Pre-clinical compartmental pharmacokinetic modeling of 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH) as a photosensitizer in rat plasma by validated HPLC method

Long-term antitrypanosomal effect of quinapyramine sulphate-loaded oil-based nanosuspension in T. evansi-infected mouse model

The goal of the present work consisted of the formulation development and evaluation of quinapyramine sulphate (QS)-loaded long-acting oil-based nanosuspension for improved antitrypanosomal effect. QS was transformed into a hydrophobic ionic complex using anionic sodium cholate (Na.C). The complex was characterized by FTIR, DSC, and XRD. Oil-based nanosuspension was prepared by dispersing the QS-Na.C complex in thixotropically thickened olive oil. The nanoformulation was found to be cytocompatible (82.5 ± 5.87% cell viability at the minimum effective concentration [MEC]) in THP-1 cell lines and selectively trypanotoxic (p < 0.0001). The pharmacokinetic studies of QS-Na.C complex-loaded oily nanosuspension showed 13.54-fold, 7.09-fold, 1.78-fold, and 17.35-fold increases in t1/2, AUC0-∞, Vz/F, and MRT0-ꝏ, respectively, as compared to free QS. Moreover, a 7.08-fold reduction in plasma clearance was observed after the treatment with the optimized formulation in Wistar rats. Furthermore, treatment with QS-Na.C complex-loaded oily nanosuspension (7.5 mg/kg) in T. evansi-infected mice model showed the absence of parasitaemia for more than 75 days after the treatment during in vivo efficacy studies. The efficacy of the treatment was assessed by observation of blood smear and PCR assay for DNA amplification. To conclude, our findings suggest that the efficient delivery of QS from the developed QS-Na.C complex-loaded oily nanosuspension could be a promising treatment option for veterinary infections against trypanosomiasis.

Reviewing the evolutive ACQ-to-AIE transformation of photosensitizers for phototheranostics

Photodynamic therapy (PDT) represents an emerging noninvasive treatment technique for cancers and various nonmalignant diseases, including infections. During the process of PDT, the physical and chemical properties of photosensitizers (PSs) critically determine the effectiveness of PDT. Traditional PSs have made great progress in clinical applications. One of the challenges is that traditional PSs suffer from aggregation-caused quenching (ACQ) due to their discotic structures. Recently, aggregation-induced emission PSs (AIE-PSs) with a twisted propeller-shaped conformation have been widely concerned because of high reactive oxygen species (ROS) generation efficiency, strong fluorescence efficiency, and resistance to photobleaching. However, AIE-PSs also have some disadvantages, such as short absorption wavelengths and insufficient molar absorption coefficient. When the advantages and disadvantages of AIE-PSs and ACQ-PSs are complementary, combining ACQ-PSs and AIE-PSs is a "win-to-win" strategy. As far as we know, the conversion of traditional representative ACQ-PSs to AIE-PSs for phototheranostics has not been reviewed. In the review, we summarize the recent progress on the ACQ-to-AIE transformation of PSs and the strategies to achieve desirable theranostic applications. The review would be helpful to design more efficient ACQ-AIE-PSs in the future and to accelerate the development and clinical application of PDT.

Targeted implementation strategies of precise photodynamic therapy based on clinical and technical demands

With the development of materials science, photodynamic-based treatments have gradually entered clinics. Photodynamic therapy is ideal for cancer treatment due to its non-invasive and spatiotemporal properties and is the first to be widely promoted in clinical practice. However, the shortcomings resulting from the gap between technical and clinical demands, such as phototoxicity, low tissue permeability, and tissue hypoxia, limit its wide applications. This article reviews the available data regarding the pharmacological and clinical factors affecting the efficacy of photodynamic therapy, such as photosensitizers and oxygen supply, disease diagnosis, and other aspects of photodynamic therapy. In addition, the synergistic treatment of photodynamic therapy with surgery and nanotechnology is also discussed, which is expected to provide inspiration for the design of photodynamic therapy strategies.

