Characterization of Cannabis users and products and the experience of negative mental emotions following Cannabis use.

There is a potential link between cannabis and mental disorders. Cannabis exposure involves in many cases negative mental emotions, which are unpleasant sensations or thoughts. Whereas mild cases of negative mental emotions inflict patient's quality of life, more severe cases lead to therapy discontinuations, or even hospitalizations and death. This study characterizes cannabis users who experienced negative mental emotions after cannabis exposure. The Releaf App database was utilized to evaluate the association between personal and cannabis use characteristics on reporting a negative mental emotion during cannabis exposure. This global mobile lets individuals track real-time cannabis experience use with cannabinoid-based products, containing data points such as gender, age, reasons for use, product type, cannabis composition, and feelings and emotions experienced after cannabis use. Multivariable logistic regression models were constructed, adjusting for potential confounders such as gender and previous experience with cannabis use. The study population comprised 4,435 users, and 34,279 sessions were collected from various countries, mainly from North America, and included in the primary analysis. Reporting on negative mental emotions was associated with users in the age group of 18-30 years. Using cannabis for a mental purpose was associated with a small increase in reporting on negative mental emotions (OR = 1.10, 95%CI [1.03-1.19]). Oral products were associated with reporting on negative mental emotions. THC-dominant products were associated with reporting negative mental emotions compared to balanced products (OR = 1.21, 95%CI [1.06-1.38]). This study suggests that some characteristics of cannabis use, such as young age and oral consumption are associated with negative mental emotions. Further studies should examine the interface between cannabis consumption, characteristics of consumers, and negative emotional experience or even long-term mental disorders.

[ROUTES OF MEDICAL CANNABIS ADMINISTRATION- IS SMOKING THE PREFERRED ROUTE?]

INTRODUCTION: The number of medical cannabis licenses in Israel is increasing persistently (over 120,000 approved licenses in October 2022), reaching about 1.5% of adult population. Medical cannabis products are available in two main forms: inflorescence (administered by smoking or evaporation) and cannabis oil (administered sub-lingually). Data from the Israel ministry of health, regarding the split between these forms, show a major preference for inflorescence products over cannabis oils. This preference is increasing over time. This article reviews the main differences between the administration of these forms and their effects on the quality of treatment. It's conclusion is that for the most common cases of cannabis treatment, sublingual oils should be preferred and that the medical community has an important role in driving this change.

Optimal Treatment with Cannabis Extracts Formulations Is Gained via Knowledge of Their Terpene Content and via Enrichment with Specifically Selected Monoterpenes and Monoterpenoids.

Differences between therapeutic effects of medical cannabis inflorescences and those of their extracts are generally attributed to the differences in administration form and in the resultant pharmacokinetics. We hypothesized that difference may further extend to the composition of the actually consumed drug. Cannabinoid and terpene contents were compared between commercial cannabis inflorescences (n = 19) and decarboxylated extracts (n = 12), and between inflorescences and decarboxylated extracts produced from them (n = 10). While cannabinoid content was preserved in the extracts, a significant loss of terpenes was evident, mainly in the more volatile monoterpenes and monoterpenoids (representing a loss of about 90%). This loss changes the total terpene content, the proportion of monoterpenes out of the total terpenes, and the monoterpene/cannabinoid ratio. Terpene deficiency might impair extracts' pharmacological efficacy and might contribute to the patients' preference to inflorescences-smoking. This argues against the validity of terms such as "whole plant" and "full spectrum" extracts and creates a misleading assumption that extracts represent the pharmacological profile of the sourced inflorescences. Furthermore, it reduces the diversity in extracts, such as loss of differences between sativa-type and indica-type. Enriching cannabis extracts with selected terpenes may provide a suitable solution, generating a safe, precise, and reproducible drug with tailored cannabinoid and terpene contents. Careful selection of terpenes to be added enables tailor-made extracts, adjusted for various medicinal aims and for different populations.

Anesthetic considerations in medical cannabis patients.

