A pH-independent instantaneous release of flurbiprofen: a study of the preparation of complexes,their characterization and in vitro/in vivo evaluation

In this study, furbiprofen/hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complexes were prepared to improve the drug dissolution and facilitate its application in hydrophilic gels. Inclusion complexes were prepared using a supercritical fluid processing and a conventional optimized co-lypholization method was employed as a reference. The entrapment efficacy and drug loading of both methods were investigated. Evaluation of drug dissolution enhancement was conducted in deionized water as well as buffer solutions of different pH. Carbopol 940 gels of both flurbiprofen and flurbiprofen/HPβCD inclusion complexes, with or without penetration enhancers, were prepared and percutaneous permeation studies were performed using rat abdominal skin samples. Formation of flurbiprofen/HPβCD inclusion complexes was confirmed by Fourier transform-infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. The results obtained showed that SCF processing produced a higher EE (81.91?±?1.54%) and DL (6.96?±?0.17%) compared with OCL with values of 69.11?±?2.23% and 4.00?±?1.01%, respectively. A marked instantaneous release of flurbiprofen/HPβCD inclusion complexes prepared by SCF processing (103.04?±?2.66% cumulative release within 5?min, a 10-fold increase in comparison with flurbiprofen alone) was observed. In addition, this improvement in dissolution was shown to be pH-independent (the percentage cumulative release at pH 1.2, 4.5, 6.8 and 7.4 at 5?min was 95.19?±?1.71, 101.75?±?1.44, 105.37?±?4.58 and 96.84?±?0.56, respectively). Percutaneous permeability of flurbiprofen-in-HPβCD-in-gels could be significantly accelerated by turpentine oil and was related to the water content in the system. An in vivo pharmacokinetic study showed a 2-fold increase in C_max and a shortened T_max as well as a comparable relative bioavailability when compared with the commercial flurbiprofen Cataplasms (Zepolas^®). With their superior dissolution, these flurbiprofen/HPβCD inclusion complexes prepared by SCF processing could provide improved applications for flurbiprofen.     

Interaction of Antimalarial Agent Artemisinin with Cyclodextrins

To obtain an effective solution of the poorly water soluble antimalarial agent artemisinin, the use of several kinds of cyclodextrins (CDs) as solubilizers was examined. The following CDs were used in this study: α-CD, β-CD, γ-CD as parent CDs, 2-hydroxypropyl-β-CD (HP-β-CD), sulfobutyl ether β-CD (SBE7-β-CD), heptakis (2,6-di-O-methyl)-β-CD (DM-β-CD), 2,3,6-partially methylated-β-CD (PM-β-CD) as modified CDs, and glucosyl-β-CD (G1-β-CD), and maltosyl-β-CD (G2-β-CD) as branched CDs. The solubility curves of artemisinin with CDs can all be classified as type A_L. The apparent stability constants for artemisinin-parent CD complexes increased in the order of α- < γ- ≤ β-CD. The constants for artemisinin-β-CD derivative (and β-CD) complexes increased in the order of G2-β-CD ? G1-β-CD cong; PM-β-CD ? β-CD < HP-β-CD < SBE7-β-CD < DM-β-CD. These results suggest that the addition of CDs enables the solubilization of artemisinin.     

Preparation and characterization of self nano-emulsifying drug delivery system (SNEDDS) for oral delivery of heparin using hydrophobic complexation by cationic polymer of β-cyclodextrin

Objective: The aim of this study was the preparation of a self nano-emulsifying drug delivery system (SNEDDS) for oral delivery of heparin.

Significance: Preparation of hydrophobic complexes between heparin as the hydrophilic macromolecule and cationic polymer of β-cyclodextrin (CPβCD) was considered for preparation of orally administered SNEDDS in which the drug incorporated in internal oil phase of O/W nano-droplets.

Methods: Hydrophobic complexes of heparin-CPβCD were prepared by electrostatic interaction. The lipophilic feature of complexes was characterized by determining their partition co-efficients. SNEDDS prototypes were prepared by mixing liquid paraffin, Tween 80, propylene glycol and ethanol, diluted 1:100 in an aqueous medium. Central composite response surface methodology was applied for statistical optimization. Independent variables were the amount of liquid paraffin and the amount of Tween 80, while responses were size and poly dispersity index (PdI). Optimized SNEDDS were studied morphologically using transmission electron microscopy (TEM). In vitro release of heparin was studied in the simulated gastric and simulated intestinal media.

