PVP solid dispersions containing Poloxamer 407 or TPGS for the improvement of ursolic acid release

Abstract Solid dispersions (SDs) of ursolic acid (UA) were developed using polyvinylpyrrolidone K30 (PVP K30) in combination with non-ionic surfactants, such as D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) or poloxamer 407 (P407) with the aim of enhancing solubility and in vitro release of the UA. SDs were investigated using a 24 full factorial design, subsequently the selected formulations were characterized for water solubility, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), particle diameter, scanning electron microscopy, drug content, physical-chemical stability and in vitro release profile. SDs showed higher UA water-solubility than physical mixtures (PMs), which was attributed by transition of the drug from crystalline to amorphous or molecular state in the SDs, as indicated by XRD and DSC analyses. SD1 (with P407) and SD2 (with TPGS) were chosen for further investigation because they had higher drug load. SD1 proved to be more stable than SD2, revealing that P407 contributed to ensure the stability of the UA. Furthermore, SD1 and SD2 increased UA release by diffusion and swelling-controlled transport, following the Weibull model. Thus, solid dispersions obtained with PVP k-30 and P407 proved to be advantageous to enhance aqueous solubility and stability of UA.

Selective photodynamic effects on cervical adenocarcinoma cells provided by F127 Pluronic®-based micelles modulating hypericin delivery

Abstract Cervical cancer is a leading cause of death among women. The endocervical adenocarcinoma (ECA) represents an aggressive and metastatic type of cancer with no effective treatment options currently available. We evaluated the antitumoral and anti-migratory effects of hypericin (HYP) encapsulated on Pluronic F127 (F127/HYP) photodynamic therapy (PDT) against a human cell line derived from invasive cervical adenocarcinoma (HeLa) compared to a human epithelial cell line (HaCaT). The phototoxicity and cytotoxicity of F127/HYP were evaluated by the following assays: colorimetric assay, MTT, cellular morphological changes by microscopy and long-term cytotoxicity by clonogenic assay. In addition, we performed fluorescence microscopy to analyze cell uptake and subcellular distribution of F127/HYP, cell death pathway and reactive oxygen species (ROS) production. The PDT mechanism was determined with sodium azide and D-mannitol and cell migration by wound-healing assay. The treatment with F127/HYP promoted a phototoxic result in the HeLa cells in a dose-dependent and selective form. Internalization of F127/HYP was observed mainly in the mitochondria, causing cell death by necrosis and ROS production especially by the type II PDT mechanism. Furthermore, F127/HYP reduced the long-term proliferation and migration capacity of HeLa cells. Overall, our results indicate a potentially application of F127/HYP micelles as a novel approach for PDT with HYP delivery to more specifically treat ECA.

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 de organogel injetável subcutâneo de Pluronic®-F127 e lecitina de soja (OPL) contendo meloxicam para uso veterinário / Development of a veterinary organogel formulation containing soy lecithin, Pluronic® F-127 and meloxicam for the treatment of acute and chronic pain in small animals

O organogel é formado por uma matriz tridimensional composta de filamentos que se auto-organizam em uma rede entrelaçada e que, por seu tipo de estrutura, pode ser utilizado com o objetivo de atuar como um implante que se forma in situ, sendo capaz de se comportar como uma forma farmacêutica de liberação prolongada. Esse trabalho tem, por tanto, o objetivo desse trabalho foi desenvolver, caracterizar, quantificar e traçar perfis de dissolução para formulações de organogel contendo meloxicam como principio ativo. O material está dividido em quatro capítulos, sendo apresentada inicialmente (I) revisão da literatura a respeito da lecitina de origem vegetal, com suas principais fontes de obtenção, como soja, girassol e colza, e também seu uso farmacêutico na obtenção de formulações como organogéis, microemulsões e lipossomas. Os demais capítulos abordam (II) desenvolvimento e otimização de uma formulação de organogel contendo lecitina de soja e Pluronic® F-127 como formadores da matriz tridimensional e meloxicam como principio ativo. (III) Desenvolvimento e validação de um método de quantificação do teor de meloxicam por cromatografia líquida de alta eficiência (CLAE). (IV) Desenvolvimento de um método de dissolução para formulações de organogel, que fosse capaz de ser utilizado na caracterização do perfil de dissolução de diferentes formulações. Com os resultados obtidos, foi possível desenvolver formulações de organogel contendo lecitina de soja, Pluronic® F-127 e meloxicam, assim como um método analítico validado para as analises de teor. Por fim, foram obtidos também os perfis de dissolução de duas formulações mais promissoras

