Pharmacokinetics and subjective effects of 1P-LSD in humans after oral and intravenous administration

Buy 1P-Lsd online, 1-Propanoyl-lysergic acid diethylamide (1P-LSD) appeared as a non-controlled alternative to LSD a few years ago. Although evidence is beginning to emerge from in vitro and animal studies that 1P-LSD might serve as a prodrug for LSD, an equivalent evaluation in humans is unavailable. Controlled oral and intravenous self-administrations of 100 μg 1P-LSD hemitartrate are reported in two human volunteers followed by analyses of urine and serum samples using a fully validated LC–MS/MS method. Psychometric evaluations included assessment of selected subjective drug effects and administration of the Five-Dimensions of Altered States of Consciousness rating scale (5D-ASC). In serum and urine, oral administrations of 1P-LSD only led to the detection of LSD reflecting biphasic elimination with a terminal elimination half-life of approx. t1/2 = 6.4 h. 1P-LSD could be detected for only up to 4.16 h in serum and 2.7 h in urine following intravenous administration, whereas LSD was detected in all serum samples (last sampling after approx. 24 h) and up to 80 h in urine. LSD showed first order elimination kinetics with an approx. t1/2 = 5.7 h, whereas 1P-LSD showed a rapid decrease in concentration within the first hour followed by a slower decrease, most probably due to hydrolysis. The bioavailability of LSD after oral ingestion of 1P-LSD was close to 100%. The psychosensory effects of 1P-LSD and their time course were comparable to those seen after uptake of LSD in other studies which further supports the prodrug hypothesis. The 5D-ASC scores were higher after oral compared with intravenous administration of 1P-LSD.


Lysergic acid diethylamide (LSD) soon became a widely used experimental drug after Albert Hofmann discovered its psychoactive effects in 1943. The ability to induce psychoactive effects at low doses (< 100 μg) and the finding that it interacted with the serotonergic system, triggered wide-ranging research into the neurotransmitter system at the time.1 LSD induces a wide spectrum of psychotropic effects, including euphoria or dysphoria, hallucinatory phenomena, synesthesia, perceptual alterations, remembrance of significant life events, mystical experiences, ego-dissolution, and cathartic experiences. Deep-reaching insightful experiences, but also anxiety-producing experiences were described by users.2 LSD was also used in psychotherapy.3 Nearly ten thousand scientific papers on experiments with LSD have been published since the 1950s (cf.4). In the mid-1960s, LSD became a major drug of abuse. Since the 1970s, its recreational use became more widespread internationally without loss of popularity ever since (cf.5). Buy 1P-Lsd online

Several analogs of LSD have been explored in scientific research68 and in more recent years, a number of LSD derivatives have emerged on the market that did not appear to have any established history in the scientific literature. One of these LSD derived “designer drugs” is 1-propanoyl-LSD (1P-LSD) that was first reported to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) in 2015.9 Anecdotal reports published on various Internet forums suggested 1P-LSD to show LSD-like effects but formal studies were not available. However, 1P-LSD was shown to display LSD-like effects in mice when using the head-twitch response (HTR) assay and it was confirmed that pretreatment with the selective 5-HT2A antagonist M100,907 blocked the HTR.10 The binding affinity of 1P-LSD to cloned human 5-HT1A and 5-HT2A receptors dropped 67- and 13-fold but increased by a factor of 3.5 at the human 5-HT2C receptor when compared with LSD. Furthermore, when measuring 5-HT2A receptor activation (Gq-mediated Ca2+ flux in HEK cells), it was revealed that 1P-LSD (and two other 1-acyl-LSD derivatives) only functioned as very weak partial agonists and antagonists, whereas no agonist activity was observed at 5-HT2B and 5-HT2C receptors.11

In vitro studies assessing the metabolic stability of 1P-LSD and other 1-acyl substituted lysergamides showed the formation of LSD12 which suggested that 1P-LSD and other lysergamides acylated at the indole nitrogen atom might function as a prodrug. Consistent with this observation, the subcutaneous administration of 1P-LSD (0.1 or 0.3 mg/kg) to male Sprague–Dawley rats led to the detection of LSD and LSD metabolites when plasma samples were analyzed taken 15 min later which suggested the appearance of rapid hydrolysis in vivo.11

