Pharmacokinetic and pharmacodynamic comparison of epinephrine, administered intranasally and intramuscularly: An integrated analysis.

BACKGROUND: Manual intramuscular epinephrine injection is the standard of care for treating severe allergic reactions and anaphylaxis. Epinephrine autoinjectors were approved on the basis of the assumption that their pharmacokinetic and pharmacodynamic profiles are equivalent to manual intramuscular injection; however, although there is emerging evidence for product-related differences in pharmacokinetic profiles, very little is known about the comparative pharmacodynamic profiles. OBJECTIVE: To compare pharmacokinetic and pharmacodynamic profiles of epinephrine delivered through manual intramuscular injection, autoinjectors, and intranasal spray. METHODS: This integrated analysis was based on data from 4 randomized cross-over phase 1 trials that compared the pharmacokinetics and pharmacodynamics of epinephrine using manual intramuscular epinephrine 0.3 mg injection, epinephrine 0.3 mg autoinjectors (Symjepi and EpiPen), and epinephrine 1 mg intranasal spray (neffy). RESULTS: Data from 175 participants showed that although neffy (1.0 mg intranasal spray) resulted in a maximum concentration (258 pg/mL) that was lower than or comparable with manual epinephrine intramuscular injection (254 pg/mL), Symjepi (438 pg/mL) and EpiPen (503 pg/mL), it led to comparable increases in systolic blood pressure (maximum effect [Emax], 16.9, 10.9, 14.9, and 18.1 mm Hg, respectively). The effect of neffy on diastolic blood pressure was also markedly more pronounced than that of other products (Emax, 9.32, 5.51, 5.78, and 5.93 mm Hg, respectively). CONCLUSION: Intranasal delivery of epinephrine using neffy increases systolic blood pressure more efficiently than do manual intramuscular injection and epinephrine autoinjectors, despite lower maximum plasma concentrations.

Biorelevant In Vitro Skin Permeation Testing and In Vivo Pharmacokinetic Characterization of Lidocaine from a Nonaqueous Drug-in-Matrix Topical System.

Recently, lidocaine topical systems utilizing nonaqueous matrices have been developed and provide efficient lidocaine delivery through the skin, such that lower concentrations of drug provide equivalent or greater drug delivery than drug-in-matrix hydrogel lidocaine patches. This study characterizes drug delivery from a nonaqueous lidocaine topical system with increasing drug load both in vitro and in vivo. Topical systems formulated with either 1.8% or 5.4% lidocaine were applied to healthy volunteers' backs (n = 15) for 12 h in a single-center, open-label, four-treatment, four-period crossover pharmacokinetic study. Subjects were dosed with either three 1.8% systems or one, two, or three 5.4% systems in each period. Blood was collected for up to 48 h, and plasma lidocaine levels were measured with a validated HPLC method. In parallel, human and mouse skin models characterized the in vitro skin permeation profile. The pharmacokinetic profile was linear between one, two, and three lidocaine 5.4% applications. Application of three lidocaine 1.8% systems (108 mg lidocaine) was bioequivalent to one lidocaine 5.4% system (108 mg lidocaine). Both topical systems remained well adhered to the skin and irritation was mild. The 5.4% system had approximately threefold higher skin permeability than the 1.8% system in the mouse and human skin models. The results indicate increasing the drug load by three times results in triple the drug delivery both in vivo and in vitro. The relationship between the in vitro permeation and in vivo absorption correlates and is nonlinear.

Bioavailability and safety of diazepam intranasal solution compared to oral and rectal diazepam in healthy volunteers.