Results: The data revealed that in molar ratio 1:3 (heparin:CPβCD), the n-octanol recovery was maximized and reached 67.6?±?11.86%. Size, PdI, zeta potential, EE% in gastric medium and EE% in intestinal medium for optimized nano-droplets were reported as 307?±?30.51?nm, 0.236?±?0.02,?+2.1?±?0.66?mV, 90.2?±?0.04 and 96.1?±?0.73%, respectively. Microscopic images revealed spherical nano-droplets. The obtained data revealed no burst release of heparin from nano-droplets.

Conclusions: The obtained results indicate that SNEDDS could be regarded as a good candidate for oral delivery of heparin as the hydrophilic macromolecule.     

Characterization,inclusion mode,phase-solubility and in vitro release studies of inclusion binary complexes with cyclodextrins and meglumine using sulfamerazine as model drug

In order to investigate the effect on the aqueous solubility and release rate of sulfamerazine (SMR) as model drug, inclusion complexes with β-cyclodextrin (βCD), methyl-β-cyclodextrin (MβCD) and hydroxypropyl-β-cyclodextrin (HPβCD) and a binary system with meglumine (MEG) were developed. The formation of 1:1 inclusion complexes of SMR with the CDs and a SMR:MEG binary system in solution and in solid state was revealed by phase solubility studies (PSS), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), thermal analysis and X-Ray diffractometry (XRD) studies. The CDs solubilization of SMR could be improved by ionization of the drug molecule through pH adjustments. The higher apparent stability constants of SMR:CDs complexes were obtained in pH 2.00, demonstrating that CDs present more affinity for the unionized drug. The best approach for SMR solubility enhancement results from the combination of MEG and pH adjustment, with a 34-fold increment and a S_max of 54.8?mg/ml. The permeability of the drug was reduced due to the presence of βCD, MβCD, HPβCD and MEG when used as solubilizers. The study then suggests interesting applications of CD or MEG complexes for modulating the release rate of SMR through semipermeable membranes.     

Incorporation of organic acids turns classically brittle zein films into flexible antimicrobial packaging materials

This study aimed to turn classically brittle zein films into flexible antimicrobial ones by the use of lactic (LA), malic (MA) and tartaric acids (TA). The most effective plasticizer was LA (400% elongation at break [EB] at 4%), while MA (189% EB at 4.5%) and TA (68% EB at 5%) showed moderate and limited plasticizing effects, respectively. The LA- and MA-loaded films maintained their flexibility during 30-day storage at 4°C or 25°C. Fourier transform infrared (FTIR) analysis suggested that the plasticization of LA and MA could be related to secondary structural changes in zein such as increased α-helix and random coils (mainly by MA) and spaced/modified intermolecular (only by LA) and intramolecular (mainly by MA) β-sheets. Atomic force and scanning electron microscopy showed that LA and MA gave more homogenous and smoother films than TA. Films with LA showed the highest water vapour permeability followed by those of control, MA- and TA-loaded films. Films with 3%–4% LA or MA formed clear zones on Listeria innocua and Klebsiella pneumonia, but only films with LA formed clear zones on Escherichia coli. All OA-loaded films gave unclear zones on Staphylococcus aureus in disc-diffusion tests, but this bacterium was inactivated rapidly in antimicrobial tests based on surface inoculation tests. LA is the best OA to develop flexible antimicrobial films from zein, an industrial by-product that films could not have been utilized as a widespread packaging material due to their brittleness.     

The Influence of Lactose Pseudopolymorphic Form on Salbutamol Sulfate–Lactose Interactions in DPI Formulations

A series of 63- to 90-μm sieve-fractioned lactose pseudopolymorphs were investigated in terms of carrier functionality for dry powder inhaler (DPI) formulations. Stable α-anhydrous, α-monohydrate, and β-anhydrous were chosen as model pseudopolymorphs. In addition, the β-anhydrous was further purified to remove residual α-monohydrate content (β-treated). The carriers were investigated in terms of morphology, particle size, crystallinity, and surface energy using inverse gas chromatography. Furthermore, the lactose samples carrier performance was evaluated by studying the aerosolization efficiency of the model drug, micronized salbutamol sulfate, from drug–carrier blends using a next generation impactor (NGI). In general, the aerosol performance of drug from carrier followed the rank order α-monohydrate?>?β-anhydrous?>?β-treated?>?α-anhydrous. Significant difference in carrier size was observed, specifically with relation to the amount of fines (where a rank order of β-treated?>?β-anhydrous?>?α-monohydrate?>?α-anhydrous. No direct relationship between fine content and particle morphology was observed. In comparison, an inverse relationship between surface energy and aerosolization efficiency was found, where a plot of fine particle fraction (aerodynamic diameter < 4.46?μm) against total surface energy resulted in R²?=?.977. Such observations are most likely due to increased particle carrier adhesion and reduced drug liberation during the aerosolization process, indicating surface chemistry (in this case due to the existence of different pseudopolymorphs) to play a dominating role in DPI systems.     

