Study on L-carnitine modified quercetin-coloading chitosan-stearic acid nanomicelles as oral paclitaxel delivery system: Preparation, characterization and in vivo intestine absorption in rats / 中草药

Objective: To prepare a drug delivery system based on L-carnitine modified and quercetin (QUE)-coloading chitosan-stearic acid (LC-SA/CS-SA) nanomicelles, investigate the properties of micelles, and evaluate the enhanced absorption effect of the micelles by in vivo intestinal absorption in rats. Methods: The CS-SA copolymer was synthesized by the amidation of free amino groups on CS. The chemical structure of CS-SA was characterized by Fourier transform-infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). Taking PTX was the main drug and quercetin as the auxiliary drug, the particle size distribution, Zeta potential, drug loading and entrapment efficiency of the micelles were investigated. The micromorphology of the micelles was observed by transmission electron microscope (TEM). The critical micelle concentration (CMC) of LC-SA/CS-SA micelles was measured by fluorescent probe method. The in vitro release of paclitaxel from polymeric micelles was evaluated by dialysis method. The absorption rate coefficient (Ka) of paclitaxel (PTX)-loaded micelles was assessed by in vivo intestine absorption in rats. Results: The results of FT-IR and 1HNMR indicated that the copolymer (CS-SA) was synthesized. The LC-SA/CS-SA@ QUE+PTX micelles showed regular spherical shapes with particle size of (148.3 ± 1.7) nm, PDI of 0.16 ± 0.07, Zeta potential of (24.600 ± 0.167) mV and CMC of 14.31 µg/mL. Compared to the commercial formulation of PTX, LC-SA/CS-SA@QUE+PTX micelles and LC-SA/CS-SA@PTX micelles showed significantly sustained release behaviors. The enhanced absorption effect of PTX in the micelle system was confirmed by intestine absorption test in rats. Conclusion: The LC-SA/CS-SA@QUE+PTX micelles, as a potential oral absorption promoter, enhanced the intestinal absorption of PTX in rats.

Preparation of Aspirin Sustained Release Pellets Using Stearic Acid and Microcrystalline Cellulose / 中国药学杂志

OBJECTIVE: To evaluate microcrystalline cellulose(MCC) and stearic acid(SA) on extrusion-spheronisation(E-S) for aspirin sustained release pellets. METHODS: Mixtures with varying drug concentration and SA/MCC ratios were processed via non-aqueous E-S. Multi-index evaluation method were assessed by rheological behavious, drug stability and release in vitro compared with aqueous E-S. RESULTS: The extrusion was easier when SA/MCC was > 35%. When the ratio of SA/MCC was about 1, the roll effect was the best. The drug content was 65%. Compared with aqueous E-S, non-aqueous E-S was small and homogeneous pellets, better apparent characteristics, stability. There were no obvious different in drug release in vitro. CONCLUSION: These prove to be superior aids for water sensitive aspirin when exposed to non-aqueous solvent by E-S.

Research on the accumulation process of main fatty acids in Eucommia seeds / 中国药学杂志

OBJECTIVE: To study the accumulation process of main fatty acids in Eucommia ulmoides seeds. METHODS: Gas chromatography was used to determine the change of the fatty acid composition in Huazhong No.6 Eucommia ulmoides seeds in the process of development. RESULTS: The fatty acids in Eucommia ulmoides seeds were mainly composed of palmitic acid, stearic acid, oleic acid, linoleic acid, and α-linolenic acid, among which α-linolenic acid had the highest content followed by oleic acid, and stearic acid had the lowest one. CONCLUSION: During seed development, the contents of palmitic acid and oleic acid are higher in the early period of grain development, but gradually drop with the maturation of the grains. The content of stearic acid also declines with the gradual maturation of the grain. On the contrary, the contents of α-linolenic acid and linoleic acid keep rising as the grains mature.

Development of Hydrophobic Carriers based tablets for Sustained Release of Verapamil.