PURPOSE OF REVIEW: Growing numbers of patients, consuming cannabinoids admitted to surgery, create a challenge to anesthesia providers. This review provides a summary of recent literature related to cannabis and anesthesia, with specific recommendations to the anesthetic management of medical cannabis consumers. RECENT FINDINGS: At present, cannabis has found its way to public consensus in many countries and is penetrating slower to different medical fields. We relate and discuss recent findings investigating effects of cannabis consumption on the various aspects including perioperative measures, post-operative pain, PONV, cardiovascular stability, and anesthesia monitoring. SUMMARY: Recent surveys estimate that 10-20% of adult populations have consumed cannabis in the past year. Medical cannabis consumers are a newer group of cannabis users. Anesthesia providers have to update their knowledge on cannabis and possible anesthetic interaction. It is unreasonable to make recommendations that apply to the whole heterogeneous group of cannabis users, but is easier with the more homogenous group of Medical cannabis users, characterized by frequent use and relatively high cannabis doses, combined with good knowledge of administered composition and protocol, as well as adverse and withdrawal effects. Anesthesia providers have to know the effects and modify anesthetic plan accordingly. We provide perioperative anesthetic recommendations related to medical cannabis consumers. Collecting information of the effects of medical cannabis use in perioperative setting will further create a highly useful database for anesthetics in the close future.

[NEW ANALGESIC PROTOCOL FOR THE TREATMENT OF PAIN AND ANXIETY IN PEDIATRIC BURN PATIENTS - DEVELOPMENT, IMPLEMENTATION AND FIRST RESULTS].

INTRODUCTION: Burns are one of the most common and painful injuries among babies and children. The pain endured during and in between treatment can be minimized with sedation. These sedations, however, are not without side effects and risks. Given the potential complications, we devised a Burn Analgesic Treatment Protocol that incorporates safe analgesia during burn treatment and throughout the day, thus minimizing the necessity for sedations. AIMS: Assessment of the effectiveness of the analgesic protocol by quantification of overall number of sedations needed for burn treatment and by assessment of the overall experience of the treating medical team exposed to burn care before and after implementation of the protocol. METHODS: A retrospective analysis of analgesic treatment regimens among admitted pediatric burn patients both before and after the implementation of our analgesic protocol was performed. Furthermore, questionnaires were given to the nurses of the treating medical team in order to better assess overall experience with the new analgesic protocol. RESULTS: A total of 87 patients were treated with the new analgesic protocol and 46 patients served as the control group. A significantly lower number of sedations were performed in the group treated with the new protocol compared to the control group (18% vs 30%, p=0.057). The questionnaires filled out by the treating nurses revealed an average score of 4.5 (between 1 - 5), indicating high satisfaction with the protocol. CONCLUSIONS: Our new analgesic protocol allows for highly effective treatment of burn wounds while minimizing the necessity for sedations, thus increasing overall patient safety and reducing potential complications.

[EFFECTS OF CANNABIS EXTRACT PREMEDICATION ON ANESTHETIC DEPTH].

BACKGROUND: Cannabis is the most widely used illicit drug in the world, used by approximately 2.7-4.9% of the world's population, and 7.6-10.2% of Israel's adults. During the past few years, legal systems around the world have enacted large scale adoption of the legalization of both medical and recreational cannabis. Anesthetists should therefore be prepared to treat patients who used cannabis and are undergoing elective or emergency operations. However, the interactions between cannabinoids and general anesthetic agents and the possible implications for patient care are not yet fully understood. OBJECTIVES: The study aimed to examine how preoperative use of cannabis affects the anesthesia process, and whether this use requires special attention by the anesthesiologists during surgery. Hence, we examined the effect of preoperative administration of cannabis extract Sativex (nabiximols) on obtained BIS value relative to the concentration of anesthetic gases. METHODS: This study is a double-blind randomized controlled trial. Twenty-seven patients undergoing elective orthopedic surgery under general anesthesia were randomly allocated to one of the following regimes: high dose cannabis (6), low dose cannabis (8), active placebo (6) and placebo (7). The study drugs were administered as premedication 20 minutes before induction of general anesthesia in a double-blind fashion. Cannabis was administered in the form of nabiximols (Sativex®), which is a highly-standardized extract of cannabis plants containing known drug dosages. During the surgery, hemodynamic parameters were monitored, and the anesthesia depth was measured using a BIS monitor, which is based on brain activity analysis. RESULTS: We found a significant effect of treatment groups on bispectral index (BIS) after controlling for minimum alveolar concentration (MAC). The average BIS values, as measured during steady state anesthesia, were significantly higher in the high dose cannabis treatment group. CONCLUSIONS: This study provides the first evidence that cannabinoids may affect the BIS. We speculate that the cannabinoid-induced increase in BIS may be the result of changes in EEG activity rather than an indication of a shallower anesthetic state. However, this hypothesis should be examined in further studies. The clinical importance of this study is that with patients who use cannabis adjacent to general anesthesia induction, one cannot rely on the BIS monitoring for the purpose of determining the patient sedative state.