Synergistic chemotherapy and phototherapy based on red blood cell biomimetic nanomaterials

Novel drug delivery systems (DDSs) have become the mainstay of research in targeted cancer therapy. By combining different therapeutic strategies, potential DDSs and synergistic treatment approaches are needed to effectively deal with evolving drug resistance and the adverse effects of cancer. Nowadays, developing and optimizing human cell-based DDSs has become a new research strategy. Among them, red blood cells can be used as DDSs as they significantly enhance the pharmacokinetics of the transported drug cargo. Phototherapy, as a novel adjuvant in cancer treatment, can be divided into photodynamic therapy and photothermal therapy. Phototherapy using erythropoietic nanocarriers to mimic the unique properties of erythrocytes and overcome the limitations of existing DDSs shows excellent prospects in clinical settings. This review provides an overview of the development of photosensitizers and research on bio-nano-delivery systems based on erythrocytes and erythrocyte membranes that are used in achieving synergistic outcomes during phototherapy/chemotherapy.

A novel UPLC-MS/MS method for simultaneous quantification of trigonelline, 4-hydroxyisoleucine, and diosgenin from Trigonella foenum-graecum extract: Application to pharmacokinetic study in healthy and type 2 diabetic rats

Trigonelline (TR), 4-hydroxyisoleucine (4-HI), and diosgenin (DG) are the main bioactives of the purified standardized extract of the popular plant Trigonella foenum-graecum L. (TFG), and it has been proven effective for the treatment of various diseases. However, to the best of our knowledge, no study has investigated the pharmacokinetic parameters of purified standardized T. foenum-graecum extract in normal and diabetic Wistar rats. The present study has developed and validated a rapid, reliable, and sensitive simultaneous ultra-performance liquid chromatography MS method to estimate these bioactives. The chromatographic separation was achieved using methanol, acetonitrile, and 0.1% formic acid with the ideal gradient flow system on a BEH Shield RP 18 column. A positive electrospray ionization mode was selected to estimate m/z values of TR (138.14 > 94.63), 4-HI (148.19 > 74.08), and DG (415.54 > 271.33). The method was robust and reproducible over the linearity range of 60-5000, 6-5000, and 15-5000 ng/mL for TR, 4-HI, and DG, respectively. Using this novel validated method, we investigated the pharmacokinetic parameters of bioactives using Phoenix WinNonlin version 8.0 (Certera) in normal and diabetic rats. The assay was successfully applied for the estimation of pharmacokinetic parameters using noncompartmental analysis. This investigation shows that the absorption rate increased, whereas distribution and elimination processes slowed down in diabetic rats compared with normal rats.

Design of experiment-driven stability-indicating RP-HPLC method for the determination of tofacitinib in nanoparticles and skin matrix

Background

Tofacitinib—an oral JAK inhibitor—has been recently approved by US FDA to treat moderate to severe RA. The delivery of tofacitinib to specific inflammation site at joint via topical route using nanoformulations helps in managing the potential adverse effects. The objective is to develop and validate a simple, specific, and sensitive stability-indicating HPLC method for quantification of tofacitinib in topical nanoformulations and different matrices (adhesive tape, and skin layers, i.e., stratum corneum, viable epidermis, and dermis). The major objective was to avoid use of instruments like LC–MS/MS and to ensure a widespread application of the method.

Result

A 32 factorial ‘design of experiments’ was applied to optimize process variables, to understand the effect of variables on peak properties. The calibration curve showed regression coefficient (R2) 0.9999 and linearity in the concentration range of 50 to 15,000 ng/mL, which is suitable for the analysis of conventional dosage forms and nanoformulations. Method validation was performed as per ICH guideline Q2 (R1). The accuracy by recovery studies ranged between 98.09 and 100.82%. The % relative standard deviations in intraday and interday precisions were in the range of 1.16–1.72 and 1.22–1.80%, respectively. Forced degradation studies indicated the specificity of method and showed stability-indicating potential for tofacitinib peak.

