Association of S(+) ketamine, dexmedetomidine and butorphanol for chemical restraint in scarlet macaws (Ara macao) / Associação cetamina S(+), dexmedetomidina e butorfanol na contenção química de araracangas (Ara macao)

The present study aimed at assessing the effects of combining 20 mg/kg S(+) ketamine with 25 µg/kg dexmedetomidine and 0.4 mg/kg butorphanol on the physiological parameters and anesthetic recovery time and score of eight captive scarlet macaw (Ara macao) specimens. These specimens were captured at the Marabá Zoobotanic Foundation (Fundação Zoobotânica de Marabá), Pará, using butterfly and mist nets, and subsequently subjected to the proposed protocol. The following physiological parameters were evaluated: heart rate (HR), respiratory rate (RR), saturation of peripheral oxygen (SpO2), body temperature (BT), and non-invasive blood pressure 5 min after drug administration (M0) and every 10 min thereafter (M1‒M5), with a total of 55 min of analysis of anesthetic effects. Glycemia was measured 5 min after drug administration and every 30 min thereafter. Anesthetic induction and recovery times were also determined. Among the parameters evaluated in this study, both HR and BT significantly decreased throughout the anesthetic period, with the lowest levels at 55 min after drug administration (M5). In contrast, RR did not significantly differ, and all animals remained stable, maintaining an RR close to a mean of 20 ± 8 cpm. Throughout the anesthetic period, SpO2was 92 ± 5%, with no significant difference. The birds remained under spontaneous ventilation and without oxygen supplementation. Systolic, diastolic, and mean blood pressures remained stable, with no significant differences in any of these measurements. At M0 and M3, the glycemia decreased slightly, albeit with no significant difference justifying an adverse effect or even hypoglycemia. The anesthetic induction time, from M0 to decubitus, was 2.4 ± 0.7 min. The anesthetic recovery time, from M0 to effortless bipedal position and adequate phalangeal flexion, was 99.3 ± 32.4 min. The sedation was assessed as intense, and the anesthetic recovery was rated excellent in 62.5% and good in 37.5% of the animals.(AU)

O presente estudo objetivou avaliar os efeitos do uso da cetamina S(+) 20 mg/kg associada à dexmedetomidina 25 µg/kg e butorfanol 0,4 mg/kg sobre os parâmetros fisiológicos, tempo e qualidade da recuperação anestésica de araracangas (Ara macao). Foram utilizados oito espécimes de Ara macao cativas da Fundação Zoobotânica de Marabá, Pará. A captura foi realizada com o uso de puçá e rede de contenção e em seguida as aves foram submetidas ao protocolo proposto. Foram avaliados: frequência cardíaca, frequência respiratória, saturação parcial da oxihemoglobina (SpO2), temperatura corporal e pressão arterial não-invasiva a partir de 5 minutos após a aplicação dos fármacos (M0) e a cada 10 minutos seguintes (M1, M2, M3, M4 e M5), totalizando 55 minutos de contemplação dos efeitos anestésicos. A glicemia foi avaliada aos 5 minutos da aplicação dos fármacos e repetida após 30 minutos. Também foi determinado o tempo de indução e de recuperação. Dentre os parâmetros avaliados, a frequência cardíaca e a temperatura demonstraram queda estatisticamente significativa ao longo do período anestésico, ambas com os menores valores registrados aos 55 minutos após a aplicação dos fármacos (M5). A frequência respiratória não apresentou diferença estatística e todos os animais se mantiveram estáveis e com a frequência próxima a média de 20±8mpm. A saturação da oxihemoblobina (SpO2) ao longo do período anestésico foi de 92±5%, não houve diferença estatisticamente relevante, as aves permaneceram sob ventilação espontânea e sem suplementação de oxigênio. As pressões arteriais sistólica, diastólica e média, mantiveram-se estáveis e não houve diferença estatística para nenhuma dessas medidas. A glicemia, mensurada em M0 e M3 demonstrou queda discreta, sem diferença significativa capaz de justificar um efeito adverso ou mesmo hipoglicemia. O tempo de indução, desde aplicação dos anestésicos até o decúbito, foi de 2,4±0,7 minutos. O tempo de recuperação, compreendido desde a aplicação dos fármacos (M0) até a constatação da posição bipedal sem esforço e adequada flexão das falanges, foi de 99,3±32,4 minutos. A qualidade de sedação foi considerada intensa e a recuperação anestésica foi classificada como ótima para 62,5% e boa para 37,5% dos animais.(AU)

Effect of Packaging Materials and the Leached Iron on the Stability of Butorphanol Tartrate Injection.

