Challenges in estimating the encapsulation efficiency of proteins in polymersomes - Which is the best method?

Abstract Polymersomes are nanometric vesicles that can encapsulate large and hydrophilic biomolecules, such as proteins, in the aqueous core. Data in literature show large variation in encapsulation efficiency (%EE) values depending on the method used for calculation. We investigated different approaches (direct and indirect) to quantify the %EE of different proteins (catalase, bovine serum albumin-BSA, L-asparaginase and lysozyme) in Pluronic L-121 polymersomes. Direct methods allow quantification of the actual payload of the polymersomes and indirect methods are based on the quantification of the remaining non-encapsulated protein. The protein-loaded polymersomes produced presented approximately 152 nm of diameter (PDI ~ 0.4). Higher %EE values were obtained with the indirect method (up to 25%), attributed to partial entanglement of free protein in the polymersomes poly(Ethylene Glycol) corona. For the direct methods, vesicles were disrupted with chloroform or proteins precipitated with solvents. Reasonable agreement was found between the two protocols, with values up to 8%, 6%, 17.6% and 0.9% for catalase, BSA, L-asparaginase and lysozyme, respectively. We believe direct determination is the best alternative to quantify the %EE and the combination of both protocols would make results more reliable. Finally, no clear correlation was observed between protein size and encapsulation efficiency.

Mini-Review of Poloxamer as a Biocompatible Polymer for Advanced Drug Delivery

Abstract Poloxamer is a biocompatible polymer that has already been approved by the US FDA for multiple applications. Poloxamer itself has many grades and functional categories that enable the improvement of both physicochemical and biological properties of drugs. In this minireview, the functional properties of poloxamer for physicochemical modification, such as solubility and stability, and biological response modification, such as neuroprotection, cell apoptosis, efflux pump modification, membrane cell modification, and cellular uptake, are discussed to provide a broader understanding to assist the development of poloxamer-based formulations.

Poloxamer-enhanced solubility of griseofulvin and its related antifungal activity against Trichophyton spp

Abstract Poorly water-soluble drugs, such as the antifungal drug griseofulvin (GF), exhibit limited bioavailability, despite their high membrane permeability. Several technological approaches have been proposed to enhance the water solubility and bioavailability of GF, including micellar solubilization. Poloxamers are amphiphilic block copolymers that increase drug solubility by forming micelles and supra-micellar structures via molecular self-association. In this regard, the aim of this study was to evaluate the water solubility increment of GF by poloxamer 407 (P407) and its effect on the antifungal activity against three Trichophyton mentagrophytes and two T. rubrum isolates. The GF water solubility profile with P407 revealed a non-linear behavior, well-fitted by the sigmoid model of Morgan-Mercer-Flodin. The polymer promoted an 8-fold increase in GF water solubility. Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and 2D nuclear magnetic resonance (NMR Roesy) spectroscopy suggested a GF-P407 interaction, which occurs in the GF cyclohexene ring. These results were supported by an increase in the water solubility of the GF impurities with the same molecular structure. The MIC values recorded for GF ranged from 0.0028 to 0.0172 mM, except for T. Mentagrophytes TME34. Notably, the micellar solubilization of GF did not increase its antifungal activity, which could be related to the high binding constant between GF and P407.

Desenvolvimento e caracterização de dispersões sólidas de efavirenz / Development and characterization of efavirenz solid dispersions

