Dermal pharmacokinetics of pyrazinamide determined by microdialysis sampling in rats

Unraveling the mystery of efficacy in Chinese medicine formula: New approaches and technologies for research on pharmacodynamic substances

Traditional Chinese medicine (TCM) is the key to unlock treasures of Chinese civilization. TCM and its compound play a beneficial role in medical activities to cure diseases, especially in major public health events such as novel coronavirus epidemics across the globe. The chemical composition in Chinese medicine formula is complex and diverse, but their effective substances resemble "mystery boxes". Revealing their active ingredients and their mechanisms of action has become focal point and difficulty of research for herbalists. Although the existing research methods are numerous and constantly updated iteratively, there is remain a lack of prospective reviews. Hence, this paper provides a comprehensive account of existing new approaches and technologies based on previous studies with an in vitro to in vivo perspective. In addition, the bottlenecks of studies on Chinese medicine formula effective substances are also revealed. Especially, we look ahead to new perspectives, technologies and applications for its future development. This work reviews based on new perspectives to open horizons for the future research. Consequently, herbal compounding pharmaceutical substances study should carry on the essence of TCM while pursuing innovations in the field.

OUP accepted manuscript

Objectives

More effective topical treatments remain an unmet need for the localized forms of cutaneous leishmaniasis (CL). The aim of this study was to evaluate the efficacy and safety of a topical berberine cream in BALB/c mice infected with Leishmania major parasites.

Methods

A cream containing 0.5% berberine-β-glycerophosphate salt and 2.5% menthol was prepared. Its physicochemical and stability properties were determined. The cream was evaluated for its capacity to reduce lesion size and parasitic load as well as to promote wound healing after twice-a-day administration for 35 days. Clinical biochemical profile was used for estimating off-target effects. In vitro time-to-kill curves in L. major-infected macrophages and skin and plasma pharmacokinetics were determined, aiming to establish pharmacokinetic/pharmacodynamic relationships.

Results

The cream was stable at 40°C for 3 months and at 4°C for at least 8 months. It was able to halt lesion progression in all treated mice. At the end of treatment, parasite load in the skin was reduced by 99.9% (4 log) and genes involved in the wound healing process were up-regulated compared with untreated mice.

The observed effects were higher than expected from in vitro time-to-kill kinetic and plasma berberine concentrations, which ranged between 0.07 and 0.22 μM.

Conclusions

The twice-a-day administration of a topical berberine cream was safe, able to stop parasite progression and improved the appearance of skin CL lesions. The relationship between drug plasma levels and in vivo effect was unclear.

Hybrid Poly(AMPS-CS)-Au Microneedle Arrays to Enrich Metabolites from Skin for Early Disease Diagnosis

Recently, some metabolites in skin interstitial fluid (SIF) have become emerging re×sources for early disease diagnosis. However, their low level in SIF and difficulty to sampling are the biggest obstacle to further potential application. Here, a swellable microneedle array patch (MNAP) with high mechanical strength is presented, and the rapid enrichment of positively charged metabolites is achieved. The MNAP is fabricated by poly (chondroitin sulfate-acrylamido-2-methylpropane sulfonic acid)-gold nanoparticles (GNPs) composites via a micro-molding. The negatively charged copolymer hydrogel not only enrich positively charged metabolites, but also provide swellable capacity. The in situ synthesis of GNPs in the process of copolymerization make the GNPs cross-link to the hydrogel, which further enhance the MNAP mechanical strength and enrichment efficiency for positively charged metabolites. By using the MNAP, around 5 mg SIF in 10 min from the high fat/cholecalciferol/methimazole-induced atherogenesis rat is extracted and 23 metabolites including 13 quaternary ammonium cationic compounds can be detected and quantified by using a LC-QTOF-MS. Dysregulated L-carnitine and choline metabolism are discovered a week earlier in the SIF than in the serum, achieving early diagnosis of the metabolism syndrome disease. This MNAP also helps users complete home sampling for early disease diagnosis and monitoring.