Conclusion

The validated method provides a quantification method of tofacitinib in the presence of formulation excipients, dissolution media, and skin tissues in detail. In addition, the method was successfully utilized for determination of various dermatokinetics profile of tofacitinib.

Preparation, Characterization and Pharmacokinetic Study of N-Terminal PEGylated D-Form Antimicrobial Peptide OM19r-8

Recently, new cationic antibacterial peptide OM19R has been designed with low minimum inhibitory concentration (MIC) values against some gram-negative bacteria, such as Escherichia coli, Salmonella, and Shigella. However, this hybrid peptide, like most antibacterial peptides, has low enzyme stability and short half-life, which, in turn, increases the drug's cost. In this study, an antibacterial peptide (OM19r-8) was obtained containing some D-Arg amino acids. The new preparations were carried out through the replacement of l-Arginine by d-Arginine and the addition of PEG chains. Firstly, eight OM19r series of antibacterial peptides were obtained by designing D-Arg. Then, a polyethylene glycol-modified product mPEG₅-butyrALD-OM19r-8 (mPEG₅-OM19r-8) was isolated and purified by reverse-phase high-performance liquid chromatography (RT-HPLC). The enzyme stability test showed that the resistance of antibacterial peptide OM19r-8 to protease degradation increased by 4-32-fold. Moreover, the Time-kill studies showed that the germicidal kinetics curves of mPEG₅-OM19r-8 and OM19r-8 to Escherichia coli had a similar trend, thus suggesting that PEG modification has an acceptable effect on the activity of the original peptide. Furthermore, the elimination of half-life (28.09 ± 2.81min) of mPEG₅-OM19r-8, and the area under the drug concentration-time curve (2686.48 ± 651.36min∗ug/ml) was significantly prolonged. The current study demonstrates an example that optimizes the AMP by utilizing L-to-D amino acid replacement and including PEG chains. These results provide useful data for the clinical application of the mPEG₅-OM19r-8.

In vivo and in silico characterization of apocynin in reducing organ oxidative stress: A pharmacokinetic and pharmacodynamic study

Apocynin has been widely used in vivo as a Nox2-contaninig nicotinamide adenine dinucleotide phosphate oxidase inhibitor. However, its time-dependent tissue distribution and inhibition on organ reactive oxygen species (ROS) production remained unclear. In this study, we examined apocynin pharmacokinetics and pharmacodynamics (PKPD) after intravenous (iv) injection (bolus, 5 mg/kg) of mice (CD1, 12-week). Apocynin was detected using a HPLC coupled to a linear ion-trap tandem mass spectrometer. Apocynin peak concentrations were detected in plasma at 1 minute (5494 ± 400 ng/mL) (t1/2  = 0.05 hours, clearance = 7.76 L/h/kg), in urine at 15 minutes (14 942 ± 5977 ng/mL), in liver at 5 minutes (2853 ± 35 ng/g), in heart at 5 minutes (3161 ± 309 ng/g) and in brain at 1 minute (4603 ± 208 ng/g) after iv injection. These were accompanied with reduction of ROS production in the liver, heart and brain homogenates. Diapocynin was not detected in these samples. Therapeutic effect of apocynin was examined using a mouse model (C57BL/6J) of high-fat diet (HFD, 16 weeks)-induced obesity and accelerated aging. Apocynin (5 mmol/L) was supplied in drinking water during the HFD period and was detected at the end of treatment in the brain (5369 ± 1612 ng/g), liver (4818 ± 1340 ng/g) and heart (1795 ± 1487 ng/g) along with significant reductions of ROS production in these organs. In conclusion, apocynin PKPD is characterized by a short half-life, rapid clearance, good distribution and inhibition of ROS production in major organs. Diapocynin is not a metabolite of apocynin in vivo. Apocynin crosses easily the blood-brain barrier and reduces brain oxidative stress associated with metabolic disorders and aging.

