Dosage research on Ipamorelin

Preclinical research dose ranges

In published preclinical research on Ipamorelin, administered dose ranges in rodent pharmacology studies have most commonly fallen in the 1 to 100 microgram per kilogram range delivered subcutaneously or intravenously. The Raun and colleagues seminal 1998 work characterised the selective GH-secretagogue profile across dose levels in this range, with the higher end of the range producing the more pronounced GH-pulse amplitude in rat pharmacology.

Pharmacokinetic studies in pigs and dogs have used a comparable dose range. Hansen and colleagues’ pharmacokinetic evaluation work used single-bolus subcutaneous administration in the microgram-per-kilogram range for half-life and bioavailability characterisation. The structure-activity-relationship work characterising Ipamorelin against other peptidyl growth hormone secretagogues used in-vitro and acute in-vivo pharmacology with doses in the same span.

Surgical-research applications have appeared in the published literature in postoperative-ileus and gastric-motility model systems. Doses in these applications have generally fallen in the same microgram-per-kilogram range delivered subcutaneously, with the postoperative protocols using multi-day dosing across the immediate-postoperative observation window.

Dose-response considerations from the published literature

The published Ipamorelin literature has reported dose-response characteristics that scale GH-pulse amplitude with administered dose across the 1 to 100 microgram per kilogram range in rodent pharmacology. Effects on cortisol, prolactin, ACTH, and aldosterone remain minimal across the same dose range, which is the central feature of the published characterisation as the first selective growth-hormone secretagogue.

A small number of human pilot reports have appeared in the published clinical literature. These pilots used doses in the microgram-per-kilogram range comparable to the rodent pharmacology and reported GH-pulse amplitude effects consistent with the rodent characterisation. The pilots do not constitute Phase 1 dose-ranging trials, and the research community continues to rely on the rodent pharmacology and these pilots for dose-design inference.

Reconstitution math and per-vial dose calculation

A 10 mg lyophilised Ipamorelin vial reconstituted with 2 mL of bacteriostatic water yields a stock concentration of 5 mg per mL. From this stock, a research aliquot of 0.1 mL contains 500 micrograms; an aliquot of 0.02 mL contains 100 micrograms. Researchers working with the microgram-per-kilogram dose ranges reported in published rodent pharmacology further dilute the stock to a working concentration appropriate to the model and the body weight of the animal subject. Refrigerated storage at 2 to 8 degrees Celsius, protected from light, is the standard handling practice reported across the rodent in-vivo work.

Research-protocol design considerations

Protocol-design choices in the published Ipamorelin literature reflect several recurring considerations. Dose selection anchors at the 1 to 100 microgram per kilogram range in rodent pharmacology, with the choice of point within that range determined by whether the endpoint is GH-pulse-amplitude characterisation, pharmacokinetic profiling, or surgical-research application. Acute single-dose protocols predominate in the pharmacology literature; multi-day protocols appear in the surgical-research applications.

Route of administration in the published rodent work most commonly uses subcutaneous injection, which matches the delivery route used in any future human investigation. Intravenous administration appears in pharmacokinetic studies where absorption-rate questions are the protocol focus. Intramuscular administration appears in a smaller subset of the pharmacology literature.

The selectivity profile is a protocol-design consideration unique to Ipamorelin among the growth-hormone secretagogues. Investigators choosing Ipamorelin over earlier-generation secretagogues (GHRP-2, GHRP-6, hexarelin) are typically doing so because the minimal cortisol, prolactin, ACTH, and aldosterone release is the protocol requirement. Protocol designs that need to isolate ghrelin-receptor effects from off-target hormone elevations use Ipamorelin as the tool compound of choice in the published research.

References

1. Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 1998. [PMID 9849822]
2. Hansen BS et al. Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues. Drug Metabolism and Disposition, 1999. [PMID 9879640]
3. Hansen TK et al. Highly potent growth hormone secretagogues: hybrids of NN703 and ipamorelin. Bioorganic & Medicinal Chemistry Letters, 2001. [PMID 11459660]
4. Bowers CY. Growth hormone-releasing hormone and growth hormone-releasing peptide as therapeutic agents. Journal of Pediatric Endocrinology and Metabolism, 1997. [PMID 9238854]
5. Andersen NB et al. The growth hormone secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. Journal of Endocrinology, 2001. [PMID 11457455]
6. Beck DE et al. A pilot study of ipamorelin on postoperative ileus. Annals of Surgery, 2014. [PMID 24299680]