A baixa solubilidade aquosa dos insumos farmacêuticos ativos (IFA) é um grande desafio no desenvolvimento de formulações farmacêuticas, pois pode resultar em biodisponibilidade insuficiente e variável. Diversas estratégias de modificação do estado sólido dos compostos ativos, têm sido propostas para incrementar a solubilidade de fármacos pouco solúveis em água. Dentre as estratégias abordadas a ispersão sólida (DS) é uma das formas mais promissoras de aumentar a solubilidade, dissolução e a biodisponibilidade de IFAs com baixa solubilidade aquosa. O efavirenz (EFV) é um inibidor não nucleosídeo da transcriptase reversa (NNRTI) e um dos componentes da terapia antirretroviral de alta atividade (HAART), sendo parte da primeira linha de tratamento de infecções do vírus HIV tipo 1. O antirretroviral está classificado como pertencente à classe II do SCB, e exibe baixa solubilidade aquosa (solubilidade menor que 10 µg/mL) e alta permeabilidade com absorção dependente da taxa de dissolução, resultando em biodisponibilidade oral baixa e variável. A administração de fármacos pouco solúveis na forma de DS é um método atraente para aumentar a biodisponibilidade in vivo. Neste estudo, um método de triagem rápida por evaporação de solvente foi empregado para preparar DS de EFV, variando-se proporções em misturas compostas pelos carreadores, polivinilpirrolidona K-28/32 (PVP K-28/32), copovidona (CoPVP), hidroxipropilmetilcelulose ftalato (HPMCP-50, HPMCP-55 e HPMCP-55s), poloxâmero 188 (P188) e poloxâmero 407 (P407). A solubilidade das DS foi avaliada por meio do método do equilíbrio (shake-flask), onde selecionou-se os polímeros P188 e P407 que conduziram a uma elevada capacidade de saturação em meio aquoso, superior a 1.000 vezes ao fármaco puro. As propriedades físico-químicas e do estado sólido das amostras foram avaliadas por meio de calorimetria exploratória diferencial (DSC); termogravimetria (TG); espectroscopia do infravermelho com transformada de Fourier (FTIR), difratometria de raios X pelo método do pó (DRXP) e ensaios de dissolução com emprego do aparato IV USP. Os resultados de DRXP demonstraram que os carreadores P188 e P407 foram capazes de estabilizar o EFV na forma amorfa nas DS, fato esse evidenciado pela ausência de picos característicos do antirretroviral

he low aqueous solubility of the active pharmaceutical ingredient (API) is a major challenge in the development of pharmaceutical formulations as it may result in insufficient and variable bioavailability. Several strategies for modifying the solid-state of the active compounds have been proposed to increase solubility of drugs that are poorly soluble in water. Among the strategies approaches, solid dispersion (SD) is one of the most promising ways to increase solubility, dissolution and bioavailability of APIs with low aqueous solubility. Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and one of the components of highly active antiretroviral therapy (HAART), being part of the first line of treatment of type 1 HIV virus infections. The antiretroviral is classified as belonging to BCS class II, and exhibits low aqueous solubility (solubility less than 10 µg / mL) and high permeability with dissolution ratedependent absorption, resulting in low and variable oral bioavailability. Drug delivery of poorly aqueous soluble drugs in form SD is an appealing method to increase in vivo bioavailability. In this study, a fast screening method of solvent evaporation method was used to prepare EFV SD, varying the proportions in mixtures composed by the carriers polyvinylpyrrolidone K-28/32 (PVP K-28/32), copovidone (CoPVP), hydroxypropylmethylcellulose phthalate (HPMCP-50, HPMCP-55 e HPMCP-55s), poloxamer 188 (P188) e poloxamer 407 (P407). The solubility of the samples was evaluated by the method of equilibrium (shake-flask), wherein the polymers P188 and P407 were selected due to the capacity to promote high saturation in aqueous medium, 1,000 times superior to the pure drug. The physicochemical and solid-state properties of the samples were evaluated by differential scanning calorimetry (DSC); thermogravimetry (TG); Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and dissolution assays using the IV USP apparatus. The results of XRPD demonstrated that the carriers P188 and P407 were able to stabilize the EFV in amorphous form in the SD, a fact evidenced by the absence of characteristic peaks of the antiretroviral

Study Of The Anti-Hyperlipidemic Effect Of The Combined Administration Of Three Natural Extracts In A Poloxamer-407 Hyperlipidemic Model And Their Lc-Esi-Ms/Ms2 And Hplc Profiling

Objective: Dyslipidaemia is considered a high-risk factor for inducing atherosclerosis and cardiovascular diseases (CVDs). This study aims to investigate the anti-hyperlipidemic effect of the co-administration of the ethanol extracts of both ginger (root and rhizome) and leek (leaves and bulbs) in addition to the aqueous extract of gum arabic.  Methods: Rats were divided into eight groups: Hyperlipidaemia was induced in rats by a single intraperitoneal injection of Poloxamer 407 (P-407) [1 g/kg], negative control [saline injected], hyperlipidemic control [P-407 injected], positive control [Atorvastatin 70 mg/kg], groups four, five and six received ginger extract (400 mg/kg), leek extract (500 mg/kg) and gum arabic aqueous extract (7.5 g/kg) respectively and groups seven and eight received a co-administration of ginger, leek and gum arabic extracts at doses A and B respectively. Lipid profile was monitored. The profiling of all the tested extracts was performed by LC-ESI/MS and HPLC. Results: A significant anti-hyperlipidemic activity (P<0.05) was seen for group eight among all the tested groups producing ≈54%, 72%, 50% and 72% decrease in the measured parameters total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) respectively. An overall of 56 and 45 compounds were tentatively identified in the ethanol extracts of ginger and leek, respectively. Galactose and arabinose sugars were found to be the major saccharides in gum arabic and glucuronic acid was the major polyuronide part. Conclusion: the co-administration of a group of natural extracts in the given concentration proved to be more effective than the use of synthetic drugs or the use of a single component.

