Formulation and evaluation of mucoadhesive glipizide microspheres

The purpose of this research was to formulate and system-atically evaluate in vitro and in vivo performances of mucoadhesive microspheres of glipizide. Glipizide microspheres containing chitosan were prepared by simple emulsification phase separation technique using glutaraldehyde as a cross-linking agent. Results of preliminary trials indicate that volume of cross-linking agent, time for cross-linking, polymer-to-drug ratio, and speed of rotation affected characteristics of microspheres. Microspheres were discrete, spherical, and free flowing. The microspheres exhibited good mucoadhesive property in the in vitro wash-off test and also showed a high percentage drug entrapment efficiency. A 3² full factorial design was employed to study the effect of independent variables, polymer-to-drug ratio (X ₁), and stirring speed (X ₂) on dependent variables percentage mucoadhesion, t₈₀, drug entrapment efficiency, and swelling index. The best batch exhibited a high drug entrapment efficiency of 75% and a swelling index of 1.42; percentage mucoadhesion after 1 hour was 78%. The drug release was also sustained for more than 12 hours. The polymer-to-drug ratio had a more significant effect on the dependent variables. In vivo testing of the mucoadhesive microspheres to albino Wistar rats demonstrated significant hypoglycemic effect of glipizide.     

Effect of heating temperature and time on pharmaceutical characteristics of albumin microspheres containing 5-fluorouracil

Conclusion  In this study, we found that both heating temperature and heating time affect mean particle size, particle size distribution, and drug entrapment efficiency of albumin microspheres. The change in heating temperature may affect the particle size of the product, especially when heating is carried out at a lower temperature (90°C–120°C). Hence the temperature should be selected on the basis of desired size range. Given that it is desirable for a maximum amount of the drug used in the preparation to become entrapped in microspheres, heating temperature and heating time for denaturation of albumin should be selected cautiously, as both have a significant effect on drug entrapment efficiency. In the present case, the highest entrapment was found in batches prepared by heating at 90°C for 5 minutes. However, the extent of stabilization at the selected temperature and the time of heating should also be taken into consideration, as they may affect the release of drugs to target tissue.     

Spectroscopic studies of bovine serum albumin adsorbed onto magnetic–thermosensitive carbon microspheres

To investigate the influence of magnetic–thermosensitive carbon microspheres (MTCMSs) as a targeting drug carrier on serum albumins in vitro, in this study, bovine serum albumin (BSA) was chosen as a template protein to explore the interaction between serum proteins and MTCMSs. Fluorescence spectrophotometry, ultraviolet–visible absorbance (UV–vis) spectrophotometry and circular dichroism spectrometry were used to investigate the interaction between MTCMSs and BSA. Results indicate that BSA interacts with MTCMSs and the fluorescence intensity of BSA is quenched by 50% in a static quenching at 310 K when the concentration of MTCMSs reaches 30 mg/L. Thermodynamic parameters including free energy change (△G^θ), enthalpy change (△H^θ) and entropy change (△S^θ) were calculated. The results (△G^θ < 0, △H^θ < 0 and △S^θ > 0) suggest a spontaneous process and the formation of a hydrogen bond between MTCMSs and BSA. UV–vis measurements reveal that the micro‐environment of an amino acid residue is altered in the presence of MTCMSs. The α‐helix content of BSA decreases by 4% and the β‐sheet content increases by 3.2% with increasing concentrations of MTCMSs to 30 mg/L, illustrating a change in the skeletal structure of BSA. These results demonstrate that MTCMSs as a targeting drug carrier impact the structure of serum albumins. This work provides not only a theoretical basis of BSA adsorption onto MTCMSs, but also an understanding of safe drug carriers in biomedicine. Copyright © 2016 John Wiley & Sons, Ltd.     

应用实验设计优化制备适于口服的聚酯微球

采用双乳溶剂蒸发法制备包裹蛋白质的聚酯微球 ,蛋白质包裹率大于 80 %。应用均匀设计和正交设计试验研究了 8种因素对微球粒径的影响。结果表明 ,粒径主要受有机相中聚合物浓度和外水相中稳定剂浓度的影响。通过二次回归组合设计 ,建立了微球平均粒径与聚合物浓度及稳定剂浓度之间的数学关系式。根据此式 ,选择不同的聚合物浓度和稳定剂浓度可制备适于蛋白质口服给药的微球。     

Preparation, characterization, and in vivo evaluation of salmon calcitonin microspheres

