非离子表面活性剂微乳的制备及抗菌性考察

目的:制备一种药用非离子表面活性剂空白微乳,并评价其抗菌性.方法:采用拟三元相图考察表面活性剂、助表面活性剂及其质量比、添加剂、温度等对微乳区的影响;高速离心法和37℃恒温1个月考察微乳稳定性;抗菌试验考察其抗菌能力.结果:油酸乙酯为油相、聚氧乙烯蓖麻油为表面活性剂、异丙醇为助表面活性剂的微乳区范围较大,可无限稀释;稳定性试验未见相分离;水相中的添加剂及温度的变化对微乳区范围无显著性影响;微乳均能有效杀灭绿脓杆菌、金黄色葡萄球菌、大肠杆菌、白色念珠菌,其中作用8 h后绿脓杆菌杀灭完全.结论:本品能自身抗菌,有可能成为适合眼用、注射等的潜在给药载体.     

Effect of combined use of nonionic surfactant on formation of oil-in-water microemulsions

PURPOSE: This study evaluated the effects of combined use of two nonionic surfactants on the characteristics (i.e., appearance, emulsification time, and particle size) of oil-in-water microemulsions generated from flurbiprofen-loaded preconcentrates. METHODS: Three phase diagrams were constructed using Capmul PG8 (propylene glycol monocaprylate) as the oil, Tween 20 (polysorbate 20) and/or Cremophor EL (polyoxyl 35 castor oil) as surfactants. A number of preconcentrates were selected based on phase diagrams: O20T80 (20% Capmul PG8, 80% Tween 20), O20C80 (20% Capmul PG8, 80% Cremophor EL), O20T40C40 (20% Capmul PG8, 40% Tween 20, 40% Cremophor EL). Flurbiprofen loading in preconcentrates was tested at 0%, 1%, 2.5%, and 5% (w/w). The resulting mixtures of these preconcentrates upon dilution 100-fold with aqueous medium were characterized by visual and microscopic observation, HPLC and photon correlation spectroscopy. RESULTS: (a) For preconcentrates using single surfactant, either O20T80 or O20C80, the dilution generated emulsions with visible cloudiness. The particle size increased as the drug loading increased; (b) for preconcentrates using two surfactants O20T40C40, the dilution generated clear microemulsions with small particle sizes (10-11nm), and the increased drug loading seemed to have little effect on the particle size. The microemulsions from preconcentrate O20T40C40 was also found to be stable at ambient temperature over 20 days without significant change in particle size at different drug loadings. Dilution with different aqueous medium, either water, or simulated gastric fluid or simulated intestinal fluid, also did not change the particle sizes of the microemulsions. CONCLUSIONS: The combined use of surfactants in preconcentrate showed the promise in generating desired self-emulsifying microemulsions with small particle size, increased drug loading, and improved physical stability. This will have significant implications in future dosage development for poorly water-soluble drugs in using self-emulsifying microemulsions drug delivery system (SMEDDS).     

Formation of drug/surfactant catanionic vesicles and their application in sustained drug release

The aggregation behavior of the cationic drug/anionic surfactant vesicles formed by tetracaine hydrochloride (TH) and double-chain surfactant, sodium bis(2-ethylhexyl)sulfosuccinate (AOT), was investigated. By controlling the molar ratio of TH to AOT, a transition from catanionic vesicles to micelles was observed. The catanionic aggregates exhibited different charge properties, structures, interaction enthalpies and drug release behaviors depending on the composition. To characterize the cationic drug/anionic surfactant system, transmission electron microscopy (TEM), dynamic light scattering (DLS), isothermal titration calorimetry (ITC), conductivity, turbidity and zeta potential (ζ) measurements were performed. The drug release results indicate that the present drug-containing catanionic vesicles have promising applications in drug delivery systems. Furthermore, the percentage of drug distributed in the catanionic vesicles or micelles can be obtained by comparing the cumulative release of the corresponding aggregates with the pure drug solution.     