Screening of Ketoprofen-Poloxamer and Ketoprofen-Eudragit solid dispersions for improved physicochemical characteristics and dissolution profile

The aim of the present study was to enhance the dissolution rate of an NSAID drug Ketoprofen by formulating it into solid dispersions with water soluble carrier Poloxamer 188 and Eudragit S 100. The solid dispersions of Ketoprofen with Poloxamer 188 were prepared at 1:1, 1:1.5 and 1:2 (Ketoprofen: Poloxamer 188) ratio by Solvent evaporation methods. The same concentration ratio was used for the preparation of solid dispersion with Eudragit S 100 by melting/fusion technique. Further, solid dispersions were investigated by solubility, ATR-FTIR, XRD, DSC, surface morphology, in-vitro dissolution and accelerated stability study. Results demonstrated that both Poloxamer 188 and Eudragit S 100 improve solubility of drugs by 8­10 folds. The result of ATR-FTIR study showed the slight shifting/broadening of principle peaks. In vitro dissolution studies showed that in the solid dispersion system containing Ketoprofen: Poloxamer 188 batch P2 (1:1.5) gives faster dissolution rate of Ketoprofen than the physical mixtures. The solid dispersion with Eudragit S 100, batch E1 (1:1) gives faster dissolution rate of Ketoprofen than the physical mixtures. In phase solubility study with Poloxamer 188 showed concentration dependent solubilization of drug but Eudragit S 100 produced opposite result. The effect of pH on solubility of Eudragit S 100 was carried out which showed solubility at pH 7.4. The dissolution profile of solid dispersion with Eudragit S 100 at pH 7.4 gives excellent result. The Accelerated stability of solid dispersions & its physical mixtures were studied at 400±2 °C/75 ± 5% RH for a period of 1 month. In these studies, Solid Dispersion batches produced an unstable formulation. The Ketoprofen solid dispersions with Poloxamer 188 and Eudragit S 100 could be introduced as a suitable form with improved solubility

Formulation Optimization of Citalopram Hydrobromide Thermosensitive Nasal Gel and Its In Vitro Properties / 中国药学杂志

OBJECTIVE: To optimize the formulation of citalopram hydrobromide (CTH ) thermosensitive nasal gel and further evaluate its in vitro properties. METHODS: With gelling temperature and gelling time as evaluating indexes, central composite design-response surface and single factor experimental design method were used to optimize the formulation of CTH thermosensitive nasal gel by using poloxamer 407(F127) and carbomer 940 (CP940) as gel materials. Meanwhile, nasal mucosa permeation enhancer for CTH was then sieved by using Franz diffusion cell and ex vivo sheep nasal mucosa as experimental model. Finally, CTH thermosensitive nasal gel was prepared with cold method and then its in vitro properties was evaluated. In vitro cumulative erosion and cumulative release rate of the drug thermosensitive nasal gel were investigated by membrane-free dissolution method and dialysis membrane method, respectively. Moreover, the effect of temperature and pH on the viscosity of the drug nasal gel formulation was also evaluated. RESULTS: The optimal formulation of the thermosensitive nasal gel consisted of CTH 8.0%, F127 20.27%, CP940 0.17%, DM-β-CD 3.0%, ethylparaben 0.05% and distilled water. The gelling temperature, gelling time and pH of the drug thermosensitive nasal gel were found to be about 32.5 ℃,42 s and 5.0, respectively. The in vitro cumulative erosion and cumulative release percentage were both greater than 90% in 55 min and furthermore there was good linear correlation between these two parameters (r=0.998 6). Additionally, in vitro cumulative release of the drug from the gel formulation was determined to be 92% within 8 h, which conformed to Higuchi kinetic equation. Furthermore, the viscosity of the drug nasal gel was influenced by temperature as well as pH in different extent. CONCLUSION: The optimized formulation of the CTH thermosensitive nasal gel with central composite design-response surface method and single factor design method shows suitable gelling temperature, gelling time, pH value for nasal preparation and obvious in vitro drug sustained release characteristics.

