Modification of the plasma clearance and liver uptake of steroid ester-conjugated oligodeoxynucleotides by association with (lactosylated) low-density lipoprotein

Low-density lipoprotein (LDL) has been proposed as carrier for the selective delivery of anticancer drugs to tumor cells. We reported earlier the association of several lipidic steroid-conjugated anticancer oligodeoxynucleotides (ODNs) with LDL. In the present study, we determined the stability of these complexes. When the complexes were incubated with a mixture of high-density lipoprotein and albumin, or with rat plasma, the oleoyl steroid-conjugated ODNs appeared to be more stably associated with LDL than the cholesteryl-conjugated ODN. Intravenously injected free lipid-ODNs were very rapidly cleared from the circulation of rats. The area under the curve (AUC) of the lipid-ODNs in plasma was <0.4 microg x min/mL. After complexation with LDL, plasma clearance of the lipid-ODNs was delayed. This was most evident for ODN-5, the ODN conjugated with the oleoyl ester of lithocholic acid (AUC = 6.82 +/- 1.34 microg x min/mL). The AUC of ODN-4, a cholesteryl-conjugated ODN, was 1.49 +/- 0.37 microg x min/mL. In addition, the liver uptake of the LDL-complexed lipid-ODNs was reduced. The lipid-ODNs were also administered as a complex with lactosylated LDL, a modified LDL particle that is selectively taken up by the liver. A high proportion of ODN-5 was transported to the liver along with lactosylated LDL (69.1 +/- 8.1% of the dose at 15 min after injection), whereas much less ODN-4 was transported (36.6 +/- 0.1% of the dose at 15 min after injection). We conclude that the oleoyl ester of lithocholic acid is a more potent lipid anchor than the other steroid lipid anchors. Because of the stable association, the oleoyl ester of lithocholic acid is an interesting candidate for tumor targeting of anticancer ODNs with lipoproteins.     

肿瘤趋向性N-(2-羟丙基)甲基丙烯酰胺聚合物-米托蒽醌接合物研究肿瘤趋向性N-(2-羟丙基)甲基丙烯酰胺聚合物-米托蒽醌接合物研究

目的制备N-(2-羟丙基)甲基丙烯酰胺(HPMA)聚合物-米托蒽醌(DHAQ)接合物以提高DHAQ在实体瘤中的分布。方法采用DHAQ与四肽间隔基连接,再与HPMA进行自由基沉淀聚合反应的方法,合成目标接合物;考察了接合物在不同介质中的稳定性及荷瘤小鼠体内的分布情况。结果合成的接合物经UV,HPLC和FPLC鉴定为目标化合物。其总DHAQ含量为132.4 mg·g^-1接合物,游离DHAQ含量为3.5 mg·mg^-1接合物。摩尔质量19 000 g·mol^-1,分子量分布1.4。在不同pH磷酸盐缓冲液及血浆中较稳定,在肿瘤中的释药明显加快。与原药相比,接合物在荷瘤小鼠体内的分布明显不同。肿瘤中AUC为游离药物3倍;血液循环时间延长;在心脏中的分布明显减少。表明接合物具有一定的肿瘤趋向性,并能降低原药对心脏的毒性。结论将具有仲氨基的DHAQ连接于HPMA聚合物,能提高DHAQ在肿瘤中的分布,为实体瘤靶向高分子给药系统的研究提供新的思路。     

Synthesis, characterization andin vitro evaluation of triptolide-lysozyme conjugate for renal targeting delivery of triptolide

