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Correlating gastric emptying of amphotericin B and paracetamol solid lipid nanoparticles with changes in particle surface chemistry

Amekyeh H, Billa N, Roberts C

Int J Pharm, 2017 Jan 30;517(1-2):42-49.
PMID: 27923696 DOI: 10.1016/j.ijpharm.2016.12.001

Oral delivery of pharmaceuticals requires that they retain their physical and chemical attributes during transit within the gastrointestinal (GI) tract, for the manifestation of desired therapeutic profiles. Solid lipid nanoparticles (SLNs) are used as carriers to improve the absorption of hydrophobic drugs. In this study, we examine the stability of amphotericin B (AmB) and paracetamol (PAR) SLNs in simulated GI fluids during gastric emptying. On contact with the simulated fluids, the particles increased in size due to ingress of the dissolution media into the particles. Simulated gastric emptying revealed that the formulations had mean sizes <350nm and neutral surface charges, both of which are optimal for intestinal absorption of SLNs. There was ingress of the fluids into the SLNs, followed by diffusion of the dissolved drug, whose rate depended on the solubility of the loaded-drug in the particular medium. Time-of-flight secondary ion mass spectrometry analyses indicated that drug loading followed the core-shell model and that the AmB SLNs have a more drug-enriched core than the PAR SLNs do. The AmB SLNs are therefore a very suitable carrier of AmB for oral delivery. The stability of the SLNs in the simulated GI media indicates their suitability for oral delivery.

Matched MeSH terms: Acetaminophen/pharmacology*
The effect of various drugs on the glucuronidation of zidovudine (azidothymidine; AZT) by human liver microsomes

Sim SM, Back DJ, Breckenridge AM

Br J Clin Pharmacol, 1991 Jul;32(1):17-21.
PMID: 1909542

1. Zidovudine (3'-azido-3'-deoxythymidine; AZT) is the drug of proven efficacy available for the treatment of patients with AIDS or ARC. It is eliminated mainly by hepatic glucuronidation. Therefore, interference with this metabolic pathway may lead to enhancement of AZT effect or to increased toxicity of the drug. We have examined the effect of a number of drugs which themselves undergo glucuronidation on AZT conjugation by human liver microsomes in vitro. 2. AZT glucuronidation followed Michaelis-Menten kinetics. The apparent Km and Vmax values (mean +/- s.d., n = 5), were 2.60 +/- 0.52 mM and 68.0 +/- 23.4 nmol h-1 mg-1, respectively, as determined from Eadie-Hofstee plots. 3. Dideoxyinosine, sulphanilamide and paracetamol were essentially non-inhibitory at concentrations up to 10 mM (4 times the concentration of AZT in the incubation). The most marked inhibitory effects were seen with indomethacin, naproxen, chloramphenicol, probenecid and ethinyloestradiol, with enzyme activity decreased by 97.7, 94.9, 88.7, 83.4% and 79.0%, respectively, at a concentration of 10 mM. Other compounds producing some inhibition of AZT conjugation were oxazepam, salicylic acid and acetylsalicylic acid. 4. Further studies are necessary to characterise the inhibition observed but the method described enables a screen of potentially important drug interactions to be carried out.

Matched MeSH terms: Acetaminophen/pharmacology
Evaluation of the anti-pyretic potential of Orthosiphon stamineus Benth standardized extract

Yam MF, Ang LF, Basir R, Salman IM, Ameer OZ, Asmawi MZ

Inflammopharmacology, 2009 Feb;17(1):50-4.
PMID: 19127348 DOI: 10.1007/s10787-008-8038-3

The anti-pyretic activity of a standardized methanol/water (50/50) extract of Orthosiphon stamineus Benth. (SEOS) was investigated for its effect on normal body temperature and yeast-induced pyrexia in Sprague Dawley (SD) rats. The SEOS showed no effect on normal body temperature. Doses of 500 and 1000 mg/kg body weight of SEOS significantly reduced the yeast-induced elevation in body temperature. This effect persisted up to 4 h following the administration of the extract. The anti-pyretic effect of SEOS was comparable with that of paracetamol (acetaminophen in U.S) (150 mg/kg p.o.), a standard anti-pyretic agent. HPLC study revealed that rosmarinic acid, sinensetin, eupatorin and tetramethoxyflavone were present in SEOS in the amounts of 7.58%, 0.2%, 0.34% and 0.24% respectively. The LD(50) of the extract in rats was higher than 5000 mg/kg body weight. Therefore, the present study ascertained that SEOS possesses a significant anti-pyretic activity.

Matched MeSH terms: Acetaminophen/pharmacology
Sunitinib-paracetamol sex-divergent pharmacokinetics and tissue distribution drug-drug interaction in mice

Liew MH, Ng S, Chew CC, Koo TW, Chee YL, Chee EL, et al.

Invest New Drugs, 2017 04;35(2):145-157.
PMID: 28070719 DOI: 10.1007/s10637-016-0415-y

The sex-divergent pharmacokinetics and interaction of tyrosine kinase inhibitor sunitinib with paracetamol was evaluated in male and female mice. Mice (control groups) were administered 60 mg/kg PO sunitinib alone or with 200 mg/kg PO paracetamol (study groups). Sunitinib concentration in plasma, brain, kidney and liver were determined and non-compartmental pharmacokinetic analysis performed. Female control mice showed 36% higher plasma sunitinib AUC0→∞, 31% and 27% lower liver and kidney AUC0→∞ and 2.2-fold higher AUC0→∞ in brain (all p

Matched MeSH terms: Acetaminophen/pharmacology*
Sunitinib DDI with paracetamol, diclofenac, mefenamic acid and ibuprofen shows sex-divergent effects on the tissue uptake and distribution pattern of sunitinib in mice

Tan SY, Wong MM, Tiew AL, Choo YW, Lim SH, Ooi IH, et al.

Cancer Chemother Pharmacol, 2016 10;78(4):709-18.
PMID: 27495788 DOI: 10.1007/s00280-016-3120-9

PURPOSE: Pharmacokinetic interaction of sunitinib with diclofenac, paracetamol, mefenamic acid and ibuprofen was evaluated due to their P450 mediated metabolism and OATP1B1, OATP1B3, ABCB1, ABCG2 transporters overlapping features.
METHODS: Male and female mice were administered 6 sunitinib doses (60 mg/kg) PO every 12 h and 30 min before the last dose were administered vehicle (control groups), 250 mg/kg paracetamol, 30 mg/kg diclofenac, 50 mg/kg mefenamic acid or 30 mg/kg ibuprofen (study groups), euthanized 6 h post last administration and sunitinib plasma, liver, kidney, brain concentrations analyzed.
RESULTS: Ibuprofen halved sunitinib plasma concentration in female mice (p

Matched MeSH terms: Acetaminophen/pharmacology*