The main aim of the study is to formulate sustained release matrix tablets of verapamil hydrochloride using hydrophobic carriers or meltable binders like stearic acid, carnauba wax and bees wax by melt granulation technique. The influence of a hydrophilic polymer like polyethylene glycol (PEG) was studied on the waxy matrices. Two grades of PEG (4000 and 6000) were used in the preparations. The granules were prepared and compressed into tablets and they are evaluated for their physicochemical properties and in vitro dissolution studies were done. The IR spectral analysis revealed that there are no interactions between drug and the polymers and are compatible with other. The release data were subjected to various release kinetic models and also compared with those of a commercial brand. The tablets prepared fulfilled all the official requirements according to the pharmacopeia. From the dissolution studies it was observed that carnauba wax acts a good retardant (more than 16 h). Among the two grades of PEG used 4000 and 6000, PEG 6000 increases the drug release to a greater extent than PEG 4000. It was concluded that hydrophobic carriers which act as very good retardants of the drug and also PEG can be used as a channeling agent in waxy matrices to regulate the release of the drug.

Stability of anticoagulant peptide Hirulog-S / 军事医学

Objective To study the stability of anticoagulant peptide Hirulog-S and its lyophilized product, and to provide data on the storage conditions and clinical applications.Methods RP-HPLC was used to determine the content and the related substances of Hirulog-S and its lyophilized powder with influence factor test, accelerated test and long-term storage test.Results Light, temperature and humidity had no significant effect on the stability of Hirulog-S and its lyophilized powder in the influence factor test.The content and related substances of Hirulog-S and its lyophilized powder did not significantly change in the accelerated test ( 40℃, RH75%) and 24-month long-term storage test at room temperature and 4℃.Conclusion Hirulog-S and its lyophilized product are very stable, even after being stored at room temperature for two years.

Use of solid dispersions to increase stability of dithranol in topical formulations

The present study was planned to improve the stability of dithranol using solid dispersions (SD). Two different SD at a 1:9 ratio of dithranol/excipient were prepared: one of them using glyceryl behenate as excipient and the other using a mixture of argan oil with stearic acid (1:8 ratio) as excipient. Pure dithranol and SD of dithranol were incorporated in an oil-in-water cream and in a hydrophobic ointment in a drug/dermatological base ratio of 1:10. The physical and mechanical properties of semisolid formulations incorporating the pure drug and the developed SD were evaluated through rheological and textural analysis. To evaluate the stability, L*a*b* color space parameters of SD and semisolid formulations, and pH of hydrophilic formulations were determined at defined times, during one month. Each sample was stored at different conditions namely, light exposure (room temperature), high temperature exposition (37 °C) (protected from light) and protected from light (room temperature). Despite higher values of firmness and adhesiveness, hydrophobic ointment exhibited the best rheological features compared to the oil-in-water cream, namely a shear-thinning behavior and high thixotropy. These formulations have also presented more stability, with minor changes in L*a*b* color space parameters. The results of this study indicate that is possible to conclude that the developed SD contributed to the increased stability of dithranol.

Este trabalho teve como objetivo aumentar a estabalidade do ditranol através da preparação de dispersões sólidas (DS). Prepararam-se duas DS diferentes em proporção de 1:9 de ditranol/excipiente: em uma das DS utilizou-se beenato de glicerila como excipiente e na outra se utilizou mistura de óleo de argan com ácido esteárico (razão 1:8). Posteriormente, efetuou-se a incorporação de ditranol puro e das DS contendo este fármaco num creme hidrófilo ou óleo-água (O/A) e em pomada hidrófoba, na proporção 1:10 (fármaco ou respetivas DS/base dermatológica). As propriedades físicas e mecânicas das formulações semissólidas incorporando fármaco ou as respetivas DS previamente desenvolvidas, foram avaliadas através da análise do comportamento reológico e das propriedades de textura. Para avaliar a estabilidade, os parâmetros do espaço de cor L*a*b* das DS e das formulações semissólidas e o pH das preparações hidrófilas foram determinados em períodos de tempo definidos, durante um mês para cada amostra armazenada sob diferentes condições, especificamente, exposição à luz (à temperatura ambiente), protegidas da luz à temperatura elevada (37 °C) e protegidas da luz (temperatura ambiente). Embora tenham apresentado valores de firmeza e de adesividade mais elevados, as pomadas hidrófobas apresentaram melhores características reológicas do que os cremes óleo-água. Além disso, as pomadas hidrófobas também apresentaram melhor estabilidade, com pequenas alterações nos parâmetros do espaço de cor L*a*b*. Os resultados deste trabalho permitiram concluir que as DS desenvolvidas contribuíram para o aumento da estabilidade do ditranol.

