Population Pharmacokinetics of Imatinib in Nigerians With Chronic Myeloid Leukemia: Clinical Implications for Dosing and Resistance

Imatinib, a tyrosine kinase inhibitor, is the drug of choice for the treatment of chronic myeloid leukemia in Nigeria. Several studies have established interindividual and interpopulation variations in imatinib disposition although no pharmacokinetic study have been conducted in an African population since the introduction of the drug. This study explored a population pharmacokinetic approach to investigate the disposition of imatinib in Nigerians and examined the involvement of some covariates including genetic factors in the variability of the drug disposition with a view to optimize the use of the drug in this population. A total of 250 plasma concentrations from 126 chronic myeloid leukemia patients were quantified using a validated method. A population pharmacokinetic model was fitted to the data using NONMEM VII software, and the influences of 12 covariates were investigated. The mean population-derived apparent steady-state clearance, elimination half-life, area under the concentration-time curve over 24 hours, and volume of distribution were 17.2 ± 1.8 L/h., 12.05 ± 2.1 hours, 23.26 ± 0.6 μg·h/mL, and 299 ± 20.4 L, respectively. Whole blood count, ethnicity, CYP3A5*3, and ABCB1 C3435T were found to have significant influence on the apparent clearance, while the interindividual variability in clearance and interoccasion variability in bioavailability were 17.4% and 20.4%, respectively. There was a wide variability in apparent clearance and area under the curve compared to those reported in other populations. Thus, treatment with a standard dose of imatinib in this population may not produce the desired effect in most of the patients, whereas continuous exposure to a low drug concentration could lead to pharmacokinetic-derived resistance. The authors suggest the need for therapeutic drug monitoring-guided dose individualization in this population.

Hypnotic, anticonvulsant and anxiolytic effects of 1-nitro-2-phenylethane isolated from the essential oil of Dennettia tripetala in mice

This study investigated the hypnotic, anti-convulsant and anxiolytic effects of 1-nitro-2-phenylethane (BPNE) obtained from the oil of Dennettia tripetala G. Baker (Annonaceae) and established its mechanism of action. The essential oil (EO) from the leaf, fruit and seed was obtained by hydrodistillation, followed by isolation of BPNE purified to 99.2% by accelerated gradient chromatography on silica, and identified by NMR and GC-MS. The pure BPNE and EO of the dried seed (93.6%) were comparatively evaluated for hypnotic, anticonvulsant and anxiolytic effects in mice. The acute toxicity of BPNE was determined and the LD50 was 490 mg/kg, intrapritonealy. The hypnotic activities of the EO and BPNE (50-400 mg/kg, i.p.) were assessed by loss of righting reflex, while sodium pentobarbitone (PBS) and diazepam (DZM) were used as positive controls. The anticonvulsant and anxiolytic effects of the EO and BPNE were evaluated in mice. Both BPNE and EO at doses ≥100 mg/kg induced spontaneous hypnosis with loss of righting reflex, significantly decreased sleep latency (SL) and also increased total sleeping time (TST) dose-dependently. They had comparable activity with NAP in TST. The BPNE exhibited higher hypnotic potency than EO at the same dose levels. The EO and BPNE offered comparable dose-related protections against PTZ- and strychnine-induced convulsions. Flumazenil (2 mg/kg) blocked the hypnotic and anticonvulsant (PTZ-convulsions) effects of both EO and BPNE. The essential oil at 5-20 mg/kg dose levels significantly (p<0.05) increased the percentage time spent and number of entries into the open arms. While at the same dose range BPNE significantly (p<0.05) increased the percentage time spent and the number of entries into the open arms respectively. The study concluded that 1-nitro-2-phenylethane exhibited dose dependent significant hypnotic, anticonvulsant and anxiolytic effects and it is the compound largely responsible for the neuropharmacological effects of the oil.

Distribution of iridiod glucosides and anti-oxidant compounds in Spathodea campanulata parts

The antioxidant principles isolated from the various parts of the plant are verminoside (leaf, stem bark and flowers; EC(50) = 2.04 µg/ml), Specioside (flowers; EC(50) = 17.44 µg/ml), Kampeferol diglucoside (leaf; EC(50) = 8.87 µg/ml) and Caffeic acid (leaf and fruits). The non anti-oxidant components isolated in the study include ajugol (stem bark and fruits) and phytol (leaf).

Antinociceptive and antiinflammatory effects of essential oil of Dennettia tripetala G.Baker (Annonaceae) in rodents

In this study we evaluated the analgesic and anti-inflammatory activities of the essential oil (EO) of the fruits of Dennettia tripetala in rodents. The plant is a tropical African plant and the fruits are commonly eaten as spices and consumed as a stimulant, and its various parts are used in the treatment of fever, cough and as anti-emetics.The analgesic effects of the oil was assessed in mice using the hot plate, acetic acid-induced writhings and formalin test, while carrageenan-induced paw oedema was used to study the antiinflammatory effects in rats. The EO at 25-50 mg/kg exhibited significant (p<0.05) antinociceptive effects comparable to a potent opioid agonist, morphine (10 mg/kg) and non-steroidal anti-inflammatory drugs such as, aspirin (100 mg/kg) and indomethacin (80 mg/kg). The antinociceptive effect of the EO was also blocked by naloxone (2 mg/kg) in all the models used. The EO demonstrated significant (p<0.05) anti-inflammatory effect in the carrageenan-induced paw oedema model of inflammation that is also comparable to dexamethasone (1 mg/kg) The results showed that the essential oil of D. tripetala possesses significant antinociceptive and antiinflammatory effects in the animal models used. The results also suggest that the analgesic effects may be mediated both centrally as well as peripherally, while the antiinflammatory activity may be effective in both early and late phases of inflammation. The results obtained may therefore be used to rationalize the use of the plant in the treatment of pain and fever in traditional medicine.