Determination of ethylene glycol, diethylene glycol and triethylene glycol in poloxamer 188 by gas chromatography / 中国药科大学学报

@#The gas chromatography method was developed for the determination of ethylene glycol, diethylene glycol and triethylene glycol in poloxamer 188 to provide scientific basis for the quality control. The samples was separated on column VF-17ms(30 m×0. 53 mm, 1. 0 μm)with temperature programming, inlet temperature was 270 °C, detector temperature was 290 °C and the split ratio was 10 ∶1. The method showed great linearity over the range of 6-15 μg/mL(r≥0. 999). The injection precision(n=8)of the three residual impurities were 3. 3%, 3. 0%, 2. 3% and the average recoveries were 99. 05%(RSD=2. 9%, n=9), 102. 20%(RSD=4. 0%, n=9), 101. 91%(RSD=3. 1%, n=9), respectively. The analytical method is specific, accurate and sensitive, which is suitable for the determination of ethylene glycol, diethylene glycol and triethylene glycol in poloxamer 188, providing reference and guidance for the production and quality control of poloxamer 188.

Optimized the preparation process of thermo-sensitive Yinhuang ophthalimic gel by central composite design-response surface method / 国际中医中药杂志

Objective To optimize the preparation technology of thermo-reversible Yinhuang opthalimic gel by the central composite design-response surface method.Methods The poloxamer 407 and poloxamer 188 were used as the investigation factors, and the evaluation index was the gel temperature. Central composite design-response surface method was used to evaluate the mathematic relation between the evaluation index and tow investigation indexes to identify the optimum prescription.Results According to the quadratic models, it was found that there was reliable quantitative relation between the evaluation index and two investigation indexes,among which the optimun dosage was 20％ for P407, 1％ for P188, 0.1％ for hyaluronic acid, 0.01％ for benzalkonium chloride, 0.02％ for EDTA.Conclusions This method is reliable and feasible, whicn can realize the prescription optimization of the gel.

Incorporation of the antitumor drug miltefosine into polymeric micelles / Desenvolvimento de nanoestruturas poliméricas para encapsulação do antitumoral miltefosina

Miltefosine (hexadecylphosphocholine, HePC), a synthetic antitumor designed from natural phospholipids, is clinically approved for cutaneous metastases of breast cancer and cutaneous lymphoma. This drug acts mainly at cellular membrane level, where it accumulates and interferes with lipid metabolism and lipid-dependent signaling pathways leading the cells to apoptosis. However, HePC systemic and peroral administration induces hemolysis and mucosal toxicity, respectively. To overcome these limitations, we investigated the protective properties of colloidal polymeric micelles (PM) composed by Pluronics, triblock copolymers of poly(ethylene oxide) and poly(propylene oxide). We found that both Pluronic composition and concentration modulate the hemolytic profile of incorporated drug (HePC-PM) by increasing the drug amount to cause in vitro hemolysis. Moreover, small-angle X-ray scattering (SAXS) was used to assess structural information of interactions between HePC and PM. Additionally, we showed that HePC-PM prevented mucosal irritation, decreasing bleeding and lysis of blood vessels in a chicken chorioallantoic membrane model. Interestingly, HePC-PM increased the in vitro selective cytotoxicity against cervix tumor cells rather healthy fibroblasts, suggesting a differential uptake of these nanostructures by tumor cells. Furthermore, we also found that HePC induces cytotoxicity and decrease cell survival, migration and proliferation in osteosarcoma cells in vitro. We showed that cytotoxicity by HePC is associated with caspase-3 activation, DNA fragmentation, apoptotic-like bodys formation and inhibition of both constitutive and cytokine-stimulated Akt/PKB phosphorylation. HePC-PM clearly reduces the drug cytotoxic effects. Finally, we demonstrated that Pluronic F127 polymeric micelles are efficient for cargo delivering the encapsulated drug preferentially into tumor cells rather than healthy cells. These findings together suggest that Pluronic F127 PM reduce drug side effects and provide a potential alternative for systemic delivery of HePC, as well as other amphiphilic drugs

