LGD-3303 is a drug which acts as a selective androgen receptor modulator, with good oral bioavailability. It is a selective agonist for the androgen receptor, producing functional selectivity with effective dissociation of anabolic and androgenic effects, acting as a partial agonist for androgenic effects, but a full agonist for anabolic effects. It has been investigated as a possible treatment for osteoporosis, and was shown in animal studies to enhance the effectiveness of a bisphosphonate drug.
What is LGD3303?
LGD-3303 Chinese chemical name: [9-chloro-2-ethyl-1-methyl-3-(2,2,2-trifluoroethyl)-3H-pyrrolo [3,2-f] quinoline -7(6H)-keto],is an oral non-selective androgen receptor modulator. Selective androgen receptor modulators, SARMs. Selective androgen receptor modulators (SARMs) are a new class of molecules that are being developed to treat various diseases. SARM maintains the beneficial effects of androgens, including increased muscle mass and bone density while reducing the activity of useless side effects. The mechanism responsible for the selective activity of SARMs tissue is not fully clear and the relationship between pharmacokinetics (PK)/pharmacodynamics (PD) is unknown. The distribution of tissue-specific compounds may be the mechanism responsible for apparent tissue selectivity.
LGD3303 powder Pharmacokinetics and Pharmacodynamics (Animal Experiments)
As a latest SARM, LGD-3303 has potent activity against the levator ani muscle in a castrated rat model of androgen deficiency, but only partial agonist activity in the foreskin and ventral prostate. Although the plasma concentration of the compound increased, LGD-3303 never stimulated the ventral prostate beyond intact levels. When LGD-3303 was administered orally or by continuous infusion, tissue selective activity was maintained and the time of the two routes of administration was significantly different from the profile of exposure. Although the local tissue concentration of LGD-3303 is higher in the prostate than in the levator muscle, compared to greater muscle activity in the prostate. LGD-3303 has SARM properties that are independent of its pharmacokinetic characteristics, suggesting that the main mechanism of tissue-selective activity is the result of molecular interactions that change at androgen receptor levels.
Experimental materials and methods:
The selected compound was LGD-3303. LGD-3303 is a non-steroidal androgen receptor agonist that efficiently binds the androgen receptor and activates gene transcription. LGD-3303 has minimal binding or transcriptional activity on relevant nuclear receptors (Vajda , 2008). LGD-3303 was synthesized at Ligand Pharmaceuticals (San Diego, CA).
Chemical Structure of LGD-3303
LGD-3303 oral and infusion doses. Rats were sorted by weight, assigned to experimental groups (n = 5/group) and operated as described above. The experimental group consisted of oral administration of LGD-3303 (0.3-100 mg/kg/day) or osmotic minipump (Alzet model 2ML1; Alzet, Cupertino, CA; constant infusion of LGD-3303; dose range of 0.01-10 mg/L Kg/day). Small pumps were surgically implanted into intradermal tissue, while rats underwent ORDX under anesthesia. Seven days later, the rats were anesthetized and a small pump was surgically removed and replaced with a new small pump. LGD-3303 was formulated for oral administration as described above and formulated for micropump administration in 50% polyethylene glycol-400:50% dimethylsulfoxide. On the 14th day of the experiment, blood was collected into the lithium heparin tube (Becton Dickinson) by jugular puncture at 0, 0.5, 1, 2, 4, 8, 12 and 24 hours after administration. The blood was centrifuged and the plasma concentration of LGD-3303 was measured. On the fifteenth day, the rats were sacrificed and the wet weights of the ventral prostate and levator ani muscles were measured.
The pharmacological effects of LGD-3303 in ORDX male rats treated by oral gavage for 14 days. Trend significantly reduced levator ani muscle weight, abdominal prostate weight, and preputial gland weight, but increased serum LH. LGD-3303 inhibited the effect of ORDX on the levator anal weight at doses of 1 mg/kg/day and significantly increased muscle weight over eugonad levels at higher doses. LGD-3303 inhibited serum LH levels against eugonadale. LGD-3303 has a lesser effect on the ventral prostate, maintaining eugonadal levels in the peritoneal prostate at doses of 100 mg/kg/day or higher. Black bar, ORDX control; Solid horizontal line, sham control ¡À SEM (horizontal dotted line). *, p <0.05 compared to ORDX control; +, p < 0.05 compared to sham intact control by one-way ANOVA.