Although the pharmacokinetic (PK) and pharmacodynamic (PD) properties of LSD in humans have been thoroughly investigated,21316 data of this kind are still missing for 1P-LSD. Moreover, within the context of forensic toxicology, PK data will provide important information on casework. For example, in a recent intoxication case reportedly involving the ingestion of a 1P-LSD blotter, the implementation of urine and serum analyses only revealed the presence of LSD but without the detection of any 1P-LSD.17 Thus, this case report provided support for the hypothesis that 1P-LSD might also act as a prodrug in humans. However, it also revealed a new challenge when attempting to differentiate between intake of 1P-LSD and LSD. In order to address this knowledge gap, a controlled self-administration study was conducted that involved one oral (p.o.) and one intravenous (i.v.) administration of 100 μg 1P-LSD hemitartrate to two human volunteers. The study included analyses of urine and serum samples and the determination of subjective effects in order to investigate PK and PD properties of the drug and to assess whether 1P-LSD was indeed a prodrug in humans. Buy 1P-Lsd online


2.1 Chemicals and reagents

Boric acid (H3BO3, for molecular biology, 99.8%) was obtained from AppliChem (Darmstadt, Germany), whereas potassium chloride (KCl ≥ 99.5%, p.a.), formic acid (HCOOH, > 98%, p.a.), and propan-2-ol (Rotisolv®, ≥ 99.95%, LC–MS grade) were obtained from Carl Roth (Karlsruhe, Germany). 1-Chlorobutane (C4H9Cl, LiChrosolv®, for liquid chromatography) and sodium carbonate (Na2CO3, anhydrous, for analysis) were purchased from Merck (Darmstadt, Germany). Methanol (MeOH, Chromasolv™, LC–MS, ≥ 99.9%) was obtained from Honeywell Riedel-de Haën (Seelze, Germany), and deionized water (H2O) was prepared in-house using a Medica® Pro single high flow purification system from ELGA LabWater (Celle, Germany). Ammonium formate (10 M, 99.995%) and acetonitrile (ACN, HPLC-Super gradient grade) were obtained from Sigma Aldrich (Steinheim, Germany) and VWR International (Fontenay-sous-Bois, France), respectively. Hydrochloric acid (HCl, 3.7%) and sodium hydroxide solution (NaOH, 1%) were part of an enzyme kit (Schlüter-Enzym-Kit) obtained from Schlüter Biologie (Neudorf, Germany). 1P-LSD hemitartrate (2:1) was provided by Synex Synthetics BV (Maastricht, the Netherlands) (> 98%; residual LSD content < 1‰) and LSD was purchased from LGC Standards (Wesel, Germany). The internal standard (IS) LSD-D3 was obtained from Cerilliant (Round Rock, TX, USA). Drug free urine and serum specimens were collected from volunteers for calibration purposes.

2.2 Solutions

The borate buffer solution (pH 9) was prepared by adding 370 mL of solution 1 (consisting of 106 g Na2CO3 dissolved in 1.0 L deionized water) to 630 mL of solution 2 (consisting of 61.8 g H3BO3 and 74.6 g KCl in 1.0 L deionized water). If necessary, the pH was adjusted by further adding solution 1. Mobile phase A consisted of deionized water with 1% ACN, 0.1% formic acid, and 2 mM ammonium formate. Mobile phase B consisted of 0.1% formic acid and 2 mM ammonium formate in ACN. Stock (10 μg/mL) and working solutions (50 ng/mL and 5 ng/mL) of 1P-LSD hemitartrate and LSD were prepared in ACN (concentrations refer to the base form). The internal standard (IS) solution contained LSD-D3 at a concentration of 500 ng/mL in ACN. A separate solution of 1P-LSD hemitartrate in EtOH with a concentration of 1.0 mg/mL was prepared for the controlled self-administration study (here, the concentration refers to 1P-LSD hemitartrate). The diluted HCl solution was prepared by dilution of the 3.7% HCl solution in two steps: 4 mL of the 3.7% HCl solution was mixed with 10 mL deionized water and 5 mL of this solution was further diluted with 1 mL of deionized water (resulting pH: approx. 1). The diluted NaOH solution was obtained by addition of four drops of the 1% NaOH solution to 10 mL of deionized water (resulting pH: approx. 8). Buy 1P-Lsd online

2.3 Sample preparation and method validation

Sample preparation and analysis were performed using a fully validated method described elsewhere.17 The sample preparation consisted of a liquid–liquid extraction with 1-chlorobutane. The limit of detection (LOD) and the lower limit of quantification (LLOQ) in serum and urine were 0.005 ng/mL for 1P-LSD and 0.015 ng/mL for LSD.