OBJECTIVE: The study assesses the bioavailability of diazepam after intranasal administration (diazepam nasal spray) in healthy volunteers. Comparative agents were diazepam rectal gel, which served as the regulatory reference product; and oral diazepam, a product with decades of clinical use. Tolerability of diazepam nasal spray was also assessed. METHODS: This was a phase 1, open-label, randomized, single-dose, three-treatment, three-period, six-sequence crossover study in 48 healthy adult subjects that consisted of a screening period, a baseline period, and an open-label treatment period. Interperiod intervals were at least 28 days. RESULTS: Forty-eight healthy volunteer subjects were enrolled, two of whom discontinued before receiving study medication. For all routes of administration, the onset of diazepam absorption was rapid, with measurable concentrations of drug present by the first sample time point. The tmax (time to reach maximum plasma concentration) was similar for diazepam nasal spray and diazepam rectal gel, both of which were slower than oral diazepam in fasted individuals. Variability (as defined by % coefficient of variation of geometric mean) in peak plasma concentration and area under the curve0-∞ was lowest with oral diazepam, followed by diazepam nasal spray, with diazepam rectal gel showing the greatest variability. Overall, 131 treatment-emergent adverse events (TEAEs) were considered mild (42 subjects, 91.3%), four TEAEs were considered moderate (four subjects, 8.3%), and no TEAEs were considered severe. The most commonly reported TEAE was somnolence at 56.5% (26/46) during diazepam nasal spray treatment, 89.1% (41/46) with the rectal diazepam gel treatment, and 82.6% (38/46) with oral diazepam treatment. No nasal irritation was observed for the majority of the subjects at any time point after administration, with no score higher than 2 ("minor bleeding that stops within 1 minute"). SIGNIFICANCE: Diazepam nasal spray shows predicable pharmacokinetics and represents a potential novel therapeutic approach to control bouts of increased seizure activity (cluster seizures, acute repetitive seizures).

Effect of food intake on the pharmacokinetics of rivoceranib in healthy subjects.

Rivoceranib is a selective inhibitor of VEGFR-2 being developed for the treatment of solid tumor. The objective of the study was to evaluate the effect of food on bioavailability as well as single- and multiple-dose pharmacokinetics (PKs) of 81 and 201 mg doses of rivoceranib. The study was conducted as a two-part study. In Part 1 (single ascending dose (SAD), open-label, crossover study design), 2 oral doses of rivoceranib (81 mg or 201 mg) were given to all healthy subjects with a minimum 3-day washout period between dosing. Part 2 was a multiple ascending dose (MAD), open-label, crossover design where subjects were divided based on 81 and 201 mg doses. Both doses were administered with and without food in a crossover manner for the SAD and MAD parts. 24 healthy subjects completed Part 1 and 20 subjects completed Part 2. For the 81 mg dose in the SAD and MAD parts of the study, their food effect was not observed. For the 201 mg dose in both parts, food appeared to increase bioavailability by 20%-30% in Part 1, and 30%-40% in Part 2. Median tmax value was delayed when rivoceranib was administered with food at each dose level in both parts of the study. Dose proportionality was confirmed only for the AUC0-∞  value from Part 1-fasted cohort but inconclusive for Cmax  and AUC parameters under other dosing regimens. In conclusion, rivoceranib when taken with food delays tmax appears to increase bioavailability at 201 mg dose.

Absence of ethnic difference on single-dose pharmacokinetics of rivoceranib between healthy male Caucasian, Japanese, and Chinese subjects.

Rivoceranib (known in China as apatinib) is a selective vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitor which inhibits angiogenesis in solid tumors. The aim of study was to evaluate potential pharmacokinetic (PK) differences between the Caucasian, Japanese, and Chinese populations. An open-label, single-dose, parallel-design PK study of rivoceranib was conducted in Caucasian, Japanese, and Chinese subjects. A total of 18 healthy males were recruited to each group (54 total), and 201 mg rivoceranib tablets (as 250 mg rivoceranib mesylate) were administered orally to subjects. Plasma samples were collected, and rivoceranib plasma concentration was determined using LC-MS/MS. For PK analysis, non-compartmental and compartmental analyses were performed. Intrinsic factors (CYP2C19 and CYP3A4 genotype) were also examined. Non-compartmental analysis showed no significant difference in AUC0-t , AUC0-∞ , Cmax , tmax , and t1/2 . Apparent clearance and volume of distribution were different across the three populations; however, the extent of this difference does not require dose modification. For compartmental modeling, a two-compartment model was used to fit the plasma concentrations. No significant difference was observed in absorption, elimination, and intercompartmental transfer rate constants among the three groups. The present study shows no major ethnic PK differences between Caucasian, Japanese, and Chinese populations.

