Description

Technical Parameters

Introduction

peptides

product-1400-1400

Products Description

### Systematic introduction of Tesamorelin peptide

Tesamorelin is a synthetic growth hormone-releasing hormone (GHRH) analogue, mainly used to treat lipodystrophy associated with human immunodeficiency virus (HIV) infection. It stimulates the pituitary gland to release growth hormone (GH), thereby regulating the secretion of insulin-like growth factor-1 (IGF-1), improving metabolic abnormalities and fat distribution. The following systematically explains the characteristics of Tesamorelin from multiple dimensions.

### 1. Chemical structure and classification

#### 1. **Molecular structure**

Tesamorelin is a linear polypeptide composed of 44 amino acids with the sequence:

**H-Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH₂**

Its core modifications include:

- **N-terminal stability enhancement**: By replacing the first amino acid (Tyr→His) of natural GHRH (1-44) to improve the ability to resist enzymatic hydrolysis.

- **C-terminal amidation**: prevents degradation by carboxypeptidase and prolongs half-life.

#### 2. **Classification**

Based on function and structure, Tesamorelin belongs to:

- **Synthetic GHRH analogue**: different from natural GHRH, with optimized pharmacokinetic properties.

- **Therapeutic peptide drug**: requires subcutaneous injection, and the indications are concentrated on metabolic disorders.

### 2. Pharmacological properties

#### 1. **Mechanism of action**

- **Targeting pituitary GHRH receptor**: Activates adenylate cyclase-cAMP pathway and promotes GH pulse release.

- **Indirect regulation of IGF-1**: GH acts on the liver to produce IGF-1, synergistically improving fat metabolism and protein synthesis.

#### 2. **Pharmacodynamic advantages**

- **High selectivity**: strong affinity for GHRH receptor (Ki <1 nM), avoiding cross-reactions.

- **Pulse release**: simulates physiological GH secretion pattern and reduces side effects (such as joint edema).

#### 3. **Pharmacokinetics**

- **Half-life**: about 26-38 minutes (natural GHRH only 7-10 minutes).

- **Bioavailability**: absorption rate after subcutaneous injection >80%, peak time 15-30 minutes.

- **Metabolic pathway**: degraded by kidney and liver peptidases, no significant accumulation risk.

### 3. Physical and chemical properties

#### 1. **Basic parameters**

- **Molecular formula**: C₂₂₁H₃₆₆N₇₂O₆₇S

- **Molecular weight**: 5135.9 Da

- **Isoelectric point (pI)**: about 10.5 (because it contains multiple basic amino acids such as Arg and Lys).

- **Solubility**: easily soluble in water (>50 mg/mL), slightly soluble in ethanol, insoluble in non-polar solvents.

#### 2. **Stability**

- **Thermal stability**: lyophilized powder can be stored at -20°C for 24 months; the solution needs to be refrigerated at 2-8°C and used within 72 hours.

- **Photosensitivity**: It needs to be stored away from light to prevent oxidation (especially Met residues are easily oxidized).

- **pH dependence**: It is most stable at pH 4-6, and strong acid/base environment can easily lead to conformational destruction.

### 4. Color and morphological characteristics

#### 1. **Appearance**

- **Lyophilized powder**: White to off-white, amorphous or microcrystalline structure.

- **Reconstituted solution**: Clear and colorless, if turbid or precipitated, it indicates deterioration.

#### 2. **Impact of impurities**

- **Oxidation products**: may cause a yellowish color (such as Met oxidation to sulfoxide).

- **Degradation products**: high temperature or long-term storage may produce brown polymers.

### 5. Advantages and limitations of clinical applications

#### 1. **Core advantages**

- **Targeted fat metabolism**: significantly reduce visceral fat (clinical trials show a 15-18% reduction).

- **Higher safety**: no significant liver toxicity or glucose metabolism interference (compared to direct GH injection).

- **Convenience**: once-daily subcutaneous injection, patient compliance is better than complex therapy.

#### 2. **Limitations**

- **High cost**: annual treatment costs are about 30,000 to 50,000 US dollars, limiting popularization.

- **Side effects of injection**: local erythema (20% of patients), transient joint pain (5-10%).

- **Narrow indications**: currently only FDA-approved for HIV lipodystrophy.

### 6. Clinical application and research direction

#### 1. **Current indications**

- **HIV lipodystrophy**: Reduce abdominal fat accumulation and improve dyslipidemia (LDL ↓12%).

- **Non-alcoholic fatty liver disease (NAFLD)**: Phase II trial showed a 22% reduction in liver fat content.

#### 2. **Exploratory research**

- **Anti-aging potential**: Improve muscle mass and cognitive function by increasing IGF-1 levels (effective in animal models).

- **Cancer cachexia**: Combined nutritional support to alleviate muscle atrophy (preliminary data positive).

#### 3. **Future directions**

- **Oral delivery system**: Liposome or nanoparticle encapsulation to improve bioavailability.

- **Long-acting preparation**: Polyethylene glycol (PEG) modification extends half-life to several days.

- **Combination therapy**: Combined with GLUT4 activators to enhance insulin sensitivity.

### 7. Summary and Outlook

As the first approved GHRH analog, Tesamorelin has demonstrated the potential to precisely regulate the GH/IGF-1 axis. Its advantages lie in high efficiency and relative safety, but cost and administration remain major challenges. With the development of peptide engineering technology, its application in metabolic diseases and geriatric medicine may be expanded in the future through structural optimization and new delivery systems. Further research needs to focus on the safety of long-term use and the verification of efficacy in non-HIV populations.