A triptolide-lysozyme (TP-LZM) conjugate was synthesized to achieve renal specific delivery and to reduce the side effects of triptolide. Triptolide was coupled to lysozyme through succinic via an ester bond with an average coupling degree of 1 mol triptolide per 1 mol lysozyme. The lysozyme can specifically accumulate in the proximal tubular cells of the kidney, making it a potential carrier for targeting drugs to the kidney. The structure of triptolide succinate (TPS) was confirmed by IR, 1H-NMR, MS and UV. The concentrations of triptolide in various samples were determined by reversed-phase high-performance liquid chromatography (HPLC). In this study, the physicochemical and stability profiles of TP-LZM under various conditions were investgated the stability and releasing profiles of triptolide-lysozyme (TP-LZM) under various conditions. In vitro release trails showed triptolide-lysozyme was relatively stable in plasma (less than 30% of free triptolide released) and could release triptolide quickly in lysosome (more than 80% of free triptolide released) at 37 degrees C for 24 h. In addition, the biological activities of the conjugate on normal rat kidney proximal tubular cells (NRK52E) were also tested. The conjugate can effectively reduce NO production in the medium of NRK52E induced by lipopolysaccharide (LPS) but with much lower toxicity. These studies suggest the possibility to promote curative effect and reduce its extra-renal toxicity of triptolide by TP-LZM conjugate.     

Investigation of targeting mechanism of new dextran-peptide-methotrexate conjugates using biodistribution study in matrix-metalloproteinase-overexpressing tumor xenograft model

We conducted a biodistribution study in HT-1080 bearing mice to investigate the drug targeting mechanism and the cause of side effects of the new dextran-peptide-methotrexate conjugates. HT-1080 is a human fibrosarcoma cell line that is known to overexpress matrix-metalloproteinases (MMPs). The experiments compared conjugates carrying MMP sensitive peptide linkers, conjugates carrying MMP insensitive linkers, and free methotrexate. Passive targeting was evidenced by the prolonged plasma circulation and higher tissue accumulations of both types of the conjugates compared to free methotrexate. Independent of the peptide sequence of the linker, the ratio of drug accumulation at the tumor versus drug accumulation at the major site of side effects (small intestine) for either conjugate was increased by the effect of enhance permeation and retention (EPR). The conjugate released a sufficient amount of peptidyl methotrexate to cause inhibition of tumor growth. There was no significant difference in drug accumulation at the tumor site between the MMP-sensitive and the MMP-insensitive conjugates. We concluded that the tumor targeting effect of the dextran-peptide-methotrexate conjugate was dominantly due to passive targeting and EPR. The difference in the systemic side effects observed for conjugates with different linkers could probably be attributed to their varying susceptibility towards enzymes in normal tissues.     

Enhanced anti-hepatocarcinoma efficacy by GLUT1 targeting and cellular microenvironment-responsive PAMAM–camptothecin conjugate

The efficient targeting of drugs to tumor cell and subsequent rapid drug release remain primary challenges in the development of nanomedicines for cancer therapy. Here, we constructed a glucose transporter 1 (GLUT1)-targeting and tumor cell microenvironment-sensitive drug release Glucose–PEG–PAMAM-s-s–Camptothecin-Cy7 (GPCC) conjugate to tackle the dilemma. The conjugate was characterized by a small particle size, spherical shape, and glutathione (GSH)-sensitive drug release. In vitro tumor targeting was explored in monolayer (2D) and multilayer tumor spheroid (3D) HepG2 cancer cell models (GLUT1⁺). The cellular uptake of GPCC was higher than that in the control groups and that in normal L02 cells (GLUT1^?), likely due to the conjugated glucose moiety. Moreover, the GPCC conjugate exhibited stronger cytotoxicity, higher S arrest and enhanced apoptosis and necrosis rate in HepG2 cells than control groups but not L02 cells. However, the cytotoxicity of GPCC was lower than that of free CPT, which could be explained by the slower release of CPT from the GPCC compared with free CPT. Additional in vivo tumor targeting experiments demonstrated the superior tumor-targeting ability of the GPCC conjugate, which significantly accumulated in tumor meanwhile minimize in normal tissues compared with control groups. The GPCC conjugate showed better pharmacokinetic properties, enabling a prolonged circulation time and increased camptothecin area under the curve (AUC). These features contributed to better therapeutic efficacy and lower toxicity in H22 hepatocarcinoma tumor-bearing mice. The GLUT1-targeting, GSH-sensitive GPCC conjugate provides an efficient, safe and economic approach for tumor cell targeted drug delivery.     

