鼻腔给药促进盐酸美普他酚在大鼠体内的吸收及脑转运

目的考察大鼠鼻腔给药后血和脑脊液中盐酸美普他酚 (MEP)的浓度，并与口服比较。方法采用连续采集法收集脑脊液样品，用HPLC-荧光检测器测定各生物样品中MEP的浓度。结果鼻腔给药后药物迅速吸收入血，并在血和脑脊液中达到高浓度，而MEP口服后体内药浓很低。鼻腔给药后血和CSF的AUC值分别为口服的7.375和15.6倍。结论MEP鼻腔给药具有起效快、生物利用度高的特点，有望成为口服的替代途径。     

盐酸美普他酚的毛细管电泳手性分离

目的建立了一种盐酸美普他酚的毛细管电泳分离方法.方法采用开管式熔融石英毛细管柱,以β-环糊精为手性添加剂可使盐酸美普他酚对映体分离.对β-环糊精类型进行了选择,对缓冲液pH、三甲基-β-环糊精的浓度、有机添加剂等实验条件进行了优化.结果在所确定的条件下盐酸美普他酚对映体达到基线分离.结论所建立的方法方便、快速,可用于该类药物的手性研究.     

盐酸美普他酚鼻用温敏型凝胶的制备及其体外释放度考察

目的:制备盐酸美普他酚鼻用温敏型凝胶并考察其体外释放特性。方法:以盐酸美普他酚为主药,泊洛沙姆P407为凝胶材料制备凝胶;以影响制剂胶凝温度的泊洛沙姆P407、P188及PEG6000用量为考察因素,胶凝温度为考察指标进行正交试验优选处方;同时采用改良的Franz扩散池法,以生理盐水为介质进行体外释放特性评价。结果:以处方中含有泊洛沙姆P407为20%、泊洛沙姆P188为3%、PEG6000为2%为最佳处方,平均胶凝温度为32.4℃。所制制剂15min即释药约25%,体外释药行为符合Higuchi方程。结论:该制剂处方设计和工艺方法可行,并具有一定的缓释特性,适合鼻腔给药。     

正交试验优选拆分5种碱性药物的毛细管电泳法

目的以羧甲基-β-环糊精(carboxymethyl-β-cyclodextrin,CM-β-CD)为手性选择剂,用毛细管电泳法(capillary electrophoresis,CE)对5种碱性药物苯磺酸氨氯地平(amlodipine besilate)、二氧丙嗪(dioxopromethazine)、硫酸特布他林(terbutaline sulfate)、氢溴酸后马托品(homatropinehydrobromide)和盐酸美普他酚(meptazinol hydrochloride)进行对映体分离研究。方法采用正交试验设计的方法考察3个水平数背景电解质溶液的pH值、CM-β-CD浓度、缓冲盐浓度对对映体分离的影响,优化了分离条件。结果在最优分离条件下,苯磺酸氨氯地平、二氧丙嗪、硫酸特布他林、氢溴酸后马托品、盐酸美普他酚对映体达到良好分离,分离度分别为12.6、4.4、6.0、5.7、3.5。结论 CM-β-CD对5种碱性药物均具有较好的对映体选择性。     

采用计算机模拟技术结合Caco-2细胞模型与溶出度试验考察国产盐酸曲美他嗪片的生物等效性

目的：采用计算机模拟技术结合Caco-2细胞模型和溶出度试验，对国产盐酸曲美他嗪生物等效性进行研究。方法：首先基于Caco-2单层细胞膜模型考察盐酸曲美他嗪的渗透性，获得其表观渗透系数P_app；第二步采用HPLC法测定溶出曲线来比较10家国产企业与原研生产的盐酸曲美他嗪片在5种不同pH条件下体外溶出行为的差异；最后采用Gastrol Plus^TM软件，导入本试验实测P_app，通过该软件转化为P_eff值，建立准确的体外溶出曲线与体内药动学曲线之间的相关性模型，基于该模型预测国产盐酸曲美他嗪片的药动学曲线，对其生物等效性进行体内外相关的研究。HPLC测定法：C₁₈柱，以0.287%无水庚烷磺酸钠-甲醇（55：45）为流动相，检测波长为231 nm，流速1.0 mL·min^-1；溶出度方法：分别以0.05 mol·L^-1盐酸溶液，pH 1.2、pH 4.0、pH 6.8缓冲盐溶液和水为溶出介质，桨法50 r·min^-1，溶出体积900 mL，分别考察片剂在上述5种溶出介质中5，10，5，20，30，45，60，90 min取样的溶出曲线。结果：盐酸曲美他嗪的表观渗透系数P_app值随着药物浓度的增加反而下降，属于中等渗透的药物；不同pH的溶出介质对盐酸曲美他嗪片的溶出行为无区分性；但在每种溶出介质中，国外原研片剂溶出较慢，与国产片剂的溶出行为存在明显差异，多数国产片剂快速溶出；采用Gastrol Plus^TM软件从药物在体内具有不同释放速率时的体内吸收情况与通过体外溶出曲线模拟体内吸收情况两个方面进行模拟研究，结果显示现有的国产盐酸曲美他嗪片与原研片剂在体内能够生物等效。结论：尽管国产盐酸曲美他嗪片的体外溶出曲线与原研片剂存在差别，但体内生物等效的可能性极大。Gastrol Plus^TM软件能够预测口服固体制剂与原研制剂的生物等效性，可在一致性评价工作中推广应用。     