Effect of nano-CaCO3 modified with by stearic acid on spray drying powder of angelica / 中草药

Objective: To prepare hydrophobic nano-CaCO3 modified by stearic acid and to study its application in spray drying power of angelica. Methods: The stearic acid was used on the surface characteristic of nano-CaCO3, and the modified and unmodified nano-CaCO3 was analyzed and investigated by means of oil absorption value, activation index (H), angle of repose, transmission electron microscopy (TEM), and Fourier transforms infrared (FTIR). The effect of modified nano-CaCO3 on moisture absorption, fluidity, and in vitro dissolution of ferulic acid in spray drying power of angelica were investigated, comparing with silicon dioxide and unmodified nano-CaCO3. Results: FTIR analysis showed that stearic acid has attached to CaCO3 surface. Powder flow and powder moisture absorption were improved in modified nano-CaCO3 and the effect was better than silica dioxide and unmodified nano-CaCO3. The in vitro dissolution of ferulic acid was not affected. Conclusion: The application of the nano-CaCO3 modified by stearic acid in the spray drying power of Chinese materia medica deserves to be studied further.

Sustained release solid dispersion of tripterine carried by modified nano-CaCO3 / 中国药学杂志

OBJECTIVE: To prepare hydrophobic nano-CaCO3 by nano-CaCO3 and stearic acid. And to prepare tripterine solid dispersion using the new material as a carrier by solvent method. METHODS: The structure of modified nano-CaCO3 was characterized by TEM, DSC, XRD and FTIR. Meanwhile the solid dispersions were characterized by SEM, DSC, XRD and FTIR, and the in vitro dissolution test of tripterine was performed. RESULTS: When the ratio of drug to modified nano-CaCO3 was 1:4, tripterine could be dispersed amorphously in the carrier. And the accumulative drug-release percentage in vitro at 0.5 h was 7.05%. With the time increasing, the accumulative drug-release percentage also increased to 90.03% at 12 h. Moreover, tripterine solid dispersion had a better sustained release effect. CONCLUSION The nano-CaCO3 modified by stearic acid can be used as controlled-release carrier for tripterine.

Avaliação comparativa do efeito dos ácidos graxos oléico, palmítico e esteárico sobre biomarcadores do processo aterosclerótico / Comparative evaluation of fatty acids, oleic, palmitic and stearic, effects on atherosclerosis biomarkers

