Oral Administration In Rats Research Articles

Using the Cocrystal Approach as a Promising Drug Delivery System to Enhance the Dissolution and Bioavailability of Formononetin Using an Imidazole Coformer

Background: Natural isoflavones are recognized for their diverse pharmacological activities; however, their low aqueous solubility presents a significant challenge for further development. Here, we aimed to develop a cocrystal of formononetin (FMN) to improve its solubility. Methods: The formononetin-imidazole (FMN-IMD) cocrystal was prepared using liquid-assisted grinding method. The prepared cocrystal was identified through a thermal analysis of physical mixtures with various coformers. FTIR and solid-state NMR confirmed the presence of hydrogen bonds and π-π interactions in the FMN-IMD cocrystal. Results: The solubility of FMN-IMD was two to three times higher than that of crystalline FMN. The FMN-IMD cocrystal showed a 4.93-fold increase in the Cmax value and a 3.58-fold increase in the AUC compared to FMN after oral administration in rats. There were no changes in the PXRD of the FMN-IMD cocrystal after six months of storage at 40 °C. Conclusions: Thus, the FMN-IMD cocrystal is proposed as an effective solid form for oral delivery, offering enhanced solubility and physical stability.

In vivo antihyperglycemic effect of Ptilostemon casabonae (L.) Greuter leaf extract and its liposomal formulation

Prolonged exposure to hyperglycemia is recognized as the primary factor in the pathogenesis of diabetes, a metabolic disease that affects millions of people and one of the top 10 causes of death globally. Ptilostemon casabonae (L.) Greuter is an edible plant whose extract has recently shown inhibitory activity against α-glucosidase and antioxidant activity. This suggests that this plant could be a candidate to develop natural remedies against hyperglycemia. In this study, the in vivo antihyperglycemic effect of an extract from P. casabonae leaves is presented, and a nanoformulation is proposed to possibly enhance such effect, upon oral administration in rats. Liposomes coated with a gastro-resistant polymer, Eudragit, were developed for the loading and delivery of the extract. Nanosized (ca. 90 nm), unilamellar vesicles were produced, as demonstrated by light scattering results and cryo-TEM micrographs. The effects of the loading of the extract and the coating with Eudragit on the liposomes' bilayered structure were described by Small-Angle X-ray Scattering. The physical stability of the P. casabonae Eudragit-coated liposomes was evaluated in storage and in simulated gastrointestinal fluids, results showing that the vesicles’ key features were preserved. The vesicles efficiently entrapped rutin (57.4 % ± 5.7) and apigenin (82 % ± 9.1), main flavonoids in the extract, as indicated by the quali-quantitative characterization via HPLC-PDA. P. casabonae extract was found to exert a significant antihyperglycemic effect in rats subjected to a sucrose load, with a reduction in peak glucose level of 33 and 63 % at doses of 40 and 100 mg/kg, respectively. A 10 mg/kg dose of the extract in Eudragit-coated liposomes produced the same reduction (30 %) as that obtained with a 4-fold higher dose of the extract on its own.

Disposition Kinetics of Cathinone and its Metabolites after Oral Administration in Rats.

Cathinone is a natural stimulant found in the Catha edulis plant. Its derivatives make up the largest group of new psychoactive substances. In order to better understand its effects, it is imperative to investigate its distribution, pharmacokinetics, and metabolic profile. However, the existing literature on cathinone remains limited. This study aimed to investigate the disposition kinetics and metabolic profile of cathinone and its metabolite cathine through a single oral dose of cathinone administration in rats. Cathinone and cathine concentrations were identified and quantified using ion trap liquid chromatography- mass spectrometry (LC-IT/MS). The metabolic profile in the serum, brain, lung, liver, kidney, and heart was analyzed at specific time points (0, 0.5, 2.5, 6, 12, 24, 48, and 72 hours) using the ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) method. The highest concentration of cathinone was found in the kidney (1438.6 μg/L, which gradually decreased to 1.97 within 48 h and disappeared after 72 h. Cathinone levels in the lungs, liver, and heart were 859, 798.9, and 385.8 μg/L, respectively, within half an hour. However, within 2.5 hours, these levels decreased to 608.1, 429.3, and 309.1 μg/L and became undetectable after 24 h. In the rat brain, cathinone levels dropped quickly and were undetectable within six hours, decreasing from 712.7 μg/L after 30 min. In the brain and serum, cathine reached its highest levels at 2.5 hours, while in other organs, it peaked at 0.5 hours, indicating slower conversion of cathinone to cathine in the brain and serum. This study revealed a dynamic interplay between cathinone disposition kinetics and its impact on organ-specific metabolic profiles in rats. These results have significant implications for drug development, pharmacovigilance, and clinical practices involving cathinone. Investigating the correlation between the changes in biomarkers found in the brain and the levels of cathinone and cathine is essential for informed decision- making in medical practices and further research into the pharmacological properties of cathinone.