盐酸曲美他嗪渗透泵片的研制及在Beagle犬体内的药动学

制备了盐酸曲美他嗪渗透泵片,并采用单因素试验考察了渗透压促进剂种类、包衣材料和增重以及致孔剂用量对药物在水中释放的影响.优化后制品在水、0.1 mol/L盐酸和pH 6.8磷酸盐缓冲液中的释放行为相似.以市售盐酸曲美他嗪片(商品名万爽力)为参比制剂,考察了自制渗透泵片在Beagle犬体内的药动学.结果表明,参比制剂和自制品的tmax为(0.75±-0.29)和(5.50±1.00)h,MRT为(4.8±-0.2)和(13.0--0.7)h,可见自制品表现出明显的缓释行为.     

盐酸氨溴索缓释片体内外相关性研究

目的考察盐酸氨溴索缓释片体外释放度与体内吸收的相关性。方法应用释放度测定法研究盐酸氨溴索缓释片体外释药行为 ,采用HPLC法测定盐酸氨溴索缓释制剂在家犬体内的血药浓度 ,按照Wagner Nelson公式计算药物的吸收分数。 结果 3种自制盐酸氨溴索缓释片与参比制剂生物等效 ,以药物累积吸收百分数 f(t)与相应时刻的体外累积释放百分数F(t)建立的一元线性回归方程 ,参比制剂与 3种自制制剂的体内外相关系数分别为 0 969、0 979、0 970和 0 983。结论盐酸氨溴索缓释片的体外释放度与体内吸收具有显著的相关性。     

盐酸地尔硫控释胶囊人体内外相关性

目的:考察盐酸地尔硫控释胶囊(DTZ-CRC)的体外释放度与体内吸收的相关性.方法:测定DTZ- CRC在不同pH释放介质中的释放度;10名男性健康志愿者po 60mg DTZ-CRC,HPLC法测定血药浓度,按照Wagner-Nelson公式计算药物吸收分数.结果:不同释放介质中药物的体外释放度与体内吸收分数的相关系数r分别为0.984 8、0.986 7和0.982 8.结论:DTZ-CRC的体外释放度与体内吸收具有显著的相关性.     

pH值对盐酸吡硫醇水溶液稳定的影响

目的考察pH值对盐酸吡硫醇水溶液稳定性的影响.方法用恒温加速试验法,测定不同温度下不同pH值时盐酸吡硫醇降解的速率常数,得到不同pH值时的降解活化能及不同温度下的最稳定pH值.结果在不同温度下,当pH2时,盐酸吡硫醇水溶液相对最稳定;随着pH值升高,水溶液稳定性迅速降低.结论适当调整溶液的pH值可以显著改善盐酸吡硫醇的化学稳定性,为其制剂学研究提供了部分依据.     