2.4 Instrumentation

The LC–MS/MS system and MRM parameters were employed according to the procedure published previously.17 In brief, a Nexera LC (Shimadzu, Duisburg, Germany) was coupled to a QTRAP® 5500 mass spectrometer (Sciex, Darmstadt, Germany) using positive electrospray ionization. Chromatographic separation was achieved on a biphenyl column (100 × 2.1 mm, 2.6 μm particle size, Phenomenex, Aschaffenburg, Germany) with a corresponding guard column (SecurityGuard™ ULTRA Cartridges UHPLC Biphenyl for 2.1 mm i.d. columns, Phenomenex, Aschaffenburg, Germany). Starting with 10% mobile phase B (total flow rate: 0.3 mL/min), the gradient was increased to 30% mobile phase B within 3 min. Mobile phase B was further increased to 50% after 4 min and 75% after 6 min. Within 0.5 min mobile phase B was increased to 95% and held at this percentage for 1 min. For column re-equilibration, the starting conditions were restored within 0.5 min and kept for 7 min. Propan-2-ol was added post-column for signal enhancement (0.1 mL/min). Buy 1P-Lsd online

2.5 Pharmacokinetic analysis

MS Excel 2010 (Microsoft Corporation, Redmond, WA, USA) was used to gather pharmacokinetic (PK) data from the measured serum concentrations. cmax and tmax were obtained directly from the observed data. After semi-logarithmic transformation of the serum concentration data the elimination rate ke was estimated by log-linear regression using at least six data points. The terminal half-life was calculated using the equation t1/2 = ln (2)/ke. The area under the concentration–time curve (AUC) was estimated using the linear trapezoidal method in the respective time range without further extrapolation. The bioavailability was determined by division of the AUC after oral administration and the AUC after i.v. administration (F = AUCpo/AUCiv).

To test for instability under acidic or basic conditions in the gastrointestinal tract, 1P-LSD was treated either with diluted HCl (pH approx. 1) or diluted NaOH (pH approx. 8) for 2 hours at 37°C in an oven (final concentration in the samples: 2 μg/mL). Therefore, 2 μL of the ethanolic 1P-LSD solution (1 mg/mL) was added to 1 mL of diluted HCl solution or 1 mL of diluted NaOH solution. One mL of deionized water with 2 μL of ethanolic 1P-LSD solution (1 mg/mL) was used as reference. Both tested conditions as well as the reference were conducted in triplicates. After 2 hours of storage at 37°C, 10 μL of each sample was diluted with 990 μL of mobile phase A and B (99/1, v/v) and analyzed as described above. Buy 1P-Lsd online

2.6 Pharmacodynamics: Quality and course of subjective effects

2.6.1 Subjective drug effects

Visual analog scales (VAS) are a well-established tool that facilitate the assessment of subjective features that occur during acute phases of intoxication similar to those reported in studies involving hallucinogens such as LSD.18 In the present study, three measures were assessed using visual analog scales (VAS): “any drug effect”, “good drug effect”, and “bad drug effect”. Items were presented to each subject at 30 min intervals for 14 h (oral administration, session 1) or 12 h (i.v. administration, session 2) to monitor the time course of subjective drug effects.

2.6.2 Five-dimensions of altered states of consciousness (5D-ASC)

The 5D-ASC questionnaire is an instrument designed to record psychometric scales developed at the Psychiatric University Clinic in Zürich (Switzerland). It was validated across a broad range of studies and has become a standard tool for measuring changes in waking consciousness induced by hallucinogenic drugs.19 The 5D-ASC involves 94 items that consist of statements in one sentence that are rated on a VAS with two poles (“not more than usual” and “much more than usual”). The 5D-ASC was administered no longer than 2 h after the effects had ceased. At that time, both subjects were able to understand and answer the items presented without problems. The common subscales/dimensions of the 5D-ASC are described as follows.

Oceanic boundlessness (OB)

This scale assesses changes in the experience of the self and body, the relation to the environment, alterations in time experience, and mood changes directed towards elevation and sublimity. The state implies a positively experienced ego dissolution with euphoria. The separation between the self and the external world becomes tenuous and sometimes nonexistent. Core items for OB included: “It seemed to me that my environment and I were one” and “I felt very happy and content for no outward reason”. Buy 1P-Lsd online

Anxious ego dissolution (AED)

This scale describes an unpleasant experience with diminished self-control characterized by ego-disintegration or ego-fragmentation accompanied by great distress and anxiety. Thought processes are altered, sometimes occupied with threatening themes (e.g. loss of control) or interfered by disruptions of thinking. Time may be experienced as painfully slow. Core items for AED included: “It seemed as though there was an invisible wall between me and my surroundings” and “I was afraid to lose control over myself”.