A Novel Proliposomal Ropivacaine Oil: Pharmacokinetic-Pharmacodynamic Studies After Subcutaneous Administration in Pigs.

BACKGROUND: Liposomal local anesthetics are limited by a short liposomal shelf-life, even when under refrigeration. We describe a novel proliposomal ropivacaine that produces liposomes in situ, only after exposure to aqueous media. METHODS: In vitro: Nanoparticles were assessed (particle size distribution analyzer, cryo-transmission electron microscopy) at baseline and after exposure to saline/plasma. TOXICITY: In porcine wound healing study (n = 12), healing was assessed by photography, clinical assessment, and histology. Pharmacodynamics: Seventeen young piglets were randomly assigned to plain 0.5% ropivacaine (n = 5), proliposomal 4% ropivacaine (n = 6), or sham (n = 6). Tactile threshold was assessed using von Frey filaments applied to the surgical wound; the nonoperated skin was used as a control. Tactile threshold over time was determined using area under the curve (AUC) and assessed by 1-way analysis of variance. PHARMACOKINETICS: 8 young piglets were randomly assigned to plain 0.5% (25 mg, n = 4) or proliposomal 4% (200 mg, n = 4) ropivacaine. Plasma ropivacaine was assessed by high-performance liquid chromatography at baseline and at intervals over 36 hours. Paired ropivacaine concentration (from wound exudate and plasma) was obtained at 96 hours. Data were analyzed using noncompartmental and compartmental models. RESULTS: In vitro: On exposure to saline and plasma, the study drug was transformed from a homogenous oil to an emulsion containing liposomes of approximately 1.4-µm diameter; this effect was dilution dependent and stable over time. TOXICITY: All wounds healed well; no effect of drug group was observed. Pharmacodynamics: Plain and proliposomal ropivacaine provided sensory anesthesia for approximately 6 and 30 hours, respectively. There was an approximately 7-fold increase in the AUC of anesthesia for proliposomal ropivacaine compared with plain ropivacaine (mean difference, 1010; 95% confidence interval [CI], 625-1396 g·h/mm; P < 0.0001). PHARMACOKINETICS: There was no difference in Cmax (2.31 ± 0.74 vs 2.32 ± 0.46 mg/L), despite an approximately 8-fold difference in dose. However, proliposomal ropivacaine was associated with a marked prolongation of Tmax (6.50 ± 6.35 vs 0.5 ± 0.0 hours), terminal half-life (16.07 ± 5.38 vs 3.46 ± 0.88 hours; P = 0.0036), and ropivacaine-time AUC (47.72 ± 7.16 vs 6.36 ± 2.07 h·mg/L; P < 0.0001), when compared with plain ropivacaine. The proliposomal formulation provided an approximately 250-fold higher ropivacaine concentration in the surgical wound (mean difference, 3783 ng/mL; 95% CI, 1708-5858; P = 0.001) and an approximately 25-fold higher wound:plasma ropivacaine concentration ratio (mean difference, 126; 95% CI 38-213; P = 0.011). CONCLUSIONS: Proliposomal ropivacaine exerted prolonged anesthesia with delayed elimination, typical for liposomal drugs. The advantage of this novel proliposomal ropivacaine is its ease of preparation and its extended shelf-stability (>2 years) at room temperature.

