhile the hydrophobic PLGA can reduce the media penetration effect on the depot. The complex depot containing PLGA microspheres (in which PLGA/ drug=4 : 2, w/w) (Ris-Pm-SAIB) showed a significant effectiveness on reducing the burst release both in vitro and in vivo whereby only 0.64% drug was released on the first day in vitro and a low AUC0-4d value [(105.2± 24.4) ng.mL-1.d] was detected over the first 4 days in vivo. In addition, drug release from Ris-Pm-SAIB can be modified by varying the morphology of microspheres. The porous PLGA microspheres could be prepared by adding medium chain triglyceride (MCT) in the organic phase which served as pore agents during the preparation of PLGA microspheres. The complex depot containing porous PLGA microspheres (which were prepared by co-encapsulation of 20% MCT) (Ris-PPm-SAIB) exhibited a slightly increased AUC0-4d of (194.6±15.8) ng.mL-1d and high plasma concentration levels from 4 to 78 days [Cs(4-78d)=(7.8±1.2) ng.mL-1]. The plasma concentration on 78 day C78d was (9.0 2.5) ng.mL-1 which was higher than that of Ris-Pm-SAIB [C78d= (1.6 ± 0.6) ng.mL-1]. In comparison with Ris-Pm-SAIB, the AUC4-78d of Ris-PPm-SAIB increased from (379.0±114.3) ng.mL-1.d to (465.0 ±149.2) ng.mL-1.d, indicating sufficient drug release from the Ris-PPm-SAIB. These results demonstrate that the risperidone loaded porous PLGA microsphere/SAIB in situ forming complex depot could not only efficiently reduce the burst release of SAIB depot both in vitro and in vivo, but also release the drug sufficiently in vivo, and be capable to continuously release the drug for 78 days.

Preparation and in vitro and in vivo evaluation of etoposide submicro-emulsion for intravenous injection / 药学学报

The aim of this thesis is to prepare etoposide submicro-emulsion (ESE) for intravenous injection and investigate its characteristics in vitro and in vivo. High-pressure homogenization was used to prepare ESE, using 10% (w/w) soybean oil and 10% (w/w) medium-chain triglyceride as mixed oil phase, and 1.8% (w/w) fabaceous lecithin as emulsifier. The pH was adjusted to 5.5 with 0.1 mol x L(-1) NaOH to keep the most stability of ESE. The particle size distribution and zeta potential were measured using photon correlation spectroscopy. Ultrafiltration was used to estimate the relative percentages of etoposide in each phase. Long-term storage test and accelerated isothermal test-Weibull distribution method were used to estimate the physical and chemical stability of ESE. Plasma pharmacokinetics in rats was monitored by high performance liquid chromatography by comparison with etoposide nonaqueous solution at the same time. The mean particle size, zeta potential and entrapment efficiency of ESE were (189.9 +/- 54.6) nm, - 32.6 mV and 91.7%, respectively. The emulsion was stable during 9 month storage at 4 degrees C. The shelf life (T0.9) of etoposide in lipid emulsion was estimated to be about 665 days at 4 degrees C. The drug concentration-time curves of ESE and solution were similar and could be described by two compartment model. The area under the curve of concentration versus time from zero to the last time point and the mean residence time of ESE and solution were (18.30 +/- 8.74) and (19.32 +/- 6.45) microg x h x mL(-1), and (1.46 +/- 0.32) and (1.71 +/- 0.52) h, respectively. Etoposide was incorporated in submicro-emulsion to improve its physical and chemical stability without addition of organic solvents with insignificant different characteristics in vivo when compared with solution.

