[Core techniques and values of full-endoscopic spine surgery via transforaminal approach]

Full-endoscopic spinal surgery via transforaminal approach (TF-FESS) originated from the minimally invasive techniques of percutaneous interventional treatment of intervertebral disc diseases through posterolateral approach.Thanks to the continuous development and improvement of full-endoscopic equipment alongside surgical instruments and techniques, a developed technical system has been established in discectomy, spinal canal decompression, interbody fusion, etc. The combination of these basic techniques can treat relatively complex degenerative spinal diseases. The core techniques of TF-FESS include percutaneous puncture, foraminoplasty, spinal canal decompression, discectomy, annulus fibrosus suture, interbody fusion. This paper elaborates on the key points of the core techniques, indications, advantages, disadvantages, and prospects of the TF-FESS.

[Technical notes and clinical efficacy analysis of full-endoscopic thoracic discectomy via transforaminal approach]

Objective: To study the technical notes and clinical efficacy of full-endoscopic thoracic intervertebral discectomy via transforaminal approach. Methods: We included 16 patients with thoracic disc herniation treated by full-endoscopic thoracic discectomy via transforaminal approach between January 2017 and September 2018 in ours department of orthopedics. The average age is 53.7 years. The compressionare classified by nature: 5 cases of soft thoracic disc herniation, 7 cases of calcified or ossified thoracic disc herniation, and 4 cases of osteophyte protrusion of the posterior edge of the adjacent vertebral body of the diseased disc. All patients had symptoms of thoracic myelopathy before operation, and 7 of them had radiculopathy. Via transforaminal approach under local anesthesia, enlarged foraminoplasty and full-endoscopic thoracic discectomy were used for treatment. Observe the changes of postoperative imaging, pain symptoms and recovery of spinal cord function at 1 week, 3 months, 6 months and 1 year after operation. Back pain and radicular pain were scored with VAS, neurological function was assessed with Nurick score and mJOA score, and thoracic spine function was assessed with Oswestry disability index (ODI). Results: All operations were successfully completed, and no intraoperative conversion of surgical methods occurred. Postoperative thoracic MRI and CT examinations of all patients showed that the spinal cord was fully decompressed without any residual compression. Back pain and radicular pain were all relieved obviously in all patients, and spinal cord function was obviously restored. Transient intercostal neuralgia occurred in 2 cases after operation, and no other surgical complications occurred. Conclusions: Full-endoscopic or fluoroscopic foraminoplasty and full-endoscopic thoracic discectomyvia transforaminal approach under local anesthesia is a safe and effective treatment for soft and hard thoracic disc herniation located on the ventral side of the spinal cord.

A novel snake venom-derived GPIb antagonist, anfibatide, protects mice from acute experimental ischaemic stroke and reperfusion injury

BACKGROUND AND PURPOSE

Ischaemic stroke is a serious disease with limited therapy options. Glycoprotein (GP)Ib binding to von Willebrand factor (vWF) exposed at vascular injury initiates platelet adhesion and contributes to platelet aggregation. GPIb has been suggested as an effective target for antithrombotic therapy in stroke. Anfibatide is a GPIb antagonist derived from snake venom and we investigated its protective effect on experimental brain ischaemia in mice.

EXPERIMENTAL APPROACH

Focal cerebral ischaemia was induced by 90 min of transient middle cerebral artery occlusion (MCAO). These mice were then treated with anfibatide (4, 2, 1 μg·kg(-1) ), injected i.v., after 90 min of MCAO, followed by 1 h of reperfusion. Tirofiban, a GPIIb/IIIα antagonist, was used as a positive control.

KEY RESULTS

Twenty-four hours after MCAO, anfibatide-treated mice showed significantly improved ischaemic lesions in a dose-dependent manner. The mice had smaller infarct volumes, less severe neurological deficits and histopathology of cerebrum tissues compared with the untreated MCAO mice. Moreover, anfibatide decreased the amount of GPIbα, vWF and accumulation of fibrin(ogen) in the vasculature of the ischaemic hemisphere. Tirofiban had similar effects on infarct size and fibrin(ogen) deposition compared with the MCAO group. Importantly, the anfibatide-treated mice showed a lower incidence of intracerebral haemorrhage and shorter tail bleeding time compared with the tirofiban-treated mice.

CONCLUSIONS AND IMPLICATIONS

Our data indicate anfibatide is a safe GPIb antagonist that exerts a protective effect on cerebral ischaemia and reperfusion injury. Anfibatide is a promising candidate that could be beneficial for the treatment of ischaemic stroke.

Trans-resveratrol loaded chitosan nanoparticles modified with biotin and avidin to target hepatic carcinoma

Conventional liver targeted system focuses on delivering drugs to liver, bringing toxicity on hepatic normal tissues. The purpose of this study is to construct a new system capable of specially targeting to hepatic carcinoma instead of the whole liver. Based on the fact that nanoparticles (NPs) bound with either biotin or avidin tend to accumulate in tumors and avidin-attached reagents were quickly eliminated from blood circulation and assembled in liver, trans-resveratrol loaded chitosan nanoparticles (CS-NPs), CS-NPs with the surface modified either by biotin (B-CS-NPs) or by both biotin and avidin (A-B-CS-NPs) were prepared and their physiochemical properties were investigated. The in vitro release profiles of the three NPs all conformed to bioexponential equation. Pharmacokinetic experiment indicated that A-B-CS-NPs rapidly assembled in liver after injection, with the highest liver targeting index of 2.70, while the modification of biotin attenuated the liver targeting ability of NPs. Inhibitory study on HepG2 cells declared that compared to trans-resveratrol solution and CS-NPs, both B-CS-NPs and A-B-CS-NPs significantly improved the anticancer activity. When incubated with HepG2 cells at high concentration for longer time, A-B-CS-NPs exhibited superior cytotoxicity than B-CS-NPs. This study exclaims that A-B-CS-NPs may be a potent drug delivery vector specially targeting to hepatic carcinoma.

