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Simple high-performance liquid chromatographic method for determination of ketoconazole in human plasma

Yuen KH, Peh KK

J Chromatogr B Biomed Sci Appl, 1998 Sep 18;715(2):436-40.
PMID: 9792531

A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of ketoconazole in human plasma. The method entailed direct injection of the plasma sample after deproteinization using acetonitrile. The mobile phase comprised 0.05 M disodium hydrogen orthophosphate and acetonitrile (50:50, v/v) adjusted to pH 6. Analysis was run at a flow-rate of 1.5 ml/min with the detector operating at an excitation wavelength of 260 nm and an emission wavelength of 375 nm. The method is specific and sensitive with a quantification limit of approximately 60 ng/ml and a detection limit of 40 ng/ml at a signal-to-noise ratio of 3:1. Mean absolute recovery value was about 105%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 14%. The calibration curve was linear over a concentration range of 62.5-8000 ng/ml.

Matched MeSH terms: Biological Availability
Improved bioavailability of vitamin E with a self emulsifying formulation

Julianto T, Yuen KH, Noor AM

Int J Pharm, 2000 Apr 25;200(1):53-7.
PMID: 10845685

A single dose study was conducted to evaluate the bioavailability of a novel self-emulsifying vitamin E preparation, in comparison with that of a commercial product, Natopherol, available as soft gelatin capsules under fasted condition. The self-emulsifying preparation achieved a faster rate and higher extent of absorption. A statistically significant difference was observed between the values of the two preparations in the parameters AUC, Cmax and Tmax. Moreover, the 90% confidence interval of the logarithmic transformed AUC values of the self-emulsifying preparation over those of the soft gelatin capsule product was found to be between 2.1 and 4.1, suggesting an increase in bioavailability of between 210 and 410%. As for Cmax, the 90% confidence interval was between 2.1 and 3.0. However, no statistically significant difference was observed between the t(1/2) values estimated from the plasma concentration versus time data of the two preparations. The values are also comparable to those reported in the literature.

Matched MeSH terms: Biological Availability
Improved oral bioavailability of artemisinin through inclusion complexation with beta- and gamma-cyclodextrins

Wong JW, Yuen KH

Int J Pharm, 2001 Oct 04;227(1-2):177-85.
PMID: 11564552

The bioavailability of beta- and gamma-cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250. Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC(0-infinity)), peak plasma concentration (C(max)), and time to reach peak plasma concentration (T(max)). A statistically significant difference was observed between the values of the complexes and Artemisinin 250 for the three parameters. However, no statistically significant difference was observed between the values of the beta- and gamma-cyclodextrin complexes. Moreover, the 90% confidence interval for the ratio of the AUC(0-infinity) values of the beta-cyclodextrin complex over those of Artemisinin 250 was estimated to be between 1.51-2.04, while that of C(max) was between 1.73-2.93. For the gamma-cyclodextrin complex, the respective intervals were 1.30-1.76 and 1.43-2.43. These findings indicated that the beta- and gamma-cyclodextrin complexes had a much higher rate and extent of bioavailability compared to Artemisinin 250. In addition, the absorption of artemisinin was observed to be poor and negligible when the preparations started to arrive in the colon. This could be attributed to poor dissolution of artemisinin in the semi-solid faecal matter in the lower part of the gastrointestinal tract.

Matched MeSH terms: Biological Availability
New Insight in Improving Therapeutic Efficacy of Antipsychotic Agents: An Overview of Improved In Vitro and In Vivo Performance, Efficacy Upgradation and Future Prospects

Ei Thu H, Hussain Z, Shuid AN

Curr Drug Targets, 2018;19(8):865-876.
PMID: 27894237 DOI: 10.2174/1389450117666161125174625