Clinical evaluation of Acalypha ointment in the treatment of superficial fungal skin diseases

In an open non-comparative study to evaluate the efficacy and safety of Acalypha wilkesiana ointment in superficial fungal skin diseases, 32 Nigerian patients with clinical and mycological evidence of superficial mycoses were recruited. Twelve patients defaulted and were lost to follow up, while one patient withdrew because of intolerable excoriation at the site of the lesion. Of the 19 patients that completed the trial, clinical cure was achieved in 73.3% of the patients. The ointment was very efficacious in the treatment of Tinea pedis, Pityriasis versicolor and Candida intetrigo where the cure rate was 100% in each condition. It is recommended that Acalypha ointment can be used for the treatment of these superficial mycoses.

S. K. Adesina, O. Idowu, A. O. Ogundaini, H. Oladimeji, T. A. Olugbade, G. O. Onawunmi and M. Pais, 'Antimicrobial constituents of the leaves of EAcalypha wilkesiana and acalypha hispida'. Phytotherapy research14(5) 2000, 371-374

The original article to which this Erratum refers was published in Phytotherapy Research 14(5) 2000, 371-374. Following publication of this paper in the August 2000 issue of Phytotherapy Research (14(5):371-374), it has come to our attention that the dates of receipt and acceptance were printed incorrectly. The corrected dates appear below. The publishers would like to apologise for any confusion caused. Received 28 August 1996 Accepted 15 June 1997

Prieurianoside, a protolimonoid glucoside from the leaves of Trichilia prieuriana

The ubiquitous glycolipid 1,2-dilinolenoyl-3-galactopyranosylglycerol and a new protolimonoid glucoside, named prieurianoside, were isolated from the leaves of Trichilia prieuriana. The structure of the latter was established, by spectroscopic techniques, as 12beta,21-diacetoxy-29-beta-D-glucopyranosyloxy-23zeta -hydroxytirucalla-7,24-dien-3-one.

Antimicrobial constituents of the leaves of Acalypha wilkesiana and Aacalypha hispida

An activity directed fractionation of a 50% aqueous ethanol extract of A. wilkesiana and A. hispida leaves resulted in the isolation of gallic acid, corilagin and geraniin as the compounds responsible for the observed antimicrobial activity. Quercetin 3-O-rutinoside and kaempferol 3-O-rutinoside were also isolated from the inactive fraction of A. hispida. The structures were established by permethylation, 2D - NMR ((1)H and (13)C) and MS data.

Antimicrobial constituents of the leaves of Acalypha wilkesiana and Aacalypha hispida

An activity directed fractionation of a 50% aqueous ethanol extract of A. wilkesiana and A. hispida leaves resulted in the isolation of gallic acid, corilagin and geraniin as the compounds responsible for the observed antimicrobial activity. Quercetin 3-O-rutinoside and kaempferol 3-O-rutinoside were also isolated from the inactive fraction of A. hispida. The structures were established by permethylation, 2D - NMR ((1)H and (13)C) and MS data.

Antimicrobial constituents of the leaves of Acalypha wilkesiana and Aacalypha hispida

An activity directed fractionation of a 50% aqueous ethanol extract of A. wilkesiana and A. hispida leaves resulted in the isolation of gallic acid, corilagin and geraniin as the compounds responsible for the observed antimicrobial activity. Quercetin 3-O-rutinoside and kaempferol 3-O-rutinoside were also isolated from the inactive fraction of A. hispida. The structures were established by permethylation, 2D - NMR ((1)H and (13)C) and MS data.

Petersaponins III and IV, triterpenoid saponins from Petersianthus macrocarpus

Two new triterpenoid saponins, petersaponins III and IV (1 and 2), were isolated from an n-butanol extract of the bark of Petersianthus macrocarpus. They possess 21-O-benzoyl-22-O-acetylbarringtogenol C and 21-O-2-furoxyl-22-O-tigloylbarringtogenol C as the aglycon, respectively. For both 1 and 2, the trisaccharide moiety linked to C-3 of the aglycon consists of D-glucuronic acid, D-xylose, and D-galactose, while a L-rhamnose unit is linked to C-28. The structures of 1 and 2 were elucidated by extensive NMR experiments including (1)H-(1)H (COSY, HOHAHA, NOESY) and (1)H-(13)C (HMQC and HMBC) spectroscopy and by chemical evidence.

New amides from Zanthoxylum lemairie pericarps

Two new aromatic amides were isolated from the pericarps of Zanthoxylum lemairie. The structures were elucidated by spectroscopic methods and confirmed by synthesis. A known aromatic amide, zanthosinamide, and four dibenzylbutyrol-actone lignans were isolated.

Pharmacokinetics and bioavailability of drotaverine in humans

The pharmacokinetics and bioavailability of drotaverine was studied in 10 healthy volunteers after administration of single 80 mg oral and intravenous doses of the HCl salt of the drug, in a crossover fashion. Plasma and urine samples were analyzed for the unchanged drug by HPLC. The pharmacokinetic parameters, such as elimination half-life, plasma clearance, renal clearance and apparent volume of distribution, were not influenced by the route of drug administration. The drug was mainly eliminated by non-renal routes since renal clearance accounted for only 0.31 +/- 0.13% of the total plasma clearance. The absolute bioavailability was variable and ranged from 24.5-91% with a mean of 58.2 +/- 18.2% (mean +/- SD). It is suggested that the high variation in the bioavailability of drotaverine HCl after oral administration may result in significant interindividual differences in therapeutic response.