The aim of this study was to investigate the effect of various parameters on the stability of butorphanol tartrate injection and to screen the optimal packaging material. The effect of the headspace oxygen levels, ampoule color, manufacturer, and size on the stability of butorphanol tartrate formulation were evaluated. The headspace oxygen levels controlled by nitrogen purging were found to be particularly effective in improving stability of the butorphanol formulation, especially below 2%. Although it is a photolabile drug, butorphanol tartrate was getting degraded at much higher extent in amber color ampoules in comparison to clear ampoules. The degradation by oxidation was found to be a free radical-mediated process catalyzed by the presence of iron ions leached from the amber ampoules. The ampoule manufacturers also had a significant effect on the stability of butorphanol. Two-milliliter ampoules provided a better stability of the butorphanol tartrate injection than 1mL ampoules as 2-mL ampoules had the lower headspace oxygen level at the same level of oxygen content. The oxidation mechanism of the butorphanol tartrate injection was investigated under various conditions, which include iron powder spiking, removal of excipients, exposure to oxygen/nitrogen, exposure to stainless steel and at different pH. Iron powder spiking, presence of citric acid, exposure to oxygen, exposure to stainless steel, and high pH accelerated the oxidative degradation. The effect of oxygen, iron ion and citric acid is in agreement with a metal-catalyzed oxidation mechanism called Udenfriend reaction. Based on the formulation test results, limiting headspace oxygen level, ampoule color, manufacturer, size, controlling iron ion contamination, and pH are recommended for formulation development. In conclusion, it can be suggested that this study can lead to a better understanding of the degradation mechanism of butorphanol tartrate; hence, it would contribute to the development of butorphanol tartrate injection with improved stability. Virous packaging materials have different effects on the stability of butorphanol tartrate injection, and the leached iron of packaging ampoules and stainless steel can trigger Udenfriend reaction with butorphanol tartrate and citric acid (CA), which lead to the oxydative degradation of butorphanol tartrate injection.

Molecular Interaction Between Butorphanol and κ-Opioid Receptor.

BACKGROUND: The misuse of opioids stems, in part, from inadequate knowledge of molecular interactions between opioids and opioid receptors. It is still unclear why some opioids are far more addictive than others. The κ-opioid receptor (KOR) plays a critical role in modulating pain, addiction, and many other physiological and pathological processes. Butorphanol, an opioid analgesic, is a less addictive opioid with unique pharmacological profiles. In this study, we investigated the interaction between butorphanol and KOR to obtain insights into the safe usage of this medication. METHODS: We determined the binding affinity of butorphanol to KOR with a naltrexone competition study. Recombinant KORs expressed in mammalian cell membranes (Chem-1) were used for G-protein activation studies, and a human embryonic kidney-293 (HEK-293) cell line stably transfected with the human KOR was used for ß-arrestin study as previously described in the literature. The effects of butorphanol on KOR internalization were investigated using mouse neuroblastoma Neuro2A cells stably transfected with mKOR-tdTomato fusion protein (N2A-mKOR-tdT) cells overexpressing KOR. The active-state KOR crystal structure was used for docking calculation of butorphanol to characterize the ligand binding site. Salvinorin A, a full KOR agonist, was used as a control for comparison. RESULTS: The affinity of KOR for butorphanol is characterized by Kd of 0.1 ± 0.02 nM, about 20-fold higher compared with that of the µ-opioid receptor (MOR; 2.4 ± 1.2 nM). Our data indicate that butorphanol is more potent on KOR than on MOR. In addition, butorphanol acts as a partial agonist of KOR in the G-protein activation pathway and is a full agonist on the ß-arrestin recruitment pathway, similar to that of salvinorin A. The activation of the ß-arrestin pathway is further confirmed by KOR internalization. The in silico docking model indicates that both salvinorin A and butorphanol share the same binding cavity with the KOR full agonist MP1104. This cavity plays an important role in determining either agonist or antagonist effects of the ligand. CONCLUSIONS: In conclusion, butorphanol is a partial KOR agonist in the G-protein activation pathway and a potent KOR full agonist in the ß-arrestin recruitment pathway. The structure analysis offers insights into the molecular mechanism of KOR interaction and activation by butorphanol.