Comprehensive Analysis of Chemical Ingredients of Waiganfengsha Granule and Absorbed Components in Rat Plasma Based on UHPLC-Q-TOF-MS.

Waiganfengsha Granule, an over-the-counter drug, is commonly used for treating windheat cold and sore throat in clinical settings. However, its material basis of medicinal efficacy is still unclear. In this study, an efficient integrated analytical strategy was established for its chemical and metabolite profiles study. Firstly, to avoid the possible false-positive results of structural elucidation, an in-house component library that contains chemical constituents reported in the literature from the six individual medicines of Waiganfengsha Granule was established. Secondary, mass data post-processing techniques, including precursor ion list and neutral loss filtering, were applied to enhance the identification accuracy. Thirdly, for the rapid characterization of those absorbed components after oral administration in rats, the identified chemical constituents were used as candidate components for the serum analysis. By comparing the retention time and analyzing mass data, the metabolites in rat plasma were identified. As a result, 57 chemical ingredients were identified, including 21 phenolic acids, 9 alkaloids, 2 flavonoids, 5 lignins, 13 saponins, and 7 other compounds. Among these, 12 compounds were unambiguously identified by comparison with reference standards, and 45 were tentatively characterized by analyzing their accurate MS data, MS/MS fragmentation patterns, and also by comparison with those data reported in the literature. Additionally, 46 metabolites were detected and identified in rat plasma. This study is beneficial for understanding the chemical composition and metabolic profiles of Waiganfengsha Granule, and the results obtained might provide a solid basis for further studies on its functional mechanism.

An effective LC-MS method for the simultaneous determination of a potential anti-rheumatoid arthritis drug, carboxyamidotriazole, and its major metabolite in rat plasma.

Carboxyamidotriazole (CAI) was previously recognized as a well-tolerated anticancer drug. It has also demonstrated significant anti-inflammatory effects in various cell and animal model experiments, prompting its investigation as a potential treatment for rheumatoid arthritis. In this study, the potential biotransformation metabolites of CAI were identified both in vitro and in vivo. A sensitive, specific, and accurate LC-MS method was developed for the quantitative analysis of CAI and its major metabolite, CAI-OH, in rat plasma. CAI, CAI-OH, and telmisartan (used as an internal standard) were separated using a Zorbax SB C18 column. The mobile phase consisted of water (phase A, containing 0.1% formic acid) and acetonitrile (phase B, containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The analytes were examined using a high-resolution mass spectrometer, with detected mass-to-charge ratios of m/z 424.01293 for CAI, m/z 440.00785 for CAI-OH, and m/z 515.24415 for telmisartan. Good linearity was observed within the range of 10-5000 ng/mL. Both inter- and intra-batch precision (relative standard deviation, %) were below 6%, and the accuracy ranged from 94.9% to 106.1%. The analytes remained stable throughout the entire experimental period. This method was successfully applied in a pharmacokinetic study of CAI following oral administration in rats.

Preclinical metabolism and the disposition of vornorexant/TS-142, a novel dual orexin 1/2 receptor antagonist for the treatment of insomnia.