Psychotic disorders are recognized as severe mental disorders that rigorously affect patient's personality, critical thinking, and perceptional ability. High prevalence, global dissemination and limitations of conventional pharmacological approaches compel a significant burden to the patient, medical professionals and the healthcare system. To date, numerous orally administered therapies are available for the management of depressive disorders, schizophrenia, anxiety, bipolar disorders and autism spectrum problems. However, poor water solubility, erratic oral absorption, extensive first-pass metabolism, low oral bioavailability and short half-lives are the major factors which limit the pharmaceutical significance and therapeutic feasibility of these agents. In recent decades, nanotechnology-based delivery systems have gained remarkable attention of the researchers to mitigate the pharmaceutical issues related to the antipsychotic therapies and to optimize their oral drug delivery, therapeutic outcomes, and patient compliance. Therefore, the present review was aimed to summarize the available in vitro and in vivo evidences signifying the pharmaceutical importance of the advanced delivery systems in improving the aqueous solubility, transmembrane permeability, oral bioavailability and therapeutic outcome of the antipsychotic agents.

Matched MeSH terms: Biological Availability
The Medicinal Uses, Toxicities and Anti-inflammatory Activity of Polyalthia Species (Annonaceae)

Yao LJ, Jalil J, Attiq A, Hui CC, Zakaria NA

J Ethnopharmacol, 2018 Oct 11.
PMID: 30316887 DOI: 10.1016/j.jep.2018.10.001

ETHNOPHARMACOLOGICAL RELEVANCE: Polyalthia is one of the largest and notable genera in Annonaceae family. Polyalthia species have been widely used in folklore medicine for the treatment of rheumatic fever, gastrointestinal ulcer and generalized body pain. Numerous in vitro and in vivo studies on Polyalthia Species have also corroborated the significant anti-inflammatory potential of its extracts and secondary metabolites.
AIM OF THE STUDY: This review is an attempt to assess the anti-inflammatory activity of Polyalthia species by giving critical appraisal and establishing evidences of their traditional uses. Moreover this review will highlight the lead compounds for future drug development that can serve as a potential anti-inflammatory drug with comparative efficacy and minimum side effects.
MATERIALS AND METHODS: An extensive literature review, focusing the anti-inflammatory potential of Polyalthia species was conducted using the following databases: PubMed, ScienceDirect, SpringerLink, Ovid, Scopus and ProQuest, as well as the locally available books, journals and relevant documents. The reference lists of retrieved papers were also searched for additional studies.
RESULTS: The Polyalthia species have shown significant anti-inflammatory activity through various mechanism of action. The most significant anti-inflammatory mechanism includes the inhibition of nuclear factor kappa B (NF-κB), prostaglandins (PGs), pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS). The data suggests that hydroxycleroda-3,13-dien-15,16-olide and 16-oxocleroda-3,13-dien-15-oic acid, quercetin, rutin, spinasterol, α-spinasterol, goniothalamin and (-)-5-hydroxygoniothalamin are the most potent anti-inflammatory compounds from Polyalthia species with comparable IC50 with positive controls.
CONCLUSIONS: Numerous pharmacological studies have supported the use of Polyalthia species against pain, rheumatic fever, haemorrhages and inflammation in traditional medicine. Flavonoids, diterpenoids, sterols and styrylpyrones from genus Polyalthia are the most significant class of compounds with potent anti-inflammatory activity. Secondary metabolites from these classes should be brought into further research to fill the gaps of knowledge in pharmacokinetics, pharmacodynamics, bioavailability, and toxicity in order to convert the pre-clinical results into clinical data for further investigation.

Matched MeSH terms: Biological Availability
Fulltext Resveratrol-loaded PLGA nanoparticles mediated programmed cell death in prostate cancer cells

Nassir AM, Shahzad N, Ibrahim IAA, Ahmad I, Md S, Ain MR

Saudi Pharm J, 2018 Sep;26(6):876-885.
PMID: 30202231 DOI: 10.1016/j.jsps.2018.03.009