[Studies on in vivo release of berberine hydrochloride from carboxymethyl konjac glucomannan pellets in rats]

OBJECTIVE

To observe the absorption and concentration of berberine hydrochloride (BH) in gastric, entric, colonic tissue after intragastric administration of BH-containing carboxymethyl konjac glucomannan pellets for evaluating colon-specific drug delivery characteristics of the pellets.

METHOD

BH-containing carboxymethyl konjac glucomannan pellets (pellets group) and BH-containing carboxymethyl cellulose suspension (control group) were intragastric administrated to rats at the dose of 50 mg x kg(-1), respectively. A high performance liquid chromatography method determinated BH concentration in rat plasma and tissue. Drug delivery index (DDI) was calculated.

RESULT

The range of BH in plasma and tissue in rats were 0.025 2-2.52 mg x L(-1) (r = 0.999 2) and 0.126-25.22 mg x L(-1) (R > 0.99),respectively. The detection of BH in plasma and tissue were 10 microg x L(-1) and 8 microg x L(-1), respectively. The area under the curve (AUC(0 --> infinity)) in the plasma samples of pellets group was 0.477 times that of the control group; in the gastric, entric, colonic tissue, the AUC(0 --> infinity) of pellets group was as much as 0.187, 0.228, 2.00 times that of the control group, respectively. The DDI of the pellets was 0.392 4, 0.478 6, 4.193 in the gastric, entric, colonic tissue of the rat, respectively.

CONCLUSION

Carboxymethyl konjac glucomannan pellets may be a useful carrier of BH for colon-specific delivery.

[In vitro dexamethasone release from nanoparticles and its pharmacokinetics in the inner ear after administration of the drug-loaded nanoparticles via the round window]

OBJECTIVE

To investigate the feasibility of local drug delivery into the inner ear using solid lipid nanoparticles (SLN) and evaluate its potential for inner ear disease treatment in terms of the pharmacokinetics of the delivered drug in the inner ear.

METHODS

Dexamethasone acetate (DA)-loaded SLN was prepared with Compritol 888 ATO as the matrix by means of hot dispersion-ultrasonic technique. A high-performance liquid chromatography (HPLC) was established for determining DA and dexamethasone (Dex). The pharmaceutical properties of DA-loaded SLN including the particle size, entrapment ratio and in vitro release were estimated. DA-loaded SLN was administered via intratympanic injection or intravenous injection in guinea pigs and Dex concentration in the perilymph was measured with HPLC for estimation of the pharmacokinetic parameters.

RESULTS

The mean diameter of the DA-loaded SLN was 106.8 nm with entrapment ratio of 83.8%, and the in vitro DA release from the nanoparticles well conformed to Weibull distribution, with sustained-release of DA from the SLN exceeding 6 days. After intravenous injection of DA-loaded SLN in guinea pigs, Dex failed to be detected in the perilymph. Compared with Dex-loaded in situ gel following intratympanic injection, the relative bioavailability of Dex in the perilymph was 504% following intratympanic injection of DA-loaded SLN, which also resulted in increased t(1/2) and mean residence time (MRT) by 0.5 and 1.9 folds respectively.

CONCLUSION

Nanoparticles can be a promising tympanic drug delivery system for topical drug administration in the treatment of inner ear diseases.

[Effect of several penetration enharcers on transdermal permeation and skin accumulation of artemether]

OBJECTIVE

To investigate penetration characteristics of artemether and the effect of different permeation enhancer on transdermal permeation of artemether through rat skin.

METHOD

The permeation experiments were performed using rat skin on modified Franz diffusion cells in vitro. The concentrations of artemether in receptor compartment at specified time points were determined by HPLC.

RESULT

The permeating ratio through human skin of artemether solution was Js (2.78 +/- 0.78) microg x cm(-2) x h(-1), the quantity of drug penetrated through and accumulated in the skin by the end of the experiment were (69.07 +/- 3.01) microg x cm(-2), (58.93 +/- 3.56) microg x cm(-2) respectively. Four different permeation enhancers can improve the transdermal permeation of artemether.

CONCLUSION

Artemether have the potential to be developed to new transdermal preparation.

[Brain targeting of gastrodin nasal in situ gel]

OBJECTIVE

To investigate the biodistribution of gastrodin ion-activated nasal in situ gel in rat blood and brain tissues and to evaluate its brain targeting.

METHODS

Intravenous administration of gastrodin solution or intranasal administration of gastrodin nasal in situ gel were given to 32 rats, respectively. The concentrations of gastrodin in the plasma and gastrodigenin in the brain tissues of the rats were determined by HPLC.

RESULTS

The intranasal administration of the in situ gel of gastrodin produced more significant brain targeting effect than the intravencus administration of gstrodin solution (P < 0.01). The area under curve (AUC) of cerebrum, cerebellum and olfactory bulb increased by 1.16, 0.77 and 3.34 times, with 2.66. 2.18 and 5.34 brain targeting indexes (BTI), respectively. The mean residence time (MRT) increased by nearly four-folds.