多肽类药物鼻腔给药研究进展

随着生物制药技术的发展,越来越多的多肽类药物在医药领域得到应用。但由于这类药物稳定性不佳、口服易被酶解等问题,临床多采用注射途径给药。鼻腔给药不仅能够克服口服给药的首过效应、注射给药的顺应性差等问题,而且具有脑靶向、低剂量高活性的优点。本文主要就多肽类药物的鼻腔给药进行综述,系统地介绍了鼻腔的组织构造,药物本身性质、制剂的特性和鼻腔内环境对药物鼻腔吸收的影响,以及通过添加吸收促进剂、酶抑制剂和设计成不同药物载体等方法改善药物鼻腔吸收,并叙述了鼻腔给药的研究热点-鼻脑传递,为后续相关制剂研发提供参考。     

Chemical stability, enzymatic hydrolysis, and nasal uptake of amino acid ester prodrugs of acyclovir

The objective of this work was to improve nasal absorption of relatively impermeable small drug molecules via an amino acid prodrug approach. Acyclovir was selected as a model drug. L-Aspartate beta-ester, L-lysyl, and L-phenylalanyl esters of acyclovir were synthesized to investigate their effectiveness in enhancing nasal absorption of acyclovir. A stability study was conducted in phosphate buffer under various pH conditions at 25 and 37 degrees C. Enzymatic hydrolysis in rat nasal washings and plasma was conducted at 37 degrees C. A rat in situ nasal perfusion technique was utilized in this investigation to examine the rate and extent of nasal absorption of amino acid prodrugs. The remaining analyte concentrations in the nasal perfusate were quantitated by reversed-phase high-performance liquid chromatography. The results revealed that the L-lysyl and L-phenylalanyl esters were less stable than L-aspartate beta-ester. The stability of all three esters decreased with increasing pH and temperature. L-phenylalanyl ester is highly susceptible to plasma esterases, with an in vitro half-life 1.33 min. The rat in situ nasal perfusion study revealed that the extent of nasal absorption of acyclovir, L-lysyl and L-phenylalanyl esters was not significant (p < 1%). L-Aspartate beta-ester was absorbed to the extent of approximately 8% over 90 min of perfusion at an initial drug concentration of 100 microM. Nasal absorption of L-aspartate beta-ester of acyclovir was inhibited by L-asparagine but not by a dipeptide glycylsarcosine (Gly-Sar). The enhancement of acyclovir nasal absorption from the L-aspartate beta-ester prodrug suggests that nasal uptake of this prodrug probably involves an active transport system.     

Nasal drug delivery of sumatriptan succinate

The purpose of this work was to increase the nasal absorption of sumatriptan succinate by using bile salts. A rat in situ nasal perfusion technique was used to examine the rate and extent of absorption of sumatriptan succinate. In vitro enzymatic drug degradation studies were carried out with rat nasal washings. Various experimental conditions such as nasal perfusion rate, pH of the perfusion medium and concentrations of absorption enhancers such as sodium deoxycholate, sodium caprate, sodium tauroglycocholate and EDTA were optimized. In vivo studies were carried out for the optimized formulation in rabbits and the pharmacokinetics parameters of nasal solution were compared with marketed nasal solutions. Nasal absorption of sumatriptan succinate was pH dependent. It was found maximum at pH 5.5 and decreased at higher pH values. In in vitro enzymatic degradation studies, no measurable degradation was observed during the first week. The extent of drug absorption was increased by absorption enhancers. Sodium deoxycholate appeared to be more effective for enhancing the nasal absorption of sumatriptan succinate than the other absorption enhancers. The order of increasing absorption of sumatriptan succinate caused by theenhancers was sodium deoxycholate > sodium caprate > sodium tauroglycocholate > EDTA.     

The influence of absorption enhancers on nasal absorption of acyclovir.

The objective of this work was to increase the nasal absorption of acyclovir by using absorption enhancers. Acyclovir was selected as a model drug. A rat in situ nasal perfusion technique was utilized in the investigation to examine the rate and extent of absorption of acyclovir. In vitro enzymatic drug degradation study was carried out with rat nasal washings. Various experimental conditions such as nasal perfusion rate, pH of the perfusion medium and concentrations of absorption enhancers such as sodium deoxycholate, hydroxypropyl beta-cyclodextrin, sodium caprate, sodium tauroglycocholate and EDTA were optimized. Nasal absorption of acyclovir was pH dependent. Initial absorption rate constants were determined by the plot of log% remaining amount of drug in perfusate vs time. It was found maximum at pH 7.4 and decreased at lower and higher pH conditions. In in vitro enzymatic degradation study, no measurable degradation was observed during first week. The extent of drug absorption was increased via absorption enhancers. In vivo studies were carried out for the optimized formulation in rabbits and the pharmacokinetics parameters of nasal solution were compared with oral solution. Hydroxypropyl beta-cyclodextrin appeared to be more effective for enhancing the nasal absorption of acyclovir than the other absorption enhancers. The order of increasing absorption of acyclovir caused by the enhancers was hydroxypropyl beta-cyclodextrin>sodium deoxycholate>sodium caprate>sodium tauroglycocholate>EDTA.     

