Phenobarbital Solution Research Articles

Formulation and stability study of an oral paediatric phenobarbital 1% solution containing hydroxypropyl-β-cyclodextrins

ObjectivesPhenobarbital is a barbiturate, used to treat focal and generalised epilepsy. Since the end of marketing of the oral solution KANEURON in 2017, phenobarbital tablets remain the only available dosage...

The development and validation of the methods for enzymatic hydrolysis for the extraction of toxic compounds from the uncoloured hairs

The objective of the present study was the development of the method for the extraction of toxic compounds from the uncoloured hairs with the use of enzymatic hydrolysis by proteolytic enzymes of the toxic compounds comprising the group of pharmaceutical substances present on the uncoloured hairs collected for the forensic medical expertise. The experiments were carried out using laboratory animals, viz. guinea pigs having hair of natural white and black colour and white rats that were given per os a phenobarbital solution and a dimedrol solution as well as daily intravenous injections of tropicamide hydrochloride administered every 28 days. The hair obtained from the experimental animals was subjected to acidic, alkaline, and enzymatic hydrolysis with chymotrypsin, trypsin, and papain. The analysis of the extracted materials was performed using the gas chromatographic technique with mass-selective detection. The results of the study give evidence that the completeness of the extraction of the toxic substances from animal hairs with the use of enzymatic hydrolysis is twice and thrice that of acidic and alkaline hydrolysis respectively. The enzymatic hydrolysis methods developed in the present study are equally efficient using the naturally coloured white and black hairs of the laboratory animals which allows to recommend them for the extraction of poisonous substances from such material. The methods were validated.

Spectroscopic detection of brain propylene glycol in neonates: Effects of different pharmaceutical formulations of phenobarbital.

BackgroundThe first choice for treatment of neonatal convulsions is intravenous phenobarbital, which contains propylene glycol (PG) as a solvent. Although PG is generally considered safe, the dosage can exceed safety thresholds in neonates. High PG levels can cause lactic acidosis.Purpose/HypothesisTo investigate a relationship between brain PG concentration and medication administered to neonates, and to study if a correlation between spectroscopically detected PG and lactate was present.Study TypeRetrospective.PopulationForty‐one neonates who underwent MRI/MRS.Field Strength/SequenceShort echo time single voxel MRS at 1.5T.AssessmentSpectra were quantified. Concentrations of PG were correlated with medication administered, because intravenously administered phenobarbital solutions contained 10, 25, or 50 mg phenobarbital per ml, all containing 350 mg PG per ml. The interval between medication and MRI/MRS was determined.Statistical TestsChi‐square test, Student's t‐test, Mann–Whitney U‐test and Spearman correlation.ResultsEighteen neonates had brain PG >1 mM (median 3.4 mM, maximum 9.5 mM). All 18 neonates with high brain PG and 14 neonates with low brain PG (<1 mM) received phenobarbital as the only source of PG. Nine neonates did not receive any phenobarbital/PG‐containing medication. Neonates with high brain PG more often received 10 mg/ml phenobarbital, resulting in higher PG dose (high vs. low brain PG (median [interquartile range]: 1400 [595] vs. 350 [595] mg/kg, respectively, P < 0.01). In addition, the interval between the last phenobarbital dose and MRI was shorter in the high brain PG group (high vs. low brain PG: 16 [21] vs. 95 [83] hours, respectively, P < 0.001). Within neonates that received phenobarbital, there was no conclusive correlation between spectroscopically detected PG and lactate (Spearman's rho = 0.23, P = 0.10).Data ConclusionThese MRS findings may increase awareness of potentially toxic PG concentrations in the neonatal brain due to intravenous phenobarbital administration and its dependence on the phenobarbital formulation used. Level of Evidence: 4 Technical Efficacy: Stage 5J. Magn. Reson. Imaging 2019;49:1062–1068.