Resveratrol (RL), a natural polyphenol, is known for its diverse biological effects against various human cancer cell lines. But low aqueous solubility, poor bioavailability, and stability limit its efficacy against prostate cancer. In this study polymeric nanoparticles encapsulating resveratrol (RLPLGA) were designed and their cytotoxic and mode of apoptotic cells death against prostate cancer cell line (LNCaP) was determined. Nanoparticles were prepared by solvent displacement method and characterized for particle size, TEM, entrapment efficiency, DSC and drug release study. RLPLGA exhibited a significant decrease in cell viability with 50% and 90% inhibitory concentration (IC50 and IC90) of 15.6 ± 1.49 and 41.1 ± 2.19 μM respectively against the LNCaP cells. This effect was mediated by apoptosis as confirmed by cell cycle arrest at G1-S transition phase, externalization of phosphatidylserine, DNA nicking, loss of mitochondrial membrane potential and reactive oxygen species generation in LNCaP cells. Furthermore, significantly greater cytotoxicity to LNCaP cells was observed with nanoparticles as compared to that of free RL at all tested concentrations. RLPLGA nanoparticles presented no adverse cytotoxic effects on murine macrophages even at 200 μM. Our findings support the potential use of developed resveratrol loaded nanoparticle for the prostate cancer chemoprevention/ chemotherapy with no adverse effect on normal cells.

Matched MeSH terms: Biological Availability
Fulltext Edible Bird's Nest Protects Against Hyperglycemia-Induced Oxidative Stress and Endothelial Dysfunction

Murugan DD, Md Zain Z, Choy KW, Zamakshshari NH, Choong MJ, Lim YM, et al.

Front Pharmacol, 2019;10:1624.
PMID: 32116666 DOI: 10.3389/fphar.2019.01624

Increased oxidative stress by hyperglycemia is a major cause of vascular complications in diabetes. Bird's nest, which is made from the saliva of swiftlets has both medicinal and nutritional values dated back to ancient China. However, its role in improving endothelial dysfunction due to diabetes is yet to be elucidated. The present study examined the protective effect and mechanism of action of the aqueous extract of hydrolyzed edible bird nest (HBN) on endothelium in models of diabetes, in vitro and in vivo. Male db/m+ and db/db mice were orally administered with or without HBN and glibenclamide for 28 days, followed by vascular reactivity studies in mouse aortas. Human umbilical vein endothelial cells (HUVECs) and isolated mouse aorta from C57BL/6J were treated with high glucose (HG), HBN, sialic acid (SA), glibenclamide, and apocynin, respectively. The effects of HBN on reactive oxygen species (ROS) production and nitric oxide (NO) bioavailability were assessed by Western blot, 2',7'-dichlorofluorescin-diacetate (DCF-DA), and 4-amino-5-methylamino-2',7' difluorofluorescein (DAF-FM DA) in HUVECs, isolated mouse aorta, and db/db diabetic mice. HBN significantly reversed the endothelial dysfunction in diabetic mice and isolated mouse aorta. HBN normalized ROS over-production of NOX2 and nitrotyrosine, reversed the reduction of anti-oxidant marker, SOD-1 as well as restored NO bioavailability in both HUVECs challenged with HG and in db/db diabetic mice. Similarly, HG-induced elevation of oxidative stress in HUVECs were reversed by SA, glibenclamide, and apocynin. This attests that HBN restores endothelial function and protects endothelial cells against oxidative damage induced by HG in HUVECs, isolated mouse aorta, and db/db diabetic mice via modulating ROS mechanism, which subsequently increases NO bioavailability. This result demonstrates the potential role of HBN in preserving endothelial function and management of micro- or macrovascular complications in diabetes.