Miltefosina (hexadecilfosfocolina, HePC), um fármaco antitumoral sintético desenvolvido a partir de fosfolipídios naturais, é clinicamente aprovada para o tratamento tópico de metástases de câncer de mama e linfomas cutâneos. Atua principalmente nas membranas celulares, onde se acumula e interfere no metabolismo lipídico e nas vias de sinalização dependentes de lipídios levando as células à apoptose. No entanto, quando administrada sistemicamente ou oralmente a HePC induz hemólise e toxicidade de mucosas, respectivamente. Para superar estas reações adversas investigamos os efeitos protetores conferidos por micelas poliméricas coloidais (PM) compostas por Pluronics, copolímeros tribloco de poli(óxido de etileno) e poli(óxido de propileno). Inicialmente, encontramos que a composição e concentração do Pluronic modulam o perfil hemolítico do fármaco encapsulado (HePC-PM), aumentando a quantidade necessária de HePC para causar hemólise in vitro. Além disso, utilizamos o espalhamento de raios-X a baixo ângulo (SAXS) para obter informações estruturais das interações entre HePC e PM. Em seguida, mostramos que HePC-PM preveniu a irritação da mucosa, diminuindo a hemorragia e a vasoconstricção em membrana corioalantóica de ovos embrionados. Estudos in vitro demonstraram que a HePC-PM aumentou seletivamente a citotoxicidade contra células de carcinoma HeLa em relação a fibroblastos saudáveis, sugerindo captação diferencial dessas nanoestruturas pelas células tumorais. Além disso, relatamos que, in vitro, a HePC induz citotoxicidade, diminui a sobrevivência, migração e proliferação osteossarcomas. Esta citotoxicidade está associada à ativação da caspase-3, fragmentação do DNA, formação de corpos apoptóticos e inibição da fosforilação de Akt/PKB. Adicionalmente, HePC-PM reduz os efeitos citotóxicos nestas linhagens. Finalmente, demonstramos que as micelas poliméricas de Pluronic F127 são eficientes para a entrega intracelular fármacos preferencialmente em células tumorais, e em menor grau em células saudáveis. Em conjunto, os dados sugerem que este sistema nanoestruturado reduz a toxicidade da HePC e representa uma alternativa potencial para a administração sistêmica deste e de outros fármacos anfifílicos

Novel Thermosensitive Heparin-poloxamer Hydrogel Bridge NGF to Treat Peripheral Nerve Injury in Diabetics Rats / 中国药学杂志

OBJECTIVE: To investigate the effects of NGF-HP thermosensitive hydrogel on facilitating structural and functional regeneration in diabetic rats with sciatic nerve crush injury. METHODS: Eight-week-old male SD rats (200-220 g) were intraperitoneally injected wither steptozocin(STZ) to induce diabetes. After success of model establishment, the sciatic nerve of the diabetes rats were made crushed through two vascular clips force. Muscle and skin were then closed with 5-0 stitches. Following surgery, the rats were randomly divided into three groups: PNI-diabetics group, free NGF group and NGF-HP hygrogel group. Each group received corresponding therapeutic drugs through a microsyringe. The motor recovery in all tested rats was assessed using Basso-Beattie-Bresnahan (BBB) locomotion scale and inclined plane test at indicated time points. After 30 d, rats were sacrificed, the crushed nerve and corresponding gastrocnemius muscle were harvested and the pathology index was assessed.The expressions of structural and functional proteins were detected through immunoblotting.The improvement of axon and myelination regeneration were evaluated via immunofluorescence, Masson′s trichrom stain and transmission electron microscope. RESULTS: NGF-HP not only had a good affinity for a certain amounts of nerve growth factor (NGF), but also controlled its release in a steady fashion in vitro. In vivo, compared with administration of direct free NGF, single injection of NGF-HP hydrogel was more effective at upregulating the expression of nerve associated structural and functional proteins, enhancing axonal regeneration and remyelination, as well as improving motor function recovery. CONCLUSION: This new type of hydrogel loaded with NGF shows striking effects on functional and morphometric recovery on peripheral nerve injury (PNI) following diabetes,which may provide a theoretical basis strategies for remedying PNI-diabetes in clinical populations.

The preparation of VEGF/bFGF-loaded poloxamer thermosensitive gels and the promotive effect of the gels on the skin wound healing in rats / 国际药学研究杂志