An appraisal of the scientific current situation and new perspectives in the treatment of cutaneous leishmaniasis

Leishmaniasis is a Neglected Tropical Diseases caused by protozoan parasites of the genus Leishmania. It is a major health problem in many tropical and subtropical regions of the world and can produce three different clinical manifestations, among which cutaneous leishmaniasis has a higher incidence in the world than the other clinical forms. There are no recognized and reliable means of chemoprophylaxis or vaccination against infections with different forms of leishmaniasis. In addition, chemotherapy, unfortunately, remains, in many respects, unsatisfactory. Therefore, there is a continuing and urgent need for new therapies against leishmaniasis that are safe and effective in inducing a long-term cure. This review summarizes the latest advances in currently available treatments and improvements in the development of drug administration. In addition, an analysis of the in vivo assays was performed and the challenges facing promising strategies to treat CL are discussed. The treatment of leishmaniasis will most likely evolve into an approach that uses multiple therapies simultaneously to reduce the possibility of developing drug resistance. There is a continuous effort to discover new drugs to improve the treatment of leishmaniasis, but this is mainly at the level of individual researchers. Undoubtedly, more funding is needed in this area, as well as greater participation of the pharmaceutical industry to focus efforts on the development of chemotherapeutic agents and vaccines for this and other neglected tropical diseases.

A fast and high-sensitivity liquid chromatography-tandem mass spectrometry method combined with in vivo microdialysis for quantification of meropenem in rabbits with sepsis under the simultaneous infusion of total parenteral nutrition: Application to a pharmacokinetic study

A fast and high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) method assisted by microdialysis was established for the determination of meropenem in total parenteral nutrition (TPN) infused plasma. A 10-times dilution was arranged for sample preparation to overcome the severe matrix effect caused by the high salt content in dialysate and complex composition of TPN. This quantification method was proved to be satisfied in selectivity, accuracy, precision, linearity (R²  > 0.998), recovery, matrix effect and stability. In the optimized conditions, the calibration curve range was set from 2 to 2000 ng/ml. This validated method was applied to pharmacokinetics study of meropenem in rabbits with sepsis (induced by cecal ligation and punctures) under simultaneous infusion of TPN to simulate the clinical practice. The results demonstrated that the LC-MS/MS method assisted by microdialysis can be used successfully for the determination of meropenem in TPN-infused plasma. Moreover, the area under the curve and the maximum concentrations in the plasma of meropenem in control rabbits were significantly smaller (P < 0.05), while clearance and distribution volumes were significantly greater (P < 0.05) than in those with sepsis. It could be speculated that drug monitoring in patients with sepsis may be necessary.

Microneedle-based bioassays

Disease diagnosis and therapeutic efficacy can be monitored via a number of established bioassays that sample body fluids to assess and monitor health conditions. Traditional bioassays generally include several steps and start with invasive body fluid extraction procedures. These steps are painful and often require specialized techniques and tailored equipment, as well as the supervision of professional medical personnel. Innovations in engineering alternative bioassays to address these shortcomings are thus desired. Microneedles (MNs) represent promising tools to sample body fluids, in view of their minimal invasiveness, painlessness, and uncomplicated implementation. Recent progress in microfabrication and materials engineering, including the development of hollow and solid MNs with uniquely optimized architectures and multi-functional materials, has positioned MN-based platforms as prime candidates for bioassay solutions. In this minireview, we summarize the studies of MN-based platforms for detection and diagnosis. We categorize the platforms based on three different mechanisms: MNs as body fluid reservoirs, MNs integrated with electrochemical assays, and MNs engineered with colorimetric analyses. A discussion of design principles for MN-based bioassay platforms is presented. We also discuss the challenges and opportunities associated with MN-based bioassays in future clinical applications.

Computational Approaches in Preclinical Studies on Drug Discovery and Development

Because undesirable pharmacokinetics and toxicity are significant reasons for the failure of drug development in the costly late stage, it has been widely recognized that drug ADMET properties should be considered as early as possible to reduce failure rates in the clinical phase of drug discovery. Concurrently, drug recalls have become increasingly common in recent years, prompting pharmaceutical companies to increase attention toward the safety evaluation of preclinical drugs. In vitro and in vivo drug evaluation techniques are currently more mature in preclinical applications, but these technologies are costly. In recent years, with the rapid development of computer science, in silico technology has been widely used to evaluate the relevant properties of drugs in the preclinical stage and has produced many software programs and in silico models, further promoting the study of ADMET in vitro. In this review, we first introduce the two ADMET prediction categories (molecular modeling and data modeling). Then, we perform a systematic classification and description of the databases and software commonly used for ADMET prediction. We focus on some widely studied ADMT properties as well as PBPK simulation, and we list some applications that are related to the prediction categories and web tools. Finally, we discuss challenges and limitations in the preclinical area and propose some suggestions and prospects for the future.