Visionary restructuralization (VR)

Typical aspects of altered states of consciousness are visionary-hallucinatory phenomena. They can be divided in three different categories: elementary, amorphous “primitive” optical phenomena, organized scenic hallucinatory phenomena, and changed meaning of objects perceived in the environment. Hypnagogic imagery and synesthesia belong to this category. Core items for VR included: “I saw light or flashes of light in total darkness or with closed eyes” and “Things around me had a new, strange meaning to me”.Buy 1P-Lsd online

Vigilance reduction (VIR)

Items of this scale characterize reduced alertness and clouded consciousness, typically accompanied by reduced cognitive performance and self-control. Core items for VIR include: “I was in a doze” and “My perception is cloud”.

Auditory alterations (AA)

This dimension measures acoustic hallucinatory phenomena, e.g. hearing clicks or amorphous low noise, music or voices (possibly commenting on the subjects thinking or behavior). Core items for AA included: “I heard diffuse noises without being able to identify the source” and “I heard my own thoughts as if I was speaking”.

2.7 Controlled self-administration study

Two healthy, Caucasian males (age: 46 and 56 years, weight: both 74 kg) participated in the controlled self-administration study consisting of two experimental sessions. The environment of the sessions was non-clinical in a “living-room atmosphere”. Experiments were started 2 hours after a light breakfast. Both subjects had prior experience with LSD-like compounds in the past (no consumption in the 3 months before the study). Sleep during pre-experimental nights was more than 6 hours. In session 1, a single oral dose of 100 μg of 1P-LSD hemitartrate (2:1), equivalent to 71.2 μg LSD base assuming complete hydrolysis, was administered (gelatin capsules containing pieces of wafer soaked with 100 μL of an ethanolic 1 mg/mL 1P-LSD hemitartrate solution). Session 2 took place after a washout phase of 11 months and included the i.v. administration of the same total amount of 1P-LSD. Here, 10 mL of normal saline were mixed with 100 μL of an ethanolic 1 mg/mL 1P-LSD hemitartrate solution and administered intravenously. A venous access was placed in both the right and the left arm of each subject (one for the administration of the 1P-LSD solution and the other for taking blood samples).Buy 1P-Lsd online

To gather PK data of 1P-LSD, blood samples were taken regularly from subject A and B for up to 150 h and 26 h (session 1), respectively, and for up to 24 h in session 2. The blood samples were immediately centrifuged for 15 min at 2879 × g and the serum was transferred into sodium fluoride containing glass tubes (approx. 10 mg sodium fluoride per mL serum) to prevent hydrolysis of 1P-LSD.17 Urine samples were collected from subject A for 14 (session 1) and 10 days (session 2). Urine samples from subject B were solely taken on the day of administration. Urine concentrations were normalized to creatinine and are given in ng/mg (1 ng/mg is equivalent to 1 ng/mL in a urine sample with 100 mg/dL creatinine). Serum and urine samples were stored overnight at 5°C and subsequently stored at −20°C until analysis.


3.1 Pharmacokinetic analysis

After p.o. ingestion of 100 μg 1P-LSD hemitartrate (session 1), only LSD but no 1P-LSD was detected in serum and urine samples. LSD serum and urine concentration–time curves are shown in Figures 1 and 2, respectively. LSD urine concentrations were normalized to urinary creatinine concentrations. The creatinine concentration ranged from 28 to 230 mg/dL. The highest serum concentration of LSD was observed after approximately 2 hours in both subjects (cmax (subject A) = 3.7 ng/mL and cmax (subject B) = 2.3 ng/mL). LSD could be detected for up to 49 h in subject A and for at least 25 h in subject B (= last sampling). In urine, LSD was detected for up to 69 h in subject A. Only two urine samples were collected from subject B, and both were positive for LSD (2.0 ng/mg LSD after 4 h and 1.1 ng/mg LSD after 7.7 h). Buy 1P-Lsd online

Comments (1)

  1. I have read your article carefully and I agree with you very much. This has provided a great help for my thesis writing, and I will seriously improve it. However, I don’t know much about a certain place. Can you help me?

Leave a comment