Objective: To prepare the vascular endothelial growth factor(VEGF)and basic fibroblast growth factor(bFGF)-loaded poloxamer thermosensitive gels and investigate the in vitro drug release property as well as the therapeutic effect of the drug-loaded thermosensitive gels on the full-thickness skin defected wound healing in rats. Meth- ods: The release of VEGF and bFGF from the drug-loaded gels in vitro was determined by the membrane release meth- od. The full-thickness skin defected model of rats was established and divided into four groups: the normal saline(Con- trol)group, poloxamer thermosensitive gel(Gel)group, freeze-dried VEGF and bFGF powder(VEGF/bFGF powder) group, and the VEGF/bFGF-loaded poloxamer thermosensitive gel(VEGF/bFGF-loaded gel)group. The wound healing was observed on the 3rd, 7th and 14th day of injury. The wound tissue was stained with hematoxylin-eosin. The wound healing and inflammation were observed under the microscope. The expression of CD31 was measured by the immunohis- tochemical staining and the number of new blood vessels was counted. The content of inflammatory factors in the wound was detected by ELISA. Results: The VEGF/bFGF-loaded poloxamer thermosensitive gels were successfully prepared. The in vitro drug release test showed that only about 5% of VEGF and bFGF in the drug-loaded gels was released from the gels within 1 h of the test, however, the subsequent VEGF and bFGF release could reach 60% on the fifth day of the re- lease test, suggesting the well sustained drug-release behavior of the VEGF/bFGF-loaded gels. In the wound healing test using the full-thickness skin defected rat model, the wound healing rate reached(90.3±2.4)% on the 14th day of injury, in the VEGF/bFGF-loaded gel group, which was significantly higher than that in the other groups(P<0.05). On the 3rd day of injury, compared with the Control and Gel groups, the level of IL-6 and TNF-α in the wound was significantly de- creased in the VEGF/bFGF-loaded gel group(P<0.05). The tissue HE staining showed that the skin wound healed well in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups, and a lager number of neovascularization and the epi- dermis appeared earlier in both the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and the Gel groups. The immunohistochemical results further confirmed that the number of neovascularization was significant- ly higher in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and Gel groups(P< 0.05). Conclusion: The prepared VEGF/bFGF-loaded poloxamer thermosensitive gels in the present study could be used to repair the full-thickness skin defected wound in rats, which could reduce the early inflammatory reaction, pro- mote the angiogenesis, and thus accelerate the healing.

In Vitro Evaluation of Poloxamer 188 Modified Polyethyleneimine as Gene Vectors / 医药导报

Objective To modify polyethyleneimine (PEI) by using Poloxamer 188 (P188) , and evaluate its related feature as carriers of genes in vitro. Methods PEI was modified through conjugating one hydroxyl group of P188 to the amino group of PEI by carbonate method. Structural analysis of synthesized polymer was performed by using 1H-NMR. The particle size and Zeta potential of synthesized polymer /DNA complexes were measured. The cytotoxicity of the complexes was evaluated using MTT method in MCF-7 cells, HeLa cells and HepG2 cells. The pGL3-lus was used as a reporter gene, and the transfection efficiency of complexesat HeLa cells was evalutated by measuring activity of luciferase. Results The result of 1H-NMR showed the purity of these synthesized polymers was high. The particle size of complexes were decreased with the increment of N /P ratios. The Zeta potential of complexes increased with the increment of N /P ratios. The cytotoxicity of the complexes increased with the increment of N /P ratios. The synthesized polymers showed lower cytotoxicity than unmodified PEI. The new synthesized polymers had maintained the high transfection efficiency at high N /P ratios. In particular, the optimal transfection efficiency of (P188) 1- PEI (N /P = 24) was significantly higher than that of PEI (N /P = 6) . Conclusion The P188 modifed PEI can serve as a effective non-viral gene carriers to transfect Hela cells.

Preparation of annonaceous acetogenins nanosuspensions using poloxamer 188 as a stabilizer and their in vitro and in vivo investigation / 药学学报