A aterosclerose é classificada como enfermidade crônica não transmissível e é considerada uma das principais causas de morte e morbidade em vários países, incluindo o Brasil. Entre as possíveis causas de sua gênese está o hábito alimentar, especificamente o consumo de ácidos graxos, principalmente saturados e trans. Ácidos graxos saturados possuem características biológicas e fisico-químicas diferentes dos insaturados. Os mais abundantes na dieta humana são o palmítico e esteárico. Sua associação com acometimentos cardiovasculares vem sendo cada vez mais investigada, principalmente os que possuem mais de dez carbonos em sua cadeia interferindo no metabolismo de lipoproteínas podendo desencadear todo o processo aterosclerótico. A indústria de alimentos vem desenvolvendo algumas tecnologias opcionais para reduzir ou eliminar ácidos graxos trans, em especial, o elaídico, dentre elas a modificação no processo de hidrogenação que aumenta a quantidade de ácidos graxos saturados. Alguns alimentos industrializados necessitam de uma grande quantidade de ácidos graxos saturados promovendo um aumento no teor de ácido palmítico e esteárico, sendo este último considerado um ácido graxo saturado neutro, mas dependendo da concentração utilizada, pode contribuir no decréscimo da HDL-c (High Density Lipoprotein), dentre outras alterações deletérias. Desta forma, investigar as alterações de determinados parâmetros biológicos diante da mudança da proporção de ácidos graxos saturados, respeitando o teor total de lipídios de uma dieta é a base deste estudo. Foram realizados ensaios em material biológico para a determinação dos seguintes parâmetros: 1) Atividade de enzimas antioxidantes; 2) Peroxidação lipídica em tecidos; 3) Lipidograma; 4) Determinação do perfil de ácidos graxos de tecidos e rações e 5) Expressão de genes relacionados com o processo aterosclerótico (ICAM-1, VCAM-1, CD36 e MCP-1). A determinação da atividade de enzimas antioxidantes foi realizada considerando somente as enzimas Catalase (CAT) e Superóxido Dismutase (SOD), por se tratarem de enzimas com alteração expressiva no processo aterogênico, na ocorrência de disfunção endotelial. Neste trabalho, foi analisada a atividade das referidas enzimas no tecido hepático e cardíaco, onde não foram constatadas alterações. O mesmo processo biológico que estimula a produção excessiva de espécies reativas pode levar ao aumento da peroxidação lipídica, principalmente de ácidos graxos polinsaturados das membranas celulares, em tecidos como fígado, cérebro e coração. A peroxidação lipídica apresentou diferenças significativas no tecido hepático. O grupo alimentado com ração enriquecida com tripalmitato apresentou peroxidação lipídica aumentada em relação ao grupo controle. Correlacionando com o perfil de ácidos graxos do tecido hepático, notamos que houve maior incorporação de ácido palmítico nesse tecido, que por apresentar configuração linear, quando incorporado à membrana celular, pode levar à disfunção e possível suscetibilidade a danos, como a peroxidação. No tecido cardíaco e no tecido cerebral não foram observadas alterações e diferenças entre os tratamentos. O lipidograma consiste na quantificação de lipoproteínas e frações lipídicas, compondo o perfil lipídico no plasma sanguíneo. Os resultados obtidos mostraram que o colesterol total foi significativamente menor no grupo controle, assim como triacilglicerol e LDL colesterol (LDL-c). Já HDL colesterol (HDL-c) está reduzida no grupo que recebeu ração suplementada com ácido palmítico, assim como este grupo apresentou parâmetros aumentados nas dosagens de triacilglicerol e colesterol total. Os grupos alimentados com ração suplementada com triestearato e trioleato apresentaram resultados intermediários para a dosagem de HDL-c, com valores tendendo ao grupo suplementado com tripalmitato. Em relação à dosagem de LDL-c, foi constatada diferença entre os grupos suplementados e o grupo controle. Destaca-se que não houve diferença entre a dosagem entre os grupos suplementados. Portanto, o grupo alimentado com dieta enriquecida com ácido oleico (monoinsaturado) equipara-se aos grupos alimentados com dietas enriquecidas com ácido esteárico e palmítico (saturados). O perfil de ácidos graxos do tecido hepático mostrou uma porcentagem elevada de ácido palmítico no grupo alimentado com ração enriquecida com o mesmo ácido graxo, com diferença estatística em relação aos demais grupos. Já em relação ao ácido esteárico, não houve diferenças significativas entre os grupos. Em compensação, o teor de ácido oleico no grupo suplementado com este mesmo ácido graxo e com ácido palmítico foi significativamente diferente em relação aos demais, com valores superiores. Este resultado demonstra que não houve dessaturação do ácido esteárico a oleico, ao menos neste modelo. No tecido cardíaco, foi observado o mesmo comportamento. No tecido cardíaco não houve diferença estatística significativa da concentração de ácidos graxos, indicando que não houve incorporação ou dessaturação. Ressalta-se que de acordo com determinação realizada utilizando a técnica de cromatografia gasosa, as rações apresentavam em sua composição o teor de lipídios adequado ao modelo animal e as proporções de ácidos graxos alteradas como proposto no objetivo deste trabalho. Em relação às moléculas de adesão e quimiocinas (VCAM-1, ICAM-1, CD-36 e MCP-1) relacionadas com o processo aterosclerótico, houve somente alteração na molécula CD-36 no grupo alimentado com ração enriquecida com trioleato, com redução em relação aos demais. Mas, as moléculas de adesão relacionadas com o processo inicial da aterogênese, a expressão gênica realizada através da técnica de q-RT-PCR não foi relevante, não apresentando diferença entre os tratamentos. Conclui-se, portanto, que os tratamentos aplicados ao modelo animal selecionado possui o potencial de alterar lipoproteínas plasmáticas, mas não de manter a continuidade e desencadear o processo inflamatório relacionado à aterogênese

