Self nano-emulsifying simvastatin based tablets: design and in vitro/in vivo evaluation

The aim of this work is to improve the oral bioavailability of poorly water soluble drug, simvastatin (SV) through combining the advantages of self-nanoemulsifying systems (SNEs) and tablets. Ternary phase diagram was constructed using Labrafil, Tween 80 and Transcutol, in order to evaluate self-nanoemulsification domain. The particle size distribution and zeta potential of the prepared systems were evaluated using Malvern Zetasizer. Liquisolid powders were prepared using Aeroperl^® as a coating material and Avicel^® or Starch 1500 as carrier materials, the powder flow properties were then evaluated. Compressed SV SNE based tablets were evaluated regarding their physical characteristics, in-vitro release properties as well as in-vivo pharmacokinetic evaluation in six healthy human volunteers using a validated LC/MS/MS method. The in-vitro release results revealed that the developed SNE based tablets improved the release of SV significantly, compared to commercially available SV tablets (Zocor^®). The optimal SV SNE tablet formulation was S3St10 (10% Labrafil, 60% Tween 80, and 30% Transcutol). The in-vivo evaluation of S3St10 revealed that rapid and enhanced absorption of SV could be obtained from the SNE based tablet, with a 1.5 fold increase in bioavailability than that obtained after administration of Zocor^®. Hence such an approach could be promising in improving the bioavailability of SV.     

Controlled release effervescent buccal discs of buspirone hydrochloride: in vitro and in vivo evaluation studies

Abstract

In the present study controlled release effervescent buccal discs of buspirone hydrochloride (BS) were designed using HPMC as rate controlling and bioadhesive polymer by direct compression method. Sodium bicarbonate and citric acid were used in varying amounts as effervescence forming agents. Carbon dioxide evolved due to reaction of sodium bicarbonate and citric acid was explored for its potential as buccal permeation enhancer. The designed buccal discs were evaluated for physical characteristics and in vitro drug release studies. Bioadhesive behavior of designed buccal discs was assessed using texture analyzer. In vivo animal studies were performed in rabbits to study bioavailability of BS in the designed buccal discs and to establish permeation enhancement ability of carbon dioxide. It was observed that effervescent buccal discs have faster drug release compared to non-effervescent buccal discs in vitro and effervescent buccal discs demonstrated significant increase in bioavailability of drug when compared to non-effervescent formulation. Hence, effervescent buccal discs can be used as an alternative to improve the drug permeation resulting in better bioavailability. However, the amount of acid and base used for generation of carbon dioxide should be selected with care as this may damage the integrity of bioadhesive dosage form.     

亮菌甲素片在健康人体的药代动力学和相对生物利用度

目的 研究亮菌甲素片(利胆药)在健康人体的药代动力学和相对生物利用度.方法 用随机交叉给药自身为对照法,20名健康受试者单次口服亮菌甲素参比和受试制剂各40 mg;用液相色谱-串联质谱法测定血浆中亮菌甲素的浓度,计算两种制剂的药代动力学参数和相对生物利用度.结果 受试制剂和参比制剂主要药代动力学参数,tmax分别为(0.35±0.09)、(0.36±0.08)h;Cmax分别为(32.94±11.52)、(31.15±8.23)ng·mL-1;t1/2分别为(0.42±0.19)、(0.37±0.11)h;AUC0-t分别为(12.92±3.91)、(12.80±4.03)ng·h·mL-1;AUC0-∞分别为(13.10±3.93)、(12.95±4.07)ng·h·mL-1.受试制剂与参比制剂的平均相对生物利用度为(102.00±16.19)%.结论 亮菌甲素片参比制剂与受试制剂生物等效.     