The development of the method for enzymatic hydrolysis for the extraction of toxic substances from the hair samples

The objective of the present study was to develop and validate the method for the extraction of toxic substances from the hair samples as exemplified by enzymatic hydrolysis of barbituric acid derivatives. The experiments were carried out with the use of laboratory animals (white female rats and albino guinea pigs) that had been daily given a phenobarbital solution per os during 4 months preceding the study. The hairs obtained from the experimental animals were subjected to acid hydrolysis with a 6 mole hydrochloric acid and enzymatic hydrolysis with the use of chymopsin, trypsin, chymotrypsin, and papain solutions. The analysis of the extracted materials was performed by means of gas chromatography with mass-selective detection. The application of the proposed method for enzymatic hydrolysis produced the better results than acid hydrolysis. This technique was validated. The results of the study made possible the comparative characteristic of the effectiveness of acid and enzymatic hydrolysis.

In vivo evaluation of anticonvulsant and antioxidant effects of phenobarbital microemulsion for transdermal administration in pilocarpine seizure rat model

This study aimed to evaluate a microemulsion system (ME) containing phenobarbital in epilepsy model induced by pilocarpine in rats and to oxidative stress and histologic lesions in hippocampus. The microemulsion was applied to the shaved back of Wistar rats. The animals were divided into the following groups: control group (P400); ME50 40mg/kg, topically-t.p.; ME100, 40mg/kg, t.p.; EM50, 40mg/kg, t.p.; phenobarbital solution 40mg/kg (PS), oral. After 60min, behavioral changes were evaluated for 1h in the model of epileptical crisis induced by pilocarpine. Phenobarbital in microemulsion was able to increase the latency for status epilepticus (SE) (p<0.05), decrease the number of epileptical crisis (ME50: p<0.001; ME100: p<0.01) and decrease mortality rate by 80% compared to P400. In EM50 and PS groups, deaths were decreased by 53.3% and 100% respectively. The ME50 and ME100 groups were able to reduce oxidative stress in experimental animals when compared to the P400. The microemulsion was still capable of reducing neuronal damage in the hippocampal areas. The results of this study come in an innovative way, demonstrating the ability of transdermal ME50 and ME100 to reduce pilocarpine-induced epileptical crisis, oxidative stress, besides neuronal damages.

Transdermal delivery of phénobarbital Preformulation studies

The aim of this paper was to develop a phenobarbital solution suitable for transdermal administration, and preformulation studies were carried out in order to obtain the solution with the desired phenobarbital content. The preconditions necessary for the permeation processes through the skin and the lipophilicity of the active molecule were investigated and characterized quantitatively with its octanol/water partition coefficient. It was determined how the apparent partition coefficient values changed (logP app ) in the function of changing the pH of the solvents. The amount of phenobarbital estimated for the successful treatment of grand mal epilepsy by the solution was ensured by using solvents of polar and semipolar character. An order based on the ability of the used solvents and cosolvents to increase the solubility of phenobarbital was established.

Enhanced extraction of phenobarbital from serum with a designed artificial receptor.

The primary goal of this work was to determine whether artificial receptors that function on the basis of molecular recognition have analytical capabilities. As an example of such a receptor, we have chosen one directed toward barbiturates. Chloroform enriched with this artificial receptor (1 mM) can extract more than 90% of the phenobarbital from a 20 microM phenobarbital solution in human control serum using a volume ratio (organic/serum) as small as 0.5. In the absence of this receptor, the volume ratio must be greater than 10 to achieve similar extraction efficiencies. In addition to volume ratio, the role of pH, receptor concentration, and solvent type are discussed. The experimental results are found to be in good agreement with predictions based on chemical equilibria. Through the use of this and other similar receptors, the amount of organic solvent used in extractions can be minimized.

Dose-dependent promoting effect of phenobarbital on rat hepatocarcinogenesis.