CONCLUSION

Gastrodin nasal in situ gel can improve the brain targeting of gastrodin and slow its release.

[Study on drug release of gastrodin ion-activated nasal in situ gel in vitro]

OBJECTIVE

To study on the drug release characteristics and mechanism of gastrodin ion-activated nasal in situ gel in vitro.

METHOD

Regularity and mechanism of the drug release of gastrodin nasal in situ gel were studied by using the diffusion cell model and the membrane-less dissolution model, respectively. A novel kinesis diffusion cell model was designed according to the characteristics of release environment of nasal cavity. It was used to investigate the effect of adhesiveness on the release of the in situ gel.

RESULT

Drug release of gastrodin nasal in situ gel followed the one order release model. Erosion rate of the gel was low and not linearly correlated with the release rate. Compared with gastrodin solution, the nasal in situ gel could increase release time and release amount.

CONCLUSION

Gastrodin in the nasal in situ gel is released mainly by diffusion rather than erosion. Release amount of the in situ gel in nasal cavity may be obviously increased because of its adhesiveness.

[Preparation of self-microemusifying drug delivery system for volatile oil from rhizome of ligusticum Chuanxiong]

OBJECTIVE

To search on the optimum formula for the seif-microemulsifying drug delivery system of volatile oil from rhizome of ligusticum Chuanxiong.

METHODS

Through solubility experiment, orthogonal screen and drawing phase diagram, taking the degree of emulsifying, the volume of the rest oil and emulsion particle size as parameters, the appropriate proportion composed of Chuanxiong oil, nonionic surfactant and flux was screened for the optimum formulation of self-microemulsifying drug delivery system.

RESULTS

In the formulation of self-microemulsifying drug delivery system for volatile oil from rhizome of ligusticum Chuanxiong, taking S1 as the nonionic surfactant and C1 as the co-surfactant could get the best effect of emulsifying.

CONCLUSION

The optimum formula for seif-microemulsification of volatile oil from rhizome of ligusticum Chuanxiong is volatile oil from rhizome of ligusticum Chuanxiong, S1 and C1, with their proportion being 10 : 9 : 1.

[Study on release mechanism of berberine hydrochloride-loaded carboxymethyl konjac glucomannan pellets for colonic delivery]

OBJECTIVE

To study release mechanism of berberine hydrochloride (BH) from carboxymethyl konjac glucomannan pellets for colonic delivery.

METHOD

The pellets were prepared by ionotropic gelation technique. The effects of the kinds of enzyme and enzyme concentration of dissolution media on the release of BH and the erosion properties of the pellets were studied.

RESULT

Compared with the dissolution media without enzymes, the release of BH and the erosion of the pellets were increased obviously in the media with rat cecal and colonic content or beta-mannase, the degradation of the carrier material of pellets by enzymes was the main factor which result in the erosion of the pellets. With the increased of beta-mannase concentration, the release of BH and the erosion of the pellets increased, the amount relationships of the release of BH and the erosion of the pellets were approximately 1:1. The release of BH exhibit Peppas equation, the n value was more than 1.

CONCLUSION

The release mechanism of BH from the pellets was enzymatic erosion-controlled, which indicates the potential of the pellets to serve as a colon-specific drug delivery system.

[Comparison of kinetic behavior in both plasma and tissue after intravenous administration of alpha-asarone in lipid emulsion and aqueous solution in rats and mice]

OBJECTIVE

To compare the pharmacokinetics and tissue distribution of alpha-asarone in lipid emulsion and aqueous solution for injection and study the feasibility of lipid emulsion of alpha-asarone as the parenteral drug delivery system.

METHOD

HPLC was used to determine the drug concentration in rat plasma and mice tissues after intravenous (i.v.) administration of lipid emulsion and aqueous solution of alpha-asarone at a single dose (40 mg x kg(-1)), respectively.

RESULT

The plasma concentration-time profiles of lipid emulsion and aqueous solution of alpha-asarone after intravenous administration of them are similar and the drug concentration-time data were fitted to a two-compartment open model. The results of tissues distribution showed that distribution contents of alpha-asarone from lipid emulsion and aqueous solution in vivo are similar in lungs but lipid emulsion increased the uptake in livers and spleens, and decreased the uptake in hearts and kidneys for alpha-asarone.

CONCLUSION

The plasma concentration-time profiles of alpha-asarone in lipid emulsion and aqueous solution are similar, but lipid emulsion significantly altered the tissue distribution of alpha-asarone, which may be beneficial to decrease its potential toxicity to heart and kidney.

[Study on in vitro colon-specific enzymatic degradation performance of carboxymethyl konjac glucomannan]

OBJECTIVE

In vitro enzymatic degradation of carboxymethy konjac glucomannan (CMKGM) were studied to evaluate the feasibility of CMKGM used as carrier materials to prepare colon-specific drug delivery systems.

METHOD

The solutions with rat gastrointestinal tract (GIT) contents or with commercial enzymes were chosen to stimulate in vivo GIT environment, respectively. Enzymatic degradation of CMKGM were studied by viscometic procedure. Degradation kinetics of CMKGM and konjac glucomannan (KGM) by enzymes, the effects of the degree of substitution (DS) of CMKGM and the pH of solution on its susceptibility to degradation were investigated.

RESULT

CMKGM were degraded mainly in the simulated cecal and colonic media, but not in the simulated gastric and enteric media. Degradation of KGM and CMKGM by enzymes obeyed Michaelis-Menton kinetics. CMKGM with lower DS were more susceptible substrates. CMKGM were more susceptible substrates in solution with pH 6. 0-6. 8.