Pharmacokinetics of the Melanocortin Type 1 Receptor Agonist PL8177 After Subcutaneous Administration.

BACKGROUND AND OBJECTIVE: PL8177 is a selective melanocortin 1 receptor agonist in development for the treatment of various immunologic and inflammatory conditions. Here we describe the pharmacokinetics of PL8177 after subcutaneous (sc) delivery in animals and humans. METHODS: Mice, rats, and dogs were administered sc PL8177 at single doses of 1.0 and 3.0 mg/kg (mice); 1.0, 5.0, and 25.0 mg/kg/day (rats); or 1.5, 8.0, and 40.0 mg/day (dogs). Blood was collected over 24 h (mice) or 28 days (rats and dogs). Safety and pharmacokinetics of single and multiple sc doses were also examined in human volunteers. Two dose levels were tested in two dosing cohorts of 1.0 and 3.0 mg/day for 7 days. Blood samples were collected through Day 1 and on Days 2 to 6 at peak and trough times based on analysis of the first two single-dose cohorts. RESULTS: In mice, 3 mg/kg PL8177 resulted in an area under the plasma concentration-time curve from 0 to infinity (AUC∞) of 1727 ng·h/mL, a maximum plasma concentration (Cmax) of 2440 ng/mL, an elimination half-life (t½) of 0.5 h, and a time to maximum concentration (tmax) of 0.25 h. Results for the 1-mg/kg dose were generally proportional. In rats, mean tmax values were independent of dose and ranged from 0.25 to 1.0 h for single and multiple dosing. Cmax values ranged from 516 to 695 ng/mL (1-mg/kg dose) and from 666 to 1180 ng/mL (25-mg/kg dose). In dogs, mean tmax values ranged from 0.4 to 1.3 h for single and multiple dosing. Values for tmax decreased with increasing dose and mean plasma Cmax increased less than dose proportionally (96-129 ng·h/mL [1.5 mg], 275-615 ng·h/mL [8.0 mg], and 633-1280 ng·h/mL [40.0 mg]). In humans, PL8177 was observed in the plasma within 15 min after a single dose and persisted for up to 48 h at higher doses. The tmax was 30-45 min (single dose) and 15-45 min (multiple doses). In multiple-dose studies, maximum steady-state plasma concentration (Cmax,ss) and AUC∞ increased with dose. Geometric mean Cmax,ss values were 20.1 ng/mL (1.0 mg) and 57.2 ng/mL (3.0 mg). AUC∞ values were 54.3 ng·h/mL (1.0 mg) and 199 ng·h/mL (3.0 mg). Unchanged PL8177 excreted in the urine was ≤ 1%, and accumulation was minimal. CONCLUSION: PL8177 administration resulted in a consistent pharmacokinetic profile. The measured exposure levels resulted in pharmacologically active PL8177 concentrations at the targeted MC1R. Rapid absorption was seen in healthy volunteers, and multiple-dose administration over 7 days resulted in pharmacokinetic characteristics similar to those observed after single-dose administration. Results support the continued development of PL8177 to treat immunologic and inflammatory conditions.

Evaluation of Pharmacokinetics and Dose Proportionality of Diazepam After Intranasal Administration of NRL-1 to Healthy Volunteers.