Atherosclerosis is chronic a non-communicable disease considered one of a major cause of morbidity and mortality in several countries, including Brazil. Among all the possible causes of their genesis the dietary habit of high fatty acid intake, especially saturated and trans fatty acids is the most important. Saturated and unsaturated fatty acids possess different biological and physicochemical characteristics. The most abundant fatty acid in the human diet are palmitic and stearic and they association with cardiovascular events has been increasingly investigated, especially those one with more than ten carbons in its chain which interfers in the lipoproteins metabolism and can initiate the atherosclerotic process. The food industry has developed some optional technologies to reduce or eliminate the presence of trans fatty acids in foods, in particular elaidic, which after the hydrogenation process increases the saturated fatty acids content. Some industrialized foods requires a large amount of saturated fatty acids that promote an increase of palmitic and stearic content, the last fatty acid mentioned is considered a neutral saturated fatty acid that can contribute to the decrease in HDL-c (High Density lipoprotein), depending on the concentration used, among other deleterious changes. Thus, investigate changes of specifics biological parameters in response to consumption of different saturated fatty acids, respecting the total content of lipids in a normolipidic diet is the aim of this study. Assays were conducted to determine the following parameters in the tissues: 1) Activity of antioxidant enzymes, 2) Lipid peroxidation, 3) Lipidogram; 4) Fatty acid composition 5) Expression of genes related the atherosclerotic process (ICAM-1, VCAM-1, CD36 and MCP- 1). The determination of the activity of antioxidant enzymes was carried out considering only the enzymes Catalase (CAT) and Superoxide Dismutase (SOD), because they are enzymes more sensitive and readily available in changes resulted of an atherosclerotic process with endothelial dysfunction. In the study, no changes were observed in activity of these enzymes in the liver and heart. The same biological process that stimulates the overproduction of reactive species can lead to increased lipid peroxidation, especially of polyunsaturated fatty acids present in cell membranes of tissues such as liver, brain and heart. The group fed with diet enriched with tripalmitate showed increased lipid peroxidation compared to control group. Correlating this information with the fatty acid profile in liver tissue, we noted that there was a greater incorporation of palmitic acid, which exhibit linear configuration when incorporated into the cell membrane and can lead to dysfunction and higher susceptibility to damages such as oxidation. No differences were observed in the others tissues analyzed. The lipidogram is the quantification of lipoprotein and lipid fractions, composing the lipid profile in blood plasma. The results showed that total cholesterol was significantly lower in the control group, as well triglyceride and LDL cholesterol (LDL-c). HDL cholesterol (HDL-C) concentration is reduced and triacylglycerol and cholesterol increased n the group fed with diet supplemented with palmitic. The groups fed with diets supplemented with tristearate and trioleate presented intermediate results for the measurement of HDL-c, with values tending to the group supplemented with tripalmitate. Regarding LDL-c levels, significant differences were observed between the supplemented groups and the control group. Emphasis that there was no difference between the dosage between the supplemented groups. Therefore, the group fed with oleic acid (monounsaturated) supplemented diet equates to the groups fed with diets enriched with stearic and palmitic acid (saturated). The fatty acid profile of liver tissue showed a high percentage of palmitic acid in the group fed with diet enriched with the same fatty acid, with a statistical difference compared to the other groups. In relation to stearic acid, there were no significant differences between groups. As compensation, the oleic acid content in the group supplemented with the same fatty acid and palmitic acid was significantly higher when compared to the others. This result demonstrates that no desaturation of stearic acid to oleic happened in this experimental model. In cardiac tissue there was no statistically significant difference in the concentration of fatty acids, indicating no incorporation or desaturation. Regarding adhesion molecules and chemokines (VCAM-1, ICAM- 1, CD-36 and MCP-1) related to the atherosclerotic process, there was only change in the gene expression of CD-36 molecule in the group fed diet enriched with trioleate, with reduction in relation to others. No other alterations were observed. In conclusion, we verified that the consumption of the different fatty acids in this experimental model has potential to alter lipoproteins levels but not to iniciate or maintain the inflammatory process associated with atherogenesis

Prolonged-release solid dispersions of ibuprofen.