In vitro and in vivo evaluation of cyclodextrin-based nanosponges for enhancing oral bioavailability of atorvastatin calcium

The aim of this study was to explore the feasibility of complexing the poorly water-soluble drug atorvastatin calcium (AC) with β-cyclodextrin (β-CD) based nanosponges (NS), which offer advantages of improving dissolution rate and eventually oral bioavailability. Blank NS were fabricated at first by reacting β-CD with the cross-linker carbonyldiimidazole at different molar ratios (1:2, 1:4, and 1:8), then NS of highest solubilization extent for AC were complexed with AC. AC loaded NS (AC-NS) were characterized for various physicochemical properties. Pharmacokinetic, pharmacodynamics and histological finding of AC-NS were performed in rats. The prepared AC-NS showed particles size ranged from 408.7?±?12.9 to 423?±?15.9?nm while zeta potential values varied from ?21.7?±?0.90 to ?22.7?±?0.85?mV. The loading capacity varied from 17.9?±?1.21 to 34.1?±?1.16%. DSC, FT–IR, and PXRD studies confirmed the complexation of AC with NS and amorphous state of the drug in the complex. AC-NS displayed a biphasic release pattern with increase in the dissolution rate of AC as compared to plain AC. Oral administration of AC-NS (1:4 w/w, drug: NS) to rats led to 2.13-folds increase in the bioavailability as compared to AC suspension. Pharmacodynamics studies in rats with fatty liver revealed significant reduction (p?in vivo performance of AC.     

Encapsulation of bacteria and viruses in electrospun nanofibres

Bacteria and viruses were encapsulated in electrospun polymer nanofibres. The bacteria and viruses were suspended in a solution of poly(vinyl alcohol) (PVA) in water and subjected to an electrostatic field of the order of 1?kV?cm(-1). Encapsulated bacteria in this work, (Escherichia coli, Staphylococcus albus) and bacterial viruses (T7, T4, λ) managed to survive the electrospinning process while maintaining their viability at fairly high levels. Subsequently the bacteria and viruses remain viable during three months at -20 and -55?°C without a further decrease in number. The present results demonstrate the potential of the electrospinning process for the encapsulation and immobilization of living biological material.     

Gefitinib–cyclodextrin inclusion complexes: physico-chemical characterization and dissolution studies

Background: Gefitinib, an anticancer drug, has an extremely low aqueous solubility, and its oral absorption is limited by its dissolution rate. The solubility and dissolution of gefitinib can be improved by complexation with cyclodextrins (CDs). Methods: Phase solubility studies of gefitinib with hydroxypropyl βCD (HPβCD) and randomly methylated βCD (RMβCD) in n various aqueous systems was conducted to characterize the complexes in the liquid state. The inclusion complexes in the solid state were prepared by freeze-drying method and characterized by X-ray diffractometry (X-RD) and differential scanning calorimetry (DSC). Results: Gefitinib formed stable complexes with HPβCD and RMβCD in distilled water as indicated by the association rate constants (Ks) of 458.9 and 1096.2 M^?1 for HPβCD and RMβCD, respectively. The complexation of gefitinib with CDs in pH 4.5 acetate buffer indicated an A_N type of phase-solubility diagrams, whereas gefitinib and HPβCD in distilled water in the presence of polymers such as polyvinyl pyrrolidone K-30 (PVP) or hydroxypropyl methylcellulose E3 (HPMC) resulted in A_P-type phase-solubility diagrams. The solid-state amorphous complexes (as described by DSC and X-RD) showed substantial increases in the solubility and dissolution rate of gefitinib with both CDs. Further increases in the solubility and dissolution rate of the gefitinib-HPβCD freeze-dried complex were obtained by physically mixing the complex with PVP and HPMC. Conclusion: Gefitinib formed stable inclusion complexes with HPβCD and RMβCD, and the solubility and dissolution rate of the drug was significantly increased.     

