Update combined static Vd and weight-based settings

src/components/settings.tsx

@@ -44,7 +44,7 @@ const getDefaultsForTranslation = (pkParams: any, therapeuticRange: any, uiSetti
     // Advanced Settings
     standardVdValue: defaults.pkParams.advanced.standardVd?.preset === 'adult' ? '377' : defaults.pkParams.advanced.standardVd?.preset === 'child' ? '175' : defaults.pkParams.advanced.standardVd?.customValue || '377',
     standardVdPreset: defaults.pkParams.advanced.standardVd?.preset || 'adult',
-    bodyWeight: defaults.pkParams.advanced.weightBasedVd.bodyWeight,
+    bodyWeight: defaults.pkParams.advanced.standardVd.bodyWeight,
     tmaxDelay: defaults.pkParams.advanced.foodEffect.tmaxDelay,
     fOral: defaults.pkParams.advanced.fOral,
     fOralPercent: String((parseFloat(defaults.pkParams.advanced.fOral) * 100).toFixed(1)),
@@ -374,7 +374,7 @@ const Settings = ({
                   </Tooltip>
               </div>
               {showTherapeuticRange && (
-                <div className="ml-8 space-y-2">
+                <div className="space-y-2">
                   <div className="flex items-center gap-2">
                     <Label className="font-medium">
                       {t('therapeuticRange')}
@@ -645,7 +645,7 @@ const Settings = ({
                   </Tooltip>
               </div>
               {steadyStateDaysEnabled && (
-                <div className="ml-8 space-y-2">
+                <div className="space-y-2">
                   <FormNumericInput
                     value={pkParams.advanced.steadyStateDays}
                     onChange={val => updateAdvancedDirect('steadyStateDays', val)}
@@ -827,7 +827,7 @@ const Settings = ({
               </div>
               <Select
                 value={pkParams.advanced.standardVd?.preset || 'adult'}
-                onValueChange={(value: 'adult' | 'child' | 'custom') => updateAdvanced('standardVd', 'preset', value)}
+                onValueChange={(value: 'adult' | 'child' | 'custom' | 'weight-based') => updateAdvanced('standardVd', 'preset', value)}
               >
                 <SelectTrigger className="w-[360px]">
                   <SelectValue />
@@ -836,15 +836,16 @@ const Settings = ({
                   <SelectItem value="adult">{t('standardVdPresetAdult')}</SelectItem>
                   <SelectItem value="child">{t('standardVdPresetChild')}</SelectItem>
                   <SelectItem value="custom">{t('standardVdPresetCustom')}</SelectItem>
+                  <SelectItem value="weight-based">{t('standardVdPresetWeightBased')}</SelectItem>
                 </SelectContent>
               </Select>
-              {pkParams.advanced.weightBasedVd.enabled && (
+              {pkParams.advanced.standardVd?.preset === 'weight-based' && (
                 <div className="ml-0 mt-2 p-2 bg-blue-50 dark:bg-blue-900/20 border border-blue-200 dark:border-blue-800 rounded text-xs text-blue-800 dark:text-blue-200">
-                  ⓘ Weight-based Vd is enabled below. This setting is currently overridden.
+                  ⓘ {t('weightBasedVdInfo')}
                 </div>
               )}
               {pkParams.advanced.standardVd?.preset === 'custom' && (
-                <div className="ml-8 mt-2">
+                <div className="mt-2">
                   <Label className="text-sm font-medium">{t('customVdValue')}</Label>
                   <FormNumericInput
                     value={pkParams.advanced.standardVd?.customValue || '377'}
@@ -857,45 +858,8 @@ const Settings = ({
                   />
                 </div>
               )}
-            </div>
-
-            <Separator className="my-4" />
-
-            {/* Weight-Based Vd */}
-            <div className="space-y-3">
-              {pkParams.advanced.weightBasedVd.enabled && (
-                <div className="p-2 bg-blue-50 dark:bg-blue-900/20 border border-blue-200 dark:border-blue-800 rounded text-xs text-blue-800 dark:text-blue-200 mb-3">