Matched MeSH terms: Biological Availability
Fulltext Freeze-Dried Lopinavir-Loaded Nanostructured Lipid Carriers for Enhanced Cellular Uptake and Bioavailability: Statistical Optimization, in Vitro and in Vivo Evaluations

Khan AA, Mudassir J, Akhtar S, Murugaiyah V, Darwis Y

Pharmaceutics, 2019 Feb 25;11(2).
PMID: 30823545 DOI: 10.3390/pharmaceutics11020097

Nanostructured lipid carriers (NLCs) loaded with lopinavir (LPV) were prepared by the high-shear homogenization method. The LPV-NLCs formulations were freeze-dried using trehalose as a cryoprotectant. In vitro release studies in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8) showed a burst release. The optimized freeze-dried formulation (LPV-NLC-7-Tres) had a particle size (PS), polydispersity index (PdI), zeta potential (ZP) and % entrapment efficiency (%EE) of 286.8 ± 1.3 nm, 0.413 ± 0.017, -48.6 ± 0.89 mV and 88.31 ± 2.04%, respectively. The optimized formulation observed by transmission and scanning electron microscopes showed a spherical shape. Differential scanning calorimetry study revealed the absence of chemical interaction between the drug and lipids. In vitro cellular uptake study using Caco-2 cell line showed a higher LPV uptake from LPV-NLC-7-Tres formulation compared to the free LPV-suspension. The 6-month stability study showed a minimum rise of ~40 nm in PS, while no significant changes in PdI, ZP and drug content of the LPV-NLC-7-Tres formulation stored at 5 °C ± 3 °C. The bioavailability of LPV following oral administration of LPV-NLC-7-Tres in male Wistar rats was found 6.98-fold higher than the LPV-suspension. In conclusion, the nanostructure lipid carriers are potential carriers for improving the oral bioavailability of lopinavir.

Matched MeSH terms: Biological Availability
Bioavailability and mobility of arsenic, cadmium, and manganese in gold mine tailings amended with rice husk ash and Fe-coated rice husk ash

Tariq FS, Samsuri AW, Karam DS, Aris AZ, Jamilu G

Environ Monit Assess, 2019 Mar 21;191(4):232.
PMID: 30900076 DOI: 10.1007/s10661-019-7359-6

This study was conducted to determine the effects of rice husk ash (RHA) and Fe-coated rice husk ash (Fe-RHA) on the bioavailability and mobility of As, Cd, and Mn in mine tailings. The amendments were added to the tailings at 0, 5, 10, or 20% (w/w) and the mixtures were incubated for 0, 7, 15, 30, 45, and 60 days. The CaCl2 extractable As, Cd, and Mn in the amended tailings were determined at each interval of incubation period. In addition, the tailings mixture was leached with simulated rain water (SRW) every week from 0 day (D 0) until day 60 (D 60). The results showed that both RHA and Fe-RHA application significantly decreased the CaCl2-extractable Cd and Mn but increased that of As in the tailings throughout the incubation period. Consequently, addition of both RHA and Fe-RHA leached out higher amount of As from the tailings but decreased Cd and Mn concentration compared to the controls. The amount of As leached from the Fe-RHA-amended tailings was less than that from RHA-amended tailings. Application of both RHA and Fe-RHA could be an effective way in decreasing the availability of cationic heavy metals (Cd and Mn) in the tailings but these amendments could result in increasing the availability of anionic metalloid (As). Therefore, selection of organic amendments to remediate metal-contaminated tailings must be done with great care because the outcomes might be different among the elements.

Matched MeSH terms: Biological Availability
Fulltext Size and time-dependent induction of proinflammatory cytokines expression in brains of mice treated with gold nanoparticles

Khan HA, Alamery S, Ibrahim KE, El-Nagar DM, Al-Harbi N, Rusop M, et al.

Saudi J Biol Sci, 2019 Mar;26(3):625-631.
PMID: 30899181 DOI: 10.1016/j.sjbs.2018.09.012