Size control for fullerene C60 nanocrystals during the high temperature and high pressure fluid crystallization process

The preparation and size control for mono-dispersed fullerene C₆₀ fine particles was successfully achieved during the high temperature and high pressure fluid (HTPL) crystallization process, in which acetone was used as the HTPL solvent and pure water or the mixture of acetone and water as the cooling solvent. The prepared fullerene C₆₀ particles had spherical shape and narrow size distribution with the average size ranging from 44 nm to 110 nm depending on the various experimental conditions, such as fluid temperature, solvent flow rate, system pressure and the ratio of acetone and water in cooling solvent. The products were characterized by using X-ray powder diffraction (XRD), scan electron microscopy (SEM), dynamic light scattering technique (DLS) and UV–VIS spectrum, respectively. And the size effect of such fullerene C₆₀ nanocrystals was confirmed.     

Host–guest inclusion system of mangiferin with β-cyclodextrin and its derivatives

The characterization, inclusion complexation behavior and binding ability of the inclusion complexes of mangiferin (MGF) with β-cyclodextrin and its derivatives (hydroxypropyl-β-cyclodextrin (HPβCD), sulfobutyl ether β-cyclodextrin (SBEβCD) and mono (6-ethylene-diamino-6-deoxy)-β-cyclodextrin (ENβCD)) were investigated in both solution and solid state by means of PL spectroscopy, ¹H and 2D NMR, XRD, TG and DSC. The results showed that the water solubility and thermal stability of MGF were significantly increased in the inclusion complex with cyclodextrins. The MGF/CDs complexes will be potentially useful for the design of a novel formulation of mangiferin for herbal medicine.     

负载桑葚花青素的葛根淀粉/壳聚糖复合膜的制备与表征

目的 研究桑葚花青素（Mulberry Anthocyanins, MA）添加量对葛根淀粉/壳聚糖复合膜理化性质及功能活性的影响。方法 以葛根淀粉和壳聚糖为成膜基材，MA为指示剂，采用流延法制备一种新型可食pH指示膜，测定葛根淀粉/壳聚糖复合膜的物理性能、抗氧化性、pH指示等性质，并将指示膜用于猪肉保鲜及新鲜度检测研究。结果 通过对添加不同MA含量的复合膜进行性能测试，发现MA和葛根淀粉之间氢键的形成，极大地改善了复合膜的拉伸强度。MA的加入使得成膜厚度、不透明度、拉伸强度（Tensile Strength,TS）、水蒸气透过率（Water Vapor Permeability,WVP）显著提高，断裂伸长率（Elongation At Break,EAB）显著降低。此外，MA增强了复合膜的抗氧化性和pH敏感性，MA-4的DPPH自由基清除率达到最大值85.24%。将复合膜应用于猪肉新鲜度检测，与对照组相比，负载MA的复合膜可抑制猪肉pH值和TVB-N值，并产生肉眼可辨的颜色变化，其中MA-3的颜色变化最为敏感。结论 加入一定量MA的复合膜能够改善其拉伸强度、不透明度、pH敏感性和抗氧化...     

Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs

Conventional suspension pressurized metered dose inhalers (pMDIs) suffer not only from delivering small amounts of a drug to the lungs, but also the inhaled dose scatters all over the lung regions. This results in much less of the desired dose being delivered to regions of the lungs. This study aimed to improve the aerosol performance of suspension pMDIs by producing primary particles with narrow size distributions. Inkjet spray drying was used to produce respirable particles of salbutamol sulfate. The Next Generation Impactor (NGI) was used to determine the aerosol particle size distribution and fine particle fraction (FPF). Furthermore, oropharyngeal models were used with the NGI to compare the aerosol performances of a pMDI with monodisperse primary particles and a conventional pMDI. Monodisperse primary particles in pMDIs showed significantly narrower aerosol particle size distributions than pMDIs containing polydisperse primary particles. Monodisperse pMDIs showed aerosol deposition on a single stage of the NGI as high as 41.75?±?5.76%, while this was 29.37?±?6.79% for a polydisperse pMDI. Narrow size distribution was crucial to achieve a high FPF (49.31?±?8.16%) for primary particles greater than 2?µm. Only small polydisperse primary particles with sizes such as 0.65?±?0.28?µm achieved a high FPF with (68.94?±?6.22%) or without (53.95?±?4.59%) a spacer. Oropharyngeal models also indicated a narrower aerosol particle size distribution for a pMDI containing monodisperse primary particles compared to a conventional pMDI. It is concluded that, pMDIs formulated with monodisperse primary particles show higher FPFs that may target desired regions of the lungs more effectively than polydisperse pMDIs.     

