Bioavailability of ibuprofen from hot-melt extruded mini-matrices

The bioavailability of ibuprofen from hot-melt extruded mini-matrices based on ethyl cellulose and a hydrophilic excipient was tested. During the in vivo evaluation an oral dose of 300 mg ibuprofen was administered to healthy volunteers (n = 9) in a randomized cross-over study and compared with a commercially available sustained release product (Ibu-slow). The plasma samples were analysed by a validated HPLC-UV method. One mini-matrix formulation (F-1) consisted of 30% ibuprofen, 35% ethyl cellulose and 35% hydroxypropyl methylcellulose (Metolose 60 SH 50), while the second formulation (F-2) contained 60% ibuprofen, 20% ethyl cellulose and 20% xanthan gum. These mini-matrices were administered in hard gelatine capsules. Both formulations behaved in vivo as sustained release formulations with an HVD(t50% Cmax) value (time span during which the plasma concentration is at least 50% of the Cmax value) of 7.6 and 12.0 h for formulations F-1 and F-2, respectively, whereas a value of 5.2 h was obtained for Ibu-slow. Although a significantly higher Cmax and AUC(0-24 h) was seen for the reference product, the relative bioavailability of both experimental formulations was about 80%.     

Performance of a modified starch hydrophilic matrix for the sustained release of theophylline in healthy volunteers.

Two experimental formulations of theophylline with a hydrophilic starch matrix were evaluated for their sustained-release characteristics after single administration in healthy human volunteers. Theo-dur was chosen as a reference sustained-release formulation. In a first study, the extent of absorption was similar for a syrup, for Theo-dur, and for the experimental formulation of theophylline with 70% drum-dried corn starch as the sustained-release agent (DDCS-70). The maximal plasma concentration (Cmax) was significantly lower, and the time to reach Cmax as well as the time span during which the plasma concentration was at least 75% of the Cmax were significantly higher for Theo-dur than for the DDCS-70 formulation. A sustained-release profile, as for Theo-dur, was not reached for DDCS-70. In a second study the influence of the starch:drug ratio on the bioavailability was investigated. The decrease in starch content from 70 to 50% of the formulation did not improve the plasma concentration-time profile towards a sustained-release profile.     

Matrix mini-tablets based on starch/microcrystalline wax mixtures

Matrix mini-tablets based on a combination of microcrystalline waxes and starch derivatives were prepared using ibuprofen as a model drug. The production of mini-tablets was preferred over the production of pellets, as up-scaling of the pelletisation process seemed problematic. Prior to tabletting, melt granulation in a hot stage screw extruder and milling were required. The in vitro drug release was varied using microcrystalline waxes with a different melting range, the slowest drug release being obtained with a formulation containing a microcrystalline wax with a melting range between 68 and 72 degrees C. Generally speaking increasing the wax concentration resulted in a slower drug release. In vitro drug release profiles were also modified using different starches and mixtures of starches. Increasing the ibuprofen concentration to 70% resulted in a faster drug release rate.     

Evaluation of the absorption from three ibuprofen formulations

The pharmacokinetic differences between two sustained-release 300 mg (A) and 400 mg (B) formulations and a rapid-release 400 mg ibuprofen conventional sugar-coated formulation (C) were compared after a single dose. Mean peak levels of 25.1 micrograms/ml for preparation A (2 X 300 mg), 31.3 micrograms/ml for preparation B (2 X 400 mg) and 68.5 micrograms/ml for preparation C (2 X 400 mg) were reached at 5.3, 3 and 2 hours respectively, after ingestion of the drugs. The individual plasma-level time-profiles for the majority of doses suggested prolonged absorption of product A and B. The absorption from formulations A and B was significantly slower (p less than 0.001 and p less than 0.05 respectively) than that from the conventional tablets. The bioavailability of ibuprofen from sustained-release capsules, was not found to differ significantly from that of ibuprofen from conventional tablets. The relative bioavailability was very close to 100% in almost all subjects (coefficient of variation 14% and 17%). Projections of plasma concentrations upon multiple dosing were made from single dose data. The dosage interval concentration ratio which reflects both the frequency and the entry of the drug into and from the body was much lower for sustained-release formulations (A: 3.0; B: 3.7; C: 12.9).     