LGD-3303 distribution. Rats were sorted by weight and assigned to experimental groups (n = 3/group) and surgery was performed as described above. Rats received LGD-3303 (30 mg/kg/day) or were given oral gavage once daily. On the 14th day of administration, the rats were sacrificed by heart bleeding under isoflurane anesthesia after 2, 4 or 8 hours. Thirty minutes prior to autopsy, rats were injected intravenously with 2 ml/kg volume of 10 mg/ml high molecular weight dextran labeled with fluorescein isothiocyanate (FITC-dextran, 150 kDa; Sigma-Aldrich, St. Louis, MO). Glycan body weight. The extravasation of large-molecular-weight FITC-dextran was slow and it was used as a marker for acute study of blood volume.
Luteinizing Hormone Immunoassay
The serum samples collected at necropsy were assayed for LH by a double antisera method using reagents from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK; National Hormone and Peptide Program, Dr. Parlow, Torrance, CA). Briefly, a total volume of 200 μl of sample and standard (NIDDK-rLH-RP-3) was incubated with 100 μl of primary antiserum (rabbit NIDDK-anti-rLH-S-11) for 2 to 3 days at room temperature. 1:100,000. Thereafter, 100 μl of 125I-labeled LH (MP Biomedicals, Irvine, CA) diluted to 200,000 to 300,000 cpm/ml was added to the tube and incubation was continued for an additional 24 hours. The bound hormone was separated from free hormone by precipitation with specific goat anti-rabbit serum (Antibodies Inc., Davis, CA). For this purpose, 50 μl of 4% normal rabbit serum was added to each incubation tube, followed by 50 μl of a 1:10 goat anti-rabbit serum solution. The tubes were vortexed and incubated overnight at 4°C. The assay was terminated by centrifugation, the supernatant was decanted and discarded, and the pellet was counted in a 10-channel gamma counter. The assay has a minimal detectable amount of 0.001 ng/tube and has less than 10% intra- and inter-assay variation. To eliminate inter-assay variability, all samples from a single study were run in the same assay.
Quantification of LGD-3303 in Plasma and Tissue Samples
In order to determine plasma concentrations, the LGD-3303 standard solution was added to blank rat plasma; calibration standards were constructed from 0.001 to 10 μg/ml; 250 μl acetonitrile containing LGD-2226 was used as an internal standard (Miner et al., 2007). 50 μl of the calibration standard and 50 μl of the plasma sample were extracted by protein precipitation. After centrifugation, the supernatant was analyzed by liquid chromatography (LC) for LGD-3303 followed by tandem mass spectrometry. To determine the tissue concentration, the standard solution of LGD-3303 was added to blank rat tissues in a 2:1 ratio (v/w) standard solution and tissue. A calibration standard (from 0.01-5 μg/ml) was constructed in an extraction solution [Acetonitrile/water = 70:30 (v/v)] containing LGD-2226 as an internal standard. The tissue sample was extracted with 2 volumes of an extraction solution containing an internal standard. After overnight extraction, the supernatant was analyzed for LGD-3303 by LC tandem mass spectrometry. The analysis was performed by electrospray ionization mass spectrometry (MS) using an Applied Biosystems API 4000 or API 4000/Q-trap (Applied Biosystems, Foster City, CA). Samples were analyzed by injecting 10 to 20 μl of the supernatant into the LC/MS instrument. The LC instrument was equipped with a C8 octyl, MOS guard column (4 x 2 mm; Phenomenex, Torrance, CA) and a Gemini C6-phenyl column (50 x 2.0 mm, 5 [mu]m; Phenomenex). The mobile phases A and B are respectively 0.1% formic acid in H2O and 0.1% formic acid in acetonitrile. A multi-reaction monitoring scan using 343.1 / 245.3 atomic mass units was monitored in positive mode.
Quantification of FITC-dextran in serum and tissue samples.
One serum was diluted 1:10 in water. One hundred microliters of diluted serum was pipetted into a microtiter plate and analyzed in a fluorescent plate reader (Wallac Victor 1420; PerkinElmer Life and Analytical Sciences, Waltham, MA) to determine the FITC-dextran concentration. Blank serum was spiked with FITC-dextran and serially diluted (blank serum/water, 10:90) to generate a calibration curve. Calibration standards are analyzed on the same microtiter plate as the sample to reduce variability. Throughout the experiment, the serum was not exposed to light.