Organogels are formed by a three-dimensional matrix composed of filaments that selforganize in an interlaced network and that, due to its type of structure, can be used with the objective of acting as an implant that forms in situ, being able to behave as an extendedrelease dosage form. This work has, therefore, the objective of this work was to develop, characterize, quantify and trace dissolution profiles for organogel formulations containing meloxicam as active ingredient. The material is divided into four chapters, initially presented (I) review of the literature on lecithin of plant origin, with its main sources of production, such as soybean, sunflower and rapeseed, and also its pharmaceutical use in obtaining formulations such as organogels , microemulsions and liposomes. The remaining chapters address (II) development and optimization of an organogel formulation containing soy lecithin and Pluronic® F-127 as three-dimensional matrix formers and meloxicam as an active ingredient. (III) Development and validation of a method for quantification of meloxicam content by high performance liquid chromatography (HPLC). (IV) Development of a dissolution method for organogel formulations, capable of being used to characterize the dissolution profile of different formulations. With the results obtained, it was possible to develop organogel formulations containing soy lecithin, Pluronic® F-127 and meloxicam, as well as a validated analytical method for content analysis. Finally, the dissolution profiles of two more promising formulations were also obtained

Experimental study on the relationship between foam pressure difference and foam stability / 生物医学工程学杂志

Foam stability affects the efficacy and incidence of side effects of foam sclerotherapy. Exploring the relationship between foam pressure difference and foam stability can provide ideas and basis for obtaining more stable foam. In the experiment, sodium cod liver oleate foam was selected, and poloxamer 188 (concentration of 0%, 4%, 8%, 12%) was added to realize the change of foam pressure. By using the self-written program to process the foam pictures, the foam pressure difference and the relationship between the foam stability indicators (water separation rate curve, half-life) and the foam pressure difference were obtained. The results showed that at first the foam pressure increased with the increase of the concentration, and then it decreased with the increase of the concentration and reached a peak at the concentration of 4%. The foam pressure difference decreases continuously with the increase of decay time. When the additive concentration is low, the foam average pressure difference increases. And if the additive concentration is too high, the foam average pressure difference decreases. The smaller the foam pressure difference is, the better the foam stability is. This paper lays a foundation for the research on the stability of foam hardener.

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

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

Thermosensitive gel of polysaccharide from Ganoderma applanatum combined with paclitaxel for mice with 4T1 breast cancer / 中国中药杂志

Polysaccharide from Ganoderma applanatum has the activities of anti-tumor and enhancing immune function. There were no reports on antitumor effect of its intratumoral injection. In this study, the polysaccharide was extracted from G. applanatum by water extraction and alcohol precipitation, and purified by ceramic membrane after removing protein by Sevage method. The total polysaccharide content from G. applanatum(PGA)was about 63%. The combination of PGA and paclitaxel showed synergistic effect on cytotoxicity of 4 T1 cells at lower concentrations in vitro. In addition, the growth curve of 4 T1 cells showed that PGA could retard the growth of 4 T1 cells gradually. The PGA thermosensitive gel(PGA-TG)was prepared by using poloxamer 188 and 407. The gel temperature was 36 ℃, and the PGA-TG could effectively slow down the release rate of PGA in vitro. 4 T1 breast cancer-bearing mice were used as a model to evaluate the therapeutic effect of intratumoral injection of PGA combined with tail vein injection of nanoparticle albumin-bound paclitaxel(nab-PTX). In high and low dose PGA groups, each mice was given with 2.25, 1.125 mg PGA respectively, twice in total, and the dosage of paclitaxel was 15 mg·kg~(-1), once every 3 days, for a total of five times. The tumor inhibition rate was 29.65% in the high dose PGA-TG group, 58.58% in the nab-PTX group, 63.37% in low dose PGA-TG combined with nab-PTX group, and 68.10% in high dose PGA-TG combined with nab-PTX group respectively. The inhibitory effect in high dose PGA-TG group combined with nab-PTX on tumors was significantly higher than that in nab-PTX group(P<0.05). The results showed that paclitaxel therapy combined with intratumoral injection of PGA-TG could improve the therapeutic effect for 4 T1 mice and reduce the side effects of chemotherapy.