Xanthan gum to tailor drug release of sustained-release ethylcellulose mini-matrices prepared via hot-melt extrusion: in vitro and in vivo evaluation.

Mini-matrices (multiple-unit dosage form) with release-sustaining properties were developed by means of hot-melt extrusion using ibuprofen as the model drug and ethylcellulose as sustained-release agent. Xanthan gum, a hydrophilic polymer, was added to the formulation to increase the drug release since ibuprofen release from the ibuprofen/ethylcellulose matrices (60/40, w/w) was too slow (20% in 24 h). Changing the xanthan gum concentration as well as its particle size modified the in vitro drug release. Increasing xanthan gum concentrations yielded a faster drug release due to a higher liquid uptake, swelling and erosion rate. Regarding the effect of the xanthan gum particle size, no difference was observed for formulations containing 10% and 20% xanthan gum. However, using 30% xanthan gum, drug release was influenced by the particle size of the hydrophilic polymer due to the susceptibility of the coarser xanthan gum particles to erosion. Drug release from the mini-matrices was mainly diffusion controlled, but swelling played an important role to obtain complete drug release within 24 h. Drug release was influenced by the ionic strength of the medium as the conformation of xanthan gum molecules is determined by the salt concentration. An oral dose of 300 mg ibuprofen was administered to dogs (n=6) in a cross-over study design either as an immediate-release preparation (Junifen), as a sustained-release formulation (Ibu-Slow 600 mg (1/2 tablet)) or as the experimental mini-matrices (varying in xanthan gum concentration). Administration of the experimental formulations sustained the ibuprofen release. Although a significant difference in dissolution rate of the 20% and 30% xanthan gum mini-matrices was detected in vitro, the difference in relative bioavailability was limited (70.6% and 73.8%, respectively).     

In-vivo Evaluation in Man of a Hydrophilic Matrix Containing Propylthiouracil

To reduce the number of administrations of propylthiouracil required to treat hyperthyroidism, the bioavailability and sustained-release characteristics of 300 mg propylthiouracil formulated in hydrophilic matrix tablets were evaluated after single oral administration in healthy male volunteers. A conventional tablet was chosen as the reference formulation. For tablets formulated from three different types of hydroxypropylmethylcellulose, K15M, K4M and K100LV, propylthiouracil dissolution in-vitro was 40%, 51% and 100%, respectively, in 8 h. The three matrix formulations showed sustained plasma concentration-time profiles. The relative bioavailability was 50, 51 and 87%, respectively, for K4M, K15M and K.100LV hydroxypropylmethylcellulose matrix tablets. When reverse triiodothyronine concentrations were plotted against the corresponding propylthiouracil concentrations, an antihysteresis loop was observed with the conventional tablets and the K100LV matrix tablet. A linear concentration-response curve was obtained for both the K4M and K15M formulations. The results showed that the K100LV matrix tablet gave a sustained plasma concentration-time profile and a bioavailability and extrathyroidal effect similar to that of a conventional tablet.     

Design and evaluation of gastroretentive levofloxacin floating mini-tablets-in-capsule system for eradication of Helicobacter pylori

Gastroretentive levofloxacin (LVF) floating mini-tablets for the eradication of Helicobacter pylori (H. pylori) were prepared using the matrix forming polymer hydroxypropyl methylcellulose (HPMC K100M), alone or with Carbopol 940P in different ratios by wet granulation technique. Buoyancy of mini-tablets was achieved by an addition of an effervescent mixture consisting of sodium bicarbonate and anhydrous citric acid to some formulations. The prepared mini-tablets were evaluated for weight variation, thickness, friability, hardness, drug content, in vitro buoyancy, water uptake and in vitro release. The optimized formula was subjected to further studies: FT-IR, DSC analysis and in vivo examination in healthy volunteers. The prepared mini-tablets exhibited satisfactory physicochemical characteristics. Incorporation of gas-generating agent improved the floating parameters. HPMC K100M mini-tablet formulation (F1) offered the best controlled drug release (>8 h) along with floating lag time <1 s and total floating time >24 h. The obtained DSC thermograms and FT-IR charts indicated that there is no positive evidence for the interaction between LVF and ingredients of the optimized formula. The in vivo test confirmed the success of the optimized formula F1 in being retained in the stomach of the volunteers for more than 4 h. LVF floating mini-tablets based on HPMC K100M is a promising formulation for eradication of H. pylori.Abbreviations: LVF, levofloxacin; H. pylori, Helicobacter pylori; HPMC, hydroxypropyl methylcellulose; FT-IR, Fourier transform infrared spectroscopy; DSC, differential scanning calorimetry; PVP, polyvinyl pyrrolidone; SI, swelling index     