盐酸特比萘芬片在健康人体中的相对生物利用度及生物等效性试验

目的:评价盐酸特比萘芬片在健康人体的相对生物利用度和生物等效性。方法:20名健康受试者随机交叉单剂量口服盐酸特比萘芬片受试制剂(T)和参比制剂(R),采用液质联用分析方法(LC-MS/MS)测定血浆中特比萘芬浓度。结果:20名健康受试者口服受试制剂和参比制剂后的主要药代动力学参数为:Tmax分别为(1.7±0.6)和(2.2±0.7)h;Cmax分别为(1 590±489)和(1 266.6±432.8)ng·mL-1;t1/2分别为:(21.6±3.6)和(21.0±10.1)h;AUC0～t分别为(8 272.2±2 280.6)和(8 138.9±2 424.0)ng·h·mL-1。受试制剂的AUC0～t或Cmax的90%置信区间对应于参比制剂相应参数的93.44%～111.87%或112.83%～141.91%范围内;受试制剂相对于参比制剂的相对生物利用度为(105.5±26.3)%。结论:受试制剂与参比制剂的生物利用度相当,但受试制剂峰浓度增加,达峰时间提前,没有增加不良反应,疗效也未见降低。     

Enhanced bioavailability of rebamipide nanocrystal tablets: Formulation and in vitro/in vivo evaluation

The purpose of this study was to formulate rebamipide nanocrystal tablets (REB-NTs) by wet-milling technique to enhance its dissolution rate and oral bioavailability. The formulation and preparation technology were screened by single factor tests with particle size and distribution as indicators. Rebamipide nanocrystals (REB-NSs) was then achieved by freeze-dry from the prepared nanosuspensions which were characterized by differential scanning calorimetry (DSC) and x-ray powder diffraction (XRD), while the vitro dissolution and the plasma drug concentration of the nanocrystal tablets were investigated. The results indicated that the prepared nanosuspensions got an average particle size of 286 nm, PI of 0.173 and the average Zeta potential of −18.2 mv. The average particle size of obtained REB-NSs’ redispersibility was 278 nm, and the crystalline of REB-NSs was the same as the rebamipide bulk drug as shown by DSC and XRD. The drug dissolution rate of self-made nanocrystal tablets in different dissolutions was slightly faster than that from the reference tablets, REB-MTs (Mucosta^®), while the C_max and AUC_0–24 of REB-NTs were 1 and 1.57 times higher than that of REB-MTs, which means the nanotechnology could significantly improve the oral bioavailability of rebamipide.     

Rapid and sensitive analysis of cyclobenzaprine by LC–MS/MS: Application to a pharmacokinetic study of cyclobenzaprine in dog

A rapid and sensitive liquid chromatography–tandem mass spectrometry method was developed and validated for the quantification of cyclobenzaprine in dog plasma. After extracted with organic solvent, post-treatment samples were separated on an Agela C18 column interfaced with a triple quadrupole tandem mass spectrometer in positive electrospray ionization mode. Multiple reaction monitoring was performed using the transitions of m/z 276.2 → 216.1 and m/z 325.1 → 109.0 to quantify cyclobenzaprine and escitalopram (internal standard), respectively. The mobile phase consisted of acetonitrile: 5 mM ammonium acetate: formic acid (90:10:0.01, v/v/v) at a flow rate of 0.3 ml/min. The total analysis time was 2.4 min. The method was linear over the concentration range of 0.0200–10.0 ng/ml. The intra- and inter-day precision was within 12.8% in terms of relative standard deviation (RSD%) and the accuracy within 5.6% in terms of relative error. This method was successfully applied in a pharmacokinetic study of extended-release cyclobenzaprine in dogs.     

Formulation and optimization of duloxetine hydrochloride buccal films: in vitro and in vivo evaluation

Duloxetine hydrochloride (DH) is a serotonin–norepinephrine reuptake inhibitor (SSNRI) indicated for the treatment of depression. Duloxetine suffers from reduced oral bioavailability (≈50%) due to hepatic metabolism. This study aims to develop DH buccoadhesive films to improve its bioavailability. DH buccoadhesive films were prepared adopting the solvent casting method using hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA). The prepared films were evaluated for weight uniformity, drug content, surface pH, swelling index, mucoadhesion strength and drug release percentages. Accelerated stability and bioavailability studies in healthy human volunteers were also performed for the selected films. Results of the evaluation tests showed that the optimum physicochemical characters were obtained by the films prepared with 2% HPMC using 10% propylene glycol (F2 films). Accelerated stability studies revealed that DH showed proved stability throughout the experiment time. DH bioavailability from F2 films was determined and compared with that of the marketed oral capsules (Cymbalta^® 30?mg). The pharmacokinetic results showed that C_max for F2 was higher than the market product. In addition, ANOVA analysis showed that a T_max of F2 film was significantly lower, while, the AUC_0–72 of F2 was significantly higher than that of Cymbalta capsules. The percentage relative bioavailability of DH from F2 was found to be 296.39%. Therefore, the prepared buccal films offer an alternative route for the administration of DH with the possibility of improving its bioavailability.     

