Determination of andrographolide in human plasma by high-performance liquid chromatography/mass spectrometry

Pharmacokinetics and Metabolomic Profiling of Metformin and Andrographis paniculata: A Protocol for a Crossover Randomised Controlled Trial

This protocol aims to profile the pharmacokinetics of metformin and Andrographis paniculata (AP) and continue with untargeted pharmacometabolomics analysis on pre-dose and post-dose samples to characterise the metabolomics profiling associated with the human metabolic pathways. This is a single-centre, open-labelled, three periods, crossover, randomised-controlled, single-dose oral administration pharmacokinetics and metabolomics trial of metformin 1000 mg (n = 18), AP 1000 mg (n = 18), or AP 2000 mg (n = 18) in healthy volunteers under the fasting condition. Subjects will be screened according to a list of inclusion and exclusion criteria. Investigational products will be administered according to the scheduled timeline. Vital signs and adverse events will be monitor periodically, and standardized meals will be provided to the subjects. Fifteen blood samples will be collected over 24 h, and four urine samples will be collected within a 12 h period. Onsite safety monitoring throughout the study and seven-day phone call safety follow-up will be compiled after the last dose of administration. The plasma samples will be analysed for the pharmacokinetics parameters to estimate the drug maximum plasma concentration. Untargeted metabolomic analysis between pre-dose and maximum plasma concentration (Cmax) samples will be performed for metabolomic profiling to identify the dysregulation of human metabolic pathways that link to the pharmacodynamics effects. The metformin arm will focus on the individualised Cmax plasma concentration for metabolomics study and used as a model drug. After this, an investigation of the dose-dependent effects will be performed between pre-dose samples and median Cmax concentration samples in the AP 1000 mg and AP 2000 mg arms for metabolomics study. The study protocol utilises a crossover study design to incorporate a metabolomics-based study into pharmacokinetics trial in the drug development program. The combination analyses will complement the interpretation of pharmacological effects according to the bioavailability of the drug.

Andrographolide: A Review of Analytical Methods

Bicyclic diterpenoid lactone andrographolide is regarded as a "natural antibiotic" as it is known to exhibit a range of bioactivities including anti-inflammatory, antibacterial, antipyretic, antineoplastic, cardioprotective, hepatoprotective and hypoglycaemic, and is present in Andrographis paniculata. The aim of this article is to review the information on analytical methods for andrographolide in biological samples, pharmaceutical formulations and plant materials. This article includes various techniques such as Spectrophotometry, Chemiluminescence method, Electroanalytical method, Chromatography and various hyphenated techniques.

Andrographis paniculata (Burm. f.) Wall. ex Nees: An Updated Review of Phytochemistry, Antimicrobial Pharmacology, and Clinical Safety and Efficacy

Infectious disease (ID) is one of the top-most serious threats to human health globally, further aggravated by antimicrobial resistance and lack of novel immunization options. Andrographis paniculata (Burm. f.) Wall. ex Nees and its metabolites have been long used to treat IDs. Andrographolide, derived from A. paniculata, can inhibit invasive microbes virulence factors and regulate the host immunity. Controlled clinical trials revealed that A. paniculata treatment is safe and efficacious for acute respiratory tract infections like common cold and sinusitis. Hence, A. paniculata, mainly andrographolide, could be considered as an excellent candidate for antimicrobial drug development. Considering the importance, medicinal values, and significant role as antimicrobial agents, this study critically evaluated the antimicrobial therapeutic potency of A. paniculata and its metabolites, focusing on the mechanism of action in inhibiting invasive microbes and biofilm formation. A critical evaluation of the secondary metabolites with the aim of identifying pure compounds that possess antimicrobial functions has further added significant values to this study. Notwithstanding that A. paniculata is a promising source of antimicrobial agents and safe treatment for IDs, further empirical research is warranted.

Quantitative Determination of Andrographolide and Related Compounds in Andrographis paniculata Extracts and Biological Evaluation of Their Anti-Inflammatory Activity

Extraction, isolation and characterization of Andrographis paniculata (A.p.) products were developed. Three natural diterpenes compounds were obtained and one was used for chemical modifications. Evaluation of their inhibition of TNFα induced NFκB transcriptional activity. A rapid analytical method for the determination and quantitation of three diterpenoid lactones (andrographolide 1, didehydroandrographolide 2, neoandrographiside 3) found in A. paniculata extracts was investigated. After some optimizations on column type and injection solvent, the separation was achieved in 9 min on a monolithic Chromolith Performance RP18e column (100 mm × 4.6 mm ID, 2 µm), with a gradient solvent system of water and methanol, UV detection at 220 nm and ELSD detection. The method was proved to be suitable for the quantitation of these three diterpenes in four different commercial Andrographis dietary supplements. The anti-inflammatory activities of a mixture of known composition have been evaluated showing differences in activity depending on the relative ratio of various diterpenes and also a possible synergic activity for some of them.

