Envarsus,una novedad para los nefrólogos del trasplante: estudio observacional retrospectivo

The aim of this study was to evaluate the trough concentrations (Cp_trough) and the tacrolimus dosage regimen after the conversion of Prograf or Advagraf to Envarsus (new pharmaceutical form with MeltDose technology that improves the absorption of fat-soluble drugs) in patients with stable renal transplantation, and their renal function.We selected stable renal transplant patients who were converted to Envarsus. Two periods were defined: Baseline and Conversion (Envarsus) and they were stratified according to the pharmaceutical form used in the Baseline period. Sixty-one patients were included (24 with Advagraf and 37 with Prograf), with an average age of 52 years. The mean post-transplant time at the time of conversion to Envarsus was 76.3 months and the mean follow-up in the Baseline and Conversion period was 10.1 months and 11.6 months, respectively.In the Prograf and Envarsus group, the Cp_trough medians were 6.6 vs 6.4 ng/mL (P = .636), with a mean daily dose that decreased significantly from 3 mg to 2 mg (P < .001), respectively, maintaining the filtration rate.The median Cp_trough values in the Advagraf and Envarsus groups were 5.7 ng/mL and 6.3 ng/mL (P = .07), with a median daily dose of 7 mg and 4 mg (P < .001), respectively, and the same renal function.In stable renal transplant patients, the conversion from Advagraf to Envarsus has allowed the dose of tacrolimus to be reduced by 42.9% and, in the case of Prograf, by 33.3%, maintaining similar Cp_trough values, without renal function being altered.     

In vitro dissolution and oral bioavailability study of fenofibrate nanomatrix system prepared by hot-melt extrusion

Solvent evaporation method for preparation of nanomatrix has the disadvantages, such as residual organic solvent, environmental pollution, explosion-proofing and so on. To overcome these shortcomings, a series of fenofibrate nanomatrix drug delivery system (NDDS) consisting of nano-porous silica Sylysia^®350 (S350) and pH sensitive material Eudragit^® L100-55 (EL100-55) were prepared using hot-melt extrusion (HME), and their in vitro dissolution and in vivo bioavailability were compared. Finally, the formulation with the highest in vivo bioavailability was selected as the optimized formulation for DSC and PXRD characterization. The results showed that the optimized NDDS showed a higher bioavailability than the reference formulation, although there was crystalline form drug remaining in NDDS. The relative bioavailability of the optimized formulation was 157.1% compared with the commercial product Lipanthyl^®. In addition, the relative bioavailability of the optimized formulation was 124.8% in comparison with the formulation prepared by solvent evaporation method, showing that the NDDS prepared by the HME method was effective in improving the bioavailability of fenofibrate. In conclusion, HME was a promising method to prepare NDDS.     

In vitro and in vivo characterization of domperidone-loaded fast dissolving buccal films

The delivery of drugs via fast dissolving films is an effective alternative for drugs with low bioavailability when administered by other routes. This is the case of domperidone (DMP) an anti-emetic drug with low water solubility and vulnerable to extensive first-pass effect. To overcome these limitations, in this work, we designed and produced fast dissolving muco-adhesive buccal films of domperidone using varying amount polyvinylpyrrolidone (PVP K-90) using the solvent casting method. Films loaded with more than 10% of drug were not homogenous and opaque as indicated by white patches of drug in the film matrix. Formulation of DMP in the film form resulted in conversion of the drug from crystalline state to the semi-crystalline state as indicated by X-ray powder diffraction analysis. Moreover, about 40% of drug loaded within the films was released during the first five minutes compared to only about only 6.5% of pure drug in drug dissolution assays in vitro. In vivo pharmacokinetics analysis revealed that the DMP-loaded film had higher maximum plasma concentration (C_max) and shorter time to reach C_max (T_max) than a commercially available tablet formulation. In conclusion, the produced DMP buccal film formulation showed high absorption rate, rapid onset of action, and improved bioavailability compared with the conventional tablet. Our findings may support the development of novel dosage forms for the transmucosal delivery of DMP for convenient, rapid, and effective treatment of nausea and vomiting.     