Annonaceous acetogenins (ACGs) are effective part extracted and separated from Annona squamosa seeds, they have good antitumor activity against a variety of tumor cells. However, the solubility of ACGs is poor with serious toxic and side effects, which greatly limits their application in clinical practice. In this study poloxamer 188 (P188) was selected as a drug carrier or a stabilizer to prepare ACGs nanosuspensions (ACGs-NSps) using anti-solvent precipitation. The nanosuspensions were examined via dynamic light scattering (DLS) method to examine size of the nanosuspensions. Transmission electron microscopy was used to observe their morphology. HPLC assay was used to measure their drug loading content and the in vitro drug release. The stability of ACGs-NSps at room temperature, in various physiological media and plasma, and the hemolytic test and lyophilization were all investigated. MTT assay was performed to study the cytotoxocity of ACGs-NSps against four tumor cell lines. 4T1 bearing tumor model was used to assess their in vivo antitumor therapeutic efficacy. The obtained ACGs-NSps were spherical, the average particle size was 169.4±1.25 nm, the polydispersity index (PDI) value was 0.130±0.020, the zeta potential was -19.8 mV and the drug loading content was 48.18%. ACGs-NSps were stable at room temperature for at least 15 days. They could be lyophilized in the presence of 0.5% glucose and 2.0% P188. ACGs-NSps showed sustained in vitro drug release, and the cumulative drug release reached 80.82% within 144 hours. ACGs-NSps maintained their particle size in various physiological media, and plasma with no hemolysis and then met demands of both oral and intravenous administration. In contrast to free ACGs, ACGs-NSps displayed significantly higher cytotoxicity against 4T1 (IC50, 0.892±0.124 μg·mL-1 vs 2.495±0.108 μg·mL-1, P 50, 0.747±0.051 μg·mL-1 vs 2.204±0.064 μg·mL-1, P 50, 2.265±0.081 μg·mL-1 vs 4.159±0.071 μg·mL-1, P 50, 0.473±0.024 μg·mL-1 vs 1.196±0.022 μg·mL-1, P in vivo study demonstrated that the daily oral administration of ACGs-NSps (3 mg·kg-1) resulted in higher tumor inhibition rate compared to ACGs/oil solution (67.23% vs 53.11%), comparable to the intravenous injection of 0.5 mg·kg-1 ACGs-NSps every other day (70.34%). Nanosuspensions effectively solved the problem of ACGs insolubility and difficulty in drug delivery. Using P188, a pharmaceutic adjuvant approved by FDA for iv injection, the resultant ACGs-NSps appear promising as an anti-tumor drug that can be used in clinic.

Construction and in vitro and in vivo Preliminary Evaluation of Biotin-poloxamer Conjugate Polymeric Mi-celles for Epirubicin / 中国药师

Objective:To prepare biotin-poloxamer(BP) conjugate micelles for epirubicin through biotin conjugated on poloxam-er. Methods:Epirubicin(EPI) was encapsulated in BP micelles. The EPI-loaded BP micelles were characterized by its particle size, zeta potential,surface morphology,as well as the efficiency of drug loading and drug encapsulation and drug release. Marrow leukemia HL-60 cells were used to evaluate the cell cytotoxicity of EPI-loaded BP micelles in vitro. The tumor model in nude mice was estab-lished through the subcutaneous injection of HL-60 cells, and then the inhibitory effect of EPI-loaded BP micelles on tumor volume growth was investigated.Results:It was found that the average particle size of EPI-loaded BP micelles was about 100 nm. In addition, the enhanced cellular uptake ability of EPI-loaded BP micelles was proved by fluorescence microscope observation. The efficiency order of the tumor volume growth inhibition was:EPI-loaded BP micelles > EPI-loaded MATP micelles> EPI-loaded poloxamer micelles>EPI. BP micelles showed significant antitumor activity and low toxicity when compared with the non-targeted micelles. Conclusion:With the advantages of EPR effect and tumor-targeting potential,BP conjugate micelles might be developed as a new system for chemo-therapeutics. However,the tumor targeting technique should be demonstrated further by the other cell experiments and large animal ex-periments.

The role of poloxamer 188 for cord blood mononuclear cells into megakaryocytes cultivation and induction in three-dimensional WAVE Bioreactor / 中华血液学杂志

Objective@#To observe the effect of poloxamer 188 (P188) on megakaryocyte cultivation and induction from cord blood mononuclear cells in order to obtain more megakaryocyte progenitor cells (MPC).@*Methods@#The cord blood mononuclear cells were isolated and inoculated in cell culture bag or cell culture flask respectively. The WIGGENS shaker and cell culture bags were used to mimick WAVE Bioreactor for three-dimensional (3D) cell culture, and the P188 was added to induction medium, The cells were detected for morphology, surface marker, viability, and number on day 14.@*Results@#In the two-dimensional (2D) culture, CD41+, CD41+/CD61+, CD61+ megakaryocytic numbers increased significantly after adding P188 (all P<0.01). And in the 3D culture of adding P188, the cell volume became larger and the nuclear shape was irregular, the cytoplasm appeared magenta granules, and the megakaryocyte cells became more mature. By 3D culture, the expression of CD41/CD61 was (36.30±1.27)% vs (23.95±1.34)%, hence the differentiation for MPC was significantly higher than that in the 2D group (P<0.01). Furthermore, adding P188 in 3D culture resulted in highest differentiation efficiency for MPC [(59.45±1.20)%]. There were no significantly differences in terms of cell viability and cell number among 3D culture containing P188, 2D and 3D culture groups (all P>0.05).@*Conclusion@#3D culture was beneficial for the differentiation of MPC, but the cell viability was lower than 2D group; However, the satisfied cell growth and better induction efficiency were obtained by adding of P188, which might provide a new method of megakaryocytes production for clinical application.

