Intranasal delivery of rapamycin via brain-targeting polymeric micelles for Alzheimer’s disease treatment (or prevention)

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Researchers at Long Island University (USA) have published a compelling proof-of-concept study in the International Journal of Pharmaceutics demonstrating that intranasal delivery of rapamycin—encapsulated in specialized “brain-targeting” micelles—can reverse markers of Alzheimer’s disease (AD) in mice.

Rapamycin (sirolimus) is the gold-standard longevity drug, known for extending lifespan in every model organism tested by inhibiting the mTOR pathway. However, its translation to human neuroprotection is hampered by the Blood-Brain Barrier (BBB). To get enough rapamycin into the brain via oral tablets to clear toxic amyloid plaques, patients often require high doses that suppress the immune system or cause metabolic dysregulation (e.g., insulin resistance).

The “Big Idea” here is a bypass road. The team engineered polymer nanoparticles (micelles) tagged with a peptide (FibCS1) that acts like a VIP pass for the nasal lining and potentially the brain’s vasculature. When squirted into the noses of mice genetically engineered to develop aggressive Alzheimer’s (3xTg-AD), these nanoparticles didn’t just reach the brain—they reduced neuroinflammation (TNF-α, IL-6) and amyloid-beta (Aβ) plaques, and restored memory function. Crucially, they achieved this with a fraction of the typical oral dose, theoretically sidestepping the systemic toxicity that worries longevity enthusiasts.

While this offers a tantalizing “hack” for delivering geroprotectors directly to the command center, the technology relies on a proprietary delivery vehicle not yet available to humans.

Source:

Part 2: The Biohacker Analysis

Study Design Specifications

  • Type: In vivo (Murine) and In vitro (RPMI-2650 nasal epithelial cells).
  • Subjects: 3xTg-AD Mice (Triple Transgenic Alzheimer’s Model).
    • Note on Sex/N-number: Specific sex breakdown for this trial was not detailed in the provided abstract, but 3xTg studies typically prioritize females due to more severe pathology.
  • Dose Protocol: Intranasal administration of 0.2 mg/kg, every 4 days (q4d) for 5 total doses (20-day duration).
  • Lifespan Data: N/A. This was a short-term acute efficacy study (20 days), not a longevity survival curve.

Mechanistic Deep Dive

  • Primary Pathway: mTOR Inhibition. The study leverages rapamycin’s ability to induce autophagy (cellular cleanup). By dampening mTORC1 in the brain, the treatment upregulates the clearance of aggregated proteins (Aβ plaques) that suffocate neurons.
  • Targeting Vector: The FibCS1 peptide targets fibronectin variants often upregulated in inflamed tissues and vascular endothelium. This suggests the micelles are not just passively drifting up the olfactory nerve, but actively latching onto mucosal/vascular entry points.
  • Inflammaging Control: The treatment significantly lowered brain levels of TNF-α and IL-6. This confirms that local mTOR inhibition successfully quells the “cytokine storm” associated with neurodegeneration, a key priority for organ-specific aging.

Novelty

  • The Vehicle: The use of FibCS1-PEG-b-PLA micelles is the true novelty. Generic intranasal rapamycin (without micelles) has been tried, but these nanoparticles showed superior nasal permeation (monomodal size ~98 nm) and stability.
  • The “Micro-Dose” Efficacy: Achieving robust plaque clearance with just 5 doses of 0.2 mg/kg (spaced 4 days apart) challenges the assumption that chronic, daily dosing is required for neuroprotection.

Critical Limitations

  • Aggressive Model Bias: 3xTg mice are an extreme model of AD. Humans rarely have three simultaneous mutations driving amyloidosis. Success here does not guarantee success in sporadic, age-related human Alzheimer’s.
  • Short Duration: A 20-day study cannot assess long-term safety. We do not know if these micelles accumulate in the olfactory bulb or cause local necrosis over months of use.
  • No Systemic Comparison: The study claims reduced systemic toxicity based on the logic of lower dosing, but detailed systemic toxicity data (e.g., glucose tolerance tests, immune cell counts) for this specific cohort versus an oral control group appears limited in the summary.

Part 3: Actionable Intelligence

The Translational Protocol

  • Human Equivalent Dose (HED):
    • Animal Dose: 0.2 mg/kg (Mouse).
    • Conversion Factor: Divide by 12.3 (standard FDA BSA conversion for Mouse to Human).
    • Math: 0.2 mg/kg/12.3≈0.016 mg/kg.
    • For 60kg Human: 0.016×60≈1.0 mg per dose.
    • Frequency: Every 4 days.
    • Biohacker Note: This is remarkably close to standard low-dose oral protocols (e.g., 2–6 mg/week), but applied intranasally, the brain concentration would theoretically be multiples higher than what 1 mg oral could achieve (due to ~1% oral brain bioavailability).