Proliposomal Ropivacaine Oil: Pharmacokinetic and Pharmacodynamic Data After Subcutaneous Administration in Volunteers.

BACKGROUND: Slow-release liposomal formulations of local anesthetics prolong plasma redistribution and reduce peak plasma drug concentration, allowing safer administration of larger doses and further prolonging sensory effects. However, their clinical applicability is limited by expensive manufacture and liposomal leakage. Previously, we described the simple preparation of a novel proliposomal ropivacaine oil that produces multilamellar liposomal vesicles on exposure to aqueous media and that has a shelf-life of >2 years at room temperature. In this study, we present both pharmacodynamic and pharmacokinetic data in healthy volunteers after subcutaneous injection of this novel proliposomal preparation of ropivacaine. METHODS: In the pharmacodynamic phase of this study, 15 volunteers received 3 separate subcutaneous injections of 2.5 mL containing 1 of the following drugs: proliposomal 4% ropivacaine, plain 0.5% ropivacaine, and the ropivacaine-free proliposomal vehicle. Drugs were administered into the lower back, and their location was randomized and blinded; a separate area was used as an uninjected, open control. Experimental sensory assessment was made at repeated intervals over 72 hours using both pinprick sensation and experimental heat pain tolerance (assessed using quantitative sensory testing). In a separate pharmacokinetic phase of this study, 9 volunteers received subcutaneous injections of 2.5 mL of either proliposomal 4% ropivacaine (n = 6) or plain 0.5% ropivacaine (n = 3); these participants had plasma ropivacaine concentrations assessed at repeated intervals over 72 hours. RESULTS: The mean ± SE duration of pinprick anesthesia after proliposomal and plain ropivacaine administration lasted 28.8 ± 6.0 and 15.9 ± 3.5 hours, respectively (mean difference, 16.8 hours; 95% confidence interval, 10.0-23.7; P = 0.001). For experimental heat pain, the anesthesia duration was approximately 36 and 12 hours, respectively, with mean ± SE area under the curve of the normalized heat pain tolerance over time 55.0 ± 28.8 Δ°C·min for proliposomal ropivacaine and 9.6 ± 26.0 Δ°C·min for plain ropivacaine (mean difference, 64.6 Δ°C·min; 95% confidence interval, 10.2-119.0; P = 0.036). In the pharmacokinetic study, there was no significant difference in peak plasma concentration in the proliposomal ropivacaine group (164 ± 43 ng/mL compared with 100 ± 41 ng/mL in the plain ropivacaine group; P = 0.07) despite an 8-fold increase in ropivacaine dose in the proliposomal group. The 99% upper prediction limit for peak plasma concentrations (351 ng/mL proliposomal; 279 ng/mL plain) was well below the putative toxic plasma concentration for both groups. The mean ± SE terminal half-life and area under the curve for proliposomal ropivacaine versus plain ropivacaine were 13.8 ± 3.6 hours vs 5.9 ± 2.3 hours (P = 0.011) and 5090 ± 1476 h·ng/mL vs 593 ± 168 h·ng/mL (P = 0.0014), respectively. CONCLUSIONS: The prolonged pharmacodynamic effect of proliposomal ropivacaine, together with its delayed elimination and prolonged redistribution to plasma, is compatible to depot-related slow-release and similar to the performance of other liposomal local anesthetics. The advantage of the proliposomal oil is its ease of preparation and its extended shelf-stability at room temperature.

High Success Rates Using Ultrasound for Neuraxial Block in Obese Patients.