Physicochemical and solubilization properties of N, N-dimethyl-N-(3-dodecylcarbonyloxypropyl)amineoxide: a biodegradable nonionic surfactant

The physicochemical characteristics of N,N-dimethyl-N-(3-dodecylcar- bonyloxypropyl)amineoxide (DDCPNO), a biodegradable analogue of a N, N-dimethylalkylamine-N-oxide, are compared with those of N, N-dimethyldodecylamine-N-oxide (DDNO) to establish the effect on the properties of DDNO of inserting a propoxy linker between the hydrophobic tail and hydrophilic head region. Surface tension measurements gave a critical micelle concentration of 0.33 mM for DDCPNO compared with a value of 1.57 mM for DDNO, suggesting that the former was the more hydrophobic surfactant. This result was confirmed by laser light scattering studies in which total intensity light scattering indicated the presence of DDCPNO micelles of aggregation number 85.0. Photon correlation spectroscopy studies yielded a limiting hydrodynamic diameter of 4.0 nm in comparison with values of 57.5 and 3.3 nm obtained for the aggregation number and the limiting hydrodynamic size, respectively, of DDNO micelles. Studies demonstrated that neither a dilute aqueous solution of DDCPNO or DDNO exhibited a cloud point within the temperature range 293-373 K. Solubilization studies showed that the capacity of DDCPNO micelles for a range of drugs of varying size and polarity was less than that observed with DDNO micelles at an equivalent surfactant concentration. As a further measure of solubilization, the ability of DDCPNO to form oil-in-water microemulsions with a range of ethyl ester oils was investigated and found to be slightly higher than that achieved with DDNO. Together these studies suggest that the presence of the semipolar linker significantly alters the properties of this low molecular weight surfactant.     

Modulating pH-independent release from coated pellets: Effect of coating composition on solubilization processes and drug release

The aim of the study was to clarify the influences of three coating parameters on the drug release from chlorpheniramine maleate (CPM) pellets, coated with blends of poly(vinyl acetate) (PVAc) and poly(vinyl alcohol)-poly(ethylene glycol) (PVA-PEG) graft copolymer. A central composite design was implemented to investigate the effect of the polymer blend ratio, the film coat thickness and the plasticizer concentration on the drug release. The solubilization inside the pellets was monitored by EPR spectroscopy. The blending ratio of both the polymers and the film thickness were found to have a major influence on the drug release and the solubilization speed, in contrast to the plasticizer concentration. A pH-independent release profile was adjustable via modulating the polymer blend ratio and the coating thickness. A mathematical model was developed, providing a good predictability of the release profile, based on the film coat composition. This model offers the possibility to achieve a defined drug-release profile by selective adaptation of the film coat composition, in view of process times, feasibility or polymer costs.     

Effect of formulation variables on in vitro drug release and micromeritic properties of modified release ibuprofen microspheres

Modified release microspheres of the non-steroidal anti-inflammatory drug, ibuprofen, were formulated and prepared using the emulsion solvent diffusion technique. The contribution of various dispersed phase and continuous phase formulation factors on in vitro drug release and micromeritic characteristics of microspheres was examined. The results demonstrated that the use of Eudragit RS 100 and Eudragit RL 100 as embedding polymers modified the drug release properties as a function of polymer type and concentration. Eudragit RS 100 retarded ibuprofen release from the microspheres to a greater extent than Eudragit RL 100. The drug/polymer concentration of the dispersed phase influenced the particle size and drug release properties of the formed microspheres. It was found that the presence of emulsifier was essential for microsphere formation. Increasing the concentration of emulsifier, sucrose fatty acid ester F-70, decreased the particle size which contributed to increased drug release properties. Scanning electron microscopy revealed profound distortion in both the shape and surface morphology of the microspheres with the use of magnesium stearate as added emulsifier. The application of an additional Eudragit RS 100 coat onto formed microspheres using fluid bed technology was successful and modulated the drug release properties of the coated microspheres.     

Effects of surfactant characteristics on drug availability from suppositories

The addition of surfactants to suppository formulations is referred to in the scientific literature, but their effects on drug availability remain uncertain. Surfactants are reported to improve drug dispersion into hard fatty excipients, to increase the spreading of the melted suppository on the rectal mucosa leading to a greater contact surface, to reduce the viscosity of the molten mass and to reduce the pathway of drug particles to the interface. In the present study a systematic investigation based on tensiometric and rheological methods was carried out to evaluate the effects of nonionic surfactants with different HLBs (hydrophilic-lipophilic-balance) on drug availability and to clarify the possible mechanisms involved in the release process. The relationship between the melted suppositories and a membrane simulating the rectal barrier were investigated in the course of the in vitro release test by measuring their energy characteristics. At the same time, the potential influences of such interactions on drug release were investigated in suppositories formulated with different kinds and concentrations of surfactant additives. Drug availability was influenced not only by the interaction between the suppository and the rectal membrane but also by the interaction between surfactant, lipophilic excipient and suspended drug particles. Such interactions appear to greatly influence drug release from suppositories, which, in turn, is the main parameter determining drug availability.     