格列齐特缓释片的制备及其释药因素考察

目的以格列齐特为模型药物,考察缓释片的处方及工艺因素对其体外释放的影响。方法以羟丙基甲基纤维素(HPMC)为骨架材料,预胶化淀粉等为填充剂,以体外释放度为判断原则考察处方及工艺因素对药物溶出度的影响。结果获得了满足设计要求的缓释片处方,通过对体内生物利用度的初步研究,发现格列齐特缓释凝胶骨架片在体内的有效血药浓度可维持24h以上。结论该制剂工艺简单,所用各种辅料成本低,制得的格列齐特缓释片释放度符合规定。     

尼群地平微丸家犬体内药动学研究

目的研究自制尼群地平速释、缓释微丸在家犬体内的药物动力学,并进行相对生物利用度评价。方法分别以尼群地平国产片和日本片为参比制剂,采用高效液相色谱法测定4个制剂的家犬体内血浆药物浓度并绘制平均血药浓度-时间曲线,计算药动学参数并进行方差分析,同时对自制制剂的生物利用度进行了评价。结果尼群地平速释微丸、缓释微丸、国产片和日本片的Tmax依次为0.92±0.14、5.0、1.83±0.29和1.08±0.38h;Cmax依次为187.01±21.23、85.25±13.80、88.31±8.65和160.22±24.34ng.mL-1;AUC0~t依次为665.54±109.07、606.47±130.68、472.44±89.44和659.16±100.05 ng.h.mL-1。以国产片为参比制剂时,自制速释微丸和缓释微丸的相对生物利用度分别为146.92%和135.92%;以日本片为参比制剂时,速释微丸和缓释微丸的相对生物利用度分别为101.04%和91.63%。结论自制速释微丸接近同类产品国外制剂,优于国内制剂;缓释微丸体内作用时间延长,但生物利用度偏低,需进一步改进处方或工艺。     

Understanding the Factors That Control the Quality of Mini-Tablet Compression: Flow,Particle Size,and Tooling Dimension

Despite the increasing importance of mini-tablet for its advantages as pediatric formulations and in modified-release applications, its popularity is limited due to the lack of formulation and processing knowledge in developing such dosage forms. In this study, common grades of microcrystalline cellulose and roller compacted granules with a range of powder properties were used to evaluate the critical material properties required for the successful manufacturing of 1.7-mm mini-tablets. It was found that blends with small particle size had poor flow properties that did not support consistent die filling and also tended to cause tooling jam and damage. While the granulation process was effective in improving blend flow properties by increasing particle size, it is imperative to avoid very large particles that could also cause inadequate flow by blocking the space within the die. Successful mini-tablet compression could be achieved by removing particles larger than roughly 1/3 of the die diameter or milling the granules using a screen less than 1/3 of the die diameter.     