Ni2+-mediated mitoxantrone encapsulation: improved efficacy of fast release formulation

Despite that in solution we cannot detect the interaction between Ni(2+) and mitoxantrone (MIT), Ni(2+) could mediate effective and stable MIT loading into large unilamellar vesicles (LUVs). The presence of nigericin had almost no influences on MIT encapsulation. However, in the presence of NH(3), the drug loading kinetics significantly altered. UV-vis spectrum analysis revealed that the absorption profile of liposomal MIT prepared with NiSO(4) gradient method was markedly different from that of liposomal MIT prepared with pH gradient method and that of free MIT. Three liposomal formulations were prepared, which were made from DMPC/chol, DPPC/chol and HSPC/chol and named LM-m, LM-p and LM-s. The in vitro release T(1/2) values for the formulations were 15.0, 28.2 and 38.5h, respectively. Following an intravenous injection into BDF1 mice at a dose of 4 mg/kg, the MIT plasma levels at 24h time point were 3.3, 11.3 and 12.7 microg/mL, considerably compared to that of free MIT group. In L1210 ascitic model, LM-m therapy resulted in approximately 60% long-term survivor (>60 days), and increased survival times in comparison with other treatments. However, both LM-p and LM-s formulations were less therapeutically active than free MIT. In conclusion, transmembrane NiSO(4) gradient could mediate effective MIT loading, and the formulation prepared with fluid lipid had fast release rate and improved efficacy in L1210 ascitic tumor model.     

Pharmacokinetics and antitumor activity of vincristine entrapped in vesicular phospholipid gels

In vivo antitumoral activity, pharmacokinetics (PK) and biodistribution of a new liposomal formulation of vincristine (VCR-Lip) were compared to VCR in aqueous solution (VCR-Conv). VCR was entrapped into a vesicular phospholipid gel (VPG) consisting of densely packed liposomes. Redispersed VCR-containing VPG (VCR-Lip) consisted of 54% liposomally entrapped and 46% free VCR. In vivo efficacy of VCR-Lip versus VCR-Conv was tested using the s.c. growing human small cell lung carcinoma LXFS 650 and the human mammary carcinoma MX1. PK and biodistribution were evaluated using radiolabeled drug and lipid in LXFS 650 tumor-bearing mice. VCR-Lip at a dose of 1.0 mg/kg (dose near the maximum tolerated dose) led to partial remissions in the MX1 tumor xenograft model (T/C=3.9%). VCR-Conv at an equitoxic dose of 0.6 mg/kg produced only a tumor growth inhibition (T/C=7.0%). In LXFS 650 tumor-bearing mice, VCR-Lip was highly active at doses of 0.75 (T/C=0.7%) and 1.0 (T/C=0.0%) mg/kg, and complete tumor regressions were observed. In contrast, equitoxic doses of VCR-Conv (0.6 mg/kg) resulted only in less pronounced tumor remissions (T/C=4.1%). The PK study revealed that VCR-Lip achieved an over 10-fold higher plasma AUC (22.6 microg x h/ml) than VCR-Conv (2.16 microg x h/ml). Moreover, tumor drug levels were 2.3-fold higher when VCR was injected as VCR-Lip in comparison to VCR-Conv. In some cases, however, VCR-Lip as well as blank VPG appeared to be toxic. We conclude that VCR-Lip is an effective VCR delivery system with superior antitumor activity compared to VCR-Conv. The enhanced efficacy can be explained by sustained release and passive tumor targeting.     