Pharmacokinetics (PK/PD)

  • Bioavailability: Oral rapamycin has poor bioavailability (~14%) and is a substrate for P-glycoprotein efflux pumps at the BBB. Intranasal delivery via the olfactory/trigeminal nerves bypasses the BBB and first-pass hepatic metabolism.
  • Half-Life: Rapamycin has a half-life of ~60 hours in humans. An “every 4 days” (96 hours) protocol allows for a “washout” trough, preventing continuous mTOR suppression (which is immunosuppressive).

Biomarker Verification Panel

To validate this protocol in a self-experiment (N=1), one would track:

  • Safety: hs-CRP (systemic inflammation), Complete Blood Count (neutrophils/lymphocytes), and Lipid Panel(mTOR inhibition can raise lipids).
  • Efficacy (Surrogates): Since you cannot biopsy your brain for amyloid, use Cognitive Testing (e.g., CNS Vital Signs) and serum Neurofilament Light Chain (NfL) (a marker of neuronal injury) or p-Tau217 (blood-based Alzheimer’s marker).

Feasibility & ROI

  • Sourcing: IMPOSSIBLE for the specific formulation. The FibCS1-PEG-b-PLA micelle is a lab-bench creation.
  • Alternative: “Raw” Rapamycin powder dissolved in solvents (DMSO/Ethanol/Saline) is used by some biohackers for intranasal spray. Warning: This lacks the targeting peptide and the micelle stability. It may simply drip down the throat (oral ingestion) or damage nasal mucosa due to solvents.
  • Cost: Rapamycin (Sirolimus) is cheap (~$1–$3/mg generic). The cost is negligible; the barrier is the delivery chemistry.
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Stage-Dependent Effects of Rapamycin for Alzheimer’s Disease: Insights from Prevention and Treatment Trials
#2

FWIW…

Locate patent for more details.

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#3

Part 4: The Strategic FAQ

1. Is “snorting” generic rapamycin the same as what was done in this study? No. The study used polymeric micellessized at ~98nm with a specific surface peptide (FibCS1). Simply dissolving rapamycin powder in saline/DMSO will likely result in rapid clearance by nasal cilia (swallowed) or poor mucosal penetration. You will likely get systemic absorption (via the throat) rather than direct nose-to-brain transport.

2. Can I get these “FibCS1” micelles commercially? No. This is currently experimental research material. There are no commercial suppliers of FibCS1-conjugated PEG-PLA micelles for human use.

3. Does this bypass the immune-suppression risks of oral rapamycin? Likely, but not guaranteed. While the total dose (1 mg) is low, intranasal delivery drains into the lymphatic system of the neck. However, because it bypasses the liver/gut, it spares the systemic metabolic hit (insulin resistance) often seen with chronic oral use.

4. What is the risk of “nose-to-lung” toxicity? Moderate. If the particle size is too small (<5 microns), it enters the lungs. If too large (>10 microns), it stays in the nose. The study targeted ~98nm (nanometers), which is ultrafine. In humans, using a standard nasal spray bottle often results in significant lung inhalation. Rapamycin is known to cause interstitial lung disease in rare systemic cases; local high-dose lung exposure is a valid safety concern.

5. How does the “Every 4 Days” (q4d) dosing compare to the standard “Weekly” biohacker protocol? It is more frequent. The standard biohacker protocol is once weekly (q7d) to allow full mTOR recovery. The q4d protocol in mice is aggressive. In humans, with a longer half-life (60hrs), q4d might lead to accumulation (higher trough levels), potentially risking continuous mTOR inhibition. A weekly schedule is safer for humans starting out.

6. Could this help with “Brain Fog” in non-Alzheimer’s adults? Hypothetically, yes. If the mechanism is clearing protein aggregates and lowering neuroinflammation (IL-6), it could enhance cognitive clarity in aging adults. However, without amyloid pathology to clear, the magnitude of benefit is unknown.

7. Are there off-target effects on the sense of smell (Olfactory toxicity)? Unknown. The study did not report on olfactory sensory neuron death. Since the drug travels via these nerves, local toxicity could theoretically cause anosmia (loss of smell). This is a critical missing data point.