CONCLUSION

CMKGM had colon-specific enzymatic degradation characteristics and could be used as carrier materials to prepare colon-specific drug delivery systems.

[In vitro evaluation of self-emulsifying drug delivery system of volatile oil from rhizome of Ligusticum chuanxiong]

OBJECTIVE

To investigate the evaluation method for self-emulsifying drug delivery system of volatile oil from rhizome of Ligusticum chuanxiong (VOC SEDDS).

METHOD

The self-emulsifying ability, the efficiency of self-emulsification, the properties of emulsion, the dissolution of volatile oil from Rhizome of Ligusticum Chuanxiong and the stability of the emulsion were determined.

RESULT

The optimized formulation can fully emulsify in 5 min and the particle sizes were around 102 nm. Zeta potential was about -30 mV. The O/W emulsions were stable through centrifugation with high reproducibility. In vitro dissolution test indicated that over 80% of drug dissolved in 30 min and VOC SEDDS was stable under light and high temperature in 10 d.

CONCLUSION

VOC SEDDS has strong self-emulsifying ability, fine stability and high dissolution rate in vitro.

Determination of aesculin in rat plasma by high performance liquid chromatography method and its application to pharmacokinetics studies

A sensitive and reproducible high performance liquid chromatography method with UV detection was described for the determination of aesculin in rat plasma. After deproteinization by methanol using metronidazole as internal standard (I.S.), solutes were evaporated to dryness at 40 degrees C under a gentle stream of nitrogen. The residue was reconstituted in 100 microl of mobile phase and a volume of 20 microl was injected into the HPLC for analysis. Solutes were separated on a Diamonsil C18 column (250 mm x 4.6 mm i.d., 5 microm particle size, Dikma) protected by a ODS guard column (10 mm x 4.0 mm i.d., 5 microm particle size), using acetonitrile-0.1% triethylamine solution (adjusted to pH 3.0 using phosphoric acid) (10:90, v/v) as mobile phase (flow-rate 1.0 ml/min), and wavelength of the UV detector was set at 338 nm. No interference from any endogenous substances was observed during the elution of aesculin and internal standard (I.S., metronidazole). The retention times for I.S and aesculin were 10.4 and 12.4 min, respectively. The limit of quantification was evaluated to be 57.4 ng/ml and the limit of detection was 24.0 ng/ml. The method was used in the study of pharmacokinetics of aesculin after intraperitoneal injection (i.p.) administration in rats.

Preparation, characterization and uptake by primary cultured rat hepatocytes of liposomes surface-modified with glycyrrhetinic acid

3-succinyl-30-stearyl glycyrrhetinic acid (Suc-GLAOSt) was synthesized as a targeting molecule, and incorporated in ordinary to liposomes (LP) to prepare a liposome surface-modified with glycyrrhetinic acid (LP-GLA), which could bind to the hepatocyte through the specific binding site of glycyrrhetinic acid (GLA) on the surface of rat cellular membrane. The maximal molar ratio of Suc-GLAOSt to total lipids in LP-GLA was 1:10. Calcein loaded liposome (Cal-LP) and calcein loaded LP-GLA (Cal-LP-GLA) were prepared by an ethanol injection method. The average diameter of Cal-LP and Cal-LP-GLA was 65 nm +/- 16 nm and 68 nm +/- 21 nm, respectively. The characteristics of cellular uptake of the two types of liposome were investigated through cellular uptake and competitive inhibition experiments. The uptake of Cal-LP-GLA by rat hepatocytes was markedly higher (3.3-fold) than that of Cal-LP (P < 0.01). The uptake of Cal-LP-GLA was inhibited, but the uptake of Cal-LP was not influenced by adding extraneous GLA. LP-GLA may be internalized by hepatocytes via the specific binding site, and can be used as a novel and promising carrier for targeting drug delivery to hepatocytes.

[Preparation and characterization of biotinylated chitosan nanoparticles]

Biotinylated chitosan nanoparticles (Bio-CS-NP) were prepared for the active delivery to cancer cells and its characterization was investigated in this study. The preparation process included two steps. First, biotinylated chitosan ( Bio-CS ) was obtained through a reaction between sulfosuccinimidobiotin and chitosan (CS). Second, Bio-CS-NP were prepared by the precipitation of Bio-CS with sodium chloride solution. With a biotin reagent box, the conjugation densities of biotin on the surface of Bio-CS-NP were determined. The morphology and diameter of the nanoparticles were assayed by transmission electron microscope (TEM) and laser light scattering particle analyzer, respectively. The uptake of nanoparticles by human hepotacarcinoma HepG2 cells, for example, Bio-CS-NP and chitosan nanoparticles (CS-NP) without any modification, was quantitatively examined. The results indicated that the conjugation densities of biotin on the surface of Bio-CS-NP were 2.2 biotin CS. Bio-CS-NP were spherical, smooth on the surface. The average diameter was 296.8 nm. The polydispersion index was 0.155. The uptake of Bio-CS-NP by HepG2 cells was much higher than that of CS-NP (P < 0.05). It demonstrated that Bio-CS-NP can be applied as a new vehicle to actively deliver anticancer drugs to tumor cells. The method for the determination of biotin was simple and practical.

[Comparison of two preparation methods applied in tanshinone II(A)-loaded PLGA nanoparticles]

OBJECTIVE

To optimize formulation of tanshinone II(A)-loaded PLGA nanoparticles and compare the difference of two methods in preparation and quality of nanoparticles.