BACKGROUND: Successful neuraxial block performance relies on assessment and palpation of surface landmarks, potentially challenging in patients with a high body mass index (BMI). OBJECTIVES: To evaluate the use of ultrasound-assisted neuraxial bock in a non-obstetric population with BMI above versus below 30 kg/m2. METHODS: Healthy adult patients undergoing extracorporeal shock wave lithotripsy (ESWL) under neuraxial block were observed in this quality assurance study. Prior to the neuraxial block, an ultrasound examination was performed to identify the puncture site. Neuraxial anesthesia block was performed under aseptic surgical conditions with the patient in the sitting position. Following block placement, external landmarks were palpated. Our primary study outcome was the number of attempts (skin insertions with the needle) after pre-puncture ultrasound identification of the insertion point, comparing patients with BMI above versus below 30 kg/m2. Our secondary outcome was assessment by palpation of external anatomical landmarks. RESULTS: Our study group included 63 consecutive patients undergoing neuraxial block for ESWL. Data were assessed according to BMI (above versus below 30 kg/m2). An overall success rate at the first attempt of 90.5% (CI 0.8-0.95) was achieved using ultrasound-guided neuraxial block. This block placement success rate was similar for all patients, regardless of BMI above versus below 30 kg/m2. In contrast, the ease of palpation of anatomic landmarks, P = 0.001, and the ease of palpation of iliac crest, P < 0.001, differed significantly between the patients above versus below 30 kg/m2. The reported verbal pain scores (VPS) due to block insertion was similar among all patients regardless of BMI category (above versus below 30 kg/m2). CONCLUSIONS: We observed high success rates when ultrasound-assisted neuraxial block is performed, regardless of BMI above versus below 30 kg/m2, despite expected differences in surface landmark palpation.

Prevention of urinary tract infections with vaccinium products.

Cranberries exert a dose-dependent inhibition of the adherence of E. coli fimbriae to uroepithelial cells. This was demonstrated in vitro but also ex vivo in vitro with urine from cranberry consumers. The active principle has not been identified in detail but type-A proanthocyanidins (PAC) play an important role in the mechanism of action. Since the three species, American cranberry (Vaccinium macrocarpon), European cranberry (Vaccinium oxycoccus) and/or lingonberry (Vaccinium vitis-idaea), have different patterns of type-A PACs, results from one species cannot be transferred to the others. It seems likely that most of the studies with monopreparations from V. macrocarpon were underdosed. Whereas photometric PAC quantification may overestimate the true content on co-active compounds, reversed phase high-performance liquid chromatograpy may underestimate them. Recent studies with PAC doses in the upper range (DMAC method) or declared type-A PAC content in the daily dose reveal a dose-dependent trend of clinical effectiveness, however, with a possible ceiling effect. In order to clarify this, future three-arm studies should investigate Vaccinium preparations with higher type-A PAC doses than previously used. We analysed two popular European vitis-idaea products, a mother juice and a proprietary extract. Both preparations may be appropriate to confirm the Vaccinium urinary tract infection-preventive effect beyond doubt.

Vapor Pressure, Vaping, and Corrections to Misconceptions Related to Medical Cannabis' Active Pharmaceutical Ingredients' Physical Properties and Compositions.

Medical cannabis products contain dozens of active pharmaceutical ingredients (APIs) derived from the cannabis plant. However, their actual compositions and relative doses significantly change according to the production methods. Product compositions are strongly dependent on processing step conditions and on components' evaporation during those steps. Review of the documentation presented to caregivers and to patients show erroneous data or misinterpretation of data related to the evaporation, for example, cannabinoids' boiling points, as well as confusions between terms, such as boiling, vaporization, and evaporation. Clarifying these aspects is essential for caregivers, for researchers, and for developers of manufacturing processes. Original and literature data were analyzed, comparing composition changes during various processing steps and correlating the extent of change to components' vapor pressures at the corresponding temperature. Evaporation-related composition changes start at temperatures as low as those of drying and curing and become extensive during decarboxylation. The relative rate of components' evaporation is determined by their relative vapor pressure and monoterpenes are lost first. On vaping, terpenes are inhaled before cannabinoids do. Commercial medical cannabis products are deficient in terpenes, mainly monoterpenes, compared with the cannabis plants used to produce them. Terms, such as "whole plant" and "full spectrum," are misleading since no product actually reflects the original cannabis plant composition. There are important implications for medical cannabis manufacturing and for the ability to make the most out of the terpene API contribution. Medical cannabis products' composition and product delivery are controlled by the relative vapor pressure of the various APIs. Quantitative data provided in this study can be used for improvement to reach better accuracy, reproducibility, and preferred medical cannabis compositions.