We investigated the metabolism and disposition of vornorexant, a novel dual orexin receptor antagonist, in rats and dogs, and clarified invitro metabolite profiles in humans. Furthermore, we investigated the pharmacokinetics of active metabolites in rats and dogs and their CNS distribution in rats to elucidate its contribution to drug efficacy. [14 C]vornorexant was rapidly and mostly absorbed after the oral administration in rats and dogs. The drug-derived radioactivity, including metabolites, was distributed to major organs such as the liver, kidneys in rats, and was almost eliminated within 24 h post-dose in both species. Metabolite profiling revealed that main clearance mechanism of vornorexant was metabolism via multiple pathways by oxidation. The major circulating components were the cleaved metabolites (M10, M12) in rats, and the unchanged form in dogs, followed by M1, and then M3. Incubation with human hepatocytes resulted in formation of metabolites, including M1, M3, M10, and M12. The metabolic pathways were similar in all tested species. Resulting from the PK and CNS distribution of active metabolites (M1 and M3) with weaker pharmacological activity, the concentration of the unchanged form was higher than that of active metabolites in rat CSF and dog plasma, suggesting that the unchanged form mainly contributed to the drug efficacy. These findings demonstrate that vornorexant is absorbed immediately after administration, and vornorexant and its metabolites are rapidly and completely eliminated in rats and dogs. Thus, vornorexant may have favorable pharmacokinetic profiles as a hypnotic drug to provide rapid onset of action and minimal next-day residual effects in humans.

Integrated chemical characterization, metabolite profiling, and pharmacokinetics analysis of Zhijun Tangshen Decoction by UPLC-Q/TOF-MS.

Diabetic nephropathy (DN) is the main cause of end-stage renal disease worldwide and a major public issue affecting the health of people. Therefore, it is essential to explore effective drugs for the treatment of DN. In this study, the traditional Chinese medicine (TCM) formula, Zhijun Tangshen Decoction (ZJTSD), a prescription modified from the classical formula Didang Decoction, has been used in the clinical treatment of DN. However, the chemical basis underlying the therapeutic effects of ZJTSD in treating DN remains unknown. In this study, compounds of ZJTSD and serum after oral administration in rats were identified and analyzed using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS). Meanwhile, a semi-quantitative approach was used to analyze the dynamic changes in the compounds of ZJTSD in vivo. UPLC-Q/TOF-MS analysis identified 190 compounds from ZJTSD, including flavonoids, anthraquinones, terpenoids, phenylpropanoids, alkaloids, and other categories. A total of 156 xenobiotics and metabolites, i.e., 51 prototype compounds and 105 metabolites, were identified from the compounds absorbed into the blood of rats treated with ZJTSD. The results further showed that 23 substances with high relative content, long retention time, and favorable pharmacokinetic characteristics in vivo deserved further investigations and validations of bioactivities. In conclusion, this study revealed the chemical basis underlying the complexity of ZJTSD and investigated the metabolite profiling and pharmacokinetics of ZJTSD-related xenobiotics in rats, thus providing a foundation for further investigation into the pharmacodynamic substance basis and metabolic regulations of ZJTSD.

Hydroxymethylnitrofurazone lymphatic uptake with nanostructured lipid carrier after oral administration in rats.

Background: Leishmaniasis, caused by the protozoan Leishmania sp., infects phagocyte cells present in lymphatic organs. This study demonstrates the influence of nanostructured lipid carrier-loaded hydroxymethylnitrofurazone (NLC-NFOH) on lymphatic uptake using a chylomicron-blocking flow model in rats. Method: Lymphatic uptake of NFOH was assessed 1h after oral administration of dimethyl sulfoxide with NFOH or NLC-NFOH with and without cycloheximide pretreatment. Result: Dimethyl sulfoxide with NFOH and NLC-NFOH showed NFOH serum concentrations of 0.0316 and 0.0291μg/ml, respectively. After chylomicron blocking, NFOH was not detected. Conclusion: Despite log P below 5, NFOH was successfully taken up by the lymphatic system. Long-chain fatty acids and particle size might be main factors in these findings. NLC-NFOH is a promising and convenient platform for treating leishmaniasis via oral administration.