雷公藤内酯醇-溶菌酶偶联物的性能研究及体外评价

目的 研究肾靶向前体药物雷公藤内酯醇-溶菌酶偶联物的理化性质.方法 采用HPLC法考察偶联物在37℃不同pH缓冲液、大鼠血浆及大鼠肾脏溶酶体溶液中的稳定性及细胞毒性.结果 体外稳定性试验表明,偶联物在37℃的不同pH缓冲液及大鼠血浆中稳定,在大鼠肾脏溶酶体溶液中可降解.偶联物能降低肾近端小管的细胞毒性,减少脂多糖引导的NO产生.结论 雷公藤内酯醇-溶菌酶偶联物可提高雷公藤内酯醇的肾靶向性,并可降低不良反应.     

Pharmacokinetics and bioequivalence study of clindamycin hydrochloride formulations after single-dose administration in healthy Chinese male volunteers

The aim of the present study was to compare the bioavailability of clindamycin (CAS 18323-44-9) from three clindamycin hydrochloride (CAS 21 462-39-5) capsules (clindamycin 75 mg capsule as test 1 preparation, 150 mg capsule as test 2 preparation and a commercially available original 150 mg capsule of the drug as reference preparation) in 24 Chinese healthy male volunteers, aged between 22 and 28. The study was conducted according to a randomized, double-blind, 3-period, 3-treatment, 3-sequence, single-dose, crossover design with a wash-out phase of 7 days. Blood samples for pharmacokinetic profiling were taken up to 14 h post-dose, and clindamycin plasma concentrations were determined with a validated liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method. Maximum plasma concentrations (C(max)) of 3.06 +/- 1.10 microg/mL (test 1), 3.10 +/- 1.59 microg/mL (test 2) and 3.06 +/- 1.15 microg/mL (reference) were achieved. Areas under the plasma concentration-time curve (AUC(0-infinity)) of 10.73 +/- 4.29 microg x h/mL (test 1), 10.54 +/- 4.10 microg x h/ mL (test 2) and 11.29 +/- 4.98 microg x h/mL (reference), AUC(0-t) of 10.32 +/- 4.09 microg x h/ mL, 10.26 +/- 3.96 microg x h/mL, 10.94 +/- 4.86 g x h/mL were calculated. The median T(max) was 0.80 +/- 0.52 h, 0.77 +/- 0.37 h, 1.01 +/- 0.6 h for test 1, test 2 and reference formulation, respectively. Plasma elimination half-lives (t1/2) of 2.72 +/- 0.58 h (test 1), 2.39 +/- 0.37 h (test 2) and 2.63 +/- 0.66 h (reference) were determined. Both primary target parameters, AUC(0-infinity) and AUC(0-t) were tested parametrically by analysis of variance (ANOVA) and relative bioavailabilities were 98.0 +/- 16.2% (test 1) and 97.2 +/- 20.3% (test 2) for AUC(0-infinity), 97.5 +/- 16.3% (test 1) and 97.8 +/- 20.2% (test 2) for AUC(0-t). Bioequivalence between test and reference preparation was demonstrated for both parameters, AUC(0-infinity) and AUC(0-t). The 90% confidence intervals of the T/R-ratios of logarithmically transformed data were in the generally accepted range of 80%-125%. That means that the two test formulations are bioequivalent to the reference formulation for clindamycin.     

Folate-decorated maleilated pullulan–doxorubicin conjugate for active tumor-targeted drug delivery

A novel folate-decorated maleilated pullulan–doxorubicin conjugate (abbreviated as FA–MP–DOX) for active tumor targeting was set up. The structure of this conjugate was confirmed by ¹H NMR analysis. Furthermore, the conjugation efficiency, drug release property and stability of the conjugate were determined. The cellular uptake and cytotoxicity were assessed by using ovarian carcinoma A2780 cells as in vitro cell model. In vitro DOX release from FA–MP–DOX conjugate occurred at a faster rate at acidic pH compared to neutral pH (7.4). After 30 h of incubation at pH 2.5, 5.0 and 7.4 the released free DOX was about 68.71%, 50.08% and 26%, respectively. Based on the IC₅₀ values, the conjugate was found more effective with ovarian carcinoma A2780 cells than the parent drug after 48 h culture. These results suggested that FA–MP–DOX conjugate could be a promising doxorubicin carrier for its targeted and intracellular delivery.     