The concentration of FITC-dextran in the tissue was measured after quantifying LGD-3303 concentration as described above. The remaining tissue and extraction solution was homogenized and centrifuged. 100 microliters of supernatant (acetonitrile/water = 70:30, v/v) was pipetted into a 96-well microtiter plate. Blank prostate and levator ani extracts were added to FITC-dextran and serially diluted to produce calibration standards. To establish a separate calibration curve for each organization. Analyze calibration standards in the same microtiter plate as the tissue sample to reduce variability. The organization was protected from light during the entire experiment. Serum FITC-dextran concentration and local tissue FITC-dextran concentration were used to estimate the intra-tissue residual blood volume after cardiac bleeding. The residual blood volume of the tissue concentration of LGD-3303 measured as described above was corrected.
Pharmacokinetic analysis of plasma samples of ORDX male rats treated with LGD-3303 by oral gavage for 14 days. Exposure to LGD-3303 (AUC 0-6 ) was increased from 10 to 300 mg/kg/day after 14 days of oral gavage in ORDX male rats. Despite increased exposure, the ventral prostate weight never exceeded the level of the sham control and reached a significant plateau in the pharmacological response.
Pharmacokinetic analysis of LGD-3303
Plasma concentration-time data for each animal was analyzed by non-compartmental pharmacokinetic methods (Gibaldi and Perrier, 1982) using WinNonlin (version 5.0; Pharsight, Mountain View, CA). The highest concentration observed and the corresponding sampling time are defined as Cmax and tmax, respectively. The area under the plasma concentration time curve (AUC) was calculated by the trapezoidal method, and AUC 0-6 or AUC 0-24 was used in this study. The elimination half-life (t 1/2 ) is estimated from t 1/2 =ln 2 /λ, where λ is the slope of the regression line that best fits the end portion of the log-linear concentration time curve.
The plasma exposure profile of LGD-3303 in orthotopic and subcutaneous continuous perfusion administration of ORDX male rats. After exposure by oral gavage (circles) or continuous infusion through an osmotic minipump (triangles), the exposure characteristics are significantly different. Blood was collected from the jugular vein at 0, 0.5, 1, 2, 4, 8, 12 and 24 hours after the administration on the 14th day after the administration. LGD-3303 was extracted from plasma with acetonitrile and analyzed by liquid chromatography with tandem mass spectrometry.
The data was analyzed by one-way analysis of variance (ANOVA) and then analyzed by Tukey's significant difference post hoc test. Transformations were made as necessary to ensure that the differences between the groups were uniform, and the residuals of the one-way analysis of variance model followed a Gaussian (normal) distribution (Box and Cox, 1964; Box and Hill, 1974). For tissue distribution studies, the concentration of LGD-3303 in ventral prostate and ani ani was compared by a two-tailed paired Student's t test. Statistical analysis was
performed using commercially available software (JMP, SAS Institute, Cary, NC; Microsoft Excel, Microsoft, Redmond, WA). P-values less than 0.05 were considered statistically significant. If possible, fit the data to the improved four-parameter logistic equation (Ghosh et al., 1998). All data are expressed as mean ± SEM
Conclusion about lgd3303 powder in experiment
DHT levels in the prostate may be higher than muscle or systemic circulation. It is conceivable that other SARMs and steroidal androgens have pharmacological characteristics that differ from those of LGD-3303 due to the uneven tissue distribution and that similar evaluations of these compounds are required to perform a full comparison with LGD-3303.
In short, we have demonstrated that LGD-3303 is a full agonist of muscles that are active on partial agonists of the prostate. Partial agonist activity is not a result of changes in saturation exposure, tissue-specific compound distribution, or normal circadian rhythms of androgen exposure. The tissue selectivity of LGD-3303 may be the result of altered AR level interactions. LGD-3303: Very promising SARM still in development.
LGD-3303 is a selective androgen receptor modulator (SARM) with impeccable oral bioavailability. The drug is classified as a selective agonist designed for the androgen receptor. LGD-3303 has anabolic and androgen effects and is currently investigating this drug as a possible solution to treat osteoporosis.
This is a condition that causes the inability of the human skeleton to increase. LGD-3303 is one of the most effective SARMs at present. For many bodybuilders who want large muscles, the LGD-3303 and other equally effective SARM stacks can provide the final combination.