Development of bioadhesive buccal tablets for felodipine and pioglitazone in combined dosage form: In vitro,ex vivo,and in vivo characterization

The purpose of the present research was to develop bioadhesive buccal tablets for Felodipine (FDP) and Pioglitazone (PIO), low bioavailability drugs, in a combined dosage form for the management of diabetes and hypertension. Buccal tablets were prepared by direct compression method using bioadhesive polymers hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, and carbopol, alone or in combination of two polymers, and were evaluated for physicochemical properties, swelling index, in vitro bioadhesion, in vivo residence time, in vitro drug release, and ex vivo permeation through porcine buccal membrane. Formulation (PF6) showed peak detachment force (3.12 N), work of adhesion (0.72 mJ), swelling index (196%), erosion (10.8%), in vivo residence time of 280?min, in vitro drug release (99.65% and 98.96% in 6?h for FDP and PIO, respectively) with higuchi model release profile and permeated 66.1 and 64.6 % with a flux of 0.118 and 0.331?mg/h/cm² of FDP and PIO through porcine buccal membrane. The bioavailability study for optimized formulation (PF6) in pigs showed 2.05- and 2.13-times statistically significant (p?<?0.05) improvement in bioavailability for FDP and PIO, respectively, after administration of buccal tablets compared to oral suspension. The ex vivo–in vivo correlation was found to have a biphasic pattern and followed type A correlation. The stability of the PF6 was studied and no significant changes were detected in drug content and in vitro release and ex vivo permeation through porcine buccal membrane after 6 months.     

Liquid chromatograph/tandem mass spectrometry assay for the simultaneous determination of chlorogenic acid and cinnamic acid in plasma and its application to a pharmacokinetic study

A rapid and high sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for simultaneous determination of chlorogenic acid and cinnamic acid in human plasma was developed. The analytes and internal standard (IS), tinidazole, were extracted from human plasma via liquid/liquid extraction with ether–ethyl acetate (1:1, v/v) and separated on an Agilent Zorbax SB C18 column within 5 min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM) and negative ion mode. The precursor to product ion transitions monitored for chlorogenic acid, cinnamic acid and IS were m/z 352.9 → 191.1, 146.8 → 103.1, 245.6 → 126.0, respectively. The assay was validated with linear range of 1.00–800.00 ng/mL for chlorogenic acid and 0.50–400.00 ng/mL for cinnamic acid. The intra- and inter-day precisions (RSD%) were within 9.05% for each analyte. The absolution recoveries were greater than 74.62% for chlorogenic acid and 76.21% for cinnamic acid. Each analyte was proved to be stable during all sample storage, preparation and analytic procedures. The method was successfully applied to a pharmacokinetic study of Mailuoning injection in 10 healthy volunteers.     

复方苯磺酸氨氯地平/盐酸贝那普利片在健康志愿者的生物等效性

目的:评价2种复方苯磺酸氨氯地平/盐酸贝那普利制剂生物等效性。方法:20名健康男性志愿者随机交叉单剂量口服复方苯磺酸氨氯地平/盐酸贝那普利受试制剂和参比制剂,采用LC-MS/MS法测定血清中氨氯地平、贝那普利及其代谢产物贝那普利拉浓度,DAS2.0软件计算药动学参数与生物等效性。结果:单剂口服受试和参比制剂后的苯磺酸氨氯地平主要药动学参数Cmax分别为(6.6±1.9)μg.L-1和(7.5±2.3)μg.L-1,tmax分别为(6.2±1.4)h和(5.7±1.2)h,AUC0-t分别为(264.2±90.5)μg.h.L-1和(271.3±94.9)μg.h.L-1,受试制剂的苯磺酸氨氯地平相对生物利用度为(97.41±6.04)%;单剂口服受试和参比制剂后的贝那普利主要药动学参数Cmax分别为(136.6±66.1)μg.L-1和(143.3±50.9)μg.L-1,tmax分别为(0.6±0.2)h和(0.6±0.2)h,AUC0-t分别为(139.3±54.0)μg.h.L-1和(137.8±47.2)μg.h.L-1,受试制剂的贝那普利相对生物利用度为(100.8±7.55)%;单剂口服受试和参比...     