Highly variable mycophenolate mofetil bioavailability following nonmyeloablative hematopoietic cell transplantation

This study determined the oral bioavailability of mycophenolic acid, the active metabolite of mycophenolate mofetil, in patients undergoing nonmyeloablative hematopoietic cell transplantation. Eighteen adults receiving a preparative regimen containing fludarabine, cyclophosphamide, and total body irradiation were studied. Immune suppression consisted of cyclosporine and mycophenolate 1 g twice daily. Pharmacokinetic variability was high after intravenous and oral dosing. Intravenous dosing resulted in a median area under the curve (AUC) of 28.3 microg x h/mL (range, 9.96-70.4) and an oral AUC of 16.7 microg x h/mL (range, 9.38-35.3). Cmax after intravenous and oral dosing was 12.18 and 5.29 microg/mL, respectively. The median oral bioavailability was 72.3% (20.5%-172%), with 8-fold variability. Five patients (28%) had an oral bioavailability < or = 50%. At time of oral pharmacokinetics, 15 patients (83%) had an AUC(0-12) < 30 microg x h/mL. The initial oral dose should be at least 25% greater than the intravenous dose with follow-up assessment of plasma concentrations.     

Single-dose study to compare the pharmacokinetics of HFA flunisolide and CFC flunisolide

The hydrofluoroalkane (HFA) formulation of the inhaled corticosteroid flunisolide is a modification of the original chlorofluorocarbon (CFC) formulation. HFA flunisolide replaces CFC with an HFA propellant and uses a built-in spacer in its pressurized metered-dose inhaler. The average HFA flunisolide particle size is 1.2 microm compared with 3.8 microm for the CFC formulation. The smaller particle size improves lung targeting, allowing a reduction in the HFA flunisolide dose relative to CFC flunisolide while maintaining comparable efficacy. In a study of 12 healthy men, pharmacokinetic parameters were determined after single doses of 1000 microg CFC flunisolide delivered without a spacer, 340 microg HFA flunisolide delivered through a spacer, and 516 microg HFA flunisolide delivered without a spacer. A standard noncompartmental analysis of the concentration data was performed and mean (+/- S.D.) pharmacokinetic values were reported. Peak plasma concentrations (observed C(max)) were similar for the three treatments. Area under the curve up to the time corresponding to the last measurable concentration (AUC(0)(-)(tlast)) was similar for the CFC and HFA flunisolide, plus spacer groups (4.4 +/- 1.6 ng x h/mL and 5.0+/- 4.2 ng x h/mL, respectively); however, AUC(0)(-)(tlast) for the HFA flunisolide without spacer group was comparatively lower than for the CFC group (3.5 +/- 1.6 ng x h/mL). Observed C(max) and AUC(0)(-)(tlast) for 6 beta-OH flunisolide, the first-pass metabolite of flunisolide and an indicator of oropharyngeal deposition, were significantly higher in the CFC flunisolide group than in either HFA flunisolide group.     

Population pharmacokinetic model to predict steady-state exposure to once-daily cyclosporin microemulsion in renal transplant recipients