The efficacy of sustained-release chitosan microspheres containing recombinant human parathyroid hormone on MRONJ

Abstract Treatment of patients with bisphosphonate usage is a significant concern for oral surgeons because it interferes with jaw bone turnover and regeneration. In case of adverse effects manifesting related to bisphosphonate use, oral surgeons are usually treating and keep the patient's symptoms under control. In this study, we aimed to investigate a new treatment protocol for medication-related osteonecrosis of the jaw (MRONJ). This treatment protocol consisted of administering human parathyroid hormone (hPTH) loaded chitosan microspheres which were prepared by ionotropic gelation method or/and the prepared microspheres were suspended in a poloxamer gel. After in-vitro optimization studies, the efficacy of the chosen formulations was evaluated in-vivo studies. Zoledronic acid was administered daily to forty-eight adult female Sprague-Dawley rats, divided into four experimental groups, at a daily concentration of 0.11 mg/kg over three weeks to induce the MRONJ model. At the end of this period, maxillary left molar teeth were extracted. In the first group, the subjects received no treatment. In the negative control group, poloxamer hydrogel containing empty microspheres were immediately applied to the soft tissues surrounding the extraction socket. The treatment group-1 was treated with local injections of poloxamer hydrogel containing hPTH. The treatment group-2 was treated with a single local injection of poloxamer hydrogel containing hPTH-loaded chitosan microspheres. Both treatment groups received a total of 7 µg of hPTH at the end of the treatment protocol. Our study demonstrates successful attenuation of MRONJ through a local drug delivery system combined with hPTH, as opposed to previously attempted treatment strategies.

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

The effect of local application of neutralizing antibody to interleukin-1B on the development of vein graft intimal hyperplasia

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> Intimal hyperplasia (IH) remains one of the major obstacles to long term vein graft patency. IL-1B has been demonstrated to be one of the first inflammatory cytokines expressed in the rat vein graft model of IH and may be an important initiator of the sequence of events leading to the development of IH. This study was designed to establish the role of IL-1B by demonstrating the outcome of inhibiting its effects by the use of neutralizing antibodies on the development of IH in this model.</p><p style="text-align: justify;"><strong>METHODS:</strong> Rat epigastric vein to femoral artery interposition grafts were treated with neutralizing antibody to IL-1B suspended in pluronic gel and harvested at the end of one week and two weeks. The amount of intimal hyperplasia was measured at the anastomotic and midgraft regions.</p><p style="text-align: justify;"><strong>RESULTS:</strong> The amount of IH was less at the anastomotic and midgraft regions of the treated grafts at the end of one week (p<0.05), but did not differ significantly with the untreated group at the end of two weeks.</p><p style="text-align: justify;"><strong>CONCLUSION:</strong> Neutralizing antibody to IL-1B delivered locally retarded but did not prevent the occurrence of IH in vein grafts. The initiation of the cascade of events in the development of IH is affected in a major way , but not singularly by IL-1B</p>

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

Subchondral drilling method combined with gum-bletilla complex to repair articular cartilage defects / 中国中药杂志

Two types(A model and B model) of articular cartilage defect models were prepared by using adult New Zealand white rabbits. A model group was applied by drilling without through subchondral bone, whose right joint was repaired by composite scaffolds made by seed cell, gum-bletilla as well as Pluronic F-127, and left side was blank control. B model group was applied by subchondral drilling method, whose right joint was repaired by using composite scaffolds made by gum-bletilla and Pluronic F-127 without seed cells, and left side was blank control. Autogenous contrast was used in both model types. In addition, another group was applied with B model type rabbits, which was repaired with artificial complex material of Pluronic F-127 in both joint sides. 4, 12 and 24 weeks after operation, the animals were sacrificed and the samples were collected from repaired area for staining with HE, typeⅡcollagen immunohistochemical method, Alcian blue, and toluidine blue, and then were observed with optical microscope. Semi-quantitative scores were graded by referring to Wakitanis histological scoring standard to investigate the histomorphology of repaired tissue. Hyaline cartilage repairing was achieved in both Group A and Group B, with satisfactory results. There were no significant differences on repairing effects for articular cartilage defects between composite scaffolds made by seed cell, gum-bletilla and Pluronic F-127, and the composite scaffolds made by gum-bletilla and Pluronic F-127 without seed cell. Better repairing effects for articular cartilage defects were observed in groups with use of gum-bletilla, indicating that gum-bletilla is a vital part in composite scaffolds material.