Gold nanoparticles (GNPs) are among the ideal nano-sized materials for medical applications such as imaging and drug delivery. Considering the significance of recent reports on acute phase induction of inflammatory mediators by GNPs, we studied the effect of GNPs on proinflammatory cytokines gene expression in mouse brain. Group 1 served as control whereas groups 2-4 were given only one intraperitoneal dose of 5, 20 and 50 nm GNPs, respectively and sacrificed after 24 h. The animals in groups 5-7 also received the same treatment but sacrificed after 7 days. Groups 8-10 received two injections of GNPs (5, 20 and 50 nm, respectively), first at the beginning of study and second on day 6, and sacrificed on day 7. Total RNA was extracted from the cerebral tissue and analyzed for the gene expressions of IL-1β, IL-6 and TNF-α. A single injection of 5 nm diameter GNPs significantly increased the mRNA expression of IL-1β and IL-6 in mouse brain on day 7, which was not augmented by the second dose of the same GNPs. Larger size GNPs (20 nm and 50 nm) did not cause any significant change in the expression of proinflammatory cytokines in mouse brain. In conclusion, systemic administration of small sized GNPs (5 nm) induced a proinflammatory cascade in mouse brain indicating a crucial role of GNPs size on immune response. It is important to use the right sized GNPs in order to avoid an acute phase inflammatory response that could be cytotoxic or interfere with the bioavailability of nanomaterials.

Matched MeSH terms: Biological Availability
Chitosan-Coated Alginate Nanoparticles Enhanced Absorption Profile of Insulin Via Oral Administration

Jaafar MHM, Hamid KA

Curr Drug Deliv, 2019;16(7):672-686.
PMID: 31250754 DOI: 10.2174/1567201816666190620110748

BACKGROUND: In this study, four nanoparticle formulations (F1 to F4) comprising varying ratios of alginate, Pluronic F-68 and calcium chloride with a constant amount of insulin and chitosan as a coating material were prepared using polyelectrolyte complexation and ionotropic gelation methods to protect insulin against enzymatic degradation.
METHODS: This study describes the formulation design, optimisation, characterisation and evaluation of insulin concentration via oral delivery in rats. A reversed-phase high-performance liquid chromatography (HPLC) method was developed and validated to quantify insulin concentration in rat plasma. The proposed method produced a linear response over the concentration range of 0.39 to 50 µg/ml.
RESULTS: In vitro release study showed that dissolution of insulin in simulated gastric juice of pH 1.2 was prevented by alginate core and chitosan coating but rapidly released in simulated intestinal fluid (pH 6.8). Additionally, Formulation 3 (F3) has a particle size of 340.40 ± 2.39 nm with narrow uniformity exhibiting encapsulation efficiency (EE) of 72.78 ± 1.25 % produced highest absorption profile of insulin with a bioavailability of 40.23 ±1.29% and reduced blood glucose after its oral administration in rats.
CONCLUSION: In conclusion, insulin oral delivery system containing alginate and chitosan as a coating material has the ability to protect the insulin from enzymatic degradation thus enhance its absorption in the intestine. However, more work should be done for instance to involve human study to materialise this delivery system for human use.

Matched MeSH terms: Biological Availability
Recent update of toxicity aspects of nanoparticulate systems for drug delivery

Patnaik S, Gorain B, Padhi S, Choudhury H, Gabr GA, Md S, et al.

Eur J Pharm Biopharm, 2021 Apr;161:100-119.
PMID: 33639254 DOI: 10.1016/j.ejpb.2021.02.010

Potential research outcomes on nanotechnology-based novel drug delivery systems since the past few decades attracted the attention of the researchers to overcome the limitations of conventional deliveries. Apart from possessing enhanced solubility of poorly water-soluble drugs, the targeting potential of the carriers facilitates longer circulation and site-specific delivery of the entrapped therapeutics. The practice of these delivery systems, therefore, helps in maximizing bioavailability, improving pharmacokinetics profile, pharmacodynamics activity and biodistribution of the entrapped drug(s). In addition to focusing on the positive side, evaluation of nanoparticulate systems for toxicity is a crucial parameter for its biomedical applications. Due to the size of nanoparticles, they easily traverse through biological barriers and may be accumulated in the body, where the ingredients incorporated in the formulation development might accumulate and/or produce toxic manifestation, leading to cause severe health hazards. Therefore, the toxic profile of these delivery systems needs to be evaluated at the molecular, cellular, tissue and organ level. This review offers a comprehensive presentation of toxicity aspects of the constituents of nanoparticular based drug delivery systems, which would be beneficial for future researchers to develop nanoparticulate delivery vehicles for the improvement of delivery approaches in a safer way.