Novel nanocrystal-based solid dispersion with high drug loading, enhanced dissolution, and bioavailability of andrographolide

Objective

The current study sought to design a quickly dissolving, high drug loading nanocrystal-based solid dispersion (NC-SD) in order to improve the dissolution of poorly soluble drugs.

Methods

The NC-SD was prepared by means of combination of homogenization and spray-drying. Polymer hydroxypropylmethylcellulose (HPMC) was used as baseline dispersant for NC-SD of the model drug – andrographolide (AG). Three superdisintegrants cohomogenized with HPMC were used as codispersant for AG-NC-SD and compared to common water-soluble dispersants – mannitol and lactose. The dissolution characterization and oral bioavailability of AG-NC-SD were evaluated.

Results

The AG-NC-SD with the higher concentration of HPMC exhibited fast dissolution due to the enhanced wettability of HPMC. The water-soluble codispersants (mannitol and lactose) did not completely prevent AG-NC from aggregation during spray-drying. To achieve much faster AG release, cohomogenized superdisintegrants at a level of 20% must be used along with 25% HPMC. Compared with water-soluble dispersants like mannitol and lactose, superdisintegrants with high swelling capacity were much more effective dispersants for enhancing fast redispersion/dissolution of AG-NC-SD via a swelling-triggered erosion/disintegration mechanism. Surfactant-free AG-NC-SD with 15% cohomogenized sodium carboxymethyl starch combined with 15% HPMC and 10% lactose enhanced the dissolution further, without comprising drug loading, exhibited a barely compromised dissolution rate compared to precursor NC suspensions (f₂>50), and possessed drug loading up to 67.83%±1.26%. The pharmacokinetics results also demonstrated that the AG-NC-SD significantly improved the bioavailability in vivo of AG (P<0.05), compared with to the coarse AG.

Conclusion

This study illustrates that a quickly dissolving, high drug load, surfactant-free NC-SD can be prepared by using a superdisintegrant as codispersant, and provides a feasible strategy to improve the oral bioavailability of poorly soluble drugs.

A Natural Triterpenoid Saponin as Multifunctional Stabilizer for Drug Nanosuspension Powder

The objective of this study is to prepare a novel drug nanosuspension modified by a natural triterpenoid saponin (glycyrrhizin (GZ)) and evaluate its stability and redispersibility. A poorly soluble drug (andrographolide (AGE)) was used as a model drug. AGE nanosuspensions (AGE-NS) using GZ as natural stabilizer with mean particle size of 487 nm were firstly prepared by homogenization and converted into dried AGE nanosuspension powder (AGE-NP) by freeze-drying. It was found that GZ was able to prevent the aggregation of AGE nanocrystals and the freeze-dried AGE-NP could easily redisperse back to AGE-NS. It was related with special properties of GZ that possessed the interfacial property (37.02 ± 0.29 N/m) and electrostatic effect (-43.6 ± 0.9 mV) and could entrap AGE nanocrystals into its network structure. The freeze-dried AGE-NP/GZ exhibited excellent performance, compared with those combined with trehalose as matrix formers. The powder X-ray diffraction result demonstrated that GZ did not alter the AGE crystal state. The dissolution of AGE-NP/GZ (99.87%) was significantly enhanced, compared with the coarse AGE (42.35%). This study demonstrated that GZ could be used as a novel multifunctional stabilizer for production of drug nanosuspensions and provided a promising basis for further formulation development of poorly soluble drug.

Fabrication and in vitro/in vivo evaluation of amorphous andrographolide nanosuspensions stabilized by d-α-tocopheryl polyethylene glycol 1000 succinate/sodium lauryl sulfate

