Quantification of naltrexone and 6,beta-naltrexol in plasma and milk using gas chromatography-mass spectrometry. Application to studies in the lactating sheep

The effects of maternally administered methadone, buprenorphine and naltrexone on offspring: review of human and animal data

Most women using heroin are of reproductive age with major risks for their infants. We review clinical and experimental data on fetal, neonatal and postnatal complications associated with methadone, the current "gold standard", and compare these with more recent, but limited, data on developmental effects of buprenorphine, and naltrexone. Methadone is a micro-opioid receptor agonist and is commonly recommended for treatment of opioid dependence during pregnancy. However, it has undesired outcomes including neonatal abstinence syndrome (NAS). Animal studies also indicate detrimental effects on growth, behaviour, neuroanatomy and biochemistry, and increased perinatal mortality. Buprenorphine is a partial micro-opioid receptor agonist and a kappa-opioid receptor antagonist. Clinical observations suggest that buprenorphine during pregnancy is similar to methadone on developmental measures but is potentially superior in reducing the incidence and prognosis of NAS. However, small animal studies demonstrate that low doses of buprenorphine during pregnancy and lactation lead to changes in offspring behaviour, neuroanatomy and biochemistry. Naltrexone is a non-selective opioid receptor antagonist. Although data are limited, humans treated with oral or sustained-release implantable naltrexone suggest outcomes potentially superior to those with methadone or buprenorphine. However, animal studies using oral or injectable naltrexone have shown developmental changes following exposure during pregnancy and lactation, raising concerns about its use in humans. Animal studies using chronic exposure, equivalent to clinical depot formulations, are required to evaluate safety. While each treatment is likely to have maternal advantages and disadvantages, studies are urgently required to determine which is optimal for offspring in the short and long term.

Nano-Level Detection of Naltrexone Hydrochloride in Its Pharmaceutical Preparation at Au Microelectrode in Flowing Solutions by Fast Fourier Transforms Continuous Cyclic Voltammetry as a Novel Detector

An easy and fast Fourier transform continuous cyclic voltammetric technique for monitoring of ultra trace amounts of naltrexone in a flow-injection system has been introduced in this work. The potential waveform, consisting of the potential steps for cleaning, stripping and potential ramp, was continuously applied on an Au disk microelectrode (with a 12.5 microm in radius). The proposed detection method has some of advantages, the greatest of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The method was linear over the concentration range of 0.34-34000 pg/mL (r = 0.9985) with a limit of detection 8.0 x 10(-4) nM. The method has the requisite accuracy, sensitivity, precision, and selectivity to assay naltrexone in tablets. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the naltrexone were considered.

Transfer of naltrexone and its metabolite 6,beta-naltrexol into human milk

The excretion of naltrexone and its primary metabolite 6,beta-naltrexol in breast milk from a 30-year-old lactating opiate addict undergoing oral naltrexone pharmacotherapy (5 mg/d) was studied. Concentrations of naltrexone and 6,beta-naltrexol in serial milk and plasma samples taken over a 19.3-hour period of a dose interval at steady state were measured by gas chromatography. The calculated infant dose relative to the maternal weight was 0.03% for naltrexone and 0.83% (as naltrexone equivalents) for 6,beta-naltrexol. Total relative infant dose estimated for the complete 24-hour dose interval was 1.06%. Her 6-week-old breastfed infant was healthy, achieving expected milestones, and showed no adverse effects. Only 6,beta-naltrexol was detected in infant plasma and at a very low concentration of 1.1 micro g/L. Use of naltrexone during breastfeeding should be undertaken only after an individual risk benefit analysis.

Determination of naltrexone and 6-β-naltrexol in human plasma following implantation of naltrexone pellets using gas chromatography–mass spectrometry

An alternative to detoxification by oral therapy with the narcotic antagonist naltrexone is the subcutaneous implantation of naltrexone pellets. From detoxified patients with naltrexone implants (1g) 26 blood samples were collected up to 73 days after implantation. The assay for naltrexone and 6-beta-naltrexol in plasma was developed using automated mixed-mode solid-phase extraction, catalysed trimethylsilylation and gas chromatography-mass spectrometry in single ion monitoring mode with naloxone as internal standard. The analytical method was very sensitive with limits of detection of 0.1 ng/ml and was linear up to 60 ng/ml for naltrexone and 200 ng/ml for naltrexol. Intra-day precision for naltrexone and naltrexol were 24.3 and 22.9%, respectively, at the LLOQ (accuracy 1.4 and 0.4%, respectively) and less than 10% (2.0, 6.0 and 20.0 ng/ml, n = 6 each) above. Inter-day precision was 7.9% (accuracy -0.6%) for naltrexone and 10.9% (accuracy 1.6%) for naltrexol (20 ng/ml, n = 10). Extraction recoveries were 83% for both analytes (10 ng/ml, n = 6). The concentrations of naltrexone and naltrexol in the plasma samples were in the range of 0.7-13.7 and 0.9-17.0 ng/ml, respectively. The simple analytical procedure described provided good sensitivity for the assay of naltrexone and naltrexol in plasma after naltrexone pellet implantation.

Beta-phenylethylamines and the isoquinoline alkaloids

This review covers beta-phenylethylamines and isoquinoline alkaloids and compounds derived from them, including further products of oxidation, condensation with formaldehyde and rearrangement, some of which do not contain an isoquinoline system, together with naphthylisoquinoline alkaloids, which have a different biogenetic origin. The occurrence of the alkaloids, with the structures of new bases, together with their reactions, syntheses and biological activities are reported. The literature from July 2001 to June 2002 is reviewed, with 581 references cited.

Studying drugs in human milk: time to unify the approach

The trend globally for mothers to breastfeed has highlighted the need for information on drug transfer into breast milk and the extent to which the suckling neonate may be exposed and affected. This review discusses robust study methodologies that will yield high-quality information on all aspects of this process. Methods for assessing drug transfer into breast milk are examined. The place of the milk/plasma ratio, the amount of drug in breast milk, and the volume of milk produced are discussed in the context of their utility in estimating both absolute and relative infant dose. The measurement of plasma drug concentrations and pharmacodynamic effects in the breastfed infant exposed to drugs are identified as important factors that can assist in deciding whether drug present in breast milk is a significant risk for the nursing infant.