Effect of formulation variables on in vitro drug release and micromeritic properties of modified release ibuprofen microspheres.

Modified release microspheres of the non-steroidal anti-inflammatory drug, ibuprofen, were formulated and prepared using the emulsion solvent diffusion technique. The contribution of various dispersed phase and continuous phase formulation factors on in vitro drug release and micromeritic characteristics of microspheres was examined. The results demonstrated that the use of Eudragit RS 100 and Eudragit RL 100 as embedding polymers modified the drug release properties as a function of polymer type and concentration. Eudragit RS 100 retarded ibuprofen release from the microspheres to a greater extent than Eudragit RL 100. The drug/polymer concentration of the dispersed phase influenced the particle size and drug release properties of the formed microspheres. It was found that the presence of emulsifier was essential for microsphere formation. Increasing the concentration of emulsifier, sucrose fatty acid ester F-70, decreased the particle size which contributed to increased drug release properties. Scanning electron microscopy revealed profound distortion in both the shape and surface morphology of the microspheres with the use of magnesium stearate as added emulsifier. The application of an additional Eudragit RS 100 coat onto formed microspheres using fluid bed technology was successful and modulated the drug release properties of the coated microspheres.     

Investigation on a new scleroglucan/borax hydrogel: structure and drug release

The aim of this work is to elucidate the structure of the new hydrogel prepared with scleroglucan (Sclg) and borax, suitable for drug delivery, applying theoretical approaches, and to explain its very peculiar swelling. The possible linkages with borate ions have been investigated and original parameters for the 4,6-gluco-borate moiety have been introduced. The structures relative to the Sclg chains in the presence of borax and the possible mutual arrangements among the triple helices are given. According to molecular dynamics simulations, the most probable assembly of the chains in the network is proposed, without and in the presence of three tested model drugs with different molecular dimensions: theophylline (TPH), Vitamin B12 (Vit. B12) and myoglobin (MGB). The hydrogel supramolecular structure, formed via chemical and physical linkages among the polysaccharidic chains, is built up taking into account the steric hindrance of the entrapped molecules. It is shown that molecular dynamics analysis can be a useful tool capable to shed some light on the anomalous swelling of the hydrogel, suitable for drug release, giving a new insight on the network structure and the release rate of the guest molecules.     

Oral self-nanoemulsifying peptide drug delivery systems: impact of lipase on drug release

Abstract

It was the aim of this study to evaluate the impact of lipases on the release behaviour of a peptide drug from oral self-nanoemulsifying drug delivery systems. Octreotide was ion paired with the anionic surfactants deoxycholate, decanoate, oleate and dodecylsulphate. The lipophilic character of these complexes was characterised by determining the n-octanol/buffer pH 7.4 partition coefficient. In the following the most hydrophilic complex was incorporated in a likely lipase degradable self-nanoemulsifying drug delivery systems (SNEDDS) formulation containing a triglyceride (olive oil; Pharm.Eur.) and in a likely not lipase degradable SNEDDS containing lipids and surfactants without any ester bonds. After 1:100 dilutions in artificial intestinal fluid (AIF), the lipid droplets were characterised regarding size distribution. With these SNEDDS, drug release studies were performed in AIF with and without lipase. Results showed that the most hydrophobic complex can be formed with deoxycholate in an octreotide:anionic surfactant ratio of 1:5. Even 73.1?±?8.1% of it could be quantified in the n-octanol phase. SNEDDS containing octreotide | olive oil | cremophor EL | propylene glycol (2|57|38|3) and octreotide | liquid paraffin | Brij 35 | propylene glycol | ethanol (2|66.5|25|5|1.5) showed after dilution in AIF, a mean droplet size of 232?±?53?nm and 235?±?50?nm, respectively. Drug release studies showed a sustained release of octreotide out of these formulations for at least 24?h, whereas?>?80% of the drug was released within 2?h in the presence of lipase in the case of the triglyceride containing SNEEDS. In contrast the release profile from ester-free SNEDDS was not significantly altered (p?<?0.05) due to the addition of lipase providing evidence for the stability of this formulation towards lipases. According to these results, SNEDDS could be identified as a useful tool for sustained oral peptide delivery taking an enzymatic degradation by intestinal lipases into considerations.     