尼群地平缓释胶囊在家犬体内的药动学与相对生物利用度

目的研究尼群地平缓释胶囊在家犬体内的药代动力学与相对生物利用度。方法用高效液相色谱法测定了 6条健康家犬口服尼群地平缓释胶囊 (受试制剂 )和尼群地平普通片 (参比制剂 )后不同时间点血浆中尼群地平的浓度 ,绘制血药浓度 -时间曲线 ,计算药代动力学参数及相对生物利用度。结果受试犬口服含尼群地平 4 0mg的受试制剂和参比制剂后 ,血浆中尼群地平的tmax分别为 (6 1 7± 1 60 )和 (1 4 6± 0 5 1 )h;cmax分别为 (3 4 3 8± 1 2 2 6)和 (45 6 5± 1 0 7 4 )nmol L ;用梯形法计算 ,AUC0～t分别为 (1 93 0 1± 1 0 0 5 1 0 6)和 (1 790 8± 94 2 8)nmol·h L。以AUC计算 ,与参比制剂相比 ,受试制剂中尼群地平的相对生物利用度平均为 (1 1 0 5 9± 2 3 60 ) %。将AUC0～t经对数转换后进行方差分析 ,结果表明 ,受试制剂与参比制剂相比 ,除个体间外 ,周期间与制剂间无显著性差异 (P >0 0 5 ) ,受试制剂AUC0～t的 90 %置信区间为参比制剂的 88 5 4 %～ 1 3 1 93 %。结论尼群地平缓释胶囊与国外普通片相比 ,在犬体内具有更长的作用时间 ,且相对生物利用度相近     

布洛芬颗粒的人体药动学及生物等效性研究

目的：研究单剂量口服布洛芬颗粒的药动学特征,并评价两种制剂的生物等效性。方法：采用双周期交叉试验,18名健康志愿者分别单剂量口服受试试剂或参比制剂布洛芬颗粒600mg,用HPLC法测定血药浓度,计算药动学参数,并进行统计分析。结果：布洛芬颗粒受试制剂和参比制剂的主要药动学参数分别为tmax（2．56±0．51）和（2．56±0．51）h,fmax（42．81±8．00）和（42．76±7．84）μg／mL,t1／2（1．79±0．17）和（1．75±0．21）h,AUC0～15（105．10±12．90）和（105．67±10．32）μg·h·mL^-1,AUC0-∞（105．99±12．94）和（106．60±10．33）μg·h·mL^-1。结论：受试制剂的相对生物利用度为（99．29±4．66）％,两种制剂具有生物等效性。     

Comparison of inter- and intra-subject variation in oral absorption of theophylline from sustained-release products

A comparative study of inter- and intra-subject variation in the bioavailability of theophylline from two commercial sustained-release dosage forms (a beaded capsule and a tablet formulation) was performed in 12 healthy adult volunteers. The disposition kinetics of theophylline was characterized in each subject following a single 250 mg oral dose of a fully bioavailable liquid formulation. Duplicate single dose studies of each of the two sustained-release products were then performed on 4 separate occasions in a randomized crossover fashion. On the average, the extent of theophylline bioavailability from the two sustained-release dosage forms was equivalent and essentially complete as compared to that from the liquid formulation. Both sustained-release formulations exhibited reasonable consistency in the extent of bioavailability when tested on two different trial days in a given subject (the mean percentage difference in extent of absorption was 11.5 ± 8.3% for the beaded capsule and 11.8 ± 12.3% for the tablet). The rate of theophylline absorption from the beaded capsule formulation was more rapid than from the tablet formulation as indicated by an earlier time to reach peak serum concentration (6.0 ± 1.9 vs 8.9 ± 2.5 h). Individual time course of cumulative absorption from the sustained-release formulations was determined using the Wagner-Nelson procedure. The overall variability in the cumulative absorption profile was greater for the tablet as compared to the capsule formulation. More significant was the fact that within each subject the absorption profiles were less reproducible between trials with the tablet as compared to the capsule. Dose-to-dose variation in the release/absorption kinetics of theophylline from these sustained-release products may lead to unpredictable fluctuations in steady-state serum theophylline concentration-time profiles during chronic drug administration.     

In vivo evaluation of matrix pellets containing nanocrystalline ketoprofen

The aim of this study was to evaluate the in-vivo behaviour of matrix pellets formulated with nanocrystalline ketoprofen after oral administration to dogs. No significant differences in AUC-values were seen between pellet formulations containing nanocrystalline or microcrystalline ketoprofen and a commercial ketoprofen formulation (reference: Rofenid® 200 Long Acting). C_max of the formulations containing nano- or microcrystalline ketoprofen was significantly higher compared to reference, whereas t_max was significantly lower. The in-vivo burst release observed for the spray dried nanocrystalline ketoprofen matrix pellets was reduced following compression of the pellets in combination with placebo wax/starch pellets. These matrix tablets sustained the ketoprofen plasma concentrations during 5.6 and 5.4 h for formulations containing nano- and microcrystalline ketoprofen, respectively.     