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.

Poloxamer 407 Hydrogels for Intravesical Instillation to Mouse Bladder: Gel-Forming Capacity and Retention Performance

PURPOSE: Poloxamer 407 (P407) thermo-sensitive hydrogel formulations were developed to enhance the retention time in the urinary bladder after intravesical instillation. MATERIALS AND METHODS: P407 hydrogels (P407Gels) containing 0.2 w/w% fluorescein isothiocyanate dextran (FD, MW 4 kDa) as a fluorescent probe were prepared by the cold method with different concentrations of the polymer (20, 25, and 30 w/w%). The gel-forming capacities were characterized in terms of gelation temperature (G-Temp), gelation time (G-Time), and gel duration (G-Dur). Homogenous dispersion of the probe throughout the hydrogel was observed by using fluorescence microscopy. The in vitro bladder simulation model was established to evaluate the retention and drug release properties. P407Gels in the solution state were administered to nude mice via urinary instillation, and the in vivo retention behavior of P407Gels was visualized by using an in vivo imaging system (IVIS). RESULTS: P407Gels showed a thermo-reversible phase transition at 4℃ (refrigerated; sol) and 37℃ (body temperature; gel). The G-Temp, G-Time, and G-Dur of FD-free P407Gels were approximately 10℃–20℃, 12–30 seconds, and 12–35 hours, respectively, and were not altered by the addition of FD. Fluorescence imaging showed that FD was spread homogenously in the gelled P407 solution. In a bladder simulation model, even after repeated periodic filling-emptying cycles, the hydrogel formulation displayed excellent retention with continuous release of the probe over 8 hours. The FD release from P407Gels and the erosion of the gel, both of which followed zero-order kinetics, had a linear relationship (r²=0.988). IVIS demonstrated that the intravesical retention time of P407Gels was over 4 hours, which was longer than that of the FD solution ( < 1 hour), even though periodic urination occurred in the mice. CONCLUSIONS: FD release from P407Gels was erosion-controlled. P407Gels represent a promising system to enhance intravesical retention with extended drug delivery.

Experimental study on the in vitro osteogenic differentiation of dental pulp stem cells encapsulated in Pluronic F-127 hydrogel / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the biocompatibility and viability of nonionic triblock copolymer Pluronic F-127 as a cell scaffold for osteogenic differentiation of dental pulp stem cells(DPSC).</p><p><b>METHODS</b>DPSC were obtained via enzymatic digestion method and purified bylimited dilution method. The freeze dried hydrogel of 20% Pluronic F-127 was prepared and itsstructurewas observed usingscanning electron microscopy(SEM). After the encapsulation of cells of passage 3 in Pluronic F-127, the effects of hydrogel on the proliferations of DPSC were assessed with methyl thiazolyl terazolium(MTT) after one day and 3, 5, 7 days of incubations, respectively. On day 14, osteogenic abilities of DPSC encapsulated in the hydrogel were estimated by means of alizarin red S, immunocytochemical staining and real-time quantitative PCR(RT-qPCR).</p><p><b>RESULTS</b>DPSC were isolated and cultured successfully in the present study. SEM observations showed that porous structures which might be suitable for cell culture. A570 values of MTT were then normalized. A570 values of the cells in 2D cultures were 0.30±0.06, 0.30±0.17, 0.35±0.04 and 0.25±0.06 and A570 values of DPSC in 3D cultures were 0.36±0.06, 0.54±0.18, 0.70±0.10 and 0.32±0.10 on day 1, 3, 5 and 7, respectively. A570 value peaks were found on day 5 in both groups. The proliferation of 3D cultured DPSC was higher than that of 2D cultured cells(P<0.05). After 14 days of osteogenic induction, there were no calcium nodules observed in the control group and the numbers of calcium nodulesin the 2D and 3D groups had no significant difference(P>0.05). Inmmunocytochemical staining demonstrated strong expression of osteoblast marker Runt-related transcription factor 2(RUNX2), type Ⅰ collagen(Col-Ⅰ) and relatively low expression of osteocalcin(OCN). Moreover, RT-qPCR showed no differences between the relative expression of ALP, RUNX-2, OCN in the 2D and 3D groups (P>0.05), but a higher relative expression of Col-Ⅰ was observed in the 3D group(P=0.023).</p><p><b>CONCLUSIONS</b>Pluronic F-127 is a promising cell scaffold or cell carrier for the osteobalst differentiation of dental pulp stem cells.</p>