Rheological properties of sucrose acetate isobutyrate in situ gel / 药学学报

To study the rheological properties of sucrose acetate isobutyrate (SAIB) in situ gel and the influencing factors. Measurements of shear stress and viscosity were carried out at different shear rate. The rheological properties of SAIB solution were similar to those of Newtonian fluid. The factors such as the type of solvent, concentration, additive, drug and temperature had effect on the rheological properties. Ethanol was a suitable solvent compared with ethyl lactate and N-methylpyrrolidone (NMP). The solution viscosity of SAIB was reduced from 1.29 to 0.11 Pa x s with only increasing the content of ethanol from 10% to 20%. Polylactic acid (PLA) and risperidone could increase the intermolecular force and viscosity. However, adding 10% (w/w) PLA, the initial release of risperidone was reduced from 20.2% to 3.5%. The solution viscosity reduced significantly by stepping up the temperature. The results obtained support the using of SAIB is satisfactorily injectable in situ gel formulation.

Pharmacokinetic study of ketoprofen in rat by blood microdialysis technique / 药学学报

<p><b>AIM</b>To investigate the in vitro recovery and influencing factors of ketoprofen in microdialysis probe, and study the pharmacokinetic of unbound ketoprofen in rat after iv administration.</p><p><b>METHODS</b>The recovery of ketoprofen was detected by a concentration difference method. After microdialysis probe was inserted into the jugular vein of male Wistar rats, the probe was infused with various concentrations perfusate. The in vivo recovery and the pharmacokinetics of unbound ketoprofen in rat were investigated. Dialysate samples were determined by HPLC.</p><p><b>RESULTS</b>The recovery detected by gain was as the same as that by loss; the recovery was independent of the drug concentration surrounding the probe. The in vitro recovery was 28.75% by concentration difference method and the in vivo recovery was (40.3 +/- 2.7) % by retrodialysis method. After i.v. administration of ketoprofen in rat, T 1/2, AUC and CL of unbound ketoprofen were (181 +/- 16) min, (112 +/- 27) microg x min x mL(-1) and (0.22 +/- 0.05) L x min(-1), respectively.</p><p><b>CONCLUSION</b>Microdialysis sampling can be used for the pharmacokinetic study of unbound ketoprofen in rat.</p>

In vitro and in vivo assesemet of sodium norcantharidin lipid microsphere / 药学学报

<p><b>AIM</b>To prepare lipid microsphere of sodium norcantharidin (NCTD) and then study their characters and pharmacokinetic behavior.</p><p><b>METHODS</b>Dynamic Light Scattering, HPLC and retrodialysis technique were used to determine the in vitro characters of the NCTD loaded lipid microsphere (LM), such as the particle size, xi-potential, content, incorporation ratio, release profile and changes after dilute. And the plasma concentration was determined by HPLC-MS, compared with NCTD aqueous solution at the same time.</p><p><b>RESULTS</b>Every property showed that the LM was preferable. The average diameter was about 200 nm. The xi-potential was - 38 mV. The content was close to 100%. And the incorporation ratio exceeded 80%. After i. v. administration of single dose, the pharmacodynamic parameter of LM AUC was 111.28 microg x mL(-1) x h(-1). The data of plasma concentrations showed that the NCTD LM was of two compartment. There was no obvious difference between in vivo parameters of LM and reference solution.</p><p><b>CONCLUSION</b>The NCTD LM was eligible and the character of it in vivo was not changed.</p>

Determination of diosgenin in Shengmai Freeze-drying Preparation for Injection by RP-HPLC / 中成药

AIM: To develop a new quantitative analysis method for determining diosgenin in Shengmai Freeze-drying Preparation for Injection (Radix Ophiopogonis,etc.)by RP-HPLC with UV detector. METHODS:ODS C_(18) column (5 ?m,4.6 mm?250 mm) was used with mobile phase of acetonitrile-water (88∶12).The mobile phase flow rate was 1.0 mL?min~(-1).The detection wavelength was at 204 nm. RESULTS:The linear range of HPLC was 2.46-7.38 ?g(r=0.999 9).The average recovery was 98.3%,RSD was 0.95%(n=9). CONCLUSION:This method is reliable,accurate and suitable for the determination of diosgenin in Shengmai Freeze-(drying) Preparation for Injection.