BACKGROUND: The microemulsion formulation of cyclosporin (CsA-ME) has a less variable absorption profile than the standard formulation (CsA-S), but only limited information is available about once-daily administration of CsA-ME. OBJECTIVE: To develop a population pharmacokinetic model for once-daily CsA-ME that enables the prediction of individual steady-state area under the concentration-time curve (AUC) on the basis of blood concentration measurements and patient covariates. PATIENTS AND METHODS: The steady-state pharmacokinetics of once-daily cyclosporin were studied in 60 stable renal transplant recipients before and after conversion from CsA-S to CsA-ME. For each formulation, 7 blood samples were collected from 50 patients (group A) at sparse timepoints over 2 weeks, and 10 blood samples were collected from 10 patients (group B) at fixed timepoints over 24 hours. A 2-compartment population model assuming time-lagged first-order oral absorption was fitted to the data from group A, using nonlinear mixed effects modelling (NONMEM). The data from group B were used to evaluate the predictive performance of the model. RESULTS: Mean [+/- SD; coefficient of variation (%CV)] CsA-S doses of 245mg (+/- 92) resulted in cyclosporin blood concentrations of 214 microg/L (+/- 70) after 12 hours and 108 microg/L (+/- 23) after 24 hours; the mean estimated AUC to 24 hours was 7658 microg x h/L (30%). With mean CsA-ME doses of 206mg (+/- 59), cyclosporin blood concentrations were 212 microg/L (+/- 33) and 132 microg/L (25%) after 12 and 24 hours, respectively, and the mean estimated AUC(24) was 9357 microg x h/L (23%). A strong correlation between 12-hour concentrations and AUC(24) was observed for CsA-ME (r = 0.95, p < 0.001), but not for CsA-S (r = 0.59, nonsignificant); the correlation between 24-hour trough concentrations and AUC(24) was weaker for both formulations (r = 0.64, p < 0.05 and r = 0.37, nonsignificant, respectively). On the basis of the population model derived from group A, the single best timepoint to predict AUC(24) from blood cyclosporin concentration was at 8 hours [AUC(24) (microg x h/L) = 19.6 x cyclosporin concentration at 8 hours (microg/L) + 3035], resulting in a prediction error of 8.3 +/- 6.6% when applied to the measured AUC(24) of group B. Adverse events were observed after conversion in 18 patients; these events generally resolved spontaneously or after dosage reduction, but twice-daily administration was required in some patients. CONCLUSIONS: Switching from once-daily CsA-S to CsA-ME results in more consistent and predictable cyclosporin pharmacokinetics. Adjustment of dosage or regimen may be required in some patients.     

Pharmacokinetics of paclitaxel and cisplatin in a hemodialysis patient with recurrent ovarian cancer

This is the first report that the combination of paclitaxel and cisplatin is feasible in a patient with recurrent ovarian cancer undergoing hemodialysis. Paclitaxel at a dose of 150 mg/m(2) was administered as a 3-h continuous i.v. infusion. Thirty minutes after paclitaxel administration, cisplatin was administered at a dose of 30 mg/m(2) for 30 min. Hemodialysis was started 30 min after completion of the cisplatin infusion and performed for 5 h. The maximum plasma concentrations of paclitaxel, total platinum and free platinum were 3.26, 2.44 and 1.84 microg/ml, respectively. The AUC of paclitaxel and free platinum were 15.3 and 1.76 microg x h/ml, respectively. The pelvic tumor size was reduced by 42% on MRI after the second course of this therapy. Grade IV neutropenia and grade III thrombopenia were observed. We conclude that paclitaxel and cisplatin combination chemotherapy is efficacious and feasible for an ovarian cancer patient under hemodialysis.     

Distribution characteristics of carboxymethylpullulan-peptide-doxorubicin conjugates in tumor-bearing rats: different sequence of peptide spacers and doxorubicin contents

Plasma and tissue distribution of conjugates of carboxymethylpullulan (CMPul) and doxorubicin (DXR), either bound directly or through three types of tetrapeptide spacers, was studied after intravenous injection to rats bearing Walker 256 carcinosarcoma and compared with that of DXR. In contrast to DXR, each conjugate retained high levels of DXR in the conjugated form in plasma and displayed high accumulation in the tumor at 6 h after the administration. Disposition characteristics of [3H]CMPul in rats bearing Walker 256 carcinosarcoma indicate that pullulan, which had molecular weight over 50 kDa, is a suitable macromolecular carrier for tumor targeting in cancer chemotherapy by carboxymethylation. We find that the in vivo antitumor effect of the conjugates depends on the tumor AUC of free DXR released from the conjugates. CMPul-DXR conjugates were also distributed in the reticuloendothelial organs, such as liver, spleen and bone marrow; however, the tissue concentrations of the conjugates in the heart, lung and muscle were lower than those of DXR. We next investigated the effect of the DXR contents of CMPul-DXR conjugates on their body distribution in rats bearing Walker 256. The half life of CMPul-DXR conjugates in plasma were shorter and the conjugates had greater accumulation in the reticuloendothelial system, while they showed lower concentrations in the tumor with increasing DXR contents. Antitumor activity of CMPul-DXR conjugates were reduced and the lethal toxicities of CMPul-DXR conjugates were amplified with increasing DXR contents.     