Alginate coated chitosan core shell nanoparticles for oral delivery of enoxaparin: In vitro and in vivo assessment

The objective of present research work was to develop alginate coated chitosan core shell nanoparticles (Alg-CS-NPs) for oral delivery of low molecular weight heparin, enoxaparin. Chitosan nanoparticles (CS-NPs) were synthesized by ionic gelation of chitosan using sodium tripolyphosphate. Core shell nanoparticles were prepared by coating CS-NPs with alginate solution under mild agitation. The Alg-CS-NPs were characterized for surface morphology, surface coating, particle size, polydispersity index, zeta potential, drug loading and entrapment efficiency using SEM, Zeta-sizer, FTIR and DSC techniques. Alginate coating increased the size of optimized chitosan nanoparticles from around 213 nm to about 335 nm as measured by dynamic light scattering in zeta sizer and further confirmed by SEM analysis. The performance of optimized enoxaparin loaded Alg-CS-NPs was evaluated by in vitro drug release studies, in vitro permeation study across intestinal epithelium, in vivo venous thrombosis model, particulate uptake by intestinal epithelium using fluorescence microscopy and pharmacokinetic studies in rats. Coating of alginate over the CS-NPs improved the release profile of enoxaparin from the nanoparticles for successful oral delivery. In vitro permeation studies elucidated that more than 75% enoxaparin permeated across the intestinal epithelium with Alg-CS-NPs. The Alg-CS-NPs significantly increased (p < 0.05) the oral bioavailability of enoxaparin in comparison to plain enoxaparin solution as revealed by threefold increase in AUC of plasma drug concentration time curve and around 60% reduction in thrombus formation in rat venous thrombosis model. The core shell Alg-CS-NPs showed promising potential for oral delivery and significantly enhanced the in vivo oral absorption of enoxaparin.     

Sumatriptan succinate sublingual fast dissolving thin films: formulation and in vitro/in vivo evaluation

Sumatriptan succinate (SS) is a 5-HT1 receptor agonist used in the treatment of migraine having poor bioavailability (15%) due to its extensive first-pass effect. The aim of this work was to prepare SS sublingual fast dissolving thin films (SFDTFs) allowing the drug to directly enter the systemic circulation and bypassing the first-pass metabolism. Plain thin films were prepared using solvent casting technique adopting 2³?×?3 factorial design to study the effect of polymer and plasticizer type and concentration on mechanical properties and in vitro disintegration time of the plain prepared films using Design-Expert®. Medicated films were prepared after addition of 35?mg SS to each of the two selected plain formulae (F6 and F7) having desirability values above 0.9 showing the values of: 0.038, 0.039?kgf/mm² and 156.24, 164.16% and 0.0248, 0.0240?kgf/mm² as tensile strength, percent elongation and elastic modulus, respectively. PVP K30 was efficient as crystallization inhibitor in retarding SS crystallization. Pharmacokinetic study of the optimum formula F7 (PVP K30:SS (1:1 w/w)) in healthy human volunteers using LC/MS/MS revealed a shorter t_max (0.25?h) compared to Imitrex® tablet 25?mg (2?h) which is considered promising especially for the rapid relief of acute migraine attacks.     