Ibuprofen (IB) is one of the most important non-steroidal anti-inflammatory drugs used in the treatment of inflammatory chronic diseases. This drug presents, in the pure state, poor physical and mechanical characteristics and their use in solid dosage forms needs the addition of excipients which improve these properties. The selection of the best excipients and the suitable pharmaceutical dosage form to carry ibuprofen are very important for the industrial success of this drug. Thus, in this work, solid dispersions of ibuprofen in cethyl alcohol (SD CA), stearic acid (SD SA) and hydrogenated castor oil (SD HCO) were prepared in order to improve physical and mechanical characteristics of this drug. Physical mixtures with the same composition of solid dispersions were also prepared. Solid dispersions of ibuprofen with stearic acid and hydrogenated castor oil showed better flow characteristics than pure ibuprofen and the respective physical mixtures. Gelatin capsules filled with solid dispersions were submitted to dissolution tests in order to study the influence of the prepared systems in the release profiles of ibuprofen. Prolonged-release of ibuprofen was achieved with the solid dispersions prepared with the different types of excipients.

Development and evaluation of a hot-melt coating technique for enteric coating

Conventional enteric coating requires the use of organic based polymers which are equally hazardous to the environment and operating personnel. Hot-melt coating avoids the use of solvents and is a safer and time-saving process. The present study was designed to assess the efficacy of hot-melt coating (HMC) as an enteric coating technique. Pellets prepared by extrusion spheronization were selected as the core formulation for a model of the gastric irritant drug diclofenac sodium (DFS) because of their innate advantages over single-unit formulations. Stearic acid (SA) and palmitic acid (PA) were evaluated as enteric hot-melt coating materials. HMC was carried out in a specially modified coating pan by applying SA and PA in molten state onto preheated pellets to achieve a coating level of 5-15 %w/w. Hot-melt coated pellets were evaluated for disintegration pH and in vitro dissolution in the pH range 1.2 to 6.8, along with basic micromeritics. SEM of coated pellets showed a uniform and smooth coating. These results indicated that HMC of both SA and PA exhibited very good enteric coating ability. The coated pellets showed negligible drug release in acidic pH. As the pellets were subsequently transferred to a higher pH level, a gradual increase in release of the drug from the pellets was observed with increasing pH of the dissolution media. The release was dependent upon coating extent, providing sustained enteric release as opposed to abrupt release with mixed release kinetics.

O revestimento entérico convencional requer o uso de polímeros orgânicos os quais são igualmente danosos ao meio ambiente e ao pessoal que o executa. O revestimento por fusão a quente evita o uso de solventes e é processo mais seguro e que consome menos tempo. O presente estudo foi planejado para avaliar a eficácia do revestimento por fusão a quente (RFQ) como técnica de revestimento entérico. Os péletes preparados por esferonização por extrusão foram selecionados como formulação central para modelo de fármaco irritante gástrico, o diclofenaco sódico (DFS) em razão das vantagens inerentes sobre as formulações de única dose. O ácido esteárico (AE) e o ácido palmítico (AP) foram avaliados como materiais para o revestimento de fusão a quente. O RFQ foi realizado em recipiente especialmente modificado, aplicando AS e PA no estado fundido em péletes pré-aquecidos para atingir nível de revestimento de 5 a 15% p/P. Os péletes revestidos por fusão a quente for avaliados quanto ao pH de desintegração e à dissolução in vitro na faixa de pH de 1,2 a 6,8, juntamente com base micromerítica. O SEM dos péletes revestido mostrou revestimento uniforme e plano. Esses resultados indicaram que o RFQ tanto do AE quanto do AP apresentou capacidade de revestimento muito boa. Os péletes revestidos mostraram pouca liberação do fármaco em pH baixo. Como os péletes foram, subsequentemente, transferidos para pH mais altos, observou-se aumento gradual na liberação do fármaco dos péletes com o aumento do pH do meio de dissolução. A liberação foi dependente da extensão do revestimento, sendo a liberação entérica controlada, contrariamente à liberação abrupta com cinéticas mistas.