硬脂酸改性β-磷酸三钙及其复合材料机械性能研究

为了提高β-磷酸三钙(β-TCP)复合材料的机械性能,采用硬脂酸(C17H25COOH)对β-TCP表面进行改性处理,研究了β-TCP与C17H25COOH的界面作用机理.利用透射电镜、傅里叶红外光谱、热重分析等技术分别对改性前后β-TCP的颗粒形貌、组分和表面—OH基团进行了表征,研究了改性β-TCP/聚左旋乳酸(PLLA)复合材料的机械性能,并利用扫描电镜观察了复合材料断面形貌.研究表明:硬脂酸包覆在β-TCP表面,改性后β-TCP粉末具有一定的疏水性,硬脂酸的H+可以与β-TCP中的PO43-的一个O发生质子化反应形成—OH.改性β-TCP/PLLA复合材料的机械性能相比改性前有明显提高,改性后的β-TCP微粒在PLLA中分散均匀,两者结合紧密.     

Photocatalytic activity of β-MnO2 nanotubes grown on PET fibre under visible light irradiation

Development of visible light response semiconductor photocatalysts in degradation of organic compounds (pollutants) is one of the current research focuses due to the severe environmental pollution from various industrial and agricultural pollutants in water bodies. In this work, β-MnO₂ particles were successfully prepared by sol-gel method with potassium permanganate and manganese (II) sulphate as precursors. The transmission electron microscope/selected area electron diffraction analysis indicates that the particles were polycrystals with tubular structure. The photodegradation of Rhodamine B (RhB) solution using β-MnO₂ nanotubes under visible irradiation followed 1^st order kinetic with rate constant of 0.022 ± 0.003 min^?1 and photodegradation efficiency of 90.3% after 120 min under visible light irradiation. The N-deethylation was the dominant process in photodegradation of RhB dye by β-MnO₂ nanotubes as compared to cycloreversion process. By applying similar synthesis condition, the β-MnO₂ nanotubes were successfully synthesised on PET fibre. The photodegradation efficiency of RhB dye under circulation condition by β-MnO₂ nanotubes grown on PET fibre under visible light irradiation was 1.23 h^?1. The result suggests that β-MnO₂ nanotubes grown on PET fibre could be used as visible light-driven photocatalysts for wastewater purifier application.     

Pharmacodynamic and pharmacokinetic investigation of cyclodextrin-mediated asenapine maleate in situ nasal gel for improved bioavailability

Asenapine maleate (AM) is used in the treatment of schizophrenia. Its oral and sublingual bioavailability is <2% and 35%, respectively, due to first pass metabolism and poor solubility. To avoid first pass metabolism and to enhance solubility at all nasal pH conditions, thermo-responsive in situ nasal gel containing asenapine maleate-hydroxyl propyl β cyclodextrin inclusion complex (AM-HPβCD) was prepared in the present study. Inclusion complex (1:1 molar ratio) was characterized using UV spectroscopy, FITR and XRD techniques. Selected formulation (F8b) contained a thermo-sensitive polymer poloxamer 407 which formed gel at 23%w/v concentration and a mucoadhesive polymer PVP K 30 (0.3%w/v) in temperature range of 29–34?°c. It was analyzed for pH, clarity, gelation temperature, mucoadhesive strength, gel strength and rheological parameters using Anton paar compact rheometer. This formulation was subjected to in vitro drug diffusion study using the Franz diffusion cell. Maximum % drug diffusion was obtained at the end of 120?min (99.1?±?0.44%w/v). Dissolution in simulated nasal fluid was 92.33?±?0.15%w/v at the end of 120?min. Locomotor activity was improved with nasal gel containing AM-HPβCD as compared to AM and AM-HPβCD oral solution in rats. C_max for nasal gel was found to be more (9?ng/ml) as compared to AM-HPβCD (5.5?ng/mL) and oral standard solution (2?ng/ml). T_max was found to be 1.5?h. AUC and thus bioavailability in rats by nasal route was increased by 2.5 fold.     

A long-lasting oral preformulation of the angiotensin II AT1 receptor antagonist losartan

Losartan (Los), a non-peptidic orally active agent, reduces arterial pressure through specific and selective blockade of angiotensin II receptor AT1. However, this widely used AT1 antagonist presents low bioavailability and needs once or twice a day dosage. In order to improve its bioavailability, we used the host: guest strategy based on β-cyclodextrin (βCD). The results suggest that Los included in βCD showed a typical pulsatile release pattern after oral administration to rats, with increasing the levels of plasma of Los. In addition, the inclusion compound presented oral efficacy for 72?h, in contrast to Los alone, which shows antagonist effect for only 6?h. In transgenic (mREN2)L27 rats, the Los/βCD complex reduced blood pressure for about 6?d, whereas Los alone reduced blood pressure for only 2?d. More importantly, using this host: guest strategy, sustained release of Los for over a week via the oral route can be achieved without the need for encapsulation in a polymeric carrier. The proposed preformulation increased the efficacy reducing the dose or spacing between each dose intake.     