Formulation and in vitro evaluation of theophylline matrix tablets prepared by direct compression: Effect of polymer blends

The deformation mechanism of pharmaceutical powders, used in formulating directly compressed matrix tablets, affects the characteristics of the formed tablets. Three polymers of different deformation mechanisms were tested for their impact on theophylline directly compressed tablets namely Kollidon SR (KL SR, plastic deformation), Ethylcellulose (EC, elastic deformation) and Carnauba wax (CW, brittle deformation) at different compression forces. However, tablets based mainly on KL SR, the plastically deformed polymer (TN1) exhibited the highest hardness values compared to the other formulae which are based on either blends of KL SR with CW, the very brittle deformed polymer. The upper detected force for TN formulae and the lower punch force were found to dependent mainly on the powder deformation. This difference is attributed to the work done during the compression phase as well as the work lost during the decompression phase. Furthermore, the release profiles of TN from formulae TN2 and TN4 that are based on the composition (2KL SR:1EC) and (1KL SR:2EC), respectively, were consistent with different deformation mechanisms of KL SR and EC and on the physicochemical properties like the water absorptive capacity of EC. Upon increasing the weight ratio of KL SR (TN2), the release rate was greatly retarded (39.4%, 37.1%, 35.0% and 33.6% released after 8 h at 5, 10, 15 and 20 kN.     

基于粉末直接压片工艺的硝苯地平缓释片：制备、体外释放度及比格犬体内药动学评价

目的选用粉末直接压片工艺,以羟丙基甲基纤雏素为骨架材料制备日服1次的硝苯地平缓释片。方法建立24h的释放度测定方法并进行硝苯地平缓释片的体外评价;应用液相色谱-质谱联用技术研究缓释片在比格犬体内药代动力学,与市售参比制剂对比并计算相对生物利用度。结果受试制剂和参比制剂有相似的药代动力学参数,相对生物利用度为（100．9±12．4）％;药物体外累积释放百分数与体内吸收百分数有较好的相关性,r=0．9625。结论本工艺制得的硝苯地平缓释片可以达到缓释24h的要求。     

Role of phospholipases A2 in diabetic retinopathy: In vitro and in vivo studies

Diabetic retinopathy is one of the leading causes of blindness and the most common complication of diabetes with no cure available. We investigated the role of phospholipases A₂ (PLA₂) in diabetic retinopathy using an in vitro blood–retinal barrier model (BRB) and an in vivo streptozotocin (STZ)-induced diabetic model. Mono- and co-cultures of endothelial cells (EC) and pericytes (PC), treated with high or fluctuating concentrations of glucose, to mimic the diabetic condition, were used. PLA₂ activity, VEGF and PGE₂ levels and cell proliferation were measured, with or without PLA₂ inhibition. Diabetes was induced in rats by STZ injection and PLA₂ activity along with VEGF, TNFα and ICAM-1 levels were measured in retina. High or fluctuating glucose induced BRB breakdown, and increased PLA₂ activity, PGE₂ and VEGF in EC/PC co-cultures; inhibition of PLA₂ in mono- or co-cultures treated with high or fluctuating glucose dampened PGE₂ and VEGF production down to the levels of controls. High or fluctuating glucose increased EC number and reduced PC number in co-cultures; these effects were reversed after transfecting EC with small interfering RNA targeted to PLA₂. PLA₂ and COX-2 protein expressions were significantly increased in microvessels from retina of diabetic rats. Diabetic rats had also high retinal levels of VEGF, ICAM-1 and TNFα that were reduced by treatment with a cPLA₂ inhibitor. In conclusion, the present findings indicate that PLA₂ upregulation represents an early step in glucose-induced alteration of BRB, possibly upstream of VEGF; thus, PLA₂ may be an interesting target in managing diabetic retinopathy.     

Phenylalanine-free taste-masked orodispersible tablets of fexofenadine hydrochloride: development,in vitro evaluation and in vivo estimation of the drug pharmacokinetics in healthy human volunteers

Abstract

Context: Fexofenadine hydrochloride (FXD) is a slightly soluble, bitter-tasting, drug having an oral bioavailability of 35%. The maximum plasma concentration is reached 2.6?h (T_max) post-dose.

Objective: Developing taste-masked FXD orodispersible tablets (ODTs) to increase extent of drug absorption and reduce T_max.

Methods: Taste masking was achieved via solid dispersion (SD) with chitosan (CS) or sodium alginate (ALG). Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction were performed to identify physicochemical interactions and FXD crystallinity. Taste-masked FXD-ODTs were developed via addition of superdisintegrants (croscarmellose sodium or sodium starch glycolate, 5% and 10%, w/w) or sublimable agents (camphor, menthol or thymol; 10% and 20%, w/w) to FXD-SDs. ODTs were evaluated for weight variation, drug-content, friability, wetting, disintegration and drug release. Camphor-based (20%, w/w) FXD-ODT (F12) was optimized (F23) by incorporation of a more hydrophilic lubricant (Pruv®), visualized via scanning electron microscopy and evaluated for FXD pharmacokinetics in healthy volunteers relative to Allegra® tablets.