Purpose. This study was done to prepare, characterize, and evaluate salmon calcitonin (sCT) microspheres (ms) in vivo using a low molecular weight, hydrophilic 50∶50 poly (D,L-lactide-co-glycolide) polymer (PLGA).Methods. sCT ms were prepared by a dispersion/solvent extraction/evaporation process and characterized for drug content, particle size, surface morphology, and structural integrity of encapsulated peptide. Peptide stability and binding to the polymer was studied in 0.1 M phosphate buffer (PB), pH 7.4, and 0.1 M acetate buffer (AB), pH 4.0. Serum sCT levels were monitored for 2 weeks after subcutaneous injection of sCT ms to rats.Results. sCT ms were essentially free of discernible surface pores with a particle size distribution in the range of 16 to 89 mm and mean particle size of 51 and 53 mm for 2 batches. Fourier Transform Matrix-assisted Laser Desorption mass spectrometry of the extracted peptide showed that the encapsulation process did not alter its chemical structure. The peptide was substantially more stable in AB than in PB. Peptide binding to the polymer was dependent on pH and was markedly higher in PB than in AB. In vivo study proved that elevated serum sCT levels could be sustained for at least 10 days after administration of sCT ms to rats at a dose of 1.0 mg/kg.Conclusions. It was demonstrated that sCT could be incorporated into polymeric ms prepared from a low molecular weight, hydrophilic PLGA using a dispersion technique without altering molecular structure. A 2-week formulation was prepared at a dose of 1.0 mg/kg.     

Formation and oral administration of alginate microspheres loaded with pDNA coding for lymphocystis disease virus (LCDV) to Japanese flounder

Oral delivery of plasmid DNA (pDNA) is a desirable approach for fish immunization in intensive culture. However, its effectiveness is limited because of possible degradation of pDNA in the fish's digestive system. In this report, alginate microspheres loaded with pDNA coding for fish lymphocystis disease virus (LCDV) and green fluorescent protein were prepared with a modified oil containing water (W/O) emulsification method. Yield, loading percent and encapsulation efficiency of alginate microspheres were 90.5%, 1.8% and 92.7%, respectively. The alginate microspheres had diameters of less than 10 microm, and their shape was spherical. As compared to sodium alginate, a remarkable increase of DNA-phosphodiester and DNA-phosphomonoester bonds was observed for alginate microspheres loaded with pDNA by Fourier transform infrared (FTIR) spectroscopic analysis. Agarose gel electrophoresis showed a little supercoiled pDNA was transformed to open circular and linear pDNA during encapsulation. The cumulative release of pDNA in alginate microspheres was or=0.3) for anti-LCDV antibody from week 3 to week 16 for fish orally vaccinated with alginate microspheres loaded with pDNA, in comparison with fish orally vaccinated with naked pDNA. Our results display that alginate microspheres obtained by W/O emulsification are promising carriers for oral delivery of pDNA. This encapsulation technique has the potential for DNA vaccine delivery applications due to its ease of operation, low cost and significant immune effect.     

Effect of additives on the release of a model protein from PLGA microspheres

The purpose of this study was to investigate the effect of 2 additives, poly(ethylene glycol (PEG) 1000 and 1,2,3-tridecanoyl glycerol (tricaprin), on the physico-chemical characteristics and in vitro release of a model protein, bovine serum albumin (BSA), form poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres. BSA-loaded microspheres were prepared by the double emulsion solvent evaporation method. Additives were incorporated into microspheres to modify the release of protein. The addition of PEG 1000 and tricaprin changed the surface characteristics of microspheres from smooth and nonporous to porous and dimpled, respectively. The in vitro release profiles showed that the additives significantly (P<0.05) increased the early-stage release of BSA from microspheres.     

Assessment of the antitumour activity of targeted immunospecific albumin microspheres loaded with cisplatin and 5-fluorouracil: toxicity against a rodent ovarian carcinoma in vitro

The 3-(4,5 dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay is used successfully to estimate the number of viable cells in drug screening trials. We used the MTT assay to assess the viability of a rodent ovarian carcinoma cell line (DMBA-OC-1R) after exposure to combinations of cisplatin and 5-fluorouracil as free drug and in encapsulated (conjugated and unconjugated) forms. After 48 h of exposure to free drugs, a significant trend towards cell cytotoxicity could be observed and this was well established by 120 h. Cells treated with drug-containing immuno-microspheres showed a similar initial decrease in cell viability after 96 h, and this was maintained for 128 h. These results suggest that immuno-microspheres loaded with chemotherapeutic drugs have the potential to be successfully used in the treatment of ovarian cancer.     