METHOD

The two methods were nanoprecipitation method and emulsion-evaporation method. Single factor experiments and central composite design and response surface method were used to optimize the formulation of nanoparticles. The nanoparticles were characterized at size, morphology, entrapment efficiency, drug loading, drug recovery rate, crystallinity and drug release in vitro.

RESULT

The mean diameters were 225 nm and 183 nm, the entrapment efficiency were 95.49% and 87.99%, the drug loading were 2.03% and 0.16%, and the drug recovery rates were 38.42% and 17.59% respectively for nanoprecipitation method and emulsion-evaporation method.

CONCLUSION

Nanoprecipitation method was better than emulsion-evaporation method for preparation of tanshinone II(A)-loaded PLGA nanoparticles.

[Comparison of preparing two polylactide nanoparticles loaded lipophilic anti-cancer herb drug by nanoprecipitation method]

This paper introduced an experimental study of polylacticacid (PLA) nanoparticles of lipophilic anti-cancer herb drug using a precipitation method. Cucurbitacins (Cu) and Curcuminoids (Cur) were selected to be model drugs. They had similar solubility but their incorporation effects were significantly different: the average drug entrapment ratio, the average drug loading and the average drug recovery were 38.53%, 2.21% and 27.02% respectively; while those of Cur-PLA-NP were 94.36%, 14.35% and 91.23% respectively. To analyse the reason, drug incorporation process was investigated. By measuring solvent evaporation rate, ratio of drug PLA precipitates, drug distribution in system and entrapping ratio at different time of preparation, we found the difference of precipitation velocity of drug was the main reason. We also concluded that not all lipophilic drug can be well entrapped into PLA nanoparticle by nanoprecipitation method. The drug incorporation depended on the interations among drug, PLA and organic solvents, in addition to the solubility of the drug.

Ion-Pair Reversed-Phase HPLC Method for Determination of Sodium Tanshinone IIA Sulfonate in Biological Samples and Its Pharmacokinetics and Biodistribution in Mice

The ion-pair reversed-phase HPLC method for determination of sodium tanshinone IIA sulfonate (STS) in various biological samples was for the first time developed and validated, and was applied for pharmacokinetics and tissue distribution studies of intravenously administrated STS in mice. A linear relation was found between peak area and STS concentrations within the ranges of 0.1-5 micraog/ml for plasma, 0.1-5 microg/g of tissue for kidney homogenate, 0.1-20 microg/g of tissue for liver homogenate, 0.1-1 microg/g of tissue for heart, spleen and lung homogenates, respectively. In plasma and tissues, the limit of quantification (LOQ) and the limit of detection (LOD) for STS were 100 ng/ml and 20 ng/ml. In all biological specimens, the average inter- and intra-day precision of STS were within 4.9%. The recoveries were more than 92% at all concentration levels in each type of biological specimens. STS plasma concentration-time data were best fitted with a two-compartment model, characterized by an initial rapid phase of drug concentration decrease, and a slower terminal elimination phase. The pharmacokinetics of STS was characterized with a distribution half-life (t(1/2alpha)) of 1.2+/-0.18 min, a terminal half-life (t(1/2beta)) of 21.6+/-2.4 min, a distribution volume (V) of 0.057+/-0.011 l/kg, a plasma clearance (CL) of 0.86+/-0.12 l/h/kg and an AUC(0-infinity) of 58.41+/-6.21 microg x h/ml. STS was widely distributed into most tissues and was obviously accumulated in liver. This results indicated that STS may be promising to treat liver disease.

[Release profile of compound liposomes entrapped with vincristine sulfate and mitoxantrone chlorhydric acid in vitro and their distribution in mice]

AIM

To study on the release profile in vitro and biodistribution in mice of the compound liposomes carried with vincristine sulfate (VCR) and mitoxantrone chlorhydric acid (MTO).

METHODS

The release behaviors of the VCR and MTO from compound liposomes were studied in vitro. HPLC was developed for the determination of the contents of VCR and MTO in tissues in mice.

RESULTS

The release time of VCR from compound liposome was 24 h and that from free drug (in control solution) was 6 h. The release of MTO from compound liposome was 0.05% after 288 h and release time of MTO from free drug (in control solution) was 12 h. The liposomes and free drugs were injected intravenously at same dose to mice. The elimination half-life time (T 1/2) in plasma of liposomal and free VCR were 0.16 h and 0.14 h, and the AUCs (0 - 48 h) of them were 2.69 (ug x g(-1)) x h and 1.58 (ug x g(-1)) x h, respectively. The elimination half-life times (T 1/2) in plasma of liposomal and free MTO were 21.6 h and 0.05 h and the AUCs (0 - 48 h) of them were 17.06 (ug x g(-1)) x h and 0.42 (ug x g(-1)) x h, respectively.

CONCLUSION

The compound liposome with high entrapping efficiency and small particle size could be prepared by pH-gradients method and reverse evaporation technique. Two drugs were sustained-released from the compound liposome. Mice tail intravenous injection of compound liposomes showed that compound liposome prolonged the retention time and improved the concentration of MTO and VCR in the blood circulation system compared to control. In the mean time, compound liposome reduced the concentration of the MTO and VCR in heart, lung, kidney etc. These observations indicated that compound liposome could improve anticancer activity and reduce side effect.

[Preparation of mitoxantrone liposomes and study on its in vivo distribution in rats after transdermal delivery]

OBJECTIVE

To investigate in vivo distribution of the mitoxantrone(MIT) liposomes in SD rats after transdermal delivery.