The dose-dependent promoting effect of phenobarbital (PB) on rat 2-stage hepatocar-cinogenesis was investigated. Male F344 rats were given 600, 300, 150, 75 or 38ppm PB solutions ad libitum as their drinking water for 39 weeks following initiation with a single intraperitoneal injection of diethylnitrosamine (DEN) (100mg/kg). At week 40, the incidences of hepatic tumors were increased significantly in the DEN+PB groups given 300ppm and 600ppm PB, as compared to that in the DEN group. Linear dose-response curves for numbers and sizes of enzyme altered foci (γ-GTP or GST-P positive foci) were observed in all DEN+PB groups. Numbers and sizes of foci were increased even in the DEN+PB group given the lowest PB, as compared to that in the group given DEN only, while being not significant. Therefore, second experiment was done using a larger range of PB doses. Rats were given 1, 200, 300, 75, 16, 4 or 1ppm PB solutions in the same manner to the first experiment. The incidence of hepatic tumors was increased clearly in the DEN+PB groups given 300ppm PB or above, as compared to that in the group given DEN only. Linear dose-response curves for numbers and sizes of enzyme-altered hepatic foci were obtained in the dose range 16ppm-1, 200ppm PB, and numbers and/or sizes of enzyme-altered foci increased significantly in the DEN+PB groups given 300ppm PB or above. The minimum promoting dose level of PB for enzyme-altered foci, calculated from dose-response curves by the Logit model, was 15-23ppm. These results indicate that the calculated level was evident at low dose, while dose-dependence was demonstrated over a large range. The incidence of hepatic tumors, and numbers and sizes of foci decreased slightly in animals given the lowest dose (1ppm) of PB, as compared to those in animals receiving DEN only.

Threshold dose dependence in phenobarbital promotion of rat hepatocarcinogenesis initiated by diethylnitrosamine.

The dose-response of phenobarbital (PB) promotion of hepatocarcinogenesis in rats was investigated. Male F344 rats were given 1, 4, 16, 75, 300 or 1200 p.p.m. PB solutions given ad libitum as their drinking water for 39 weeks following initiation with a single i.p. injection of diethylnitrosamine (DEN) (100 mg/kg). At week 40, the incidence of hepatic tumors was increased clearly in the DEN + PB groups given 300 p.p.m. PB or above, as compared to that in the group given DEN only. Linear dose-response curves for numbers and sizes of enzyme-altered hepatic foci (gamma-glutamyl-transpeptidase or placental glutathione S-transferase positive foci) were obtained in the dose range 16-1200 p.p.m. PB. The minimum promoting dose level of PB for enzyme-altered foci, estimated from dose-response curves by the Logit model, was calculated to be 15-23 p.p.m. Thus while dose dependence was demonstrated over a large range, a threshold was evident at low doses.

Xenobiotic metabolism in plants: Aryl hydroxylation of diclofop by a cytochrome P-450 enzyme from wheat

A microsomal fraction from etiolated wheat shoots catalysed the aryl hydroxylation of diclofop. The reaction required oxygen and NADPH as cofactors. It was inhibited by inhibitors of NADPH-cytochrome c (P-450) reductase, by anti-reductase antibodies and by carbon monoxide. Carbon monoxide inhibition was reversed by light. Apparent K m values of 9.3 ± 0.8 μm for diclofop and 16.3 ± 2.3 μm for NADPH were determined. The activity, which was very low in etiolated wheat shoots, was strongly enhanced upon aging of seedlings on a phenobarbital solution. This enzyme may serve as a factor in the resistance of wheat to diclofop.

Barbiturate dependence and drug preference

Rats exposed to a daily 3-hr session of intermittent food delivery ingested physical-dependent levels of a 1 mg/ml sodium phenobarbital solution. This chronic, voluntary, high level of session phenobarbital intake had no effect on 21-hr home cage barbiturate preference. Substitution of water for phenobarbital during the session after 7.5 weeks precipitated various spontaneous withdrawal signs in some of the animals by the 24th hr of drug withdrawal but no change was found in home-cage barbiturate preference at any time. Physical dependence alone does not seem to play a crucial role in the maintenance of drug intake behavior.

Effect of phenobarbital on induction of liver and lung tumors by dimethylnitrosamine in newborn mice.