Matched MeSH terms: Biological Availability
Influence of route of administration on the absorption and disposition of alpha-, gamma- and delta-tocotrienols in rats

Yap SP, Yuen KH, Lim AB

J Pharm Pharmacol, 2003 Jan;55(1):53-8.
PMID: 12625867

A study was conducted to evaluate the bioavailability of alpha-, gamma- and delta-tocotrienols administered via oral, intravenous, intramuscular and intraperitoneal routes in rats. Three separate experiments, each conducted according to a two-way crossover design, were carried out to compare intravenous and oral, intramuscular and oral, and intraperitoneal and oral administration. Oral absorption of all three tocotrienols was found to be incomplete. Of the three tocotrienols, alpha-tocotrienol had the highest oral bioavailability, at about 27.7+/-9.2%, compared with gamma- and delta-tocotrienols, which had values of 9.1+/-2.4% and 8.5+/-3.5%, respectively. Such biodiscrimination was also observed in their total clearance rates (estimated from the intravenous data). alpha-Tocotrienol showed the lowest clearance rate at about 0.16 L kg(-1) h(-1), whereas that of delta- and gamma-tocotrienols was quite similar, with values of 0.24 and 0.23 L kg(-1) h(-1), respectively. Interestingly, all three tocotrienols were found to be negligibly absorbed when administered intraperitoneally and intramuscularly. Thus, these two routes of administration should be avoided when evaluating the biological activities of the tocotrienols in whole animal experiments.

Matched MeSH terms: Biological Availability
Pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under different food status

Yap SP, Yuen KH, Wong JW

J Pharm Pharmacol, 2001 Jan;53(1):67-71.
PMID: 11206194

We have investigated the pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under fed and fasted conditions in eight healthy volunteers. The volunteers were administered a single oral dose of mixed tocotrienols (300 mg) under fed or fasted conditions. The bioavailability of tocotrienols under the two conditions was compared using the parameters peak plasma concentration (Cmax), time to reach peak plasma concentration (Tmax) and total area under the plasma concentration-time curve (AUC(o-infinity)). A statistically significant difference was observed between the fed and fasted logarithmic transformed values of Cmax (P < 0.01) and AUC(0-infinity) (P < 0.01) for all three tocotrienols. In addition, the 90% confidence intervals for the ratio of the logarithmic transformed AUC(0-infinity) values of alpha-, gamma- and delta-tocotrienols under the fed state over those of the fasted state were found to lie between 2.24-3.40, 2.05-4.09 and 1.59-3.81, respectively, while those of the Cmax were between 2.28-4.39, 2.31-5.87 and 1.52-4.05, respectively. However, no statistically significant difference was observed between the fed and fasted Tmax values of the three homologues. The mean apparent elimination half-life (t(1/2)) of alpha-, gamma- and delta-tocotrienols was estimated to be 4.4, 4.3 and 2.3 h, respectively, being between 4.5- to 8.7-fold shorter than that reported for alpha-tocopherol. No statistically significant difference was observed between the fed and fasted t(1/2) values. The mean apparent volume of distribution (Vd/f) values under the fed state were significantly smaller than those of the fasted state, which could be attributed to increased absorption of the tocotrienols in the fed state.

