Pilocarpine-Induced Effects on Salivary Secretion as a Pharmacological Biomarker for Cholinergic Parasympathetic Activation.

Pilocarpine-induced salivary secretion could serve as a nontherapeutic target engagement biomarker in a clinical setting to test the activity of an M3 positive allosteric modulator (PAM). The potentiating effect on the reactivity of the M3 receptor to the agonistic effect of pilocarpine would support the mechanism of action of an M3 PAM in a variety of therapeutic areas. The aim of this study was to determine the optimal pilocarpine dose needed for evaluation of this potentiating effect. Therefore, the effects of pilocarpine on salivary secretion rate and its pharmacokinetics were explored at single doses of 2.5, 5, and 10 mg of pilocarpine or placebo. The study also explored the test-retest variability of the pilocarpine-induced effects on salivary secretion. Pilocarpine caused a reproducible, dose-related increase in overall and maximum salivary secretion rate, in line with pilocarpine exposure. Oral doses of pilocarpine from 2.5 to 10 mg were safe and well tolerated, consistent with the published safety profile. These results support the use of pilocarpine in single-dose pharmacological challenge studies. The recommended dose for evaluating M3 PAM activity would be between 2.5 and 5 mg, showing a small increase in salivary secretion rate with room for further increase due to PAM activation.

A Three-Part, Randomised Study to Investigate the Safety, Tolerability, Pharmacokinetics and Mode of Action of BC 007, Neutraliser of Pathogenic Autoantibodies Against G-Protein Coupled Receptors in Healthy, Young and Elderly Subjects.

BACKGROUND AND OBJECTIVE: BC 007 is a substance with a novel and innovative mode of action for the first-time causal treatment of chronic heart failure, associated with the occurrence of autoantibodies against the ß1-adrenoceptor, and other diseases of mostly the heart and vascular system, being accompanied by the occurrence of functionally active agonistic autoantibodies against G-protein-coupled receptors (fGPCR-AAb). The proposed mechanism of action of BC 007 is the neutralisation of these pathogenic autoantibodies which stimulate the respective receptor. To evaluate the safety, tolerability, pharmacokinetics and mode of action of BC 007, single intravenous infusions of increasing concentration were given to healthy young males and healthy elderly autoantibody-negative and autoantibody-positive participants of both sexes. METHODS: This study was subdivided into three parts. Part A was a single-centre, randomised, double-blind, placebo-controlled safety and tolerability study including healthy young male autoantibody-negative Whites (N = 23) and Asians (N = 1), testing doses of 15, 50 and 150 mg BC 007 (Cohorts 1-3) and elderly male and female Whites (N = 8), testing a dose of 150 mg BC 007 (Cohort 4), randomly assigned in a 3:1 ratio to BC 007 or placebo. Open-label Part B included fGPCR-AAb-positive subjects (50 and 150 mg BC 007, Cohorts 1 and 2, respectively). Open-label Part C included fGPCR-AAb-positive subjects for testing doses of 300, 450, 750, 1350 mg and 1900 mg BC 007. Lower doses were either given as an infusion or divided into a bolus plus infusion up to a dose of 300 mg followed by a constant bolus of 150 mg up to a dose of 750 mg, while at doses of 1350 mg and 1900 mg it was a slow infusion with a constant infusion rate. Infusion times increased with increasing dose from 20 min (15, 50 or 150 mg) to 40 min (300, 450 or 750 mg), 75 min (1350 mg) and 105 min (1900 mg). RESULTS: The mean observed BC 007 area under the concentration-time curve (AUC0-24) increased with increasing dose in a dose proportional manner (slope estimate of 1.039). No serious adverse events were observed. Drug-related adverse events were predominantly the expected mild-to-moderate increase in bleeding time (aPTT), beginning with a dose of 50 mg, which paralleled the infusion and returned to normal shortly after infusion. fGPCR-AAb neutralisation efficiency increased with increasing dose and was achieved for all subjects in the last cohort. CONCLUSION: BC 007 is demonstrated to be safe and well tolerated. BC 007 neutralised fGPCR-AAb, showing a trend for a dose-response relationship in elderly healthy but fGPCR-AAb-positive subjects. CLINICALTRIALS. GOV REGISTRATION NUMBER: NCT02955420.

In-Vivo Degradation of DNA-Based Therapeutic BC 007 in Humans.