Comparative study of sustained-release lipid microparticles and solid dispersions containing ibuprofen

Ibuprofen is one of the most important non-steroidal anti-inflammatory drugs used in the treatment of inflammatory diseases. In its pure state, ibuprofen presents poor physical and mechanical characteristics and its use in solid dosage forms needs the addition of excipients that improve these properties. The selection of the best excipients and the most suitable pharmaceutical dosage form to carry ibuprofen is very important for the industrial success of this drug. Given these factors, lipid microparticles and solid dispersions of ibuprofen with cetyl alcohol, stearic acid, and hydrogenated castor oil were prepared. These formulations were intended to improve the physical and mechanical characteristics and to sustain the release of this drug. Physical mixtures were also prepared with the same ingredients in similar proportions. The solid dispersions of ibuprofen/stearic acid and ibuprofen/hydrogenated castor oil showed the best flow characteristics compared with pure ibuprofen. Further, gelatin capsules filled with lipid microparticles and solid dispersions were submitted to dissolution tests in order to study the influence of the prepared systems in the release profiles of ibuprofen. Prolonged release of ibuprofen was achieved with the lipid microparticles and solid dispersions prepared with the different types of excipients.

O ibuprofeno é um dos antiinflamatórios não esteróides mais utilizados no tratamento de patologias associadas a processos inflamatórios. Este fármaco, quando no seu estado puro, apresenta características físicas e mecânicas pouco satisfatórias e a sua utilização em formas sólidas só é possível se forem adicionados excipientes que permitam melhorar estas propriedades. A seleção dos excipientes ideais e da forma farmacêutica mais adequada para veicular o ibuprofeno é fundamental para o sucesso industrial deste fármaco. Tendo em conta estes fatores, prepararam-se micropartículas lipídicas e dispersões sólidas de ibuprofeno com cada um dos seguintes excipientes: álcool cetílico, ácido esteárico e óleo de rícino hidrogenado. Estas formulações tinham por finalidade melhorar as características físicas e mecânicas e prolongar a liberação deste fármaco. Foram, também, preparadas misturas físicas do ibuprofeno com os mesmos excipientes e nas mesmas proporções. As dispersões sólidas de ibuprofeno/ácido esteárico e as dispersões sólidas de ibuprofeno/óleo de rícino hidrogenado foram aquelas que apresentaram melhores características de escoamento comparativamente com o ibuprofeno puro. Por outro lado, foram preparadas cápsulas de gelatina com as diferentes micropartículas lipídicas e dispersões sólidas e submetidas a ensaios de dissolução com o objetivo de estudar a influência dos sistemas preparados nos perfis de liberação do ibuprofeno. A liberação prolongada do ibuprofeno foi conseguida nas diferentes micropartículas lipídicas e dispersões sólidas preparadas com os diferentes excipientes.

Effect of stearic acid on the properties of metronidazole/methocel K4M floating matrices / Efeito do ácido esteárico nas propriedades de metronidazol / Methocel K4M matrizes flutuante

The properties of metronidazole/Methocel K4M sustained release floating tablets have been studied varying the proportion of the lubricant, stearic acid, on formulations with and without sodium bicarbonate. The variables studied include technological properties of the tablets such as tablet hardness and ejection pressure, the drug release profile, the hydration kinetics and the floating behaviour. The presence of stearic acid and sodium bicarbonate improves the floating behaviour for more than 8 hours. The hydration volume, the tablet hardness and the ejection pressure decrease as the stearic acid content increases and the polymer content decreases. Drug dissolution increases with increasing proportions of stearic acid and decreasing proportions of the polymer in the tablets. The presence of sodium bicarbonate extends the differences in dissolution produced by stearic acid. These results are attributed to decreasing matrices coherence with an increasing quantity of stearic acid and a reducing polymer proportion. The carbon dioxide bubbles produced by sodium bicarbonate expand the matrices facilitating the dissolution, although their presence obstructs also the diffusion path through the hydrated gel layer.