Results: Based on gustatory sensation test, FXD–CS (1:1) and FXD–ALG (1:0.5) SDs were selected. Taste-masked FXD-ODTs had appropriate physicochemical properties. Drug release profiles of F23 and the phenylalanine-containing Allegra® ODT were similar (f₂?=?96). Pores were observed following camphor sublimation. The pharmacokinetic studies proved F23 ability to increase extent of FXD absorption and reduce T_max.     

d-Isomer of gly-tyr-pro-cys-pro-his-pro peptide: A novel and sensitive in vitro trapping agent to detect reactive metabolites by electrospray mass spectrometry

This paper describes a d-peptide isomer-based trapping assay using an LC/MS ion-trap spectrometer with an electrospray ionization (ESI) source as the analytical tool to study bioactivation of xenobiotics. Reactive metabolites were generated from parent compounds in in vitro incubations with different sources of CYP enzymes. A short d-isomer of gly-tyr-pro-cys-pro-his-pro proved to be a sensitive trapping agent and resistant to proteases. This method was tested with 16 probe substances. Acetaminophen, 1-chloro 2,4-dinitrobenzene, clozapine, diclofenac, imipramine, menthofuran, propranolol, pulegone and ticlopidine all formed d-peptide adducts, which were analogous to the GSH adducts previously described in the literature. New adducts were identified with clopidogrel (-Cl + peptide), nicotine (-CH₃₊H + peptide), nimesulide (+peptide) and tolcapone (+peptide), i.e., no GSH adducts of those drugs have been described in the literature. No adducts were identified with ciprofloxacin, ketoconazole and verapamil. In the literature no GSH adducts have been described with ciprofloxacin and verapamil. d-Peptide-based trapping proved to be a reliable and reproducible method to identify bioactivated intermediates. d-Peptide is a new and convenient protein trapping agent for use in early phase screening of bioactivation of new chemical entities and evaluation of toxic properties of chemicals.     

New perspectives in bio-analytical techniques for preclinical characterization of a drug candidate: UPLC-MS/MS in in vitro metabolism and pharmacokinetic studies

Lead optimization requires rapid bio-analytical turnover for the generation of early absorption, distribution, metabolism, excretion (ADME) and pharmacokinetics (PK) data maintaining a high quality level. Therefore, one of the major challenges in the bio-analytical field is to achieve faster and more sensitive quantification protocols. In the present communication, a comparison between HPLC and ultra performance liquid chromatography (UPLC) performances in terms of sensitivity and resolution is shown using a pharmakokinetic study and a metabolism study as models. The studies highlight the features of the new technology and the resulting impact in the PK throughput and in the characterization of isomeric metabolites using UPLC/MS/MS technique.     

Reaction of human albumin with aspirin in vitro: Mass spectrometric identification of acetylated lysines 199, 402, 519, and 545

The aspirin esterase activity of human plasma is due to butyrylcholinesterase and albumin. Our goal was to identify the amino acid residues involved in the aspirin esterase activity of albumin. Fatty acid-free human albumin and human plasma were treated with aspirin for 5 min-24 h. Acetylated residues were identified by LC/MS/MS and MALDI-TOF/TOF mass spectrometry of tryptic peptides. Treatment with 0.3 mM aspirin resulted in acetylation of Lys-199, Lys-402, Lys-519, and Lys-545. Treatment with 20 mM aspirin resulted in acetylation of 26 lysines. There was no acetylation of Tyr-411, under any conditions. Acetylated lysine was stable for at least 21 days at pH 7.4, 37 °C. Albumin acetylated by aspirin had reduced esterase activity with β-naphthyl acetate as shown on gels stained for esterase activity. It was concluded that the aspirin esterase activity of albumin is a pseudo-esterase activity in which aspirin stably acetylates lysines and releases salicylate.