Characterization and evaluation of self-microemulsifying sustained-release pellet formulation of puerarin for oral delivery

The present study aims to develop self-microemulsifying drug delivery systems (SMEDDS) in sustained-release pellets of puerarin to enhance the oral bioavailability of puerarin. The performances of puerarin-SMEDDS including oils, emulsifiers, and co-emulsifiers were evaluated. Pseudo-ternary phase diagrams shows that the optimized formulation consisted of castor oil as the oil phase, Cremophor EL as the emulsifier, and 1,2-propanediol as the co-emulsifier. SMEDDS sustained-release pellets were prepared via extrusion-spheronization. The particle size distributions of the formulations were determined using transmission electron microscopy and scanning electronic microscopy. The mean particle size was 50 ± 8 nm. The pharmacokinetics and bioavailability of the puerarin-SMEDDS sustained-release pellets and puerarin tablets were evaluated and compared in beagle dogs. The absolute bioavailability of the puerarin-SMEDDS sustained-release pellets was enhanced by approximately 2.6-fold compared with that of the puerarin tablet. The relative bioavailability (F(rel)) of the SMEDDS pellets was 259.7% compared with the tablet group. The results demonstrated that the puerarin-SMEDDS sustained-release pellets had a sustained-release effect, and could remarkably improve the oral bioavailability of puerarin.     

盐酸伪麻黄碱脉冲小片包衣液处方优化

目的制备盐酸伪麻黄碱脉冲控释小片,并对其体外释药情况进行研究。方法制备盐酸伪麻黄碱含药片芯,采用丙烯酸树脂水分散体(Eudragit(RS 30D)制备盐酸伪麻黄碱脉冲控释小片。通过单因素实验考察药物释放的影响因素,确立处方组成,采用正交设计对包衣液处方进行优化。结果当隔离层增质量分数为2%、控释层增质量分数为5%、CMS-Na用量质量分数为25%,脉冲控释小片的时滞为6 h,体外具有脉冲释药特性。结论成功地制备了盐酸伪麻黄碱脉冲控释小片,体外释药符合脉冲释药的要求。     

布洛芬缓释胶囊生物利用度研究

10名健康志愿者随机交叉口服600mg布洛芬缓释胶囊和芬必得进行药代动力学和相对生物利用度研究。采用高效液相色谱法，测定血清中布洛芬浓度，经3p87药动学计算程序处理，得布洛芬缓释胶囊和芬必得的：AUC分别为147．75±28．78：mg／（L·h）和154．16±26．76mg／（L·h），Tmax分别为4．22±0．73h和4．10±0．83h；Cmax分别为15．97±2．84mg／L和16．76±2．92mg／L，经配对ｔ－检验，两者的AUC、Tmax、Cmax均无显著性差异（P＞0．05）。采用梯形法计算的布洛芬和芬必得的AUC。－t分别为153．53±26．11mg／（L·h）和157．88±23．06mg／（L·h），方差分析和双单侧检验结果表明两者具有生物等效性。布洛芬缓释胶囊相对生物利用度为96．07％。     

Bioavailability and bioequivalence of organic nitrates. Isosorbide dinitrate--a study of sustained-release preparations