8. Why use FibCS1 peptide? FibCS1 binds to specific integrins (VLA-4) on endothelial cells. This suggests the mechanism is partly vascular—treating the blood vessels of the brain—rather than just the neurons. This aligns with the “vascular hypothesis” of Alzheimer’s.

9. Can I use DMSO as a carrier instead of these micelles? Not recommended. DMSO is a permeation enhancer and will carry rapamycin into the tissue, but it is irritating to the nasal mucosa and can transport impurities from the skin/nose into the brain. It also lacks the sustained-release properties of the micelle.

10. What is the next logical step for a biohacker interested in this? Monitor ClinicalTrials.gov for “Intranasal Rapamycin” (e.g., for Epilepsy or Alzheimer’s). Companies like Aeolus or trials using ABI-009 (albumin-bound rapamycin) are the closest clinical equivalent. Do not attempt DIY compounding of nanoparticles without high-grade lab equipment (particle sizing, sterile filtration).

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#4

Protocol Report: Manufacturing FibCS1-PEG-b-PLA Micelles

Status: Research Grade Only (No Commercial/FDA Approved Source) IP Status: There is currently no public patentassigning exclusive rights to the specific FibCS1 + Rapamycin combination. The method relies on standard polymer chemistry (“Solvent Evaporation”) and a commercially available targeting peptide. The specific innovation is the combination, which is disclosed in the academic paper rather than an accessible manufacturing patent.

The “Open Source” Research Recipe

Based on the methodology disclosed by Sugandhi, Gattu, & Cho (St. John’s University).

This is a 3-Step “Post-Conjugation” Process. You cannot simply mix the three ingredients together. The nanoparticles must be formed first, then “decorated” with the homing peptide.

Phase 1: The Raw Materials

  1. The Payload: Rapamycin (Sirolimus).
  2. The Chassis: NHS-PEG-b-PLA (N-hydroxysuccinimide-Polyethylene Glycol-block-Poly Lactic Acid).
  • Critical Spec: The PEG end must be functionalized with an NHS-ester . This is the “sticky” end that will grab the peptide later.
  • Ratio: PEG (5k Da) / PLA (16k Da).
  1. The Homing Signal: FibCS1 Peptide .
  • Sequence: Glu-Ile-Leu-Asp-Val-Pro-Ser-Thr (EILDVPST).
  • Source: This is a standard catalog peptide (CAS 136466-51-8) derived from the Fibronectin IIICS domain. It targets the VLA-4 integrin receptor.

Phase 2: The Manufacturing Process (Solvent Evaporation)

Warning: NHS-esters are unstable in water. This step requires precise timing.

  1. Dissolution (The Organic Phase):
  • Dissolve the NHS-PEG-b-PLA polymer and Rapamycin in Acetone.
  • Why Acetone? It dissolves both the plastic and the drug, but is miscible with water.
  1. Precipitation (The Micelle Formation):
  • Heat a Phosphate Buffer (pH 8.4) to ~60°C.
  • Dropwise Addition: Slowly drip the organic phase (Acetone mix) into the hot aqueous buffer while stirring vigorously.
  • Self-Assembly: As the acetone hits the water, the hydrophobic PLA blocks panic and clump together (trapping the rapamycin inside), while the hydrophilic PEG blocks shoot outward.
  • Evaporation: Continue heating/stirring (or use a rotavap) to fully evaporate the acetone. You now have “naked” micelles floating in water.

Phase 3: The “Click” Conjugation

  1. Decoration:
  • Add the FibCS1 Peptide to the micelle solution.
  • The Reaction: The NHS-ester groups on the surface of the micelles react with the primary amines on the peptide.
  • Conditions: This happens at slightly basic pH (8.4) to deprotonate the amines, allowing them to attack the NHS ester.
  1. Purification:
  • Dialysis or Centrifugation is used to wash away unattached peptides and free rapamycin.
  • Final Size: ~98 nm.

Biohacker Feasibility Analysis

Can you make this in a garage? No.

  1. The “NHS” Problem: NHS-esters hydrolyze (break down) in water within minutes. If you are too slow during the “Precipitation” step, the sticky ends will die before you add the peptide. Lab-grade speed and pH control are essential.
  2. Particle Sizing: Without a Dynamic Light Scattering (DLS) machine, you cannot confirm if you made 100nm micelles or 10-micron sludge. Large particles (>10 microns) will just sit in your nose or enter your lungs; they will not cross the olfactory nerve barrier.
  3. Sterility: Intranasal delivery bypasses the gut’s immune defenses. Injecting non-sterile, endotoxin-loaded home-brew polymers into your brain’s vascular supply is a high-risk activity (meningitis risk).
#5

@adssx , perhaps of interest.