NRL-1 is a novel intranasal formulation of diazepam that is being evaluated as rescue medication in patients with epilepsy who experience bouts of increased seizure activity despite stable regimens of antiepileptic drugs. This phase 1, open-label, randomized, crossover study in healthy adult volunteers consisted of 3 single-dose periods (5, 10, and 20 mg) followed by a 2-dose period (2 × 10 mg) with a minimum 28-day washout between treatments. Blood samples were taken at prespecified time points after intranasal dosing, and bioanalytic analysis of diazepam and nordiazepam was conducted using a validated liquid chromatography-tandem mass spectrometry method. Plasma pharmacokinetic parameters were summarized using descriptive statistics, and dose proportionality (peak concentration [Cmax ] and area under the plasma concentration-time curve [AUC0-∞ ]) was evaluated based on a power model within a 90%CI of 0.84 to 1.16. Comparisons were also conducted between single 10-mg dose and multidose (2 × 10 mg) treatments. NRL-1 administration resulted in rapid diazepam absorption (median time to peak concentration 1.4-1.5 hours). Plasma concentration-time profiles showed similar patterns of exposure that appeared to be dose dependent, with Cmax of 85.6, 133.6, and 235.3 ng/mL for the 5-, 10-, and 20-mg doses, respectively, although the lower 90%CI for Cmax and AUC0-∞ exceeded dose proportionality criteria. The coefficient of variation ranged from 59% to 67% for Cmax and 48% to 56% for AUC parameters. Dose-normalized AUC0-∞ values were comparable between the 2 × 10-mg and single 10-mg doses. Treatment-emergent adverse events were consistent with those expected for diazepam, with transient somnolence the most frequent adverse event (94.4%). These results support NRL-1 as a potential therapy for managing seizure emergencies.

Pharmacokinetics of the dipeptidyl peptidase 4 inhibitor saxagliptin in rats, dogs, and monkeys and clinical projections.

Saxagliptin is a potent, selective, reversible dipeptidyl peptidase 4 (DPP4) inhibitor specifically designed for extended inhibition of the DPP4 enzyme and is currently under development for the treatment of type-2 diabetes. The pharmacokinetics of saxagliptin were evaluated in rats, dogs, and monkeys and used to predict its human pharmacokinetics. Saxagliptin was rapidly absorbed and had good bioavailability (50-75%) in the species tested. The plasma clearance of saxagliptin was higher in rats (115 ml/min/kg) than in dogs (9.3 ml/min/kg) and monkeys (14.5 ml/min/kg) and was predicted to be low to moderate in humans. The plasma elimination half-life was between 2.1 and 4.4 h in rats, dogs, and monkeys, and both metabolism and renal excretion contributed to the overall elimination. The primary metabolic clearance pathway involved the formation of a significant circulating, pharmacologically active hydroxylated metabolite, M2. The volume of distribution values observed in rats, dogs, and monkeys (1.3-5.2 l/kg) and predicted for humans (2.7 l/kg) were greater than those for total body water, indicating extravascular distribution. The in vitro serum protein binding was low (< or =30%) in rats, dogs, monkeys, and humans. After intra-arterial administration of saxagliptin to Sprague-Dawley and Zucker diabetic fatty rats, higher levels of saxagliptin and M2 were observed in the intestine (a proposed major site of drug action) relative to that in plasma. Saxagliptin has prolonged pharmacodynamic properties relative to its plasma pharmacokinetic profile, presumably due to additional contributions from M2, distribution of saxagliptin and M2 to the intestinal tissue, and prolonged dissociation of both saxagliptin and M2 from DPP4.

A selective small molecule agonist of the melanocortin-1 receptor inhibits lipopolysaccharide-induced cytokine accumulation and leukocyte infiltration in mice.

It is well established that melanocortins are peptides that have potent anti-inflammatory activity. Recent research has focused on understanding which of the known melanocortin receptors mediates the anti-inflammatory actions of the melanocortins. The aim of this study was to assess the anti-inflammatory activity of a synthetic MC-1R agonist. BMS-470539 is a potent, selective, full agonist of human and murine MC-1R with EC(50) values in a cAMP accumulation assay of 16.8 and 11.6 nM, respectively. BMS-470539 dose-dependently inhibited TNF-alpha-induced activation of a NF-kappaB transcriptional reporter in human melanoma cells, which endogenously express MC-1R. In vivo studies with BMS-470539 demonstrated that subcutaneous administration of BMS-470539 resulted in a dose-dependent inhibition of LPS-induced TNF-alpha production in BALB/c mice. In this model, the compound had an ED(50) of approximately 10 micromol/kg and a pharmacodynamic half-life of approximately 8 h. Pharmacokinetic analysis of the compound indicated that the compound had a t(1/2) of 1.7 h. In a model of lung inflammation, administration of 15 micromol/kg BMS-470539 resulted in a 45% reduction in LPS-induced leukocyte infiltration (an infiltrate comprised primarily of neutrophils). The compound was also effective in a model of delayed-type hypersensitivity, reducing paw swelling by 59%, comparable with that seen with 5 mg/kg dexamethasone. These studies demonstrate that a selective small molecule agonist of the melanocortin-1 receptor is a potent anti-inflammatory agent in vivo and provides compelling evidence for the involvement of this receptor in the modulation of inflammation.