BACKGROUND AND OBJECTIVES: Since there is no clear evidence in the literature to show how non-modified single-stranded DNA (ssDNA) drugs are metabolized in humans, we assessed the metabolism of BC 007, an ssDNA therapeutic, under development as a neutralizer of autoantibodies against G-protein-coupled receptors. In-vitro, investigating its stability in monkey plasma and serum, a successive 3'-exonuclease degradation resulting in several n-x degradation products has been previously reported. Here, we investigated the metabolism of BC 007 in humans after intravenous application to autoantibody-positive healthy subjects, in line with Phase I safety testing. METHODS: 1H-NMR was applied for n-x degradation product search and beta-aminoisobutyric acid (bAIBA) measurement in urine; ultra-performance liquid chromatography-mass spectrometry was also used for the latter. Colorimetric assays were used for quantification of uric acid in serum and urine. RESULTS: Fast degradation prohibited the detection of the intermediate n-x degradation products in urine using 1H-NMR. Instead, NMR revealed a further downstream degradation product, bAIBA, which was also detected in serum shortly after initial application. The purine degradation product, uric acid, confirmed this finding of fast metabolism. CONCLUSION: Fast and full degradation of BC 007, shown by nucleic bases degradation products, is one of the first reports about the fate of a ssDNA product in humans.

Glycerophosphate is interchangeable with inorganic phosphate in terms of safety and serum pharmacokinetics.

OBJECTIVE: The primary aim of the present investigation was to determine and compare the pharmacokinetic (PK) profiles of inorganic phosphate in serum and urine after intravenous administration of sodium glycerophosphate and inorganic sodium phosphate. Additionally, study product safety profiles were evaluated. SUBJECTS AND METHODS: In total, 27 healthy, white volunteers (17 male/10 female) were enrolled in this double-blinded, randomized, 2-sequence, crossover study and were assigned to receive an organic test drug (sodium glycerophosphate) and an inorganic reference preparation (sodium phosphate) on 2 occasions. Validated analytical methods were used, and concentrations of total inorganic phosphate in serum and urine were determined over 24 h following a single 4-hour continuous intravenous infusion of test and reference drugs at a dose of 80 mmol. Study days were separated by washout periods of 7 days. An analysis of variance, based on population means and 90% confidence intervals (CIs), was used for testing bioequivalence (BE; range 0.8-1.25) between investigational products. RESULTS: The geometric means of the ratio of the point estimates and corresponding 90% CIs for the area under the concentration-versus-time curve of inorganic serum phosphate from 0 to 24 h (AUC(0-24)), the phosphate's maximum concentration in serum (C(max)) and the total amount of inorganic phosphate excreted in urine over 24 h corrected for individual baseline values (Ae(0-24 bc)) were estimated. The test/reference ratios for inorganic phosphate were 1.04 (CI 1.00-1.07), 0.85 (CI 0.84-0.87) and 0.84 (CI 0.77-0.92) for AUC(0-24), C(max) in serum and Ae(0-24 bc) in urine, respectively. Hence, standard BE criteria were met for AUC(0-24) and C(max) in serum, while Ae(0-24 bc) marginally failed to demonstrate BE. After drug administration, a total of 15 subjects reported the occurrence of at least 1 treatment emergent adverse event (AE). All AEs were classified as mild to moderate in severity, and the two treatment groups were equally affected. No serious AEs occurred. CONCLUSION: The serum PK profiles of inorganic phosphate were almost superimposable following intravenous administration of equimolar doses of test and reference drugs. Thus, we conclude that the two study drugs are essentially similar in terms of serum PK profiles, safety and tolerability.

Glycerophosphate does not interact with components of parenteral nutrition.

BACKGROUND/AIMS: The primary objective of this study was to determine and compare the pharmacokinetic (PK) profiles of inorganic phosphate in the serum after continuous administration of pure glycerophosphate and glycerophosphate contained in total parenteral nutrition (TPN) emulsions. This approach was selected to identify potential PK interactions between TPN components and glycerophosphate. METHODS: The serum PK profile of inorganic phosphate after continuous intravenous administration of a sodium glycerophosphate containing TPN emulsion was determined in 10 healthy, white (5 male/5 female) volunteers. A pure sodium glycerophosphate formulation served as reference. Standard criteria of bioequivalence were applied. Subjects were enrolled in the double-blinded study and were randomly allocated to receive the test and reference preparations on two occasions in a 2-sequence crossover study design. The volunteers received 1/3 of the maximum recommended body weight- (BW) adjusted intravenous daily dosage (13.3 ml/kg BW) of the test drug over a period of 8 h. The amount of total phosphate (0.101 mmol/kg) and duration of administration were identical for the test and reference drugs. Study days were separated by washout periods of at least 88 h. Serum concentrations of total inorganic phosphate were measured serially over a 36-hour period using a validated method. A statistical mixed ANOVA, based on population averages, was used for testing bioequivalence between these study preparations. RESULTS: The 90% confidence intervals (90% CIs) of inorganic phosphate in serum were calculated for the test/reference ratios of the area under the time-concentration curve from time 0 to 36 h (AUC0₋36), the maximum concentration (C(max)) and the concentration 5 min before the end of infusion (C(ss)) for a bioequivalence range from 0.80 to 1.25. The mean test/reference ratios fell completely within the 90% CIs with values of 1.016 (90% CI 1.005-1.028), 1.013 (90% CI 0.981-1.047) and 0.932 (90% CI 0.886-0.980) for AUC(0-36), C(max) and C(ss), respectively. In total, 3 mild adverse events in the reference group were detected after starting intravenous infusion, while no adverse events were observed in the test group after treatment. CONCLUSION: Primary PK parameters were within the defined bioequivalence range of 0.8-1.25. Thus, inorganic phosphate levels were essentially similar between the two investigational medicinal products tested in the present study. These findings confirm the concept that nutritional components of the test drug do not significantly interact with glycerophosphate. The two study preparations proved to be safe during the investigation.