Assessment of Bioavailability of Organic Nitrates/Comparative bioavailability study of sustained-release isosorbide dinitrate preparations. Relative bioavailabilities of isosorbide dinitrate (ISDN, CAS 87-33-2) and the metabolite isosorbide-5-mononitrate (IS-5-MN, CAS 16051-77-7) were studied after application of Maycor retard 40 (sustained-release capsules, multiple unit formulation, test preparation) in comparison to sustained-release tablets (single unit formulation, reference preparation) with 16 healthy male volunteers in a two-way crossover design. Test and reference formulations were previously characterised in vitro by dissolution tests. ISDN, IS-5-MN (IS-2-MN) plasma concentrations were determined using a selective and sensitive GLC-method with ECD-detection. As pharmacokinetic parameters AUC, Cmax and half value duration (HVD) were evaluated. Bioequivalence was assessed by calculating 90%-confidence intervals (ANOVA, ANOVAlog, Mann-Whitney-test) for ISDN and IS-5-MN. Bioequivalence was accepted if due to the inclusion rule one of the calculated intervals fulfill the requirements of 80 and 120% (AUC) or 70 and 130% (Cmax, HVD), respectively. Relative bioavailability of the test formulation was calculated as 94% (ISDN) and 96% (IS-5-MN). Maximum plasma concentrations of ISDN (IS-5-MN) were determined for the test preparation as 14.3 +/- 3.1 ng/ml (265 +/- 45 45 ng/ml) and as 22.8 +/- 12.6 ng/ml (287 +/- 59 ng/ml) for the reference product. HVD-values were for the test preparation 4.5 +/- 1.3 h (ISDN) and 8.5 +/- 1.3 h (IS-5-MN) and for the reference formulation 3.1 +/- 1.2 h (ISDN) and 8.1 +/- 1.4 (IS-5-MN).(ABSTRACT TRUNCATED AT 250 WORDS)     

Dissolution Enhancement and Formulation of Rapid-Release Lornoxicam Mini-Tablets

,The aim was to enhance the dissolution of lornoxicam (LOR) and to produce mini-tablets with an optimised system to provide a rapid-release multi-particulate formulation. LOR systems were prepared through co-evaporation with either polyethylene glycol 6000 or Pluronic® F-68 (PLU) and adsorption onto Neusilin® US2 alone or co-adsorption in the presence of different amounts of polysorbate 80. All systems were characterised by FT-IR, differential scanning calorimetry, X-ray diffraction, flowability and dissolution techniques. Mini-tablets were prepared using the system with the optimum dissolution profile and flowability. Tensile strengths, content uniformity and dissolution profiles of the mini-tablets were evaluated. The effects of different excipients and storage conditions on mini-tablet properties were also studied. The optimised rapid-release LOR mini-tablets were further evaluated for their in vivo pharmacokinetic profile. The co-evaporate of LOR with PLU showed significantly faster dissolution and superior flowability and was evaluated together with three directly compressible excipients (Cellactose® 80, StarLac® (STA) and Emcompress®) for mini-tablet formulation. The formulation with STA provided the optimum results in terms of tensile strength content uniformity and rapid drug release following a 3-month stability study and was selected for further in vivo evaluation. The pharmacokinetic profile indicated the potential of the mini-tablets achieving rapid release and increased absorption of LOR. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:2470–2483, 2014     

A novel approach to sustained pseudoephedrine release: differentially coated mini-tablets in HPMC capsules

We developed and optimized a novel pseudoephedrine hydrochloride (PSE) sustained-release dosage form. The system comprises immediate-release mini-tablets (IRMT) and sustained-release mini-tablets (SRMT) contained in a hydroxypropyl methylcellulose (HPMC) capsule. The IRMT contained PSE, excipients and low-substituted hydroxypropyl cellulose (a disintegrant), and the tablets were coated with HPMC, a water-soluble polymer. IRMT prepared with varying amounts of low-substituted hydroxypropyl cellulose all dissolved completely within the first 60min, so low-substituted hydroxypropyl cellulose content does not greatly influence PSE release. The SRMT contained only PSE and excipients, and were coated with a mixture of HPMC and the water-insoluble polymer ethylcellulose. The PSE release profile for the SRMT could be controlled by varying the thickness of the coat, and the lag time could be controlled by varying the amount of ethylcellulose present in the polymer coat. PSE was released immediately from our encapsulated mini-tablet system and release was sustained over an extended period of time: the PSE in the IRMT dissolved within 60min, whereas the PSE in the SRMT was released over 8-10h. This system can be modified to yield various extended drug-release profiles, thereby harnessing the benefits of both SRMT and IRMT.