Formulation and evaluation of cyclodextrin-based nanosponges of griseofulvin as pediatric oral liquid dosage form for enhancing bioavailability and masking bitter taste

The aim of this study was the development of griseofulvin (GRI) loaded β-cyclodextrin (β–CD) based nanosponges for bitter taste masking, improving dissolution rate and oral bioavailability. Plain NS (NS1 NS2 and NS3) were fabricated by reacting β-CD with the cross-linker diphenyl carbonate at different molar ratios (1:2, 1:4 and 1:6, respectively) using ultrasonication method. The NS2 provided both highest %yield and GRI solubilization enhancement. Thus, the drug was loaded in NS2 at different NS2: drug weight ratios in presence or absence of 0.25%w/w polyvinylpyrolidone (PVP k30). The GRI loaded NS (F1) that provided highest drug loading capacity and entrapment efficiency (47.20 ± 0.38%, 84.91 ± 0.30%, respectively) was morphologically examined using scanning electron microscopy (SEM). Also, Particle size, zeta potential, differential scanning calorimetry (DSC), Fourier transform infra-red (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, in-vitro release, taste masking potential were evaluated. Moreover, in-vivo Pharmacokinetic studies were performed on rats. The F1 showed particle size 665.9 ± 13.8 nm and zeta potential −21.5 ± 0.7 mV. The DSC and FT-IR analysis confirmed the complexation of GRI with NS2. Nanosponges (F1) provided 3.19, folds increase in dissolution efficiency %, 2.13 and 3.78 folds increase in C_max and AUC_0-48 compared to plain GRI. Taste masking evaluation confirmed the potential of GRI nanosponges (F1) in masking the bitter taste of GRI completely. The study confirmed that complexation of GRI with NS would be a viable approach for masking the bitter taste of GRI and improving oral bioavailability, that Cmax, Tmax and AUC 0–48 were significantly higher for the developed formulation (F1).     

A novel oral medicated jelly for enhancement of etilefrine hydrochloride bioavailability: In vitro characterization and pharmacokinetic evaluation in healthy human volunteers

Etilefrine hydrochloride (ET) is a water-soluble drug that is used to treat hypotension, but it has a bitter taste and low bioavailability due to undergoing the first-pass effect. Thus, this study aimed to develop and evaluate oral medicated jelly (OMJ) containing ET that could offer an easily taken palatable dosage form with higher bioavailability. OMJ is a novel palatable drug delivery system that can easily be taken by pediatric and geriatric patients, as well as those with dysphagia. Moreover, OMJs offer rapid disintegration in saliva and rapid drug absorption through the buccal mucosa, avoiding the first-pass effect and increasing the drug bioavailability. Natural polymers such as pectin, guar gum, xanthan gum, tragacanth gum, and sodium alginate were used as jellifying agents, with the addition of calcium chloride as a crosslinking agent, to prepare OMJs using the heat and congealing method. The prepared OMJs were investigated by testing their viscosity, in vitro release, and texture analysis of firmness, consistency, stickiness, cohesiveness, springiness, gumminess, and chewiness using a texture analyzer. A full factorial design (2¹ × 5¹) was utilized to select the optimized OMJ. The optimized OMJ (J2), containing 4 % pectin, had a 7563 ± 55 cps viscosity, 8.32 ± 0.21 N firmness, 5.72 ± 0.18 µJ consistency, 1.30 ± 0.04 mJ stickiness, and 96.02 ± 3.74 % ET dissolved after 10 min. ET release was significantly increased (greater than4-fold) from the optimized OMJ compared with the market tablet. Moreover, the obtained results clarified the stability and the acceptable palatability of the optimized OMJ. The clinical investigation on healthy human volunteers revealed that the optimized OMJ (J2) had significantly higher C_max (1.7 folds) when compared with the market tablet with a relative bioavailability of 154.55 %. Therefore, OMJs can be considered as promising, palatable, and easily swallowed dosage form that could enhance the bioavailability of drugs undergoing the first-pass effect.     

Novel food drug interaction mechanism involving acyclovir,chitosan and endogenous mucus

Drug absorption from drug products may be affected by pharmaceutical excipients and/or food additives through different mechanisms. Chitosan is a recognized nutraceutical, with potential as an excipient due to its permeability enhancer properties. While chitosan properties have been evaluated in in vitro and pre-clinical models, studies in humans are scarce. Unexpectedly, a controlled clinical trial showed chitosan actually reduced acyclovir bioavailability. The effect seems to be related to an interaction with gastrointestinal mucus that prevents further absorption, although more in depth research is needed to unravel the mechanism. In this paper, we propose a mechanism underlying this excipient effect. The mucus – chitosan interaction was characterized and its effect on acyclovir diffusion, permeation and bioaccessibility was investigated. Further, pharmacokinetic modeling was used to assess the clinical relevance of our findings. Results suggest that in situ coacervation between endogenous mucus and chitosan rapidly entrap 20–30% of acyclovir dissolved dose in the intestinal lumen. This local reduction of acyclovir concentration together with its short absorption window in the small intestine would explain the reduction in acyclovir C_max and AUC. This study highlights the importance of considering mucus in any biorelevant absorption model attempting to anticipate the effect of chitosan on drug absorption.     