Effect of butorphanol on etomidate-induced myoclonus: a systematic review and meta-analysis.

Objective: To evaluate the effect of butorphanol on the prevention of myoclonus induced by etomidate. Materials and methods: We searched the PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure databases to collect relevant randomized controlled trials (RCTs) evaluating the effect of butorphanol on etomidate-induced myoclonus in January 2019 without any language restrictions. The primary outcome was the incidence of etomidate-induced myoclonus. Secondary outcomes included the incidence of myoclonus at various degrees and the incidence of adverse effects. Risk ratios (RRs) were calculated for binary outcomes. All statistical analysis were performed by using RevMan 5.3 software. Results: We identified 6 RCTs involving a total of 608 patients who reported the incidence of etomidate-induced myoclonus. In pooled analyses, the incidence of etomidate-induced myoclonus in the butorphanol group was significantly lower than that in the control group (RR =0.15, 95% CI [0.10, 0.22], P<0.00001). Subgroup analyses showed that butorphanol significantly decreased the numbers of patients with mild myoclonus (RR =0.41, 95% CI [0.25, 0.68], P=0.0005), moderate myoclonus (RR =0.18, 95% CI [0.09, 0.34], P<0.00001), and severe myoclonus (RR =0.04, 95% CI [0.01, 0.10], P<0.00001). Additionally, butorphanol did not increase the incidence of postoperative nausea/vomiting (RR =3.0, 95% CI [0.32, 28.42], P=0.34) or dizziness (RR =6.79, 95% CI [0.84, 54.84], P=0.07) associated with etomidate. Conclusion: Our findings suggest that butorphanol can effectively prevent the incidence of etomidate-induced myoclonus and alleviate the intensity of etomidate-induced myoclonus, without inducing postoperative nausea/vomiting and dizziness.

In vitro characterization of a formulation of butorphanol tartrate in a poloxamer 407 base intended for use as a parenterally administered slow-release analgesic agent.

OBJECTIVE To assess rheological properties and in vitro diffusion of poloxamer 407 (P407) and butorphanol-P407 (But-P407) hydrogels and to develop a sustained-release opioid formulation for use in birds. SAMPLE P407 powder and a commercially available injectable butorphanol tartrate formulation (10 mg/mL). PROCEDURES P407 and But-P407 gels were compounded by adding water or butorphanol to P407 powder. Effects of various concentrations of P407 (20%, 25% and 30% [{weight of P407/weight of diluent} × 100]), addition of butorphanol, and sterilization through a microfilter on rheological properties of P407 were measured by use of a rheometer. In vitro diffusion of butorphanol from But-P407 25% through a biological membrane was compared with that of a butorphanol solution. RESULTS P407 20% and 25% formulations were easily compounded, whereas it was difficult to obtain a homogenous P407 30% formulation. The P407 was a gel at avian body temperature, although its viscosity was lower than that at mammalian body temperature. The But-P407 25% formulation (butorphanol concentration, 8.3 mg/mL) was used for subsequent experiments. Addition of butorphanol to P407 as well as microfiltration did not significantly affect viscosity. Butorphanol diffused in vitro from But-P407, and its diffusion was slower than that from a butorphanol solution. CONCLUSIONS AND CLINICAL RELEVANCE But-P407 25% had in vitro characteristics that would make it a good candidate for use as a sustained-release analgesic medication. Further studies are needed to characterize the pharmacokinetic and pharmacodynamic properties of But-P407 25% in vivo before it can be recommended for use in birds.

Physicochemical stability of ternary admixtures of butorphanol, ketamine, and droperidol in polyolefin bags for patient-controlled analgesia use.