Finite Element Analysis for Predicting Skin Pharmacokinetics of Nano Transdermal Drug Delivery System Based on the Multilayer Geometry Model

Background

Skin pharmacokinetics is an indispensable indication for studying the drug fate after administration of transdermal drug delivery systems (TDDS). However, the heterogeneity and complex skin structured with stratum corneum, viable epidermis, dermis, and subcutaneous tissue inevitably leads the drug diffusion coefficient (Kp) to vary depending on the skin depth, which seriously limits the development of TDDS pharmacokinetics in full thickness skin.

Methods

A multilayer geometry skin model was established and the Kp of drug in SC, viable epidermis, and dermis was obtained using the technologies of molecular dynamics simulation, in vitro permeation experiments, and in vivo microdialysis, respectively. Besides, finite element analysis (FEA) based on drug Kps in different skin layers was applied to simulate the paeonol nanoemulsion (PAE-NEs) percutaneous dynamic penetration process in two and three dimensions. In addition, PAE-NEs skin pharmacokinetics profile obtained by the simulation was verified by in vivo experiment.

Results

Coarse-grained modeling of molecular dynamic simulation was successfully established and the Kp of PAE in SC was 2.00×10⁻⁶ cm²/h. The Kp of PAE-NE in viable epidermis and in dermis detected using penetration test and microdialysis probe technology, was 1.58×10⁻⁵ cm²/h and 3.20×10⁻⁵ cm²/h, respectively. In addition, the results of verification indicated that PAE-NEs skin pharmacokinetics profile obtained by the simulation was consistent with that by in vivo experiment.

Discussion

This study demonstrated that the FEA combined with the established multilayer geometry skin model could accurately predict the skin pharmacokinetics of TDDS.

Gelatin Methacryloyl Microneedle Patches for Minimally Invasive Extraction of Skin Interstitial Fluid

The extraction of interstitial fluid (ISF) from skin using microneedles (MNs) has attracted growing interest in recent years due to its potential for minimally invasive diagnostics and biosensors. ISF collection by absorption into a hydrogel MN patch is a promising way that requires the materials to have outstanding swelling ability. Here, a gelatin methacryloyl (GelMA) patch is developed with an 11 × 11 array of MNs for minimally invasive sampling of ISF. The properties of the patch can be tuned by altering the concentration of the GelMA prepolymer and the crosslinking time; patches are created with swelling ratios between 293% and 423% and compressive moduli between 3.34 MPa and 7.23 MPa. The optimized GelMA MN patch demonstrates efficient extraction of ISF. Furthermore, it efficiently and quantitatively detects glucose and vancomycin in ISF in an in vivo study. This minimally invasive approach of extracting ISF with a GelMA MN patch has the potential to complement blood sampling for the monitoring of target molecules from patients.

Pharmacokinetics and Pharmacodynamics of the Nitroimidazole DNDI-0690 in Mouse Models of Cutaneous Leishmaniasis

The nitroimidazole DNDI-0690 is a clinical drug candidate for visceral leishmaniasis (VL) that also shows potent in vitro and in vivo activity against cutaneous leishmaniasis (CL). To support further development of this compound into a patient-friendly oral or topical formulation for the treatment of CL, we investigated the free drug exposure at the dermal site of infection and subsequent elimination of the causative Leishmania pathogen. This study evaluates the pharmacokinetics (PK) and pharmacodynamics (PD) of DNDI-0690 in mouse models of CL. Skin microdialysis and Franz diffusion cell permeation studies revealed that DNDI-0690 permeated poorly (<1%) into the skin lesion upon topical drug application (0.063% [wt/vol], 30 μl). In contrast, a single oral dose of 50 mg/kg of body weight resulted in the rapid and nearly complete distribution of protein-unbound DNDI-0690 from the plasma into the infected dermis (ratio of the area under the curve [0 to 6 h] of the free DNDI-0690 concentration in skin tissue to blood [fAUC_{0-6 h, skin tissue}/fAUC_{0-6 h, blood}] is greater than 80%). Based on in vivo bioluminescence imaging, two doses of 50 mg/kg DNDI-0690 were sufficient to reduce the Leishmania mexicana parasite load by 100-fold, while 6 such doses were needed to achieve similar killing of L. major; this was confirmed by quantitative PCR. The combination of rapid accumulation and potent activity in the Leishmania-infected dermis indicates the potential of DNDI-0690 as a novel oral treatment for CL.

Simultaneous determination of the potent anti-tuberculosis regimen-Pyrazinamide, ethambutol, protionamide, clofazimine in beagle dog plasma using LC-MS/MS method coupled with 96-well format plate

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LC–MS/MS method for determination of Pyrazinamide, Ethambutol, Protionamide and Clofazimine in Beagle Dog Plasma.