Platelet-Derived Growth Factor-BB-Immobilized Asymmetrically Porous Membrane for Enhanced Rotator Cuff Tendon Healing

Rotator cuff tear is a common musculoskeletal disease that often requires surgical repair. Despite of recent advances in surgical techniques, the re-tear rate of the rotator cuff tendon is very high. In this study, a platelet-derived growth factor-BB (PDGF-BB)-immobilized asymmetrically porous membrane was fabricated to investigate the feasibility for enhancing rotator cuff tendon regeneration through the membrane. PDGF-BB is recognized to promote tendon regeneration. The asymmetrically porous membrane was fabricated by polycaprolactone and Pluronic F127 using an immersion precipitation technique, which can allow selective permeability (preventing scar tissue invasion into defect region but allowing permeation of oxygen/nutrients) and incorporation of bioactive molecules (e.g., PDGF-BB) via heparin binding. The PDGF-BB immobilized on the membrane was released in a sustained manner over 42 days. In an animal study using Sprague-Dawley rats, the PDGF-BB-immobilized membrane group showed significantly greater regeneration of rotator cuff tendon in histological and biomechanical analyses compared with the groups of control (suturing) and membrane without PDGF-BB immobilization. The enhancing regeneration of rotator cuff tendon of the PDGF-BB-immobilized membrane may be caused from the synergistic effect of the asymmetrically porous membrane with unique properties (selective permeability and hydrophilicity) as a scaffold for guided tendon regeneration and PDGF-BB sustainedly released from the membrane.

Novel patchouli alcohol ternary solid dispersion pellets prepared by poloxamers

The present study investigates the possibility of using poloxamers as solubility and dissolution rate enhancing agents of poorly water soluble bioactive constituent patchouli alcohol [PA] that can be used for the preparation of immediate release pellets formulation. Two commercially available grades poloxamer 188 [P 188] and poloxamer 407 [P 407] were selected, and solid dispersions [SDs] containing different weight ratio of PA and poloxamers, and the combination of P 188 and P 407 as dispersing carriers of ternary solid dispersions [tSDs] were prepared by a low temperature melting method and solidified rapidly by dropping into the 10-15 °C condensing agent atoleine. Both PA/P 188 and PA/P 407 binary solid dispersions [bSDs] could remarkably promote the dissolution rate of PA, increasing approximately 16 times in bSDs with poloxamers in comparison with pure PA within 180 min. P188 contributed to a faster dissolution rate than P 407, however, P 407 had a better solubility. It is interesting to note that the incorporation of P 188 in PA/P 407 bSD pellets could strongly enhance the dissolution rate of PA. DSC and FTIR were used to explore the characteristics of PA-SD pellets. The enhancement of dissolution from the SDs may be attributed partly to the reduction in particle size in PA crystalline due to the formation of eutectic system with poloxamers. Moreover, a simple, accurate in-vitro dissolution test method for volatility drug was established, and the process of PA-SD pellets preparation was simple, rapid, cost effective, uncomplicated and potentially scalable

Preparation, characterization and evaluation of the in vivo trypanocidal activity of ursolic acid-loaded solid dispersion with poloxamer 407 and sodium caprate

Ursolic acid is a promising candidate for treatment of Chagas disease; however it has low aqueous solubility and intestinal absorption, which are both limiting factors for bioavailability. Among the strategies to enhance the solubility and dissolution of lipophilic drugs, solid dispersions are growing in popularity. In this study, we employed a mixture of the surfactants poloxamer 407 with sodium caprate to produce a solid dispersion containing ursolic acid aimed at enhancing both drug dissolution and in vivo trypanocidal activity. Compared to the physical mixture, the solid dispersion presented higher bulk density and smaller particle size. Fourier Transform Infrared Spectroscopy results showed hydrogen bonding intermolecular interactions between drug and poloxamer 407. X-ray diffractometry experiments revealed the conversion of the drug from its crystalline form to a more soluble amorphous structure. Consequently, the solubility of ursolic acid in the solid dispersion was increased and the drug dissolved in a fast and complete manner. Taken together with the oral absorption-enhancing property of sodium caprate, these results explained the increase of the in vivo trypanocidal activity of ursolic acid in solid dispersion, which also proved to be safe by cytotoxicity evaluation using the LLC-MK2 cell line.