吲哚美辛HP MCP肠溶片的制备及溶出度考察

以吲哚美辛为模型药物 ,采用本室新研制开发的肠溶材料羟丙甲纤维素邻苯二甲酸酯(HPMCP)包衣 ,制备了吲哚美辛肠溶片。通过考察吲哚美辛HPMCP包衣片的溶出度 ,并与吲哚美辛HP55(日本信越公司同类材料 )包衣片及 5种市售吲哚美辛肠溶片的溶出度进行比较来研究HPMCP包衣膜的性质。用相似因子法和chow’s法对溶出实验数据进行统计分析 ,结果表明HPMCP包衣片与HP55包衣片溶出行为完全相似 ,相似因子F2 =70 1 ( 5 0≤F2 ≤ 1 0 0 ) ,HPMCP包衣片片心药物溶出速率明显快于 5种市售片。     

Investigation of excipient type and level on drug release from controlled release tablets containing HPMC

The purpose of this study was to investigate the influence of excipient type and level on the release of alprazolam formulated in controlled release matrix tablets containing hydroxypropyl methylcellulose (HPMC). Each tablet formulation contained alprazolam, HPMC (Methocel K4MP), excipients, and magnesium stearate. The soluble excipients investigated were lactose monohydrate, sucrose, and dextrose, and the insoluble excipients included dicalcium phosphate dihydrate, dicalcium phosphate anhydrous, and calcium sulfate dihydrate. The similarity factor (f2 factor) was used to compare the dissolution profile of each formulation. The insoluble excipients, especially dicalcium phosphate dihydrate, caused the drug to be released at a slower rate and to a lesser extent than the soluble excipients. Soluble excipients created a more permeable hydrated gel layer for drug release, increased the porosity resulting in faster diffusion of drug, and increased the rate of tablet erosion. Use of binary mixtures of lactose monohydrate and dicalcium phosphate dihydrate produced release profiles of intermediate duration. Rapid drug dissolution was obtained when only 9.1% w/w of lactose monohydrate was present in the tablet formulation. Only when the dicalcium phosphate dihydrate level was sufficiently high (36.5% w/w) was the release rate and extent decreased. It was demonstrated that the type and level of excipient influenced the rate and extent of drug release from controlled release tablets containing HPMC. The release mechanism of alprazolam from each tablet formulation was described by either the Hixson-Crowell cube root kinetics equation or Peppas's equation. However, the different excipient types investigated did not influence the release mechanism of alprazolam from the final tablets.     

Effect of alginate-pectin composition on drug release characteristics of microcapsules

Microencapsulation of model drug, acetylsalicylic acid into bio-based polymer, alginate-pectin matrix has been undertaken in this work to characterize the microcapsules based on their composition. Different proportions of the alginate-pectin solutions prepared with drug were homogenized and atomized using nitrogen gas into 1.0 M calcium chloride solution to form sol-gel microcapsules. Drug loaded microcapsules were dried using microwave energy under vacuum at low temperature. Average particle size of the microcapsules was found to be 90 micron. Scanning electron microscopy graphs and Fourier Transform Infrared Spectroscopy analysis on the microcapsules confirm the presence of drug in the polymer matrix. X-ray diffraction pattern showed that the microstructure was more like an amorphous pattern. Drug release of the microcapsules was tested in three different pH levels of 1.2, 7.4 and 8.2. Slow and controlled release of drug was observed at all the pH levels. Increase in pectin increased the drug release and also the release was more in acidic pH (1.2) as 75.6% for alginate: pectin-20:80.     