METHODS

The mitoxantrone liposomes were prepared by thin-film method. Particle size, particle distribution and delta-potential of colloid solution were obtained on laser scatterometer; the encapsulation efficiency was measured by membrane diffusion technique. The time courses of mitoxantrone concentration in vivo after the transdermal delivery of mitoxantrone liposomes were measured by HPLC assays and compared with the injection of mitoxantrone solution.

RESULTS

The mean diameter of the MIT liposomes was 50.98 nm, with the entrapping efficiency of 100%. The liposomes had perfect shape. A significantly higher amount of mitoxantrone was delivered in cutis after transdermal delivery of mitoxantrone liposomes, compared with the injection of mitoxantrone solution; meanwhile, a significantly lower amount of mitoxantrone was delivered in plasma and other tissues after transdermal delivery of mitoxantrone liposomes, compared with the injection of mitoxantrone solution.

CONCLUSION

Transdermal delivery of mitoxantrone liposomes could be a potential therapy for cutaneous malignant melanoma.

The Drosophila homolog of the human tumor suppressor gene BHD interacts with the JAK-STAT and Dpp signaling pathways in regulating male germline stem cell maintenance

Birt-Hogg-Dubé syndrome (BHD) is a rare, inherited genodermatosis characterized by hair follicle hamartomas, kidney tumors and spontaneous pneumothorax. The BHD locus was mapped to chromosome 17p11.2 by linkage analysis, and germline mutations in a novel gene (BHD) were identified in a panel of BHD families. Using RNA interference to decrease expression of the Drosophila BHD homolog (DBHD), we have demonstrated that DBHD is required for male germline stem cell (GSC) maintenance in the fly testis. Reduction of DBHD gene activity suppresses the GSC overproliferation phenotype associated with overexpression of either unpaired (upd) or decapentaplegic (dpp). Further genetic interaction experiments suggest that DBHD regulates GSC maintenance downstream or in parallel of the JAK/STAT and Dpp signal-transduction pathways. These findings suggest that the BHD protein may regulate tumorigenesis through modulating stem cells in human.

[Study on the preparation of resveratrol chitosan nanoparticles with free amino groups on the surface]

OBJECTIVE

To prepare resveratrol chitosan nanoparticles with free amine groups on the surface so as to conjugate ligands, which will actively target to special tissues or organs.

METHOD

The chitosan nanoparticles with free amine on the surface was prepared by sodium chloride precipitation. Nanoparticles with different solidification degrees were studied on turbidity, in vitro release, encapsulation efficiency, drug loading and diameter.

RESULT

The turbidity of nanoparticles with various solidification degrees decreased at different rates after ultrasonic or water bath heating treatment. All nanoparticles mentioned above obviously shew sustained release. The rate of release was slowed down with the increase of solidification agents. Solidification had no obvious effects on the encapsulation efficiency and drug loading. The diameter of chitosan nanoparticles with 200 microL solidification agents was 487 nm. The polydispersion was 0.144.

CONCLUSION

The diameter of the prepared nanoparticles was relatively small. The amine on the surface was free, which offered the possibility of designing the acive target drug delivery system.

Ion-pair reversed-phase HPLC: assay validation of sodium tanshinone IIA sulfonate in mouse plasma

Sodium tanshinone IIA sulfonate (STS), a hydrophilic ionic substance, is used as a cardiovascular drug. An ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC) method for the determination of STS in mouse plasma was initially developed. The assay involved a rapid and simple extraction process and subsequent detection at 271 nm. The retention time for STS was 7.5 min. Based on extracted STS standard mouse plasma at 1.5,10 and 50 microg/ml, the assay precision were 2.7, 2.1 and 1.7% with a mean accuracy of 96.7, 98.5 and 99.4%, respectively. At plasma concentration of 1.5, 50 and 75 microg/ml, the mean recovery of STS were 93.1, 96.3 and 97.5%. The limit of detection (LOD) and limit of quantification (LOQ) for STS was 0.1 microg/ml and 0.5 microg/ml, respectively. Linear responses were observed over a wide concentration range (0.5-100 microg/ml) for STS in mouse plasma. STS can be detected after intravenous administration. This method was performed for the first time in pharmacokinetic studies of STS in the mouse.

[Study on liver targeted drug delivery system of the effective anticancer component from Bolbstemma paniculatum]

OBJECTIVE

To study the liver targeted drug delivery system of TBMS--the effective anticancer component from Bolbstemma paniculatum, and to discuss the system's function of decreasing toxicity.

METHOD

BCA was used as carrier material. The preparation through overall feedback dynamic techniques. The properties of preparation and toxicology were also technology of nanoparticles was optimized studied. Thenanoparticles' targeting in mice vivo was observed with transmission electron microscopy. The function of decreasing toxicity was researched by the XXTX-2000 automatic quantitative analysis management system.

RESULT

D50 was 0.68 microm. Drug-loading rate and entrapment rate were 37.3% and 88.6% respectively. The release in vitro accorded with Weibull equation. The reaching release balance time and the t 1/2 extended 26 times and 19 times respectively comparing with injection. Nanoparticles mainly distributed in liver tissue. Their toxicity to lung and liver was evidently lower than injection. Nanoparticles' LD50 exceeded injection's by 13.5% and their stimulus was much lower than injection.

CONCLUSION

The TBMS can be targeted to liver by liver targeted drug delivery system. At the same time, the problem about the toxicity hindering clinical application could be solved, which lays the foundation for the further studies on TBMS.