Andrographolide (ADG) is a diterpenoid isolated from Andrographis paniculata with a wide spectrum of biological activities, including anti-inflammatory, anticancer and hepatoprotective effects. However, its poor water solubility and efflux by P-glycoprotein have resulted in lower bioavailability. In this study, ADG nanosuspensions (ADG-NS) were prepared using a wet media milling technique followed by freeze drying. d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS), a surfactant that inhibits P-glycoprotein function, and sodium lauryl sulfate were used as surface stabilizers. A Box-Behnken design was used to optimize the nanosuspension preparation. The products of these optimal preparation conditions were amorphous and possessed much faster dissolution in vitro than a coarse powder of ADG. The particle size and redispersibility index of the freeze-dried ADG-NS were 244.6±3.0 nm and 113%±1.14% (n=3), respectively. A short-term stability study indicated that the freeze-dried ADG-NS could remain highly stable as nanosuspensions during the testing period. A test of transport across a Caco-2 cell monolayer revealed that the membrane permeability (P_app) of ADG-NS was significantly higher than the permeability of the ADG coarse powder or ADG-NS without TPGS (P<0.01). Compared to the ADG coarse powder, a physical mixture, commercial dripping pills and ADG-NS without TPGS, ADG-NS exhibited significantly higher plasma exposure with significant enhancements in C_max and area under the curve of plasma concentration versus time from zero to the last sampling time (AUC_0-t ) (P<0.01). An evaluation of the anti-inflammatory effect on Carr-induced paw edema demonstrated that the ADG-NS were more effective in reducing the rate of paw swelling, producing a greater increase in the serum levels of nitric oxide (NO), Interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) (P<0.01) and an increase in superoxide dismutase activity (P<0.05) compared to the ADG coarse powder. This study indicated that nanosuspensions could act as an effective delivery device for ADG to enhance its oral bioavailability and biological efficacy.

Andrographis paniculata: Dissolution investigation and pharmacokinetic studies of four major active diterpenoids after multiple oral dose administration in healthy Thai volunteers

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata is included in 'The National List of Essential Herbal Drugs A.D. 1999' of Thailand as an herbal drug for the treatment of common cold symptoms and non-infectious diarrhea. The therapeutic activities of A. paniculata are attributed to four major active diterpenoids: andrographolide (1), 14-deoxy-11, 12-didehydroandrographolide (2), neoandrographolide (3), and 14-deoxyandrographolide (4). However, the pharmacokinetic studies in humans of this plant were performed after a single oral dose administration and reported the parameters related to be of only 1.

AIM OF THE STUDY

This study aims to determine the pharmacokinetic parameters of four major active diterpenoids after multiple oral dose administration of A. paniculata capsules in healthy volunteers. The dissolution testing of these four diterpenoids was also performed.

MATERIALS AND METHOD

The dissolution testing of four major active diterpenoids was conducted in pH 1.2, pH 4.5, and pH 6.8 for 10-100min. The pharmacokinetic study of these active diterpenoids was designed as an open-label, multiple oral dose administration of A. paniculata capsules in 20 healthy Thai volunteers at 1:1 ratio of female and male. Each volunteer was given four A. paniculata capsules each time which contained 1, 2, 3, and 4 in the quantities of 32.64, 5.40, 3.60, and 3.84mg, respectively, three times a day for three consecutive days. On the fourth day, after the first dose of the day was administered, blood samples were collected at the predefined time points. The validated LC-MS/MS method was used to simultaneously determine the concentrations of these diterpenoids in the human plasma samples. The pharmacokinetic parameters of each active diterpenoid were determined.

RESULTS

All four major active diterpenoids have been completely dissolved in the simulated pH of gastrointestinal tract within 60min of dissolution. The dissolution profiles were found to be highest in pH 6.8 and lowest in pH 1.2, especially for 3. In the pharmacokinetic study, although 1 was administered at the highest dose among these four diterpenoids, 2 exhibited the highest maximum concentrations (C_max) of 44.89ng/mL and area under the plasma concentration-time curve (AUC) of 128.17h×ng/mL. Compound 1 had the second highest C_max and AUC as 32.41ng/mL and 55.23h×ng/mL, respectively. The relative systemic exposure, represented by the dose normalized AUC [(h×ng/mL)/(mg/kg)], of 2 was approximately 14 times higher than that of 1, while those of 3 and 4 were approximately 1.5 and 1.6 times higher, respectively. C_max, AUC, apparent volume of distribution, and apparent clearance of 2 were found to be significant difference between female and male. However, when these parameters were calculated as dose normalized basis, no statistically significant difference was found.

CONCLUSION

The four major active diterpenoids in the A. paniculata capsules were soluble in all studied dissolution media. The pharmacokinetic parameters of these active diterpenoids in the present study could be applied for dose optimization of A. paniculata product in order to obtain good therapeutic efficacy and reduce the possible side effects that may occur from different active diterpenoids in this medicinal plant.

Strategies for formulation development of andrographolide

This review is the comprehensive account of the pharmaceutical aspects of andrographolide with special emphasis on its delivery that have take place over the century.

Nanonization of andrographolide by a wet milling method: the effects of vitamin E TPGS and oral bioavailability enhancement

Andrographolide (AND) has wide prospects in clinical use, but suffers from the restriction of poor oral bioavailability, due to its low solubility, rapid and extensive metabolism and efflux by P-glycoprotein (P-gp).