Preparation and characterization of cefuroxime axetil solid dispersions using poloxamer 188

The main objective of the present work was to enhance the solubility and dissolution rate of poorly water-soluble drug cefuroxime axetil (CA) by formulating it into solid dispersions (SDs) with water soluble carrier poloxamer 188. Different methods were employed to prepare the dispersion, such as: Solvent method (SM), Kneading method (KM), Melt evaporation method (MEM) and Physical mixture (PM) in different drug: carrier ratios 1:1, 1:2 and 1:3 (cefuroxime axetil: poloxamer 188). The physical mixture(s) and solid dispersion(s) were characterized for drug carrier interaction, drug content, solubility, dissolution rate, differential scanning calorimetry (DSC) and FT-IR study. The dissolution rate of the prepared solid dispersion systems was determined in phosphate buffer (pH 6.8) for 1 h. The solubility of drug from different systems was also determined in water. All SD formulations were found to have a higher dissolution rate comparatively to pure CA. The dissolution rate was enhanced in the following order SM > MEM > KM. The enhancement of dissolution rate may be caused by increase wettability, dispersibillity reduction in particle size or the formation of CA ß crystalline. The FT-IR study probability revealed that there was no chemical interaction between drug and poloxamer 188

Preparation and in vitro Release of Norfloxacin Thermosensitive in Situ Gel for Vaginal Use / 中国药师

Objective:To prepare norfloxacin thermosensitive in situ gel and investigate its in vitro drug release behavior. Meth-ods:Poloxamer 407 and poloxamer 188 were used as the matrix of norfloxacin thermosensitive in situ gel,and the gel was prepared by a cold dissolving method. The formula was optimized by a central composite design-response surface method. In vitro drug release be-havior of norfloxacin thermosensitive in situ gel was studied as well. Results:Within a certain concentration range, the gelation tem-perature decreased gradually with the amount increase of poloxamer 407, and that increased gradually with the amount increase of poloxamer 188. The optimal formula was as follows:the concentration of poloxamer 407 was 20.6%(w/v),and that of poloxamer 188 was 5.7%(w/v),which obtained suitable gelling temperature. The release of norfloxacin from the thermosensitive in situ gel reached up to (87.5% ± 5.4% 7 in 6 h. Conclusion: Norfloxacin thermosensitive in situ gel has excellent temperature sensitivity, and can slow down the drug release,which shows potential use for vaginal drug delivery system.

Preparation and in Vitro Properties of Paeonol Thermo Sensitive Gel / 世界科学技术-中医药现代化

This study aimed at preparing paeonol thermosensitive gel and preliminary exploring its properties in vitro.Tube inversion method was adopted to investigate the effects of concentrations of poloxamer 407 and poloxamer 188 on gelation temperature.Then,viscosity of the gel was detected by rotary viscometer,and in vitro erosion and drug release characteristics of the gel by no film stripping method.As a result,the gelation temperature of poloxamer 407 decreased with the increase of its concentration,while gelation temperature of poloxamer 407 increased with the accelerating concentration of poloxamer 188.The cumulative drug release of paeonol thermo sensitive gel was up to 70％ in 320 rin.Gel dissolution and drug release were simultaneously performed without burst release phenomenon.It was concluded that the preparation process of paeonol thermo sensitive gel was simple and easy to use with the overt effect of sustained-release.

Metronidazole thermogel improves retention and decreases permeation through the skin

ABSTRACT Metronidazole (MTZ) is widely used as the standard antibiotic for the treatment of rosacea and, more recently, is being used off label in Brazilian hospitals for the treatment of wounds. Following oral administration, minimal amounts of active agent reaches the skin and side effects are strongly induced. Consequently, MTZ is currently being applied topically in order to improve the therapeutic efficacy with reduced side effects, with Rozex(r) (RZ) (an MTZ gelled formulation) being the only marketed product. This study examined whether the use of MTZ 0.75% from thermogel formulations could improve drug retention and reduce dermal exposure compared to that by Rozex(r). Following a 21 h permeation study, the highest total amount of MTZ permeated through the rat healthy and disturbed skin was seen with Rozex(r), but similar to all formulations regardless of the skin condition. On the other hand, the amount retained in the epidermis/dermis was larger for thermogel formulations; at least 4 fold that of Rozex(r), when the stratum corneum was present as a barrier. In conclusion, thermogel formulations can be favorable alternatives to Rozex(r) for the topical application of MTZ with improved efficacy and reduced side effects.