Selected cannabis terpenes synergize with THC to produce increased CB1 receptor activation.

The cannabis plant exerts its pharmaceutical activity primarily by the binding of cannabinoids to two G protein-coupled cannabinoid receptors, CB1 and CB2. The role that cannabis terpenes play in this activation has been considered and debated repeatedly, based on only limited experimental results. In the current study we used a controlled in-vitro heterologous expression system to quantify the activation of CB1 receptors by sixteen cannabis terpenes individually, by tetrahydrocannabinol (THC) alone and by THC-terpenes mixtures. The results demonstrate that all terpenes, when tested individually, activate CB1 receptors, at about 10-50% of the activation by THC alone. The combination of some of these terpenes with THC significantly increases the activity of the CB1 receptor, compared to THC alone. In some cases, several fold. Importantly, this amplification is evident at terpene to THC ratios similar to those in the cannabis plant, which reflect very low terpene concentrations. For some terpenes, the activation obtained by THC- terpene mixtures is notably greater than the sum of the activations by the individual components, suggesting a synergistic effect. Our results strongly support a modulatory effect of some of the terpenes on the interaction between THC and the CB1 receptor. As the most effective terpenes are not necessarily the most abundant ones in the cannabis plant, reaching "whole plant" or "full spectrum" composition is not necessarily an advantage. For enhanced therapeutic effects, desired compositions are attainable by enriching extracts with selected terpenes. These compositions adjust the treatment for various desired medicinal and personal needs.

Nociception and pain in humans lacking a functional TRPV1 channel.

BACKGROUNDChronic pain is a debilitating illness with currently limited therapy, in part due to difficulties in translating treatments derived from animal models to patients. The transient receptor potential vanilloid 1 (TRPV1) channel is associated with noxious heat detection and inflammatory pain, and reports of adverse effects in human trials have hindered extensive efforts in the clinical development of TRPV1 antagonists as novel pain relievers.METHODSWe examined 2 affected individuals (A1 and A2) carrying a homozygous missense mutation in TRPV1, rendering the channel nonfunctional. Biochemical and functional assays were used to analyze the mutant channel. To identify possible phenotypes of the affected individuals, we performed psychophysical and medical examinations.RESULTSWe demonstrated that diverse TRPV1 activators, acting at different sites of the channel protein, were unable to open the cloned mutant channel. This finding was not a consequence of impairment in the expression, cellular trafficking, or assembly of protein subunits. The affected individuals were insensitive to application of capsaicin to the mouth and skin and did not demonstrate aversive behavior toward capsaicin. Furthermore, quantitative sensory testing of A1 revealed an elevated heat-pain threshold but also, surprisingly, an elevated cold-pain threshold and extensive neurogenic inflammatory, flare, and pain responses following application of the TRPA1 channel activator mustard oil.CONCLUSIONOur study provides direct evidence in humans for pain-related functional changes linked to TRPV1, which is a prime target in the development of pain relievers.FUNDINGSupported by the Israel Science Foundation (368/19); Teva's National Network of Excellence in Neuroscience grant (no. 0394886) and Teva's National Network of Excellence in Neuroscience postdoctoral fellowship.

Terpene-Enriched CBD oil for treating autism-derived symptoms unresponsive to pure CBD: Case report.