Safety and Toxicology Study of Hu7691, a Novel AKT Inhibitor, following Oral Administration in Rats.

Hu7691 represents a novel Pan-Akt kinase inhibitor, demonstrating excellent selectivity towards non-AGC kinase families and pronounced inhibitory effects on the proliferation of multiple tumor cell lines. However, there is currently a notable absence of in vivo toxicological research evidence concerning Hu7691. This study represents the first investigation into the 14-day repeated-dose toxicity of Hu7691 in male and female Sprague Dawley (SD) rats. Male rats were administered daily doses of 12.5, 50, 100, and 150 mg/kg/day, while female rats received doses of 12.5, 25, 50, and 75 mg/kg/day for 14 consecutive days. Hematological assessments, organ weights, and histopathological examinations revealed corresponding alterations, suggesting potential target organs for toxicity including the spleen, thymus, and gastrointestinal tract. It is worth noting that the test substance may also impact the liver, kidneys, heart, and ovaries. The No Observed Effect Level (NOAEL) was determined to be no greater than 12.5 mg/kg/day. Based on the observed gender-related toxicity differences in preliminary trials, it is recommended that the high dose reference dose for male animals in formal experiments should not be less than 100 mg/kg/day, while for female animals, it should be less than 50 mg/kg/day.

Evaluating Potential Anxiolytic Effects of Minor Cannabinoids and Terpenes After Acute and Chronic Oral Administration in Rats.

Background: Cannabis and its primary psychoactive constituent delta-9-tetrahydrocannabinol (D9-THC) produce biphasic, dose-dependent effects on anxiety. In addition to D9-THC, cannabis contains other "minor" cannabinoids and terpenes with purported therapeutic potential for the treatment of anxiety. Empirical data on potential therapeutic effects of these compounds is limited. The current study evaluated the effects of selected minor cannabinoids and terpenes in a battery of tests sensitive to anxiolytic and anxiogenic drugs. Methods: In Experiment 1, adult male Sprague Dawley rats (N=7-8/group) were administered acute oral doses of one of five minor cannabinoids: delta-8-tetrahydrocannabinol (D8-THC; 10 mg/kg), tetrahydrocannabivarin (32 mg/kg), cannabidiolic acid (32 mg/kg), cannabidivarin (32 mg/kg), and cannabigerol (100 mg/kg), or one of five terpenes: D-limonene (17 mg/kg), ⍺-pinene (100 mg/kg), ⍺-terpineol (10 mg/kg), bisabolol (100 mg/kg), and β-caryophyllene (17 mg/kg), or vehicle (medium-chain triglycerides [MCT] oil). Ethyl alcohol was tested as an active comparator. Thirty minutes post-administration, the marble burying test, the three-chamber social interaction test, and the novelty-induced hypophagia test were completed; motor activity was assessed throughout testing. Experiment 2 examined the potential anxiolytic effects of minor cannabinoids when administered chronically; rats administered MCT oil or minor cannabinoids in Experiment 1 continued receiving once-daily doses for 21 days and were assessed using the same test battery after 7, 14, and 21 days of administration. Results and Conclusions: When compared to vehicle, acute administration of bisabolol and D-limonene increased the amount of food consumed and bisabolol-, D-limonene-, ⍺-pinene-, and β-caryophyllene decreased percent time spent in the outer zone in the novelty-induced hypophagia test, suggestive of an anxiolytic effect. Only ethanol increased social interaction. After acute administration, anxiogenic effects in the marble burying test were observed for D8-THC, but not for other minor cannabinoids and terpenes. Throughout chronic administration, only D8-THC displayed anxiogenic effects in the novelty-induced hypophagia test. The other cannabinoids did not show anxiolytic or anxiogenic effects in any of the tests at the doses or times tested. The minor cannabinoids and terpenes did not impair or stimulate general motor activity. These data provide a foundation for future studies investigating cannabinoid/terpene interactions.

Toxicological Evaluation and Pain Assessment of Four Minor Cannabinoids Following 14-Day Oral Administration in Rats.