Andrographis paniculata Extract and Andrographolide Modulate the Hepatic Drug Metabolism System and Plasma Tolbutamide Concentrations in Rats

Andrographolide is the most abundant terpenoid of A. paniculata which is used in the treatment of diabetes. In this study, we investigated the effects of A. paniculata extract (APE) and andrographolide on the expression of drug-metabolizing enzymes in rat liver and determined whether modulation of these enzymes changed the pharmacokinetics of tolbutamide. Rats were intragastrically dosed with 2 g/kg/day APE or 50 mg/kg/day andrographolide for 5 days before a dose of 20 mg/kg tolbutamide was given. APE and andrographolide reduced the AUC_0–12 h of tolbutamide by 37% and 18%, respectively, compared with that in controls. The protein and mRNA levels and enzyme activities of CYP2C6/11, CYP1A1/2, and CYP3A1/2 were increased by APE and andrographolide. To evaluate whether APE or andrographolide affected the hypoglycemic action of tolbutamide, high-fat diet-induced obese mice were used and treated in the same manner as the rats. APE and andrographolide increased CYP2C6/11 expression and decreased plasma tolbutamide levels. In a glucose tolerance test, however, the hypoglycemic effect of tolbutamide was not changed by APE or andrographolide. These results suggest that APE and andrographolide accelerate the metabolism rate of tolbutamide through increased expression and activity of drug-metabolizing enzymes. APE and andrographolide, however, do not impair the hypoglycemic effect of tolbutamide.

Antioxidative and cytoprotective effects of andrographolide against CCl4-induced hepatotoxicity in HepG2 cells

This article describes antioxidative and cytoprotective property of andrographolide, a major active component of the plant Andrographis paniculata ( A. paniculata). High yields (2.7%) of andrographolide was isolated from the aerial parts of this plant via silica column chromatography. The purity of the compound was determined by high-performance thin-layer chromatography (HPTLC) and reversed phase high-performance liquid chromatography (HPLC) analysis. The structure was elucidated using techniques such as UV-visible spectrophotometry, elemental analysis, Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR) and mass spectral analysis and the data obtained were comparable with reported results. It was observed that andrographolide exhibited significant antioxidative property (IC50 = 3.2 µg/ml) by its ability to scavenge a stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) as compared to known antioxidants like ascorbic acid, butylated hydroxy toluene (BHT) and the plant extract. The cytoprotective role of andrographolide against carbon tetrachloride (CCl4) toxicity in human hepatoma HepG2 cell line was assessed using trypan blue exclusion test, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, by estimation of various leakage enzymes and by measuring the glutathione levels. The recovery obtained for andrographolide treatment in the presence of CCl4 was two-fold compared to A. paniculata extract for all other related biochemical parameters investigated. The results of the study indicate that andrographolide is a potent inhibitor of CCl4-mediated lipid peroxidation.

In vitro determination of the effect of Andrographis paniculata extracts and andrographolide on human hepatic cytochrome P450 activities

We investigated the effects of Andrographis paniculata (AP) extracts and andrographolide on the catalytic activity of three human cDNA-expressed cytochrome P450 enzymes: CYP2C9, CYP2D6 and CYP3A4. In vitro probe-based high performance liquid chromatography assays were developed to determine CYP2C9-dependent tolbutamide methylhydroxylation, CYP2D6-dependent dextromethorphan O-demethylation and CYP3A4-dependent testosterone 6β-hydroxylation activities in the presence and absence of AP extracts and andrographolide. Our results indicate that AP ethanol and methanol extracts inhibited CYP activities more potently than aqueous and hexane extracts across the three isoforms. Potent inhibitory effects were observed on CYP3A4 and CYP2C9 activities (K (i) values below 20 μg/ml). Andrographolide was found to exclusively but weakly inhibit CYP3A4 activity. In conclusion, data presented in this study suggest that AP extracts have the potential to inhibit CYP isoforms in vitro. There was, however, variation in the potency of inhibition depending on the extracts and the isoforms investigated.

Technology for improving the bioavailability of small molecules extracted from traditional Chinese medicines

Evidence that small molecules extracted from traditional Chinese medicines (TCMs) have beneficial effects on health is increasingly being reported in the scientific literature and these compounds are now widely recognized as potential therapeutic drugs. There have been several detailed studies of the absorption, distribution, metabolism and excretion of these compounds in rats and humans. However, some active components have low bioavailability owing to their unsuitable physicochemical and biopharmaceutical characteristics, resulting in differences in vivo. The main problem in using natural products as a source of pharmaceutical lead compounds is the need to improve the bioavailability of these compounds. This review presents and discusses the current methods used for improvement and their impact on the bioavailability of some new pharmaceutical lead compounds from TCMs.