Pre-clinical pharmacokinetic and pharmacodynamic modelling study of 4-hydroxyisoleucine using validated ultra-performance liquid chromatography-tandem mass spectrometry

A reliable and sensitive ultra-performance liquid chromatography-tandem mass spectrometry-based method has been developed for the estimation of 4-hydroxyisoleucine (4-HI), a potent insulinotropic and hypolipidemic agent. The extraction of 4-HI from plasma was accomplished by the protein precipitation technique using l-isoleucine as an internal standard. The separation of analytes was achieved with a mobile phase consisting of acetonitrile and 0.1% formic acid in an isocratic flow system on a BEH Shield RP-18 column (150 mm × 2.1 mm, 1.7 μm). 4-HI and l-isoleucine were detected using an electrospray ionization (ESI) ion source, using multiple reaction monitoring (MRM) in positive ion mode. The precursor to product ion transitions of 4-HI and l-isoleucine were found at m/z values of 148.19 > 74.02 and 132.17 > 69.04, respectively. As per the guidelines for bioanalytical methods, all validation parameter results were within the acceptable range. The method exhibited a robust and reproducible linearity range of 1–5000 ng mL⁻¹ with a coefficient of regression of 0.9999. The method was successfully applied for the estimation of pharmacokinetic parameters after oral administration of 4-HI (10 mg kg⁻¹) in Wistar rats, by using Thoth Pro (version: 4.3) software. Herein, the two-compartment model was statistically fitted based on AIC and SBC values for evaluation of the pharmacokinetic parameters of 4-HI. Pharmacodynamic studies were also performed by measuring the levels of triglyceride and total cholesterol, and showed that the pharmacokinetic and pharmacodynamic data of 4-HI correlated with each other.

A reliable and sensitive UPLC-MS/MS based method has been developed for the estimation of 4-hydroxyisoleucine, a potent insulinotropic and hypolipidemic agent.

Design and Biological Evaluation of Lipoprotein-Based Donepezil Nanocarrier for Enhanced Brain Uptake through Oral Delivery

Alzheimer's disease (AD) is a progressive neurodegenerative disorder associated with memory and cognitive impairment. Donepezil is an acetylcholinesterase inhibitor used for the symptomatic treatment of AD. However, high dose of donepezil is prescribed to achieve effective concentration in the brain, which leads to significant side effects, gastrointestinal alterations, and hepatotoxicity. In the present study, ApoE3 conjugated polymeric nanoparticles derived from diblock copolymer methoxy poly(ethylene glycol)-polycaprolactone (mPEG-PCL) have been used to boost the delivery of donepezil to the brain. mPEG-PCL is an amphiphilic diblock polymer with a tendency to avoid nanoparticle uptake by phagocytic cells in the liver and can significantly reduce the gastric mucosal irritations. Moreover, ApoE3-based nanocarriers showed a promising ability to enhance brain uptake, binding to amyloid beta with high affinity and accelerating its clearance. Donepezil-loaded polymeric nanoparticles were performed by using a nanoprecipitation method and further surface modified with polysorbate 80 and ApoE3 to increase the brain bioavailability and reduce the dose. Optimization of various process parameters were performed using quality by design approach. ApoE3 polymeric nanoparticles were found to be stable in simulated gastric fluids and exhibited a sustained drug release pattern. Cellular uptake studies confirmed better neuronal uptake of the developed formulation, which is further corroborated with pharmacokinetic and biodistribution studies. Orally administered ApoE3 polymeric nanoparticles resulted in significantly higher brain donepezil levels after 24 h (84.97 ± 11.54 ng/mg tissue) as compared to the pure drug (not detected), suggesting a significant role of surface coating. Together, these findings are promising and offer preclinical evidence for better brain availability of donepezil by oral administration.