O ácido ursólico é um candidato promissor para o tratamento da doença de Chagas, contudo este fármaco possui baixa solubilidade aquosa e limitada absorção intestinal, ambos os fatores limitantes da biodisponibilidade. Entre as estratégias para potencializar a solubilidade e a dissolução de fármacos lipofílicos, as dispersões sólidas estão crescendo em popularidade. Neste estudo, empregamos mistura dos tensoativos, poloxamer 407 e caprato de sódio, para produzir dispersão sólida contendo ácido ursólico, com o objetivo de aumentar tanto a dissolução do fármaco quanto a atividade tripanocida in vivo. Comparada à mistura física, a dispersão sólida apresentou maior densidade e menor tamanho de partícula. Os resultados da análise de espectroscopia no infravermelho com transformada de Fourier mostraram interações intermoleculares do tipo ligações de hidrogênio entre o fármaco e o poloxamer 407. Os experimentos de difratometria de raio-X revelaram a conversão do fármaco de sua forma cristalina para a forma amorfa, mais solúvel. Consequentemente, a solubilidade do ácido ursólico em dispersão sólida foi aumentada e o fármaco dissolveu-se de maneira mais rápida e completa. Em conjunto com as propriedades promotoras de absorção oral do caprato de sódio, estes resultados explicaram o aumento da atividade tripanocida in vivo do ácido ursólico em dispersão sólida, que também se provou segura após avaliação de citotoxicidade empregando a linhagem celular LLC-MK2.

A novel thermosensitive in-situ gel of gabexate mesilate for treatment of traumatic pancreatitis: An experimental study / 华中科技大学学报（医学）（英德文版）

Gabexate mesilate (GM) is a trypsin inhibitor, and mainly used for treatment of various acute pancreatitis, including traumatic pancreatitis (TP), edematous pancreatitis, and acute necrotizing pancreatitis. However, due to the characteristics of pharmacokinetics, the clinical application of GM still needs frequently intravenous administration to keep the blood drug concentration, which is difficult to manage. Specially, when the blood supply of pancreas is directly damaged, intravenous administration is difficult to exert the optimum therapy effect. To address it, a novel thermosensitive in-situ gel of gabexate mesilate (GMTI) was developed, and the optimum formulation of GMTI containing 20.6% (w/w) P-407 and 5.79% (w/w) P188 with different concentrations of GM was used as a gelling solvent. The effective drug concentration on trypsin inhibition was examined after treatment with different concentrations of GMTI in vitro, and GM served as a positive control. The security of GMTI was evaluated by hematoxylin-eosin (HE) staining, and its curative effect on grade II pancreas injury was also evaluated by testing amylase (AMS), C-reactive protein (CRP) and trypsinogen activation peptide (TAP), and pathological analysis of the pancreas. The trypsin activity was slightly inhibited at 1.0 and 5.0 mg/mL in GM group and GMTI group, respectively (P<0.05 vs. P-407), and completely inhibited at 10.0 and 20.0 mg/mL (P<0.01 vs. P-407). After local injection of 10 mg/mL GMTI to rat leg muscular tissue, muscle fiber texture was normal, and there were no obvious red blood cells and infiltration of inflammatory cells. Furthermore, the expression of AMS, CRP and TAP was significantly increased in TP group as compared with control group (P<0.01), and significantly decreased in GM group as compared with TP group (P<0.01), and also slightly inhibited after 1.0 and 5.0 mg/mL GMTI treatment as compared with TP group (P<0.05), and significantly inhibited after 10.0 and 20.0 mg/mL GMTI treatment as compared with TP group (P<0.01). HE staining results demonstrated that pancreas cells were uniformly distributed in control group, and they were loosely arranged, partially dissolved, with deeply stained nuclei in TP group. Expectedly, after gradient GMTI treatment, pancreas cells were gradually restored to tight distribution, with slightly stained nuclei. This preliminary study indicated that GMTI could effectively inhibit pancreatic enzymes, and alleviate the severity of trauma-induced pancreatitis, and had a potential drug developing and clinic application value.