[Preparation of transfersomes of vincristine sulfate and study on its prcutaneous penetration]

OBJECTIVE

To select the best preparation method of vincristine transfersomes (VCR-T) and predict its possibility of being a new formulation of VCR.

METHOD

Orthogonal design was used to optimize the preparation methods on the basis of single factor pretests; and the permeation tests in vitro were performed in modified Franz diffusion cells.

RESULT

The optimum formula was: pH was equal to 7.3, the ratio of lecithin to sodium deoxycholate is 70/20, the weight of VCR is 10 mg, hydrating time is 30 minutes. The optimized solution was light yellow and transparent colloid solution. The VCR-T are spherical and smooth with average diameters of 94 nm and an encapsulation ratio of 90%. The test in vitro showed that VCR-T could permeat through mouse skin at zero rate with the cumulative penetrating quality amounting to 63.8%.

CONCLUSION

Transfersomes may become a promising carrier of VCR for clinic use.

Uptake of albumin nanoparticle surface modified with glycyrrhizin by primary cultured rat hepatocytes

AIM: To investigate the uptake difference between bovine serum albumin nanoparticle (BSA-NP) and bovine serum albumin nanoparticles with their surface modified by glycyrrhizin (BSA-NP-GL) and to develop a novel hepatocyte targeting BSA-NP-GL based on active targeting technology mediated by specific binding site of GL on rat cellular membrane.

METHODS: Calcein loaded bovine serum albumin nanoparticles (Cal-BSA-NP) were prepared by desolvation process. Glycyrrhizin was conjugated to the surface reactive amino groups (SRAG) of Cal-BSA-NP by sodium periodate oxidization, which resulted in calcein-loaded bovine serum albumin nanoparticles with their surface modified by glycyrrhizin (Cal-BSA-NP-GL). The morphology of the two types of prepared nanoparticles (NP) was observed by transmission electron microscopy. The diameter of NP was measured with a laser particle size analyzer. The interaction between Cal-BSA-NP-GL and primary cultured hepatocytes was studied through cellular uptake experiments. The uptake amount of Cal-BSA-NP-GL and Cal-BSA-NP by rat hepatocytes was determined by fluorospectrophotometry. Uptake characteristics were investigated through experiments of competitive inhibition of specific binding site of GL.

RESULTS: Both Cal-BSA-NP-GL and Cal-BSA-NP had regular spherical surfaces. The average diameter of Cal-BSA-NP-GL and Cal-BSA-NP was 77 and 79 nm respectively. The uptake amount of the two NP by hepatocytes reached its maximum at 2 h after incubation. The uptake amount of Cal-BSA-NP-GL by rat hepatocytes was 4.43-fold higher than that of Cal-BSA-NP. There was a significant difference in the uptake of Cal-BSA-NP-GL and Cal-BSA-NP by hepatocytes (P<0.01). The uptake of Cal-BSA-NP-GL was inhibited when GL was added previously to isolated rat hepatocytes, and the uptake of Cal-BSA-NP was not affected by GL.

CONCLUSION: A binding site of GL is present on the surface of rat hepatocytes, BSA-NP-GL may be internalized via this site by hepatocytes and can be used as a drug carrier for active targeting of delivery drugs to hepatocytes.

[Studies on the optimized extraction technology of Paeonia suffruticosa]

OBJECTIVE

To obtain the optimized extraction technology of Paeonia suffruticosa by comparing several extraction method.

METHOD

Extract P. suffruticosa by ethanol circumfluence, distillation-decoction, CO2-SFE and traditional decoction, and analyse the results according to the total extraction rate, extraction rate of paeono, extraction of other ingredients and production feasibility.

RESULT

Total extraction rates of which are 12.66%, 13.51%, 7.28%, 7.56% respectively; extraction rates of paeonol are 2.45%, 2.26%, 0.31%, 1.15% in turn; Phenolic glycosides can be extracted by ethanol circumfluence, distillation-decoction, traditional decoction, but not by CO2-SFE.

CONCLUSION

Distillation-decoction is the most proper extraction technology of P. suffuticosa at present.

[The preparation of the polylacticacid nanoparticles of cucurbitacin and their drug loading]

This paper introduced an experimental study of the preparation of polylacticacid (PLA) nanoparticles of cucurbitacin (CuC) using a precipitation method. The residual acetone, ratio of CuC PLA precipitates, and the relationships between the ratios of two precipitates and drug incorporation rates were measured. It appeared that the nanoparticles with 60% of PLA incorporated with 5.5% of CuC were formed when acetone was injected into the aqueous phase. As the acetone gradually evaporated, drug incorporation/encapsulation continued, with most of CuC (about 70%) formed new crystalline cores and suspended in the form of microcrystals in the medium, resulting a suspension containing both nanoparticles and microcrystals. We also concluded that this system may not necessarily be suitable for all lipophilic drugs to be prepared to PLA nanoparticles with good incorporation rate. The drug incorporation depended on the interactions among drug, PLA, and organic solvents, in addition to the solubility of the drug.