Matched MeSH terms: Biological Availability
In vitro and in vivo evaluation of hydrophilic and hydrophobic polymers-based nicorandil-loaded peroral tablet compared with its once-daily commercial sustained-release tablet

Tamilvanan S, Venkatesh Babu R, Nappinai A, Sivaramakrishnan G

Drug Dev Ind Pharm, 2011 Apr;37(4):436-45.
PMID: 20923389 DOI: 10.3109/03639045.2010.521161

Hydrophilic and hydrophobic polymer-based nicorandil (10 mg)-loaded peroral tablets were prepared using the wet granulation technique. The influence of varying amounts of hydroxypropyl methylcellulose (HPMC) (30-50 mg), ethylcellulose (2-4 mg), microcrystalline cellulose (5-20 mg) and Aerosil® (5-12 mg) in conjunction with the constant amounts (3 mg) of glidant and lubricant (magnesium stearate and talc) on the in vitro performances of the tablets (hardness, friability, weight variation, thickness uniformity, drug content, and drug release behavior) were investigated.

Matched MeSH terms: Biological Availability
Comparative bioavailability study of two atenolol tablet preparations

Peh KK, Yuen KH, Wong JW, Toh WT

Drug Dev Ind Pharm, 1999 Mar;25(3):357-60.
PMID: 10071830

A study was conducted to compare the bioavailability of a generic product of atenolol (Normaten FC) with the innovator product, Tenormin. Twelve healthy adult volunteers participated in the study conducted according to a randomized, two-way crossover design. The preparations were compared using area under the plasma concentration-time curve AUC0-infinity, peak plasma concentration Cmax, and time to reach peak plasma concentration Tmax. No statistically significant difference was obtained between the Tmax values and the logarithmic transformed AUC0-infinity and Cmax values of the two products. Moreover, the 90% confidence interval for the ratio of the logarithmically transformed AUC0-infinity values of Normaten FC over those of Tenormin was found to lie between 0.82 and 0.98, while that of the logarithmically transformed Cmax values was between 0.82 and 1.09, both being within the bioequivalence limit of 0.80-1.25. The values of elimination half-life t1/2 between the two products were also found comparable and not significantly different statistically. The t1/2 values obtained in our study were slightly longer than those reported in the literature for other population groups.

Matched MeSH terms: Biological Availability
Comparative bioavailability study of a generic naltrexone tablet preparation

Yuen KH, Peh KK, Billa N

Drug Dev Ind Pharm, 1999 Mar;25(3):353-6.
PMID: 10071829

The bioavailability of a generic preparation of naltrexone (Narpan) was compared with the innovator product, Trexan. Twelve healthy volunteers participated in the study, conducted according to a completely randomized, two-way crossover design. The preparations were compared using the parameters area under the plasma concentration-time curve AUC0-infinity, peak plasma concentration Cmax, and time to reach peak plasma concentration Tmax. No statistically significant difference was observed between the logarithmic transformed AUC0-infinity and the logarithmically transformed Cmax values of the two preparations. Also, no statistically significant difference was observed between the untransformed Tmax values. In addition, the 90% confidence interval for the ratio of the logarithmic transformed AUC0-infinity values of Narpan over those of Trexan was found to lie between 0.87 and 1.01, while that of the logarithmic transformed Cmax values was between 0.94 and 1.23, both being within the bioequivalence limit of 0.80-1.25. The numerical values of the elimination half-life (t1/2) obtained with the two preparations were also not significantly different and were comparable to those reported in the literature.

Matched MeSH terms: Biological Availability
Pharmacokinetics and tissue distribution of hydrazinocurcumin in rats

Satyavert, Gupta S, Choudhury H, Jacob S, Nair AB, Dhanawat M, et al.

Pharmacol Rep, 2021 Dec;73(6):1734-1743.
PMID: 34283375 DOI: 10.1007/s43440-021-00312-5

BACKGROUND: Curcumin, a natural polyphenol from Curcuma longa, is known to possess diversified pharmacological roles including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic properties; however, its bioavailability is severely limited due to its poor solubility, poor absorption, rapid metabolism, and significant elimination. Hydrazinocurcumin (HZC), a novel analogue of curcumin has been reported to overcome the limitations of curcumin and also possesses multiple pharmacological activities. The present study aimed to evaluate the unexplored pharmacokinetic profile of this agent in experimental rats.
METHODS: Drug formulations were administered to the experimental animals via oral, intravenous and intraperitoneal routes. Blood samples were collected at different pre-determined time intervals to determine the pharmacokinetic parameters. To understand the biodistribution profile of HCZ, tissue samples were isolated from different groups of Sprague-Dawley rats at different time points. The pharmacokinetic parameters of HZC were evaluated after administration through oral (100 mg/kg), intraperitoneal (100 mg/kg) and intravenous (10 mg/kg) routes.
RESULTS: Significantly (p

