Source: https://guthlabs.ai/docs/instruments/loading-maintenance-dose-calculator/mechanism/

instrument mechanism / verified-clean

# Loading & Maintenance Dose Calculator mechanism

The inspectable method record for Loading & Maintenance Dose Calculator, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The formulas are valid simplified pharmacokinetic formulas under consistent units, first-order linear kinetics, and F = 1. The specification needs an explicit distinction between maintenance dose per interval and maintenance rate, plus an explicit bioavailability assumption and target-concentration definition. The existing educational-only, not-medical-advice label is appropriate but does not resolve these ambiguities.

- MD = target concentration × clearance × dosing interval is the standard maintenance dose per dosing interval, not a maintenance rate; the maintenance rate would be target concentration × clearance. The output label 'maintenance dose/rate' is ambiguous.

- Both formulas implicitly assume bioavailability F = 1. If oral, extravascular, or otherwise incomplete administration is supported, the standard formulas require division by F: LD = Cp,target × Vd / F and maintenance dose = Cp,target × CL × τ / F.

- The loading-dose formula assumes the target concentration is the concentration to be achieved immediately and that the relevant volume of distribution is known; the target may need to be distinguished as target steady-state average, peak, or trough concentration.

## Units and conventions

- Target concentration must use concentration units compatible with clearance and volume of distribution; for example, mg/L with Vd in L and CL in L/h.

- Vd must be in volume units and clearance in volume-per-time units.

- Dosing interval τ must be in the same time unit used in clearance; with CL in L/h, τ must be in hours.

- With mg/L, L, and hours, loading dose and maintenance dose are in mg, and maintenance rate is in mg/h.

- The calculations assume F = 1, no dose rounding, and no unit conversion beyond explicitly supplied inputs.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "target_concentration": "10 mg/L",
    "Vd": "35 L",
    "clearance": "4.2 L/h",
    "dosing_interval": "12 h"
  },
  "expected_outputs": {
    "loading_dose": "350 mg",
    "maintenance_dose_per_interval": "504 mg",
    "maintenance_rate": "42 mg/h"
  },
  "working": "Loading dose = 10 mg/L × 35 L = 350 mg. Maintenance dose = 10 mg/L × 4.2 L/h × 12 h = 42 mg/h × 12 h = 504 mg. Maintenance rate = 10 mg/L × 4.2 L/h = 42 mg/h."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The extreme-magnitude vector produces Infinity for both outputs under plain JavaScript arithmetic. The instrument should reject non-finite inputs or outputs rather than display Infinity as a usable educational dose. The specification also contains no actual formula branch, so an implementation inventing a threshold-based branch would be unsupported.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/loading-maintenance-dose-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/loading-maintenance-dose-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/loading-maintenance-dose-calculator/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-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`