Introduction: Despite growing consumer interest and market availability, the safety of minor cannabinoids, generally present in low concentrations in Cannabis sativa L., is not well understood. Materials and Methods: Cannabichromene (CBC; 3.2, 10, 17, 22, 32, or 100 mg/kg-bw/day), cannabinol (CBN; 1, 3.2, 10, 17, 32, or 100 mg/kg-bw/day), delta-8-tetrahydrocannabinol (D8-THC; 0.32, 1, 3.2, or 10 mg/kg-bw/day), tetrahydrocannabivarin (THCV; 3.2, 10, 17, 22, 32, or 100 mg/kg-bw/day), and vehicle (medium-chain triglyceride oil) preparations were administered via oral gavage once daily for 14 days to Sprague Dawley rats. Changes in behavior, body weight, food consumption, clinical pathology, organ weights, body temperature, and thermal pain sensitivity (tail flick assay) were assessed. Select organ tissues were collected at terminal necropsy and fixed for histopathological examination. Results: No treatment-related deaths were observed throughout the study, and cannabinoids were generally well tolerated. While some significant trends in body weight differences from controls (increases and decreases) were observed, these occurred independently of food consumption. Overall, differences in serum chemistry and hematology parameters between cannabinoid groups and their respective control groups were considered to occur due to biological variation among rats. No treatment-related gross abnormalities were observed in examined organs. Significant changes in absolute and relative organ weights occurred primarily in males and were generally of negligible magnitude. There were no biologically significant histopathological observations. While pain tolerance was significantly improved in animals treated with D8-THC (3.2 and 10 mg/kg-bw/day, day 14), results across minor cannabinoids were inconsistent and warrant further study. Conclusion: Minor cannabinoids were well tolerated across 14 days of daily oral administration at the doses assessed. Modest, dose-dependent trends in relative organ weights and serum chemistry parameters warrant exploration at higher oral doses. These data will assist in dose selection for future studies investigating the long-term safety and effects of CBC, CBN, D8-THC, and THCV.

Micropipette-guided Drug Administration (MDA) as a non-invasive chronic oral administration method in male rats

BackgroundIn preclinical studies resorting to rodents, the effects of prolonged oral intake of active substances are difficult to evaluate. Indeed, to get closer to clinical reality, oral gavage (OG) is frequently used but the repetition of administrations induces risks of lesions of the digestive tract, and stress for animals which can compromise the quality of the results. New methodThis study describes the development of a non-invasive oral administration method in male Sprague Dawley rats, as a safe alternative of OG, more faithful to clinical reality and limiting biases in pharmacokinetics and/or pharmacodynamics interpretation. Micropipette-guided Drug Administration (MDA) is based on the administration by micropipette of a sufficiently palatable vehicle for the animals to voluntarily take its contents. ResultsMDA was not demonstrated as less stressful than OG. A pharmacokinetics equivalence between MDA and OG was demonstrated for pregabalin administration but not for aripiprazole. Despite the use of a sweet vehicle, the MDA method does not result in weight gain or significant elevation of blood glucose and fructosamines level. Regarding the time needed to administrate the solution, the MDA method is significantly faster than OG. Comparison with existing method(s)Contrastingly to procedures using food or water, this method allows for a rigorous control of the time and dose administered and is delivered in discrete administration windows which is therefore closer to the clinical reality. This method appears particularly suitable for pharmacological evaluation of hydrophilic compounds. ConclusionsThe MDA procedure represents a respectful and adapted pharmacological administration method to study the effects of chronic oral administration in rats.

Liver and Plasma Concentrations of Food Chemicals after Virtual Oral Doses Extrapolated Using in silico Estimated Input Pharmacokinetic Parameters to Confirm Reported Liver Toxicity in Rats.