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Method validation was conducted according to FDA and NMPA guidelines.

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Hemolysis effect was investigated in detail.

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The method is robust and high throughput cooperated with 96-well format plates.

Tuberculosis is one of the top concerns in the world and acutely threatens human health. A new potent candidate regimen containing pyrazinamide (PZA), ethambutol (EMB), protionamide (PTO) and clofazimine (CFZ) was proposed by Parabolic Response Surface/Feedback System Control (FSC/PRS) system and showed excellent outcomes in vitro and vivo studies. Here, a convenient liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) method was developed for the simultaneously determination of four compounds in beagle dog plasma. The plasma samples, 50 μL for each, were pretreated by methanol on 96-well format plates and a further dilution step was designed to reduce predictable matrix effect and lessen the burden of subsequent analysis. The chromatographic separation was achieved on an Agilent SB-Aq column (4.6 mm × 150 mm, 5 μm) at 30 °C by a gradient elution within 6 min. The mobile phase was a mixture of 0.2% formic acid-5 mM ammonium acetate aqueous solution (phase A) and 0.2% formic acid methanol (phase B) with a total flow rate of 1 mL/min. The 30% of post-column eluant was injected into mass spectrometer, equipped with electrospray ionization (ESI) source under positive mode and multiple-reaction monitoring (MRM). This quantification method was proved to be satisfied in selectivity, accuracy, precision, linearity (r² > 0.998), recovery, matrix effect and stability. Under the specialized conditions, the calibration curves ranged from 20 to 5000 ng/mL for PZA, 1 to 500 ng/mL for EMB, 1 to 500 ng/mL for PTO, and 1 to 200 ng/mL for CFZ. The quantitative accuracy was further assessed under different degrees of hemolyses in detail. This method was proved to be robust and efficient, and successfully applied to the pharmacokinetic study of the new regimen in Beagle dogs.

Determination of Dermal Pharmacokinetics by Microdialysis Sampling in Rats

The evaluation of absorption and availability at the site of action of a drug candidate is an important element of drug discovery and development, as clinical response is a function of the bioavailability of the active agent and its continued presence at the site of action. Evaluation of dermal pharmacokinetics facilitates the selection of new compounds or chemical structures for advancement as possible clinical candidates. An advantage of microdialysis is that it allows the measurement of compound concentrations at the site of action without disturbing the tissue milieu, making it possible to determine the relationship between this important variable and plasma concentrations of the agent. Described in this unit are laboratory protocols for performing dermal microdialysis experiments in rat for the purpose of defining the pharmacokinetics parameters of test agents. © 2019 by John Wiley & Sons, Inc.

Microemulsions vs chitosan derivative-coated microemulsions for dermal delivery of 8-methoxypsoralen

Background

8-methoxypsoralen (8-MOP) is one of the most commonly utilized drugs in psoralen-ultraviolet A therapy for treatment of vitiligo. However, poor skin retention and systemic side effects limit the clinical application of 8-MOP.

Methods

Microemulsions (MEs) and chitosan derivative-coated 8-MOP MEs were developed and compared for dermal delivery of 8-MOP. Ex vivo skin retention/permeation study was performed to select the ME formulation with the highest retention:permeation ratio. Four different chitosan-coated MEs were prepared and compared with the ME formulation for their ability to distribute 8-MOP in the skin.

Results

Among various ME formulations developed, a formulation containing 2.9% ethyl oleate, 17.2% Cromophor EL35, 8.6% ethanol and 71.3% water showed the highest ex vivo skin retention:permeation ratio (1.98). Of four chitosan-coated MEs prepared, carboxymethyl chitosan-coated MEs (CC-MEs) and hydroxypropyl chitosan-coated MEs (HC-MEs) showed higher ex vivo skin retention:permeation ratio (1.46 and 1.84). and were selected for in vivo pharmacokinetic study. AUC_skin (0–12 h) for 8-MOP MEs (4578.56 h·ng·mL⁻¹) was higher than HC-MEs (3422.47 h·ng·mL⁻¹), CC-MEs (2808.51 h·ng·mL⁻¹) and tincture (1500.16 h·ng·mL⁻¹). Also, AUCplasma (0–12 h) for MEs (39.35±13.90 h·ng·mL⁻¹) was significantly lower than HC-MEs (66.32 h·ng·mL⁻¹), CC-MEs (59.70 h·ng·mL⁻¹) and tincture (73.02 h·ng·mL⁻¹).

Conclusion

These combined results suggested that the MEs developed could be a promising and safe alternative for targeted skin delivery of 8-MOP.