Pharmacokinetics of articaine hydrochloride in tumescent local anesthesia for liposuction.

The aim of the investigation was to assess the pharmacokinetic characteristics and safety of articaine HCl used in tumescent local anesthesia for liposuction. Maximum plasma concentrations of articaine HCl were observed from 136 to 264 ng/mL, on average, from 1.2 to 4.3 hours after the start of infiltration, depending on the area of liposuction. The average extent of absorption ranged from 827 to 2203 ng*h/mL. Average maximum plasma concentrations of articainic acid ranged from 1719 to 7292 ng/mL. The high articainic acid concentrations at 1 hour after the start of infiltration indicate that articaine HCl was hydrolyzed rapidly by esterases in tissue and plasma. Although up to 38.2 mg/kg body weight articaine HCl was applied, no cardiac side effects or symptoms of central nervous intoxication occurred. Articaine HCl provided a safe and sufficient analgesia for tumescent liposuction.

Mechanisms of beta-adrenergic receptor-mediated venodilation in humans.

OBJECTIVES: Recent studies suggest that stimulation of beta-adrenergic receptors results in both endothelium-dependent and endothelium-independent venodilation, but results of former studies are inconsistent. This study was designed to elucidate the underlying mechanisms of isoproterenol (INN, isoprenaline)-induced venodilation by investigation of dorsal hand vein responses. METHODS: In phenylephrine-constricted veins, isoproterenol (2-514 ng/min) was infused with and without oral pretreatment with 1 g acetylsalicylic acid (n = 7) or 5 mg of the selective beta(1)-adrenergic receptor antagonist bisoprolol (n = 7). In addition, isoproterenol was coinfused with the nitric oxide inhibitor N(G)-monomethyl-l-arginine (l-NMMA) (6.3 micromol/min [n = 6]), with selective blockers of calcium (Ca(++))-dependent potassium (K(+)) channels (tetraethylammonium, 300 microg/min [n = 6]) and adenosine triphosphate (ATP)-sensitive K(+) channels (glyburide [INN, glibenclamide], 20 microg/min [n = 6]) or with the cyclic guanosine monophosphate inhibitor methylene blue (13 microg/min [n = 6]). Finally, L-NMMA was coinfused with potassium chloride (20 mmol/L) to inhibit hyperpolarization (n = 6). RESULTS: Isoproterenol induced dose-dependent venodilation to 67.4% +/- 6.8%. Oral pretreatment with bisoprolol (P =.340) or acetylsalicylic acid (P =.760) did not affect isoproterenol-induced venodilation. Coinfusion of isoproterenol and L-NMMA relaxed the veins to the same extent as in the presence of isoproterenol alone. Neither inhibition of ATP-sensitive K(+) channels (P =.196) nor blockade of Ca(++)-dependent K(+) channels (P =.640) modulated isoproterenol-induced venodilation. In contrast, methylene blue reduced the maximum response to isoproterenol by about one third (68.5% +/- 4.3% versus 41.7% +/- 5.5%, P =.001). Infusion of L-NMMA alone raised vein size to 38.8% +/- 6.5%, yielding an L-NMMA-sensitive increase of 20% (P =.001), which was antagonized by coinfusion of potassium chloride to 17.1% +/- 6.7% (P =.02). CONCLUSIONS: Isoproterenol dilates human hand veins exclusively via beta(2)-adrenergic receptors without involvement of endothelium-derived epoprostenol. Although a contribution of endothelium-derived nitric oxide appears unlikely, the venodilating effect of L-NMMA could have obscured the nitric oxide component of isoproterenol. beta(2)-Adrenergic receptor-mediated dilation is mediated in part by cyclic guanosine monophosphate-dependent mechanisms, whereas ATP- and Ca(++)-dependent K(+) channels are not involved, excluding a significant contribution of smooth muscle cell hyperpolarization. In addition, high concentrations of the nitric oxide synthase blocker L-NMMA dilate human hand veins via activation of endothelium-derived hyperpolarizing factors.