The estimation of health risks of chemical substances was historically investigated using animal studies; however, current research focuses on reducing the number of animal experiments. The toxicity of chemicals in fish screening systems is reportedly correlated with their hydrophobicity. The inverse relationship between absorption rates (intestinal cell permeability) and virtual hepatic/plasma pharmacokinetics of diverse chemicals has been previously evaluated by modeling oral administration in rats. In the current study, internal exposures, i.e., virtual maximum plasma concentrations (Cmax) and areas under the concentration-time curves (AUC), of 56 food chemicals with reported hepatic lowest-observed-effect levels (LOELs) of ≤1000 mg/kg/day in rats were pharmacokinetically modeled using in silico estimated input pharmacokinetic parameters. After a virtual single oral dose of 1.0 mg/kg of 56 food chemicals, the output Cmax and AUC values in rat plasma generated by modeling using the corresponding in silico estimated input parameters were not significantly correlated with the reported hepatic LOEL values. However, significant inverse relationships between hepatic/plasma concentrations of selected lipophilic food chemicals (i.e., octanol-water partition coefficient logP >1) using forward dosimetry and reported LOEL values (≤300 mg/kg/day) were observed (n = 14, r = -0.52-0.66, p ≤ 0.05). This simple modeling approach, which uses no experimental pharmacokinetic data, has the potential to play a significant role in reducing the use of animals to estimate toxicokinetics or internal exposures of lipophilic food components after oral doses. Therefore, these methods are valuable for estimating hepatic toxicity by using forward dosimetry in animal toxicity experiments.

Screening anti-fatigue components of American ginseng saponin by analyzing spectrum-effect relationship coupled with UPLC-Q-TOF-MS.

American ginseng has an obvious anti-fatigue effect, but the effective material basis is still unclear. The spectrum-effect relationship is a scientific method that studies the correlations between chemical spectra and pharmacological effect. To reveal the real bioactive compounds in American ginseng saponin (AGS) based on a study of the underlying correlations between these compounds' occurrence in rat serum after their intake of AGS and the anti-fatigue effect of AGS. We utilized ultra-performance liquid chromatography (UPLC) with quadrupole and time-of-flight mass spectrometry (Q-TOF-MS) to analyze the extract of AGS and its constituents in serum after oral administration in rats. The anti-fatigue effect of AGS in rats was measured using the time weight-bearing swimming technique, the content of blood urea nitrogen, hepatic glycogen, and blood lactic acid. The relationship between the peak area values in fingerprints from rat serum and pharmacodynamic parameters of AGS was established using correlation analysis with partial least square regression (PLSR) method and gray correlation method. We detected and identified 22 compounds from extract, and 8 prototype components from serum. Through PLSR and gray correlation method, it was found that the ginsenosides Re, Rb1, and Rb2 were significantly positively related to the pharmacodynamic data. Based on the spectrum-effect relationship, PLSR and gray correlation method can be used to screen for the anti-fatigue components available in AGS. Such an approach is of practical significance as it provides an effective means for exploring the material basis for the efficacy of American ginseng, particularly as an anti-fatigue agent.

Toxicological safety evaluation of zengye granule through acute and 30-day toxicity studies in rats

Ethnopharmacological relevanceZengye granule (ZYG), a traditional Chinese medicine formula composed of Radix Scrophulariae, Radix Ophiopogonis, and Radix Rehmanniae in the ratio of 1.0:0.8:0.8, is listed in the Chinese Pharmacopoeia for treating diseases associated with yin deficiency, such as inner heat, dry mouth and pharynx, and dry bound stool. However, little information is available on its toxicological safety. Aim of the studyTo evaluate the acute and subacute toxicity of ZYG after oral administration in rats. Materials and methodsIn the acute toxicity study, ZYG was orally administered to rats at a single dose of 10 g/kg/day. In the subacute toxicity study, ZYG was administered orally to rats at repeated daily doses of 2.5, 5.0, or 10 g/kg/day for 30 days. The toxicological effects were evaluated by assessing the rats’ general behavior, body weight, food intake, water consumption, blood biochemical and hematological parameters, organ coefficients, and organ histopathology. ResultsNo obvious adverse reactions were found in the rats in the acute toxicity study, indicating that ZYG was non-toxic. In the subacute toxicity study, ZYG had no toxic effect on the rats at a dose of 2.5 g/kg/day but showed slight toxicity in the kidneys, and spleens of the rats at doses of 5 and 10 g/kg/day. Significant drug toxicity was observed in male and female rats at 5 and 10/kg/day; however, elevated WBCs counts, ALT, and LYMs levels were found in female rats. ConclusionsThe oral administration of ZYG at a dose of less than 10 g/kg/day for 1 day or 2.5 g/kg/day for 30 consecutive days can be considered safe, as these doses showed no distinct toxicity or side effects in the rats in this study. Therefore, the dosage should be set according to the clinically recommended dosage to ensure its safety.

