Source: https://guthlabs.ai/docs/instruments/drug-half-life-accumulation-elimination/implementation/

instrument implementation / implementation-contract

# Drug Half-Life Accumulation / Elimination implementation

A source-bound implementation contract for Drug Half-Life Accumulation / Elimination; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t6-007

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-half-life input creates undefined divisions in both the decay and accumulation formulas and should be rejected. The negative-concentration convention probe also exposes a validation hazard if the instrument accepts physically nonsensical signed concentrations without warning.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "model": "single-dose elimination",
    "C0_mg_per_L": 10,
    "half_life_h": 8,
    "time_h": 24
  },
  "expected_outputs": {
    "concentration_mg_per_L": 1.25,
    "curve_features": {
      "roots": "none at finite time for C0>0",
      "monotonicity": "strictly decreasing",
      "horizontal_asymptote_mg_per_L": 0
    }
  },
  "working": "t/t½=24/8=3. Therefore C(t)=10·(1/2)^3=10·1/8=1.25 mg/L. The exponential is positive for every finite t, decreases monotonically, and approaches 0 only as t approaches infinity."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/drug-half-life-accumulation-elimination/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/drug-half-life-accumulation-elimination/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/drug-half-life-accumulation-elimination/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`