Novel glycerol crosslinked poly(methyl methacrylate) synthesized by chemo-enzymatic method for controlled release application

Novel glycerol crosslinked poly(methyl methacrylate)(PMMA) was synthesized in one step in the presence of cocktail of chemical initiator and the biocatalyst Novozym 435 under mild reaction conditions. The objective of the study was to investigate the feasibility of glycerol to crosslink PMMA by biocatalytic route and to explore glycerol crosslinked PMMA as controlled release vehicle Effect of reaction time, temperature, glycerol to methylmethacrylate ratio, and methacrylate to toluene ratio was studied. Glycerol crosslinked PMMA swelled 289(± 9)% in acetone and collapsed when immersed in water and in hexane. Swelling and shrinking of glycerol crosslinked PMMA was reversible in nature. Nanoparticles of glycerol crosslinked poly(methyl methacrylate) were synthesized by nanoprecipitation technique. The particles were spherical and of nanosize. The nanoparticles were used for the encapsulation and release of mosquito repellent N,N-diethyl-m-toluamide. Nanoparticles could encapsulate 8.5 mg of repellant in 4 h. The repellant got released from the nanoparticles at a controlled rate for a prolonged time interval. Release was more pronounced in deionized water and pH 7 buffer than in acetone. Addition of 1% NaCl further improved the release profile. 80% of encapsulated repellant was released from the nanoparticles in pH 7 buffer with 1% NaCl.     

Solubility and dissolution rate improvement of the inclusion complex of apigenin with 2-hydroxypropyl-β-cyclodextrin prepared using the liquid antisolvent precipitation and solvent removal combination methods

Apigenin (AP) has many pharmacological activities. AP has poor solubility in some solvents. AP is insoluble in water and slightly soluble in ethanol (1.93?mg/ml). It has limited application and exploitation. Therefore, the liquid antisolvent precipitation (LAP) method was applied to improve the solubility of AP in ethanol by changing its crystal form or producing ultra-fine particles. Then, the inclusion complex of AP with 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) is prepared using the solvent removal method. The effects of various experimental parameters on the solubility of AP in ethanol were investigated through the single factor design. Under the optimum conditions, the AP–ethanol solution of 6.19?mg/ml was obtained. The inclusion complex of AP with HP-β-CD was obtained by the solvent removal method. The load efficiency (LE) and drug encapsulation efficiency (EE) of the inclusion complex of AP with HP-β-CD were 13.98%±0.14% and 97.86%±1.07%, respectively. SEM, FTIR, ¹HNMR, XRD, DSC and TG were used to analyze the characteristics of the inclusion complex of AP with HP-β-CD. These results showed that the inclusion complex has significantly different characteristics with AP. In addition, the dissolution rate and solubility of the inclusion complex were approximately 15.24 and 68.7 times higher than AP in artificial gastric juice, and was separately 10.4 times and 40.05 times higher than AP in artificial intestinal juice. The bioavailability of inclusion complex increased 3.97 times compared with AP.     

Multicolor polystyrene nanospheres tagged with up-conversion fluorescent nanocrystals

Compared to conventional down-conversion fluorescent materials, NIR-to-visible up-conversion fluorescent materials which emit visible light upon near-infrared (NIR) excitation are better suited for biodetection/bioimaging due to their advantages such as minimum photo-damage to living organisms, weak background fluorescence, low signal-to-noise ratio and high detection sensitivity. Uniform hexagonal NaYF(4) (β-NaYF(4)) nanocrystals with up-conversion fluorescence were synthesized. Monodisperse polystyrene nanospheres with an average size of 400?nm in diameter, tagged with different color β-NaYF(4) nanocrystals, were prepared using a miniemulsion polymerization method. More than 20 β-NaYF(4) nanocrystals were encapsulated in a single polystyrene nanosphere. The nanospheres emit multicolor NIR-to-visible up-conversion fluorescence upon excitation at a wavelength of 980?nm. The nanospheres could be used for a variety of biological applications which require high-sensitivity detection of biomolecules.