A cochleate formulation optimized by D-optimal mixture design enhances oral bioavailability of Revaprazan

A cochleate formulation was developed to enhance the oral bioavailability of revaprazan (RVP). Dimyristoyl phosphatidylcholine (DMPC) liposome containing dicetyl phosphate (DCP) successfully formed a cochleate after treatment with CaCl2, whereas that containing sodium deoxycholate did not. Cochleate was optimised using a D-optimal mixture design with three independent variables—DMPC (X1, 70.58 mol%), cholesterol (X2, 22.54 mol%), and DCP (X3, 6.88 mol%)—and three response variables: encapsulation efficiency (Y1, 76.92%), released amount of free fatty acid at 2 h (Y2, 39.82%), and released amount of RVP at 6 h (Y3, 73.72%). The desirability function was 0.616, showing an excellent agreement between the predicted and experimental values. The cylindrical morphology of the optimised cochleate was visualised, and laurdan spectroscopy confirmed the dehydrated membrane interface, showing an increased generalised polarisation value (approximately 0.5) over small unilamellar vesicle of RVP (RVP-SUV; approximately 0.1). The optimised cochleate showed greater resistance to pancreatic enzyme than RVP-SUV. RVP was released in a controlled manner, achieving approximately 94% release in 12 h. Following oral administration in rats, the optimised cochleate improved the relative bioavailability of RVP by approximately 274%, 255%, and 172% compared to RVP suspension, a physical mixture of RVP and the cochleate, and RVP-SUV, respectively. Thus, the optimised cochleate formulation might be a good candidate for the practical development of RVP.

Comparative Study on the Pharmacokinetics of Paeoniflorin, White Peony Root Water Extract, and Taohong Siwu Decoction After Oral Administration in Rats

Taohong Siwu Decoction (TSD) is a classic traditional Chinese medicine (TCM) compound with pharmacological effects such as vasodilation and hypolipidemia. Paeoniflorin (PF) is one of the active ingredients of TSD. The aim of this study was to evaluate the pharmacokinetics of PF in herbal extracts and their purified formsin rats. A sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method for the determination of PF in rat plasma was developed. Rats were divided into three groups, and given PF solution, water extract of white peony root (WPR), or TSD by gavage. At different predetermined timepoints after gavage, blood was collected from the orbital vein. The pharmacokinetic parameters of PF in the plasma of rats in the three groups was determined. The pharmacokinetic studies showed that the time to reach maximum concentration (Tmax) of PF in the purified forms group was relatively high, while the half-lives (T½) of PF in the TSD and WPR groups were longer. Among the three groups, PF in the purified forms group had the maximum area under the concentration-time curve (AUC0-t=732.997µg/L·h) and the largest maximum concentration (Cmax=313.460µg/L), which showed a significant difference compared with the TSD group (P<0.05). Compared with the purified group, the clearance (CLz/F=86.004L/h/kg) and the apparent volume of distribution (Vz/F=254.787L/kg) of PF in the TSD group increased significantly (P<0.05). A highly specific, sensitive, and rapid HPLC-MS-MS method was developed and applied for the determination of PF in rat plasma. It was found that TSD and WPR can prolong the action time of paeoniflorin in the body.