Mechanism of nasal absorption of drugs I: Physicochemical parameters influencing the rate of in situ nasal absorption of drugs in rats

The effect of rate of perfusion, volume, pH of the perfusate, and partition coefficient of the drug on the rate of in situ nasal absorption in rats was examined. The studies showed that the rate constant for the nasal absorption of phenobarbital was independent of the rate of perfusion above a value of 2 mL/min. The nasal absorption of benzoic acid was found to depend on the pH of the perfusate with the benzoate anion being absorbed at a rate one-fourth of that of benzoic acid. The effect of lipid solubility on the extent of nasal absorption was studied using a series of barbiturates. The rate and extent of absorption was found to be dependent on the chloroform-water partition coefficient of the barbiturate. The effect of the volume of the perfusate on the absorption rate constant of phenobarbital, phenol red, tyrosine, and propranolol was studied. The data obtained showed that a linear relationship existed between the rate constants of absorption and the reciprocal of the volume of the perfusate. Using this in situ relationship it was possible to predict in vivo absorption rate constants for propranolol and L-tyrosine when volumes of 0.1 mL were administered. The calculated values for these compounds were found to be close to those determined in in vivo experiments. This indicates that the in situ technique can be used to predict in vivo absorption rate constants.     

雌二醇甲基化-β-环糊精包合物鼻黏膜吸收动力学研究

目的研究雌二醇甲基化 β环糊精包合物鼻黏膜吸收动力学,考察循环液的体积和流速对雌二醇甲基化 β环糊精包合物鼻黏膜吸收的影响。方法采用大鼠在体灌流模型,并固定循环液体积和流速。结果吸收速度常数(k)随着循环液体积的增加呈下降趋势;当流速较小时,随着流速的增加,k增大,但超过2 5mL·min-1后,k反而随着流速的增加而减小;循环液为5mL、流速2 5mL·min-1时,不同浓度的雌二醇甲基化 β环糊精包合物鼻黏膜吸收速度常数不同,且随药液浓度的增加而增大,经t检验(P <0 0 5 ) ,不同浓度间存在显著差异。结论雌二醇环糊精包合物鼻黏膜吸收具有浓度依赖性,在固定浓度条件下其动力学过程符合零级动力学模型,吸收速度常数与包合物的药物动力学解离 缔合平衡有关     

Mechanism of nasal absorption of drugs. III: Nasal absorption of leucine enkephalin

The nasal absorption of a model peptide, leucine enkephalin (LE), was studied in rats using an in situ technique in which 4 mL of perfusion solution was circulated. Leucine enkephalin (LE) was found to undergo hydrolysis to its major metabolite des-tyrosine leucine enkephalin (DTLE). The addition of 1% sodium glycocholate (SGC) to the perfusion solution resulted in an increase in the overall rate of disappearance of LE and a decrease in the rate of formation of DTLE. When LE was added to nasal washings (i.e., Ringer's buffer that was precirculated through the nasal cavity to extract enzymes), LE was found to form DTLE. When SGC or puromycin was added to the nasal washings prior to the addition of LE, the rate of conversion of LE to DTLE was significantly reduced, suggesting that these two agents can inhibit peptidase enzyme activity in the nasal cavity. Since the volume of the solution has been shown to influence the kinetics of absorption of drugs administered nasally, a new experimental technique, the in vivo-in situ technique, which utilizes small volumes of solution and simulates realistic use of nose drops, was employed to further examine the mechanism of absorption and hydrolysis of LE in rats. Leucine enkephalin (LE) dissolved in 100 microL of Ringer's buffer was placed in the isolated nasal cavities of rats. The disappearance of LE and the appearance of DTLE were followed by rinsing the nasal cavity with fresh buffer. Disappearance of LE was always accompanied by appearance of DTLE, and the fraction of LE converted to DTLE decreased as the concentration of LE increased, suggesting a saturable enzymatic process.(ABSTRACT TRUNCATED AT 250 WORDS)     

Direct drug transport from the rat nasal cavity to the cerebrospinal fluid: the relation to the dissociation of the drug

Abstract— We aimed to clarify the relationship between drug dissociation (sulphisomidine) and its direct transport from the nasal cavity to the cerebrospinal fluid (CSF). Rat nasal cavities were perfused in a single pass system with buffers (pH 5·5, 6·5, 7·4, 8·7 and 9·4). Plasma and CSF were collected and the concentration of sulphisomidine was measured. Nasal clearance increased with the increase in the un-ionized fraction of the drug. The ratio of the drug concentration in CSF to that in the nasal perfusion fluid (the index of the degree of the drug transport from the nasal cavity to CSF), was changed in accordance with the un-ionized fraction of drug. These results show that both the nasal absorption and the drug transport conform to the pH partition theory.     