Preparation and evaluation of bovine serum albumin immobilized chiral monolithic column for affinity capillary electrochromatography

A system of capillary silica monolith with bovine serum albumin (BSA) functionalized through two approaches for affinity monolithic capillary electrochromatography (AMCEC) was developed. Covalent immobilization conditions for two different Schiff base methods, which employed 3-glycidopropyl trimethoxysilane (GPTS) and 3-aminopropyl trimethoxysilane (APTS) as starting materials, respectively, were investigated to obtain good and stable chiral separation. The BSA immobilized silica monoliths were evaluated in terms of morphology, electroosmotic flow, retention time, column efficiency and resolution of model compound (±)-tryptophan. The columns exhibited satisfactory run-to-run, column-to-column repeatability and maintained their enantioselectivity for more than 3 months. Both developed methods can baseline separate tryptophan enantiomers, whereas shorter retention time, better column efficiency, and enantiomeric recognition between two pairs of drug enantiomers (pantoprazole and atenolol) were obtained by the GPTS method.     

The lymphatic route. VIII. Distribution and plasma clearance of recombinant human interleukin-2 after SC administration with albumin in patients

It has been postulated that favouring the absorption of interleukin-2 via lymphatics rather than venous capillaries after subcutaneous adminstration may improve its therapeutic index. We have now evaluated in 12 cancer patients the plasma pharmacokinetic of interleukin-2 either dissolved in water or in 20% albumin solution with an internal cross-over after at least three days. Our data show that when albumin is present, the plasma concentrations of interleukin-2 versus time is increased and swelling at the injection sites is reduced. It remains to be seen whether efficacy improves during a prolonged treatment.Abbreviations AUC Area Under Plasma Curve - BRM Biological Response Modifiers - IFN Interferon - IL-2 Interleukin-2 - IV Intravenous - SC Subcutaneous - MU Megaunit     

The preparation of CdTe nanoparticles and CdTe nanoparticle-labelled microspheres for biological applications.

Different sizes of CdTe semiconductor nanoparticles were prepared in aqueous solution. These nanoparticles exhibit narrow fluorescence with full width at half-maximum (FWHM) of 35-45 nm that spans the visible spectrum, and they also have high PL quantum yield with high resistance to photodegradation. In addition, CdTe quantum dot (QD)-labelled microspheres, comprising polystyrene (PS) cores and CdTe/polyelectrolyte (PE) shells, were also prepared by the layer-by-layer technique in this paper. The optical properties of the CdTe nanoparticles and CdTe-labelled microspheres were investigated by UV-Visible absorption and luminescence spectroscopy, and fluorescence microscopy was employed for microscopic identification behaviour of the luminescent microspheres.     

一株法夫酵母虾青素高产菌株的生产性能

为了评价虾青素高产菌株-法夫酵母JMU-MVP14的生产性能及建立虾青素高产发酵技术,通过测定糖、生物量、虾青素产量、总类胡萝卜素产量等发酵参数,用摇瓶试验对比了法夫酵母JMU-MVP14和出发菌株的差异,用7 L罐试验对比了pH值调控方式及补料培养基成分对发酵的影响,用1 m3罐试验评估了法夫酵母JMU-MVP14高密度发酵虾青素的产量水平。摇瓶发酵结果表明,法夫酵母JMU-MVP14虾青素及总类胡萝卜素的细胞产率分别达到6.01 mg/g及10.38 mg/g;7 L罐分批发酵试验结果表明,自动流加调     

Serum and salivary levels of albumin as diagnostic tools for oral pre-malignancy and oral malignancy

The role of oxygen free radicals in the initiation, promotion and progression of carcinogenesis and the protective role of antioxidants has been a subject of much speculation. There are few studies that report evaluation of serum albumin and only one study in which salivary albumin was found and only one study that reports of salivary albumin in oral Leukoplakia and Oral Squamous Cell Carcinoma (OSCC). We evaluated serum and salivary albumin levels in normal individuals, patients with oral pre-malignancy and patients with oral malignancy, and we compared serum and salivary albumin levels in patients with oral pre-malignancy and oral malignancy. Our study comprised 45 subjects separated into three groups of 15: normal healthy, oral pre-malignancy and oral malignancy patients. Venous blood was drawn and unstimulated saliva was collected early in the morning. Albumin levels were estimated using the bromocresol green method. Serum albumin levels decreased in oral pre-malignancy and oral malignancy cases compared to healthy individuals. Salivary albumin levels increased in oral pre-malignancy and oral malignancy cases compared to healthy individuals. Our results suggest that albumin may play a role in early diagnosis and prognosis of oral pre-malignant and oral malignant tissues.     