Evaluation of metabolism and cytochrome P450 mediated interaction liabilities of naringenin

Naringenin is one of the major components of grapefruit juice. It has a broad spectrum of pharmacological activities, and many studies report that grapefruit juice inhibits cytochrome P450 (CYP) 3A4 leading to drug interactions. Naringenin was profiled through various in vitro studies like metabolic stability and glucuronidation in rat and human liver microsomes while, CYP inhibition using human liver microsomes. In addition, pharmacokinetic profiling was conducted upon intravenous (i.v.) and oral administration in rats. Naringenin undergoes both phase I and phase II metabolism in rat liver microsomes, and in human liver microsomes, it is predominantly metabolized by phase II. Glucuronidation which is addition (conjugation) of glucuronic acid to various functional groups is one of the major metabolic pathways of Naringenin. Naringenin, at 1.0 μM and 10.0 μM, did not elicit any appreciable inhibition of the 5 major CYP isoforms (CYP1A2, CYP3A4, CYP2C9, CYP2C19, and CYP2D6). Oral pharmacokinetic studies at 100, 300,and 1000 mg/kg dose and intravenous pharmacokinetic studies at 1 mg/kg dose were performed in male SD rats. Naringenin exhibited very short half-life (0.27 h) and rapid elimination (Clearance=110.65 mL/min/kg) after i.v. administration. There was saturation in Cmax and exposure beyond 100 mg/kg, and the absolute bioavailability was found to be ≤ 5% at the tested oral doses. This present experiment suggests that naringenin does not substantially inhibit CYP3A4 (or any of the tested five isoforms) isoforms per se. Given the minimal involvement of CYP enzymes in the metabolism of naringenin and minimal inhibition of CYP enzymes (IC50&gt; 10 μM), the potential for drug-drug interactions involving CYP substrates and inhibitors is very minimal in humans.

Development of a Rapid LC-MS/MS Method for Simultaneous Quantification of Donepezil and Tadalafil in Rat Plasma: Its Application in a Pharmacokinetic Interaction Study after Oral Administration in Rats.

This study aimed to establish a simple and sensitive analytical method to simultaneously quantify donepezil (DPZ) and tadalafil (TAD) in rat plasma using lansoprazole (LPZ) as an internal standard (IS) by using liquid chromatography tandem mass spectrometry. The fragmentation pattern of DPZ, TAD, and IS was elucidated using multiple reaction monitoring in electrospray ionization positive ion mode for the quantification of precursor to production at m/z 380.1 → 91.2 for DPZ, m/z 390.2 → 268.1 for TAD, and m/z 370.3 → 252.0 for LPZ. The extracted DPZ and TAD from plasma using acetonitrile-induced protein precipitation was separated using Kinetex C18 (100 × 2.1 mm, 2.6 µm) column with a gradient mobile phase system consisting of 2 mM ammonium acetate and 0.1% formic acid in acetonitrile at a flow rate of 0.25 mL/min for 4 min. The selectivity, lower limit of quantification, linearity, precision, accuracy, stability, recovery, and matrix effect of this developed method was validated according to the guidelines of the U.S. Food and Drug Administration and the Ministry of Food and Drug Safety of Korea. The established method achieved acceptance criteria in all validation parameters, ensuring reliability, reproducibility, and accuracy, and was successfully implemented in a pharmacokinetic study on the co-administration of DPZ and TAD orally in rats.

Oral metformin transiently lowers post-prandial glucose response by reducing the apical expression of sodium-glucose co-transporter 1 in enterocytes

Metformin (MET) is the most prescribed antidiabetic drug, but its mechanisms of action remain elusive. Recent data point to the gut as MET's primary target. Here, we explored the effect of MET on the gut glucose transport machinery. Using human enterocytes (Caco-2/TC7 cells) invitro, we showed that MET transiently reduced the apical density of sodium-glucose transporter 1 (SGLT1) and decreased the absorption of glucose, without changes in the mRNA levels of the transporter. Administered 1h before a glucose challenge in rats (Wistar, GK), C57BL6 mice and mice pigs, oral MET reduced the post-prandial glucose response (PGR). This effectwas abrogated in SGLT1-KO mice. MET also reduced the luminal clearance of 2-(18F)-fluoro-2-deoxy-D-glucose after oral administration in rats. In conclusion, oral metformin transiently lowers post-prandial glucose response by reducing the apical expression of SGLT1 in enterocytes, which may contribute to the clinical effects of the drug.