非诺贝特制剂的研究进展

非诺贝特属于贝特类降血酯药,是降低甘油三酯的首选药物之一,临床使用率高。由于非诺贝特难溶于水,不易于被吸收,导致生物利用度较低,影响药物疗效。为解决这一问题,不同类型的药物传递系统被应用与研究。本文综述非诺贝特制剂的研究进展,以期为其制剂的进一步开发提供思路。     

乙酰半胱氨酸颗粒在健康人体的生物等效性研究

目的：建立人血浆乙酰半胱氨酸浓度测定方法,研究乙酰半胱氨酸颗粒在健康人体内的相对生物利用度与生物等效性。方法采用二制剂三周期自身对照完全三交叉试验设计,其中每位受试者有一周期不服药,健康男性受试者24例分别单剂量口服乙酰半胱氨酸受试制剂或参比制剂0.6 g。高效液相色谱串联质谱法测定血浆乙酰半胱氨酸浓度,应用DAS 3.0版统计软件计算药动学参数并评价两种制剂生物等效性。结果单剂量口服乙酰半胱氨酸颗粒受试制剂和参比制剂0.6 g的主要药动学参数：AUC0→t分别为(8547.64±2860.04)和(8783.07±4042.10)μg·h·L-1;AUC0→∞分别为(9481.64±3444.76)和(9540.51±4239.30)μg·h·L-1;Cmax分别为(1994.39±726.42)和(2090.27±885.46)μg·L-1;tmax分别为(1.18±0.60)和(1.13±0.53) h;t1/2分别为(8.60±3.76)和(7.75±5.01) h;相对生物利用度以AUC0→t和AUC0→∞计算分别为(107.0±43.3)％和(106.5±40.1)％。结论乙酰半胱氨酸颗粒两种制剂具有生物等效性。     

Toxic trace elements at gastrointestinal level

Many trace elements are considered essential [iron (Fe), zinc (Zn), copper (Cu)], whereas others may be harmful [lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As)], depending on their concentration and chemical form. In most cases, the diet is the main pathway by which they enter our organism. The presence of toxic trace elements in food has been known for a long time, and many of the food matrices that carry them have been identified. This has led to the appearance of legislation and recommendations concerning consumption. Given that the main route of exposure is oral, passage through the gastrointestinal tract plays a fundamental role in their entry into the organism, where they exert their toxic effect. Although the digestive system can be considered to be of crucial importance in their toxicity, in most cases we do not know the events that occur during the passage of these elements through the gastrointestinal tract and of ascertaining whether they may have some kind of toxic effect on it. The aim of this review is to summarize available information on this subject, concentrating on the toxic trace elements that are of greatest interest for organizations concerned with food safety and health: Pb, Cd, Hg and As.     

Preclinical Pharmacokinetic Evaluation of β-Lapachone: Characteristics of Oral Bioavailability and First-Pass Metabolism in Rats

β-Lapachone has drawn increasing attention as an anti-inflammatory and anti-cancer drug. However, its oral bioavailability has not been yet assessed, which might be useful to develop efficient dosage forms possibly required for non-clinical and clinical studies and future market. The aim of the present study was thus to investigate pharmacokinetic properties of β-lapachone as well as its first-pass metabolism in the liver, and small and large intestines after oral administration to measure the absolute bioavailability in rats. A sensitive HPLC method was developed to evaluate levels of β-lapachone in plasma and organ homogenates. The drug degradation profiles were examined in plasma to assess the stability of the drug and in liver and intestinal homogenates to evaluate first-pass metabolism. Pharmacokinetic profiles were obtained after oral and intravenous administration of β-lapachone at doses of 40 mg/kg and 1.5 mg/kg, respectively. The measured oral bioavailability of β-lapachone was 15.5%. The considerable degradation of β-lapachone was seen in the organ homogenates but the drug was quite stable in plasma. In conclusion, we suggest that the fairly low oral bioavailability of β-lapachone may be resulted from the first-pass metabolic degradation of β-lapachone in the liver, small and large intestinal tracts and its low aqueous solubility.