Development and characteristics of temperature-sensitive liposomes for vinorelbine bitartrate

A novel liposome with temperature-sensitivity for vinorelbine bitartrate (VB) was designed to enhance VB targeted delivery and antitumor effect. Liposomes without drugs were prepared by thin film hydration, and then VB was entrapped into liposomes by pH gradient loading method. The mean particle size of the liposomes was about 100 nm, and the drug entrapment efficiency was more than 90%. Stability data indicated that the liposome was physically and chemically stable for at least 6 months at 4 °C. In vitro drug release study showed that drugs hardly released at 37 °C; while at 42 °C, drugs released quickly. For in vivo experiments, the lung tumor model was established by subcutaneous inoculation of cell suspension on mice, liposomes and free VB were injected i.v. in mice, followed by exposure the tumors to hyperthermia (HT) for 30 min after administration. The ratio of inhibition tumor of temperature-sensitive liposomes group was significantly higher than the normal injection group. Combining temperature-sensitive liposomes with HT enhanced the delivery of VB and, consequently, its antitumor effects. This liposome could potentially produce viable clinical strategies for improved targeting and delivery of VB for treatment of cancer.     

Bioequivalence of two subcutaneous pharmaceutical products of interferon beta la

Blastoferon, in the following referred to as the test product, is a pharmaceutical product of interferon beta la (CAS 220581-49-7) currently marketed as a biosimilar to the innovator Interferon beta la product (referred to as the reference product). Pharmacokinetics and pharmacodynamIcs assays are critically relevant to demonstrate similarity between biopharmaceuticals. The aims of the present study were to investigate the bioavailability (BA) of the test product (either absolute or relative to the innovator product) and to compare the extent of increase of neopterin concentration following administration of either product. Two studies were performed: initially, an absolute BA assay with i.v. and s.c. injection of test product to 12 healthy subjects. Second, a formal relative BA study with s.c. injections of 88 microg of both products to 24 healthy volunteers. Blood samples for pharmacokinetic and pharmacodynamic profiling were drawn at different intervals after injection. Interferon beta (IFNB) concentrations were determined by ELISA. In the absolute BA study, a single s.c. dose of 44 microg of the test product resulted in a median bioavailable fraction of 29%, a median T(max) of 4 h (4-6) and a C(max) of 3.69 (3.27-4.41) IU x ml(-1). In the relative BA study, values for the test product were: median T(max) of 3 h (2-18), C(max) of 5.39 (4.99-6.31) IU x ml(-1), AUC (0-72) of 142.86 (134.16-190.15) IU x h x ml(-1) and AUC(0-infinity) of 190.95 (174.23-303.13) IU x h x ml(-1). The corresponding values for the innovator product were: T(max) of 3 h (1-24), C(max) of 4.44 (4.12-5.40) IU x ml(-1), AUC(0-72) of 128.77 (121.18-170.92) IU x h x ml(-1) and AUC(0-affinity) of 192.61 (183.04-286.46) IU x h x ml(-1). The AUC(0-72) ratio was 111% (CI 90%: 106-116), the AUC(0-affinity) was 99% (CI 90%: 92-107) and the C(max) ratio was 121% (CI 90%: 112-131). IFNB1a increased neopterin levels in both studies. Both products induced side-effects commonly reported for IFN with no serious adverse events. This study presents pharmacokinetics parameters of the test product and demonstrates similar bioavailability of IFNB1a for both pharmaceutical products.     