The effect of phenobarbital on simultaneous induction of liver and lung tumors was examined in inbred DDD mice. Group 1 of newborn mice received a single intraperitoneal (ip) injection of dimethylnitrosamine (DMN) and after weaning they were given 0.05% phenobarbital solution to drink. Group 2 received an injection of DMN like Group 1 but were then given normal water. Group 3 were injected ip with 0.9% NaCl solution and then given phenobarbital solution to drink as in Group 1, and Group 4 were injected with 0.9% NaCl solution like Group 3, and then given tap water to drink. The animals were examined 16 weeks after birth. In Group 1, 27 of 35 mice (77%) had liver tumor and 15 (43%) had lung tumor. In Group 2, 8 of 24 mice (33%) had liver tumor and 16 (67%) had lung tumor. Animals in Groups 3 and 4 did not develop tumors. The difference in the incidences of liver tumor, but not lung tumor, in Groups 1 and 2 was statistically significant (P less than 0.01); that is, a promoting effect of phenobarbital was observed in induction of liver tumor, but not lung tumor.

Effect of phenobarbital on UDP-glucosyltransterase activity and phenolic glucosidation in the mollusc Arion ater

1. Slugs fed leaves dipped in phenobarbital solution possessed consistently increased activity of UDP-glucosyltransferase towards o-aminophenol in enteric gland microsomes and sonicates, the enzyme probably being induced. 2. Overall glucosidation of o-aminophenol in gut segments also consistently increased after phenobarbital feeding. 3. UDP-Glucuronyltransferase remained undetectable in slug tissues despite exposure to phenobarbital.

Studies on liver regeneration. II. Effects of phenobarbital on the onset and pattern of rat liver regeneration following partial hepatectomy.

Abstract. Partially hepatectomized rats were given a single intraperitoneal injection of a phenobarbital solution or of water immediately after surgery. At various time intervals following the operation, the animals were injected with 131 iododeoxyuridine (113IDU), sacrificed 2 hr later, and radioactivity retained in formalin‐fixed liver tissue was determined as a measure of DNA synthesis at the time of administration of the labeled precursor. In control animals without phenobarbital treatment, 131IDU incorporation into liver began to increase between 14 and 16 hr after partial hepatectomy. Phenobarbital treatment (0.1 mg per g of body weight) resulted in a delay of the increase in 131IDU incorporation by several hours. This delay was observed in animals subjected to partial hepatectomy in the morning as well as in those operated on in the evening. After phenobarbital treatment, the increase of mitotic activity was either delayed or occurred more slowly. the results are compared with the reported effects of partial hepatectomy on the time course of microsomal enzyme induction by phenobarbital.

Degradation of DDT by goldfish.

Goldfish were fed DDT for three weeks, then exposed to phenobarbital solution for one week to study the possibility of microsomal enzyme induction and therefore possibly enhanced insecticide excretion. Analysis of DDT, DDE and DDD were made at intervals up to six weeks. Forty percent of the DDT fed was incorporated during the feeding. It was recovered mainly as DDE (68 to 96%). Significant differences between pesticide levels of phenobarbital treated and control fish were not found.

Solubilization and Stability of Phenobarbital by Some Aminoalcohols

Four well-known surface-active aminoalcohols—namely, monoethanolamine, triethanolamine, N , N -dimethylethanolamine and N -methylglucamine—were found to be effective solubilizers for phenobarbital in water. Equimolar solubilization was possible only at extremely low concentrations. The relative stabilities of the resultant phenobarbital solutions at both autoclaving and room temperatures were generally comparable and in several cases even superior to aqueous solutions of the sodium salt of phenobarbital as stabilized by the inclusion of some polyhydric alcohols.

The Effect of Hydrogen Ion and Alcohol Concentration on the Solubility of Phenobarbital

The solubility of phenobarbital in alcohol with varying pH has been determined. The data should make it possible to determine the approximate solubility of phenobarbital for any pH and any alcohol concentration up to 50 per cent. The data indicate that it is possible to prepare phenobarbital solutions which have both good stability and solubility using minimal amounts of alcohol if the pH is adjusted.

The Ultraviolet Spectrophotometric Determination of Official Phenobarbital Preparations

An ultraviolet spectrophotometric method of assay for phenobarbital in official phenobarbital preparations is described. Procedures are presented utilizing the optical density of phenobarbital solutions in a borate buffer at pH 9.5 to obtain assay results. The results of 21 assays are reported with satisfactory agreement with known or labeled values. The assay method is shown to be applicable to phenobarbital tablets containing stearates. A change in the absorption characteristics of phenobarbital allowed to stand in 2 per cent sodium hydroxide is reported.