Albumin-deficient mouse models for studying metabolism of human albumin and pharmacokinetics of albumin-based drugs

Serum albumin is the major determinant of blood colloidal osmotic pressure acting as a depot and distributor of compounds including drugs. In humans, serum albumin exhibits an unusually long half-life mainly due to protection from catabolism by neonatal Fc receptor (FcRn)-mediated recycling. These properties make albumin an attractive courier of therapeutically-active compounds. However, pharmaceutical research and development of albumin-based therapeutics has been hampered by the lack of appropriate preclinical animal models. To overcome this, we developed and describe the first mouse with a genetic deficiency in albumin and its incorporation into an existing humanized FcRn mouse model, B6.Cg-Fcgrt^tm1Dcr Tg(FCGRT)32Dcr/DcrJ (Tg32). Albumin-deficient strains (Alb^-/-) were created by TALEN-mediated disruption of the albumin (Alb) gene directly in fertilized oocytes derived from Tg32 mice and its non-transgenic background control, C57BL/6J (B6). The resulting Alb^-/- strains are analbuminemic but healthy. Intravenous administration of human albumin to Tg32-Alb^-/- mFcRn^-/- hFcRn^Tg/Tg) mice results in a remarkably extended human albumin serum half-life of ～24 days, comparable to that found in humans, and in contrast to half-lives of 2.6–5.8 d observed in B6, B6-Alb^-/- and Tg32 strains. This striking increase can be explained by the absence of competing endogenous mouse albumin and the presence of an active human FcRn. These novel albumin-deficient models provide unique tools for investigating the biology and pathobiology of serum albumin and are a more appropriate rodent surrogates for evaluating human serum albumin pharmacokinetics and albumin-based compounds.     

Albumin-deficient mouse models for studying metabolism of human albumin and pharmacokinetics of albumin-based drugs

Serum albumin is the major determinant of blood colloidal osmotic pressure acting as a depot and distributor of compounds including drugs. In humans, serum albumin exhibits an unusually long half-life mainly due to protection from catabolism by neonatal Fc receptor (FcRn)-mediated recycling. These properties make albumin an attractive courier of therapeutically-active compounds. However, pharmaceutical research and development of albumin-based therapeutics has been hampered by the lack of appropriate preclinical animal models. To overcome this, we developed and describe the first mouse with a genetic deficiency in albumin and its incorporation into an existing humanized FcRn mouse model, B6.Cg-Fcgrt^tm1Dcr Tg(FCGRT)32Dcr/DcrJ (Tg32). Albumin-deficient strains (Alb^-/-) were created by TALEN-mediated disruption of the albumin (Alb) gene directly in fertilized oocytes derived from Tg32 mice and its non-transgenic background control, C57BL/6J (B6). The resulting Alb^-/- strains are analbuminemic but healthy. Intravenous administration of human albumin to Tg32-Alb^-/- mFcRn^-/- hFcRn^Tg/Tg) mice results in a remarkably extended human albumin serum half-life of ∼24 days, comparable to that found in humans, and in contrast to half-lives of 2.6–5.8 d observed in B6, B6-Alb^-/- and Tg32 strains. This striking increase can be explained by the absence of competing endogenous mouse albumin and the presence of an active human FcRn. These novel albumin-deficient models provide unique tools for investigating the biology and pathobiology of serum albumin and are a more appropriate rodent surrogates for evaluating human serum albumin pharmacokinetics and albumin-based compounds.     

Effectiveness of weekly subcutaneous recombinant human erythropoietin administration for chemotherapy-induced anemia

The effects of weekly subcutaneousrecombinant human erythropoietin (r-hEPO)administration on anemia during chemotherapy includingcisplatin and 5-fluorouracil in patients with head andneck carcinomas were examined. Weekly subcutaneousr-hEPO administration in cancer patients has not beeninvestigated previously. Patients were treated withr-hEPO 100 IU/kg (2 patients), 200 IU/kg (6 patients),or 400 IU/kg (5 patients), or placebo, andeffectiveness was evaluated by monitoring hemoglobinconcentration changes after administration for 8weeks. Hemoglobin concentrations in all 3 r-hEPOdosage groups were higher than that in the controlgroup during chemotherapy. All r-hEPO doses producedimprovements in the anemia induced by chemotherapy;however, the 400 IU/kg dose was most effective. Therequirement for blood transfusions decreased inpatients receiving r-hEPO therapy, and no significantside-effects were associated with r-hEPOadministration. These results suggest thatchemotherapy-induced anemia can be prevented by weeklysubcutaneous r-hEPO administration.     