Biphenylsulfonamide endothelin receptor antagonists. 4. Discovery of N-[[2'-[[(4,5-dimethyl-3-isoxazolyl)amino]sulfonyl]-4-(2-oxazolyl)[1,1'-biphenyl]- 2-yl]methyl]-N,3,3-trimethylbutanamide (BMS-207940), a highly potent and orally active ET(A) selective antagonist.

We have previously disclosed the selective ET(A) receptor antagonist N-(3,4-dimethyl-5-isoxazolyl)-4'-(2-oxazolyl)[1,1'-biphenyl]-2-sulfonamide (1, BMS-193884) as a clinical development candidate. Additional SAR studies at the 2'-position of 1 led to the identification of several analogues with improved binding affinity as well as selectivity for the ET(A) receptor. Following the discovery that a 3-amino-isoxazole group displays significantly improved metabolic stability in comparison to its 5-regioisomer, the 3-amino-isoxazole group was combined with the optimal 2'-substituent leading to 16a (BMS-207940). Compound 16a is an extremely potent (ET(A) K(i) = 10 pM) and selective (80,000-fold for ET(A) vs ET(B)) antagonist. It is also 150-fold more potent and >6-fold more selective than 1. The bioavailability of 16a was 100% in rats and the systemic clearance and volume of distribution are higher than that of 1. In rats, intravenous 16a blocks big ET pressor responses with 30-fold greater potency than 1. After oral dosing at 3 micromol/kg, 16a displays enhanced duration relative to 1.

Exploration of structure-activity relationships at the two C-terminal residues of potent 11mer Glucagon-Like Peptide-1 receptor agonist peptides via parallel synthesis.

We report the identification of potent agonists of the Glucagon-Like Peptide-1 receptor (GLP-1R) via evaluation of two positional scanning libraries and a two-dimensional focused library, synthesized in part on SynPhase Lanterns. These compounds are 11 amino acid peptides containing several unnatural amino acids, including (in particular) analogs of biphenylalanine (Bip) at the two C-terminal positions. Typical activities of the most potent peptides in this class are in the picomolar range in an in vitro functional assay using human GLP-1 receptor.

Eleven amino acid glucagon-like peptide-1 receptor agonists with antidiabetic activity.

Glucagon-like peptide 1 (GLP-1) is a 30 or 31 amino acid peptide hormone that contributes to the physiological regulation of glucose homeostasis and food intake. Herein, we report the discovery of a novel class of 11 amino acid GLP-1 receptor agonists. These peptides consist of a structurally optimized 9-mer, which is closely related to the N-terminal 9 amino acids of GLP-1, linked to a substituted C-terminal biphenylalanine (BIP) dipeptide. SAR studies resulted in 11-mer GLP-1R agonists with similar in vitro potency to the native 30-mer. Peptides 21 and 22 acutely reduced plasma glucose excursions and increased plasma insulin concentrations in a mouse model of diabetes. These peptides also showed sustained exposures over several hours in mouse and dog models. The described 11-mer GLP-1 receptor agonists represent a new tool in further understanding GLP-1 receptor pharmacology that may lead to novel antidiabetic agents.

Design, synthesis, and structure-activity relationships of tetrahydroquinoline-based farnesyltransferase inhibitors.

Tetrahydroquinoline-based small molecule inhibitors of farnesyltransferase (FT) have been identified. Lead compounds were shown to have nanomolar to sub-nanomolar activity in biochemical assays with excellent potency in a Ras-mutated cellular reversion assay. BMS-316810 (9e), a 0.7 nM FT inhibitor, was orally-active in a nude mouse tumor allograft efficacy study.