BACKGROUND: Delivery of drug admixtures by intravenous patient-controlled analgesia is a common practice for the management of postoperative pain; however, analytical confirmation of the compatibility and stability of butorphanol tartrate, ketamine hydrochloride, and droperidol combined in ternary admixtures is not available. METHODS: Butorphanol tartrate, ketamine hydrochloride, and droperidol have been examined for compatibility and stability when combined with 0.9% sodium chloride injection stored at 4°C and 25°C with light protection for a total of 14 days. Concentrations were 0.067 mg/mL, 1.33 mg/mL, and 0.033 mg/mL for butorphanol tartrate, ketamine hydrochloride, and droperidol, respectively. Drug concentrations were determined using high-performance liquid chromatographic analysis. RESULTS: All three drugs were very stable (>97%) at 4°C and 25°C for 14 days. The ternary admixtures were initially clear and colorless throughout the observation period, and the pH value did not change significantly. CONCLUSION: The results confirm that the ternary admixture of butorphanol tartrate 0.067 mg/mL, ketamine hydrochloride 1.33 mg/mL, and droperidol 0.033 mg/mL in 0.9% sodium chloride injection were stable for 14 days when stored in polyolefin bags at 4°C and 25°C and protected from light.

Physico-chemical stability of butorphanol-tramadol and butorphanol-fentanyl patient-controlled analgesia infusion solutions over 168 hours.

This study was to investigate the physical and chemical compatibility of butorphanol with tramadol or fentanyl in 0.9% sodium chloride injections for patient controlled analgesia administration. The solutions were prepared in polyvinyl chloride (PVC) infusion bags and stored without protected from light exposure at room temperature (25 degrees C) or refrigerated (4 degrees C). Over a period of 168 hours, stabilities were determined by visual inspection, pH measurement, and high-pressure liquid chromatography (HPLC) assay of drug concentrations. At both temperatures, admixtures of butorphanol-tramadol and butorphanol-fentanyl were clear in appearance, and no color change or precipitation was observed during the study period. The maximum losses obtained were lower than 5% for the three drugs after 168 hours of storage. The results indicate that, at ambient or refrigerated storage conditions, the drug mixtures of butorphanol-tramadol and butorphanol-fentanyl in 0.9% sodium chloride injections were physically and chemically stable for at least 168 hours when stored in PVC syringes.

Synthesis and binding affinity of novel mono- and bivalent morphinan ligands for κ, µ, and δ opioid receptors.

A novel series of homo- and heterodimeric ligands containing κ/µ agonist and µ agonist/antagonist pharmacophores joined by a 10-carbon ester linker chain were synthesized and evaluated for their in vitro binding affinity at κ, µ, and δ opioid receptors, and their functional activities were determined at κ and µ receptors in [(35)S]GTPγS functional assays. Most of these compounds had high binding affinity at µ and κ receptors (K(i) values less than 1nM). Compound 15b, which contains butorphan (1) at one end of linking chain and butorphanol (5) at the other end, was the most potent ligand in this series with binding affinity K(i) values of 0.089nM at the µ receptor and 0.073nM at the κ receptor. All of the morphinan-derived ligands were found to be partial κ and µ agonists; ATPM-derived ligands 12 and 11 were found to be full κ agonists and partial µ agonists.

Synthesis and pharmacological evaluation of hydrophobic esters and ethers of butorphanol at opioid receptors.

We synthesized several hydrophobic esters and ethers of butorphanol and assessed their affinities at opioid receptors in CHO cell membranes. Tested compounds displayed moderate to high affinities to the mu and kappa receptors. The findings accord with previous evidence of a lipophilic binding pocket in the opioid receptors that can be accessed to afford good binding affinity without the need for a phenolic hydrogen-bond donor group. The most potent (K(i)=61 pM at mu and 48 pM at kappa) novel agent was (-)-N-cyclobutylmethylmorphinan-3-yl-14-ol phenoxyacetate (4d).

Effect of elevated temperature and light on the stability of butorphanol tartrate.

The purpose of this investigation was to determine the short-term stability of butorphanol tartrate in presence of diluents. A 10-mg/mL solution of butorphanol tartrate was diluted to 5 mg/mL using normal saline, 5% dextrose in water (D5W), or sterile water for injection. The diluted solutions were divided into two groups. The effect of temperature was tested by placing one group of sealed amber vials at room temperature and at 37 degrees C. The effect of light was studied by placing a second group in amber and clear vials, then exposing them directly to light. At regular time intervals over a period of 5 weeks, the solutions were analyzed for butorphanol tartrate and degradation products using a high-performance liquid chromatography assay. The concentration of butorphanol tartrate remained practically unchanged, indicating that butorphanol tartrate is not affected by heat or light in the presence of any of the diluents over a period of 5 weeks.