There have been previous intranasal delivery trials with rapamycin, successfully using 1% DSMO and saline water as a delivery mechanism.

2.3 Therapeutic Efficacy of Generic Solutions

Despite the limitations of the formulation, the generic approach yielded significant disease-modifying effects in animal models.

2.3.1 Restoration of Molecular Signaling

  • mTORC1 Inhibition: In the Ts65Dn hippocampus, generic intranasal rapamycin reduced the phosphorylation of S6 and S6K1 (downstream targets of mTOR) to levels observed in healthy euploid mice.
  • Autophagy Induction: The treatment increased the levels of LC3-II (a marker of autophagosome formation), indicating a restoration of the brain’s waste-clearance mechanisms.
  • Insulin Signaling: By dampening mTOR, the treatment relieved the feedback inhibition on IRS1, thereby restoring brain insulin signaling pathways (Akt/GSK3β) which are crucial for neuronal survival.

Comparative Critical Analysis: Generic vs. Targeted Micelles

This section synthesizes the data to provide a direct head-to-head comparison of the two approaches, fulfilling the user’s request to identify differences and missing links.

2.3.3 Cognitive Rescue

  • Behavioral Tests: Mice treated with the generic solution showed improved performance in the Radial Arm Maze (RAM) and Novel Object Recognition (NOR) tests, demonstrating that the biochemical changes translated into functional memory improvements.

2.4 Limitations of the Generic Approach

While scientifically successful, the “generic” approach faces translation hurdles:

  • Mucociliary Clearance: The nasal cavity turns over its mucus layer every 15–20 minutes. Simple solutions are rapidly swept away into the nasopharynx and swallowed, limiting the window for absorption.
  • Dosing Variability: The “sniffing” of liquid drops leads to high variability in deposition.
  • Vehicle Toxicity: As noted, DMSO is not a viable vehicle for a daily, lifelong therapy for Alzheimer’s patients.

4.1 Comparison of Delivery Efficiency

Parameter Generic Solution (Tramutola et al.) FibCS1-PEG-b-PLA Micelles (Sugandhi et al.) Comparative Insight
Transport Mechanism Passive Diffusion Active Receptor Targeting ($\alpha4\beta1$) + Passive Micelles: Active targeting recruits biological transport machinery (olfactory ensheathing cells), bypassing the saturation kinetics of passive diffusion.
Nasal Permeability 11.27 µg/cm² (Free drug) 19.78 µg/cm² Micelles: ~1.75x increase in flux across the nasal epithelium.11
Direct Transport % High (inferred from ratios) 80.32% Micelles: Quantified high efficiency indicates the vast majority of brain drug comes from the nose, not blood.18
Retention Time Minutes (rapid clearance) Hours (sustained release) Micelles: The sustained release (24h) allows for a “depot” effect in the nasal cavity, maximizing absorption over time.

4.2 Comparison of Safety and Toxicology

Feature Generic Solution Polymeric Micelles Implication
Vehicle Saline + DMSO(1-5%) Aqueous Buffer (PBS) Micelles: Elimination of DMSO removes the risk of mucosal irritation and ciliotoxicity, making the formulation suitable for chronic AD therapy.
Cytotoxicity Low at experimental doses, but vehicle is toxic No notable toxicity (up to 25 µM) Micelles: Validated safety on glial cells supports long-term safety profile.11
Systemic Exposure Very Low (6.7 ng/mL) Likely Very Low Both methods excel at sparing peripheral organs, but micelles likely have lower systemic Cmax due to sustained release preventing a plasma “spike.”

4.3 Comparison of Stability and Scalability

  • Generic: Rapamycin is unstable in aqueous mixtures and sensitive to hydrolysis. Solutions must be prepared ex tempore (immediately before use) or stored in high concentrations of DMSO, which is impractical for patient self-administration.
  • Micelles: The Sugandhi paper describes a lyophilizable system. PEG-PLA micelles can be freeze-dried into a powder and reconstituted or formulated as a stable nasal spray. The core-shell structure protects the rapamycin from degradation, offering a shelf-life suitable for commercial distribution.

Google Gemini Deep Search Details here: Comparative Pharmacological and Pharmaceutical Analysis of Intranasal Rapamycin Delivery Systems: Generic Solutions versus Brain-Targeting Polymeric Micelles

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