Cannabidiol (CBD) rich products are successfully used in some countries for treating symptoms associated with autism spectrum disorder (ASD). Yet, CBD provides insufficient intervention in some individuals, or for some characterizing symptoms of ASD, raising the need for improved compositions. The current study presents a case wherein pure CBD was sufficient for treating ASD during childhood and early adolescence. However, it became insufficient during puberty accompanied by increased hyperactivity, agitation, and frequent severe aggressive behavior. Increasing the CBD dose did not result in significant improvement. Enriching the pure CBD with a carefully selected blend of anxiolytic and calming terpenes, resulted in gradual elimination of those aggressive events. Importantly, this was achieved with a significantly reduced CBD dose, being less than one-half the amount used when treating with pure CBD. This case demonstrates a strong improvement in efficacy due to terpene enrichment, where pure CBD was not sufficient. Combined with terpenes' high safety index and the ease with which they can be incorporated into cannabinoid-containing products, terpene-enriched CBD products may provide a preferred approach for treating ASD and related conditions. The careful selection of terpenes to be added enables maximizing the efficacy and tailoring the composition to particular and changing needs of ASD subjects, e.g., at different times of the day (daytime vs nighttime products).

High-dose bupivacaine remotely loaded into multivesicular liposomes demonstrates slow drug release without systemic toxic plasma concentrations after subcutaneous administration in humans.

BACKGROUND: Depot formulations prolong the analgesic effect of local anesthetics and reduce peak plasma drug concentration. This allows for safer administration of larger doses of local anesthetics, which further prolongs the duration of analgesic effect. We previously reported the development of large multivesicular vesicles (LMVVs) remotely loaded with bupivacaine (LMVV liposomal bupivacaine) and demonstrated a >5-fold prolongation of analgesic effect in animals and humans. In this study, we present pharmacokinetic data of LMVV liposomal bupivacaine in humans. METHODS: Healthy volunteers received subcutaneous injections of 20 mL plain 0.5% bupivacaine and, 1 week later, 20 mL of 2% LMVV liposomal bupivacaine in a prospective, open-label, crossover, controlled study. RESULTS: Eight subjects were studied. No subjective side effects of local anesthetics were observed. The maximal plasma concentration and the time to achieve maximal plasma concentration were assessed by modeling plasma concentration-time profiles. Maximal plasma concentration was not significantly different between groups (0.87 +/- 0.45 microg/mL and 0.83 +/- 0.34 microg/mL for plain and liposomal bupivacaine, respectively; P = not significant, 0.83). These values are well below the putative toxic plasma concentration of 2 to 4 microg/mL. Time to achieve maximal plasma concentration was 7-fold greater for the liposomal preparation (262 +/- 149 minutes vs 37.5 +/- 16 minutes, P < 0.01). CONCLUSIONS: Peak plasma bupivacaine concentrations were not different in the 2 groups, despite a 4-fold increase in total bupivacaine dose administered in the novel liposomal preparation. The delayed elimination and prolonged redistribution of liposomal bupivacaine to plasma is compatible with the depot-related slow-release effect leading to the prolonged pharmacodynamic effect previously reported.

Magnetic resonance imaging findings after uneventful continuous infusion neuraxial analgesia: a prospective study to determine whether epidural infusion produces pathologic magnetic resonance imaging findings.

BACKGROUND: Magnetic resonance imaging (MRI) is considered the preferred diagnostic tool to determine whether postepidural neurologic symptoms are due to hematoma or abscess. However, there is currently no published information regarding the normal appearance of a MRI after a continuous epidural infusion. In this prospective cohort study, we defined the characteristic appearance of MRI findings after uneventful epidural analgesia. METHODS: Thirty women were prospectively enrolled to undergo a lumbar MRI after labor and delivery. The study group consisted of 15 women who received neuraxial analgesia with a combined spinal epidural technique followed by continuous epidural infusion, whereas the control group included 15 women who delivered without receiving neuraxial analgesia. All patients received a MRI within 12 h of delivery via a 1.5T scanner. MRIs were reviewed by two neuroradiologists who were blinded to the patient's study group allocation and asked to document the presence or absence of fluid collection, air collection, or soft tissue abnormalities. RESULTS: There were no radiologically significant fluid collections, hematomas, or mass effects noted on the thecal sac of any of the 30 MRI studies. A small amount of epidural air was seen in 77% of MRI studies after epidural analgesia, but there was no indention on the thecal sac. CONCLUSIONS: The lack of significant collections or mass effects seen in the MRIs of our patients after continuous infusion of epidural analgesia suggests that the presence of these findings in a patient with new neurologic symptoms after administration of epidural analgesia should be considered pathologic and warrant immediate attention.