Estudaram-se as propriedades de comprimidos flutuantes de metronidazol/Methocel K4M de liberação controlada, variando-se a proporção do lubrificante, ácido esteárico, nas formulações com e sem bicarbonato de sódio. As variáveis estudadas incluem propriedades tecnológicas dos comprimidos, tais como dureza, pressão de ejeção, perfil de liberação do fármaco, cinética de hidratação e comportamento de flutuação. A presença de ácido esteárico e do bicarbonato de sódio melhora o comportamento de flutuação para mais de 8 horas. O volume de hidratação, a dureza e a pressão de ejeção do comprimido decrescem à medida que o conteúdo de ácido esteárico e de polímero diminui. A dissolução do fármaco aumenta com o aumento das proporções de ácido esteárico e a diminuição das proporções de polímero nos comprimidos. A presença de bicarbonato de sódio amplia as diferenças na dissolução produzidas pelo ácido esteárico. Estes resultados são atribuídos à coesão decrescente das matrizes, com o aumento da quantidade de ácido esteárico e a redução da proporção de polímero. Bolhas de dióxido de carbono produzidas pelo bicarbonato de sódio expandem as matrizes, facilitando a dissolução, embora a presença delas obstrua, também, a difusão através da camada de gel hidratado.

Effects of Chlorhexidine digluconate on Rotational Rate of n- (9-Anthroyloxy)stearic acid in Model Membranes of Total Lipids Extracted from Porphyromonas gingivalis Outer Membranes

The purpose of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Large unilamellar vesicles (OPGTL) were prepared with total lipids extracted from cultured Porphyromonas gingivalis outer membranes (OPG). The anthroyloxy probes were located at a graded series of depths inside a membrane, depending on its substitution position (n) in the aliphatic chain. Fluorescence polarization of n- (9-anthroyloxy)stearic acid was used to examine effects of chlorhexidine digluconate on differential rotational mobility, while changing the probes' substitution position (n) in the membrane phospholipids aliphatic chain. Magnitude of the rotational mobility of the intact six membrane components differed depending on the substitution position in the descending order of 16- (9-anthroyloxy)palmitic acid (16-AP), 12, 9, 6, 3 and 2- (9-anthroyloxy)stearic acid (12-AS, 9-AS, 6-AS, 3-AS and 2-AS). Chlorhexidine digluconate increased in a dose-dependent manner the rate of rotational mobility of hydrocarbon interior of the OPGTL prepared with total lipids extracted from cultured OPG, but decreased the mobility of membrane interface of the OPGTL. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.

Neuroprotective effects of stearic acid in primarily cultured hippocampal neurons insulted by excitotoxicity / 中国药理学通报

Aim To evaluate neuroprotective effects of stearic acid on primarily cultured hippocampal neurons and to study the mechanism of neuroprotection afforded by stearic acid.Methods Primarily cultured hippocampal neurons were insulted by OGD(oxygen-glucose deprivation),H_2O_2,glutamate and NaN_3;MTT assay was utilized to evaluate cell viability;Inhibitors of PPAR?and PI-3K signal pathway were used to study mechanisms of neuroprotection of stearic acid.Results Compared with control neurons,A_(570) in MTT assay were increased significantly by stearic acid in hippocampal neurons insulted by OGD(oxygen-glucose deprivation),H_2O_2 and glutamate(P

Effects of Chlorhexidine Digluconate on Rotational Rate of n- (9-Anthroyloxy) stearic Acid in Porphyromonas ginginvalis Outer Membranes

The aim of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Fluorescence polarization of n- (9-anthroyloxy) stearic acid was used to examine the effect of chlorhexidine digluconate on differential rotational mobility of different positions of the number of membrane bilayer phospholipid carbon atoms. The six membrane components differed with respect to 2, 3, 6, 9, 12, and 16- (9-anthroyloxy) stearic acid (2-AS, 3-AS, 6-AS, 9-AS, 12-AS and 16-AP) probes, indicating different membrane fluidity. Chlorhexidine digluconate increased the rate of rotational mobility of hydrocarbon interior of the cultured Porphyromonas gingivalis outer membranes (OPG) in a dose-dependent manner, but decreased the mobility of surface region (membrane interface) of the OPG. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.

Studies on Chemical Constituents of Galeola Shweliensis W. W. Sm / 第二军医大学学报

Three crystals (Ⅰ, ⅡandⅢ) were isolated from Galeola shweliensis W.W. Sm. and identified by means of physical nd chemical properties, and spectral data. It shows that crystal I was a novel com-pound, named galeolate (CH3-(CH2)12-C-O-CH2 -(CH2)12-C-O-C-CH3). Crystal ⅡandⅢwere confirmed as steanc acid and ?-sitosterol, respectively. These three constituents were found inthis plant for the first time.