In vitro evaluation of the potential of thiomers for the nasal administration of Leu-enkephalin

Summary. It was the aim of this study to evaluate the potential of thiolated polycarbophil for the nasal administration of Leucine-enkephalin (Leu-enkephalin). The enzymatic degradation of Leu-enkephalin on freshly excised bovine nasal mucosa was analysed qualitatively via thin layer chromatography and quantitatively via high performance liquid chromatography (HPLC). The potential of thiolated polycarbophil gels to provide a sustained release for the therapeutic peptide was investigated via diffusion studies. Permeation studies were performed in Ussing-type diffusion chambers with freshly excised bovine nasal mucosa. Results demonstrated that Leu-enkephalin is mainly degraded by the cleavage of tyrosine from the N-terminus of the peptide. Within one hour more than 63.5 ± 2% of this therapeutic peptide are degraded on the nasal mucosa. In the presence of 0.25% thiolated polycarbophil, this degradation process, however, could be significantly lowered. Diffusion studies demonstrated that Leu-enkephalin being incorporated in a 0.5% thiolated polycarbophil gel is sustained released out of it. The appearent permeability coefficient (P_app) for Leu-enkephalin on the nasal mucosa was determined to be 1.9 ± 1.2 × 10⁻⁷ cm/sec. Furthermore, in the presence of 0.5% thiolated polycarbophil and 1% glutathione, which is used as permeation mediator for the thiomer, the uptake of Leu-enkephalin from the nasal mucosa was even 82-fold improved. According to these results thiolated polycarbophil might be a promising excipient for nasal administration of Leu-enkephalin.     

CdTe quantum dots (QDs) improve the affinities of baicalein and genistein for human serum albumin in vitro

Baicalein and genistein were studied for the affinities for human serum albumin (HSA) in the presence and absence of three CdTe quantum dots (QDs) with different sizes. Three typical CdTe QDs with maximum emissions of 535 nm (green-emitting, G-QDs), 598 nm (yellow-emitting, Y-QDs), and 654 nm (red-emitting, R-QDs) were tested. The fluorescence intensities of HSA decreased remarkably with increasing concentration of QDs. Baicalein resulted in an obvious blue-shift of the λ_em of HSA from 340 to 334 nm. However, the extents of blue-shifts induced by baicalein and genistein in the presence of QDs were much bigger than that in the absence of QDs. The quenching process of baicalein for HSA was easily affected by the QDs size than that of genistein. QDs increased the quenching constant from 136.97% to 162.24% for baicalein. However, QDs only increased the quenching constants from 20.56% to 32.23% for genistein. G-QDs, Y-QDs, and R-QDs increased the affinities of baicalein for HSA about 3.02%, 6.38% and 9.40%. G-QDs, Y-QDs, and R-QDs increased the affinities of genistein for HSA about 2.56%, 13.46% and 19.44%. The binding affinities of baicalein and genistein for HSA increased with increasing QDs size.     

Identification of 2-hydroxymethyl-4-[5-(4-methoxyphenyl)-3-trifluoromethyl-pyrazol-1-yl]-N-propionylbenzenesulfonamide sodium as a potential COX-2 inhibitor for oral and parenteral administration

Synthesis of prodrugs of orally active COX-2 inhibitor 3 involving sulfamoyl (SO₂NH₂) and hydroxymethyl (CH₂OH) groups, and their biological evaluation are described. Of these prodrugs, the N-propionyl sulfonamide sodium 3k was found to be much superior to the parent compound 3 and other marketed COX-2 inhibitors in carrageenan induced rat paw edema model of inflammation due to highly elevated drug levels in systemic circulation. This prodrug has a potential both for oral as well as parenteral administration due to impressive analgesic activity, antipyretic potency, and extraordinary water solubility.     

Cold ethanol fractionation and heat inactivation of hepatitis a virus during manufacture of albumin from human plasma

The purpose of the present study was to examine the efficacy and mechanism of fraction IV cold ethanol fractionation and pasteurization (60°C heat treatment for 10h), involved in the manufacture of albumin from human plasma, in the removal and/or inactivation of the hepatitis A virus (HAV). Samples from the relevant stages of the production process were spiked with HAV and the amount of virus in each fraction then quantified using a 50% tissue culture infectious dose (TCID₅₀). HAV was effectively partitioned from albumin during the fraction IV cold ethanol fractionation with a log reduction factor of 3.43. Pasteurization was also found to be a robust and effective step in inactivating HAV, where the titers were reduced from an initial titer of 7.60 log TCID₅₀ to undetectable levels within 5 h of treatment. The log reduction factor achieved during pasteurization was≽4.76. Therefore, the current results indicate that the production process for albumin has sufficient HAV reducing capacity to achieve a high margin of virus safety.