Matched MeSH terms: Biological Availability
Bioavailability and pharmacokinetic studies of eurycomanone from Eurycoma longifolia

Low BS, Ng BH, Choy WP, Yuen KH, Chan KL

Planta Med, 2005 Sep;71(9):803-7.
PMID: 16206032

A validated HPLC analysis of eurycomanone (1), a bioactive quassinoid, in rat plasma following oral and intravenous administration of Eurycoma longifolia Jack extract was developed for pharmacokinetic and bioavailability studies. Relatively high plasma eurycomanone concentrations were detected after an intravenous injection of 10 mg/kg extract F2 containing 1.96 mg/kg of the quassinoid. However, it declined rapidly to zero after 8 h. Its mean elimination rate constant (k(e)), biological half-life (t(1/2)), volume of distribution (V(d)) and clearance (CL) were 0.88 +/- 0.19 h (-1), 1.00 +/- 0.26 h, 0.68 +/- 0.30 L/kg and 0.39 +/- 0.08 L/h/kg, respectively. Following oral administration of eurycomanone, its Cmax and Tmax values were detected as 0.33 +/- 0.03 microg/mL and 4.40 +/- 0.98 h, respectively. The plasma concentration of the quassinoid after oral administration was much lower than after intravenous application in spite of the oral dose being 5 times higher. The results indicate that eurycomanone is poorly bioavailable when given orally. A comparison of the AUC (0-->infinity) obtained orally to that obtained after an intravenous administration (normalized for dose differences) revealed that the absolute bioavailability of the compound was low with 10.5 %. Furthermore, the compound appeared to be well distributed in the extravascular fluids because of its relatively high V(d) value. The poor oral bioavailability was not attributed to instability problems because eurycomanone has been shown to be stable under different pH conditions. Thus, its poor oral bioavailability may be due to poor membrane permeability in view of its low P value and/or high first-pass metabolism.

Matched MeSH terms: Biological Availability
Estimation and influence of physicochemical properties and chemical fractions of surface sediment on the bioaccessibility of Cd and Hg contaminant in Langat River, Malaysia

Kadhum SA, Ishak MY, Zulkifli SZ

Environ Geochem Health, 2017 Oct;39(5):1145-1158.
PMID: 27848092 DOI: 10.1007/s10653-016-9883-4

This study applied the use of sequential extraction technique and simple bioaccessibility extraction test to quantify the bioavailable fractions and the human bioaccessible concentration of metals collected from nine stations in surface sediment of the Langat River. The concentrations of total and bioaccessible metals from different stations were in the range of 0.49-1.04, 0.10-0.32 μg g-1 for T-Cd, Bio-Cd, respectively, and 12.9-128.03, 2.06-8.53 μg kg-1 for T-Hg, Bio-Hg, respectively. The results revealed highest R-Bio-Cd in Banting station (55.3 %), while the highest R-Bio-Hg was in Kajang station (49.61 %). The chemical speciation of Cd in most sampling stations was in the order of oxidisable-organic > residual > exchangeable > acid-reducible, while speciation of Hg was in the order of exchangeable > residual > oxidisable-organic > acid-reducible. The correlation matric of mean content showed that the TOM, particle size and Mg++ in polluted surface sediments was highly correlated with total mercury. The PCA showed that the main factors influencing the bioaccessibility of Hg in surface sediments were the sediment TOM, F1 (EFLE) and F3 (oxidation-organic), while the factor influencing the bioaccessibility of Cd was the F3 (oxidation-organic) and T-Cd.

Matched MeSH terms: Biological Availability

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