Compaction, compression and drug release properties of diclofenac sodium and ibuprofen pellets comprising xanthan gum as a sustained release agent

Compaction and compression of xanthan gum pellets were evaluated and drug release from tablets made of pellets was characterised. Two types of pellets were prepared by extrusion-spheronisation. Formulations included xanthan gum, at 16% (w/w), diclofenac sodium or ibuprofen, at 10% (w/w), among other excipients. An amount of 500 mg of pellets fraction 1000-1400 microm were compacted in a single punch press at maximum punch pressure of 125 MPa using flat-faced punches (diameter of 1.00 cm). Physical properties of pellets and tablets were analysed. Laser profilometry analysis and scanning electron microscopy of the upper surface and the surface of fracture of tablets revealed that particles remained as coherent individual units after compression process. Pellets were flatted in the same direction of the applied stress evidencing a lost of the original curvature of the spherical unit. Pellets showed close compressibility degrees (49.9% for pellets comprising diclofenac sodium and 48.5% for pellets comprising ibuprofen). Xanthan gum pellets comprising diclofenac sodium experienced a reduction of 65.5% of their original sphericity while those comprising ibuprofen lost 49.6% of the original porosity. Permanent deformation and densification were the relevant mechanisms of compression. Fragmentation was regarded as non-existent. The release of the model drug from both type of tablets revealed different behaviours. Tablets made of pellets comprising ibuprofen released the model drug in a bimodal fashion and the release behaviour was characterised as Case II transport mechanism (release exponent of 0.93). On the other hand, the release behaviour of diclofenac sodium from tablets made of pellets was anomalous (release exponent of 0.70). For the latter case, drug diffusion and erosion were competing mechanisms of drug release.     

表面活性剂对疏水片面润湿性的调节及其对崩解和药物释放的影响

目的表面活性剂对疏水片面润湿性的调节及其对崩解和药物释放的影响。方法采用静态液滴法测定其液滴在辅料表面或混有表面活性剂的辅料表面上的接触角。结果离子型表面活性剂与泊洛沙姆系列溶液均可提高疏水性辅料的润湿性;混有表面活性剂的疏水辅料片的接触角较无表面活性剂时小,润湿性得到改善,同时润湿性的改善可有效缩短崩解时间,提高药物的溶出度。F68与F127对辅料片润湿性质改善能力仅次于SDS。并初步建立了辅料润湿、片崩解时间、药物释放百分率之间的关系。结论在片剂润湿、崩解、药物释放过程中,泊洛沙姆系列表面活性剂可部分替代离子型表面活性剂作为润湿调节剂,研究结果对制剂的处方设计及筛选具有指导意义。     

卡托普利渗透泵控释片的制备及体外释放度考察

目的研究卡托普利渗透泵控释片的制备工艺及体外释药影响因素。方法以比色法为分析方法 ,采用综合评分法评价体外释放行为。结果卡托普利渗透泵控释片的体外释药符合零级释放规律 ,释药速率受HPMCK1 5含量、渗透压促进剂用量影响较大 ,在一定范围内 ,释药孔大小和片芯硬度对其影响较小 ,与溶出方法、介质 pH值、桨转速无关。 结论体外释放规律符合控释制剂要求 ,可进一步进行体内释药行为考察     

布洛芬固体分散体的制备

目的:利用熔融法制备布洛芬Kollidon CL和Kollidon CL-SF固体分散体,提高布洛芬的体外溶出性质。方法:以Kollidon CL和Kollidon CL-SF为载体,利用熔融法制备难溶性药物布洛芬固体分散体,并进行体外溶出研究。采用差示扫描量热分析、粉末X射线衍射分析及扫描电镜观察对制备的固体分散体进行物相鉴别。结果:熔融法制备的布洛芬-Kollidon固体分散体中,布洛芬以无定形态存在,体外溶出速率显著提高,5 min时以Kollidon CL和Kollidon CL-SF为载体的固体分散体中布洛芬累积溶出度是67.1%和67.6%,分别是布洛芬原药的17.8倍和17.9倍。结论:固体分散体技术是提高布洛芬溶出性质的一种有效可行的方法。     

Swelling and erosion of pectin matrix tablets and their impact on drug release behavior.

The aim of this study was to investigate swelling and erosion behaviors of hydrophilic matrix tablets using pectin and their impact on drug release. The matrix tablets were prepared by direct compression using different types of pectin. Swelling and erosion studies of pectin matrix tablets were carried out in various media. The pectin matrix tablets formed a continuous gel layer while in contact with the aqueous medium undergoing a combination of swelling and erosion. The swelling action of pectin matrices was controlled by the rate of its hydration in the medium. Release studies showed that the swelling and erosion of matrices influenced the drug release. The extent of matrix swelling, erosion and diffusion of drug determined the kinetics as well as mechanism of drug release from pectin-based matrix tablets. The release data showed a good fit into the power law or the Korsmeyer-Peppas equation indicating the combined effect of diffusion and erosion mechanisms of drug release.