Pathomorphological and quantitative bacteriological findings in various forms of primary surgery on gunshot wounds of extremities

It is well-known that 'wound excision' is essential in the primary treatment of wounds in war, particularly thorough debridement of the devitalized tissues around the path of a penetrating projectile. Nowadays, the gunshot wounds in peacetime have become prevalent. Instead of the traditional method of 'wound excision' (excision), we used the method of 'incision and drainage' (incision) in the primary surgery of these gunshot wounds of extremities. To determine the treatment effectiveness of these different surgical methods (incision and excision), two groups of dogs were shot in the proximal part of one hind leg with an American M-16 rifle. One group was treated by the method of 'excision'; in the other group 'incision' were performed. No difference in infection rate was noted between the two groups. Similarly, no difference in bacterial count was found between the two groups during the observation period. Also, there was no difference in healing time; the wounds in both groups had healed by 19.2-21.4 days. Microscopic examination revealed a little normal muscle tissue in the necrotic zone of the incision group which might augment the repair process. These results suggest that there are no differences in the effectiveness in preventing infection between the two methods. 'Incision' might be superior to 'excision' for the management of the gunshot wounds of extremities in peacetime, as it involves a simple operation and there are advantages for tissue healing.

[A study on lyophilization injection of cucurbitacin polylactic acid nanoparticles]

OBJECTIVE

To prepare stable and redispersable Lyophilization injection of cucurbitacin polylactic acid nanoparticles(Cu-PLA-NP).

METHOD

An optimal supporting agent was chosen to prepare the Cu-PLA-NP lyophilization injection. The physical and chemical properties of the injection were evaluated.

RESULTS

The shape, diameters, association ratio, drug loading and pH of Cu-PLA-NP colloidal solution and lyophilization injection were not changed. The content of water consisted with the requirement of lyophilization injection. The critical relative humidity was 69.52%. The stability was good.

CONCLUSION

It is practicable to prepare Cu-PLA-NP lyophilization injection with proper formulas and preparation processes.

[Stable life prediction for a complex injection of Chinese materia medica by initial average rate stability test]

OBJECTIVE

To predict the stable life for a complex injection of Chinese materia medica.

METHOD

The prediction was carried out by initial average rate stability tests, and the contents of puerarin and danshensu (major active components of the injection) were assayed by HPLC.

RESULT

The degradation of puerarin followed the first order action, while danshensu was hard to determine; the t0.9,25 degrees C was 3.49 years and 1.69 years respectively.

CONCLUSION

The stable life of the injection has been determined as 1.5 years.

Inhibitory effects of chlorpheniramine and astemizolum on contraction of isolated rat and rabbit uteri induced by oxytocin and PGF2 alpha

The contraction of isolated rat and rabbit uteri induced by oxytocin and PGF2 alpha was markedly inhibited by chlorpheniramine (Chl) and astemizolum (Ast), both of which also decreased the resting tension of uteri, and their spontaneous contraction. The inhibitory effects of both drugs were dose-dependent. At high concentrations, Chl 7.4 x 10(-4) mol/L and Ast 10(-4) mol/L could counteract the contraction of the uteri induced by Oxy and PGF2 alpha, and their spontaneous contraction as well. They decreased the resting tension to the lower level. The mechanism of their non-special relaxed action on uteri could not be completely explained only by their H1-receptor blocking action. Whether they act by blocking calcium channel or by inhibiting calmodulin (CaM) remains to be further explored.

[Study on mitoxantrone polycyanoacrylate nanospheres]

The mitoxantrone polybutylcyanoacrylate nanosparticles (DHAQ-PBCA-NP) were prepared by emulsion polymerization method. The surface charge, drug loading, morphology, size and size distribution, release characteristics in vitro, stability and distribution in animals of DHAQ-PBCA-NP were studied. The results showed that the mean size was d(av) = 55.23 nm, drug loading was 46.77%, embedding ratio was 84.89%. The surface carried negative charge and the release characteristics in vitro was in accord with two phases kinetics law. The colloidal solution of DHAQ-PBCA-NP can undergo boiling for 30 min sterilization. The radioactivity concentrated mainly in liver after iv 3H-DHAQ-PBCA-NP. The radioactivity in liver tumor was higher than that in the liver tissue. DHAQ-PBCA-NP was observed in parenchymal cell 15 min after iv DHAQ-PBCA-NS. This preparation seems to have important value for increasing the anti-liver tumor effect and decreasing the toxicity of DHAQ.

[Determination of the contents of bufadienolide and borneol in liushen pills]

The contents of bufadienolide and borneol in 01 and 02 Liushen Pills were determined by second-derivative spectrophotometry and gas chromatography respectively. The average recover of bufadienolide by SDS was 100.12% (n = 6, RSD = 1.44%) and of borneol by GC 97.68% (n = 4, RSD = 1.32%).

[Application of beta-cyclodextrin inclusion complex in liushen pills]

01 Liushen Pills (prepared by beta-CD inclusion complex) and 02 Liushen Pills (prepared according to the normal way) were compared by quality inspection, stability test, pharmacological experiments of irritative effects and dissolution test. The results indicated that 01 Liushen Pills were superior to 02 Liushen Pills.

[Optimization of the preparing process for sinitang drop pills by orthogonal test]

The preparing process for Sinitang drop pills was optimized by orthogonal test. The results from nine experiments were subjected with three indexes to objective analysis and variance analysis, and an optimum preparing process for Sinitang drop pills was sieved out. The quality of the drop pills prepared in this way was examined to be up to the standard.

[Study on cisplatin albumin microspheres for neck external artery embolization]

In this paper the technique of emulsion chemical-crosslinking was used to prepare cisplatin albumin microsphere for jaw squamous cancer by neck external artery embolization. It was yellow powder with yield 80 +/- 5%, mean size 56.3 microns, cisplatin concentration 14.02-14.20%, loading rate 97.08-97.95%. The release characteristics in vitro, sterilization, stability and recipe of disperse solvent of cisplatin albumin microsphere were investigated. Animal test showed that cisplatin albumin microsphere may plug the branches of neck external artery well and remain in local tissue.