Model of Disposition of Drugs Administered into the Human Nasal Cavity

A mathematical model was developed to describe the rate processes involved in the disposition of drugs placed in their delivery systems into the human nasal cavity. The model contains first-order parallel and sequential irreversible rate processes representing the convective drug and carrier transport by fluid flow, mucociliary clearance and peristalsis, drug release and absorption, and decomposition of the drug prior to its appearance in the systemic circulation. The numerical values of the parameters used are based on literature data from clearance studies of nonabsorbable markers deposited in the human nasal cavity, and data obtained under a variety of experimental conditions are consistent with the model. The effect of bioadhesive carriers is successfully simulated by reducing the mucociliary clearance rate constants for the transport from the posterior part of the nose into the gastrointestinal tract. The simulation shows that bioadhesion improves bioavailability and reduces the variability in absorption which might be caused by a variable pattern of deposition in the nose. Variable bioavailability could result from removal of the drug from the nasal cavity by sniffing, blowing, or wiping the nose, leading to different drug residence times in the nose. The model simulations further suggest that drug decomposition in the nose, while lowering bioavailability, also reduces variable absorption due to variable residence times of the drug in the nose.     

Toxicological Implications of Nasal Formulations

Various nasal formulations have been tested for their suitability to deliver drugs through the nasal cavity. This route is especially of interest where the dose of drug is small and the drug may undergo an extensive first-pass metabolism and/or decomposition while passing through the gastrointestinal tract. Unfortunately, the nasal mucosa does not have same type of tolerability to all drugs and additives used in formulations. Some chemicals may damage the nasal epithelia or alter the mucociliary defensive mechanism of the nose. There also is a possibility that the drug can transport directly from nasal cavity to the brain via the olfactory route. Several methods have been developed to study the impact of drugs and excipients on the integrity of the nose. In some cases, the in vitro results did not correlate well with in vivo data, due to lack of reproducibility of the natural body environment, and some in vitro methods may not be sensitive enough and thus may complicate interpretation of the results. This review provides a toxicological evaluation of different drugs and additives used to optimize a nasal formulation. Certain chemicals are now routinely used as additives in nasal formulations. Although these compounds are most likely safe, if they are used over the long term, they may damage the epithelia of the nose. For multidose preparations, preservatives are often included in nasal delivery systems and may cause ciliotoxic effects. Both physicochemical parameters of drugs as well as formulation materials should be considered in evaluating the overall effect ofa drug product on the nose. Therefore, any prior knowledge of the effect of drugs and additives on the nasal epithelia ultimately will assist in the development of nasal products. Furthermore, as the sites of absorption in the nasal cavity are somewhat limited, evaluation of the long-term tolerability of a nasal formulation is of great importance.     

In situ nasal absorption of midazolam in rats

Intranasal (i.n.) midazolam (MDZ) administrations may be used successfully for preoperative sedation, especially in young patients. However, clinicians have to use the commercial parenteral formulation, the low pH of which (3.3), necessary to solubilize MDZ (pK(a) 6.1), is probably responsible for the signs of local irritation frequently reported. As a starting point to design a formulation suitable for the nasal route, MDZ nasal absorption was investigated in rats. The effects of the MDZ solution concentration (10--100 microg/ml), osmolality (from less than 10 mOsm/kg up to 450 mOsm/kg) and pH (3.3--7.4) were studied using an in situ perfusion technique. MDZ was determined by reversed-phase HPLC in the circulating solution and results were expressed in clearance terms. MDZ absorption was independent of its concentration. The pH of the solutions was the key-parameter and only a pH above 4 allowed significant absorption. These results were consistent with a passive diffusion absorption of MDZ and partly followed the pH partition theory. In conclusion, satisfactory MDZ absorption should be expected with a formulation at a pH suitable for the nasal route in human (5.5--6.5).