A simple high-performance liquid chromatographic method for the determination of acyclovir in human plasma and application to a pharmacokinetic study

A rapid, simple and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the measurement of acyclovir (CAS 59277-89-3) concentrations in human plasma and its use in bioavailability studies is evaluated. The method was linear in the concentration range of 0.05-4.0 microg/ml. The lower limit of quantification (LLOQ) was 0.05 microg/ml in 0.5 ml plasma sample. The intra- and inter-day relative standard deviations across three validation runs over the entire concentration range were less than 8.2%. This method was successfully applied for the evaluation of pharmacokinetic profiles of acyclovir capsule in 19 healthy volunteers. The main pharmacokinetic parameters obtained were: AUC(o-t) 6.50 +/- 1.47 and 7.13 +/- 1.44 microg x h/ml, AUC(0-infinity) 6.77 +/- 1.48 and 7.41 +/- 1.49 microg x h/ml, C(max) 2.27 +/- 0.57 and 2.27 +/- 0.62 microg/ml, t(1/2) 2.96 +/- 0.41 and 2.88 +/- 0.33 h, t(max) 0.8 +/- 0.3 and 1.0 +/- 0.5 h for test and reference formulations, respectively. No statistical differences were observed for C(max) and the area under the plasma concentration--time curve for acyclovir. 90% confidence limits calculated for C(max) and AUC from zero to infinity (AUC(0-infinity)) of acyclovir were included in the bioequivalence range (0.8-1.25 for AUC).     

抗IV型胶原酶单抗与平阳霉素新型免疫偶联物的抗肿瘤作用

目的考察抗IV型胶原酶单抗3G11与平阳霉素(PYM)偶联物的抗肿瘤作用。方法采用多聚谷氨酸(PLG)为中间载体制备3G11-PLG-PYM偶联物,MTT法测定其对肿瘤细胞增殖的抑制作用,以小鼠移植性肝癌H22为模型观察体内抗肿瘤作用。结果偶联物保留了单抗3G11对IV型胶原酶的免疫活性,对体外培养H22和KB细胞的杀伤作用弱于PYM。动物实验中PYM 10 mg·kg^-1对H22肝癌的抑制率为60.6%,而等细胞毒性剂量的3G11-PLG-PYM偶联物抑瘤率达到90.8%,与PYM相比可显著延长小鼠的中位生存时间。结论3G11-PLG-PYM偶联物对小鼠肝癌H22的抑瘤作用比PYM强,可能成为新型的抗肿瘤靶向药物。     

Kinetic analysis of in vitro and in vivo release of prednisolone from the conjugate of glycol-chitosan and succinyl-prednisolone

Recently, many people have developed rheumatoid arthritis (RA), and prednisolone (PD) is often used for treatment; however, long use and a large dose of PD can cause toxic side effects. In this study, in order to enhance the therapeutic effects and to suppress the toxic side effects, the conjugate (GC-SP) was prepared by coupling between glycol-chitosan (GC) and succinyl-prednisolone (SP). The drug-release properties of GC-SP were examined and analyzed kinetically. The plasma concentration-time profiles of GC-SP and released PD were investigated after i.v. injection to normal rats, and their pharmacokinetic profiles were analyzed. PD was stable and released gradually (ca. 1%/h) from GC-SP at physiological pH, while PD was unstable at basic pH and the release from GC-SP was accelerated at basic pH. GC-SP showed good systemic retention (more than 16-fold area under the plasma concentration-time curve (AUC) as compared to PD alone), and released PD gradually in vivo. The in vivo release rate was calculated to be much faster than the in vitro rate. From these results, it is expected that GC-SP will be accumulated at inflammatory sites based on enhanced permeability and retention (EPR) effects, and release PD there effectively.