Pharmacokinetic investigation of synthetic cannabidiol oral formulations in healthy volunteers.

Recent advances in the research of medicinal cannabis has placed the non-intoxicating cannabinoid cannabidiol (CBD) at the front of scientific research. The reasons behind this popularity is the compound's therapeutic properties, alongside a safe profile of administration lacking addictive properties such as euphoric state of mind and a wide dosing range. Oral administration of CBD is challenging due to poor solubility in the gastro-intestinal system and susceptibility to extensive first pass metabolism. As a result, the practice in clinic and investigational trials is to administer cannabinoids in edible oils or oil-based solutions. Nonetheless, reported pharmacokinetics of cannabinoids and CBD in particular are not uniform among research groups and are affected by the vehicle of administration. The purpose of the work presented here is to investigate oral absorption processes of synthetic CBD when given in different oral formulations in healthy volunteers. The study design was a three way, blind, cross-over single administration study of 12 healthy male volunteers. CBD was administered in powder form, dissolved in sesame oil and in self-nano-emulsifying drug delivery system (SNEDDS). Administration of CBD in lipid-based vehicles resulted in a significant increase in Cmax and AUC of CBD, as compared to powder form. Overall plasma exposure of CBD did not differ between sesame oil vehicle and the SNEDDS formulation. However, administration of CBD in pure oil resulted in two absorption behaviors of early and delayed absorption among subjects, as opposed to SNEDDS platform that resulted in a uniform early absorption profile. Results of this trial demonstrate the importance of solubilization process of lipophilic drugs such as CBD and demonstrated the ability of the nano formulation to achieve a reliable, predictable PK profile of the drug. These findings offer a standardized oral formulation for the delivery of cannabinoids and contribute data for the growing field of cannabinoid pharmacokinetics.

Piperine-pro-nanolipospheres as a novel oral delivery system of cannabinoids: Pharmacokinetic evaluation in healthy volunteers in comparison to buccal spray administration.

Nowadays, therapeutic indications for cannabinoids, specifically Δ9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) are widening. However, the oral consumption of the molecules is very limited due to their highly lipophilic nature that leads to poor solubility at the aqueous environment. Additionally, THC and CBD are prone to extensive first pass mechanisms. These absorption obstacles render the molecules with low and variable oral bioavailability. To overcome these limitations we designed and developed the advanced pro-nanolipospheres (PNL) formulation. The PNL delivery system is comprised of a medium chain triglyceride, surfactants, a co-solvent and the unique addition of a natural absorption enhancer: piperine. Piperine was selected due to its distinctive inhibitory properties affecting both Phase I and Phase II metabolism. This constellation self emulsifies into nano particles that entrap the cannabinoids and the piperine in their core and thus improve their solubility while piperine and the other PNL excipients inhibit their intestinal metabolism. Another clear advantage of the formulation is that its composition of materials is approved for human consumption. The safe nature of the excipients enabled their direct evaluation in humans. In order to evaluate the pharmacokinetic profile of the THC-CBD-piperine-PNL formulation, a two-way crossover, single administration clinical study was conducted. The trial comprised of 9 healthy volunteers under fasted conditions. Each subject received a THC-CBD (10.8mg, 10mg respectively) piperine (20mg)-PNL filled capsule and an equivalent dose of the oromucosal spray Sativex® with a washout period in between treatments. Single oral administration of the piperine-PNL formulation resulted in a 3-fold increase in Cmax and a 1.5-fold increase in AUC for THC when compared to Sativex®. For CBD, a 4-fold increase in Cmax and a 2.2-fold increase in AUC was observed. These findings demonstrate the potential this formulation has in serving as a standardized oral cannabinoid formulation. Moreover, the concept of improving oral bioavailability described here, can pave the way for other potential lipophilic active compounds requiring enhancement of their oral bioavailability.