-                  ⓘ When enabled, this overrides the Standard Vd setting above. Disable to use Standard Vd presets (Adult/Child/Custom).
-                </div>
-              )}
-              <div className="flex items-center gap-3">
-                <Switch
-                  id="weightBasedVdEnabled"
-                  checked={pkParams.advanced.weightBasedVd.enabled}
-                  onCheckedChange={checked => updateAdvanced('weightBasedVd', 'enabled', checked)}
-                />
-                <Label htmlFor="weightBasedVdEnabled" className="font-medium">
-                  {t('weightBasedVdScaling')}
-                </Label>
-                  <Tooltip open={openTooltipId === 'weightBasedVd'} onOpenChange={(open) => setOpenTooltipId(open ? 'weightBasedVd' : null)}>
-                    <TooltipTrigger asChild>
-                      <button
-                        type="button"
-                        onClick={handleTooltipToggle('weightBasedVd')}
-                        onTouchStart={handleTooltipToggle('weightBasedVd')}
-                        className="inline-flex items-center justify-center rounded-sm text-muted-foreground hover:text-foreground focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2"
-                        aria-label={t('weightBasedVdTooltip')}
-                      >
-                        <Info className="h-4 w-4" />
-                      </button>
-                    </TooltipTrigger>
-                    <TooltipContent side={tooltipSide}>
-                      <p className="text-xs max-w-xs">{tWithDefaults(t, 'weightBasedVdTooltip', defaultsForT)}</p>
-                    </TooltipContent>
-                  </Tooltip>
-              </div>
-              {pkParams.advanced.weightBasedVd.enabled && (
-                <div className="ml-8 space-y-2">
+              {pkParams.advanced.standardVd?.preset === 'weight-based' && (
+                <div className="mt-2">
                   <div className="flex items-center gap-2">
                     <Label className="text-sm font-medium">{t('bodyWeight')}</Label>
                     <Tooltip open={openTooltipId === 'bodyWeight'} onOpenChange={(open) => setOpenTooltipId(open ? 'bodyWeight' : null)}>
@@ -916,8 +880,8 @@ const Settings = ({
                     </Tooltip>
                   </div>
                   <FormNumericInput
-                    value={pkParams.advanced.weightBasedVd.bodyWeight}
-                    onChange={val => updateAdvanced('weightBasedVd', 'bodyWeight', val)}
+                    value={pkParams.advanced.standardVd?.bodyWeight || '70'}
+                    onChange={val => updateAdvanced('standardVd', 'bodyWeight', val)}
                     increment={1}
                     min={20}
                     max={300}
@@ -930,8 +894,6 @@ const Settings = ({
 
             <Separator className="my-4" />
 
-            <Separator className="my-4" />
-
             {/* Food Effect Absorption Delay */}
             <div className="space-y-3">
               <div className="flex items-center gap-2">
@@ -1084,7 +1046,7 @@ const Settings = ({
                 </Tooltip>
               </div>
               {(pkParams.advanced.renalFunction?.enabled) && (
-                <div className="ml-8 space-y-2">
+                <div className="space-y-2">
                   <div className="flex items-center gap-2">
                     <Label className="text-sm font-medium">{t('renalFunctionSeverity')}</Label>
                   </div>

src/constants/defaults.ts

@@ -39,8 +39,7 @@ export const DEFAULT_F_ORAL = 0.96;
 
 // Type definitions
 export interface AdvancedSettings {
-  standardVd: { preset: 'adult' | 'child' | 'custom'; customValue: string }; // Volume of distribution (L)
-  weightBasedVd: { enabled: boolean; bodyWeight: string }; // kg
+  standardVd: { preset: 'adult' | 'child' | 'custom' | 'weight-based'; customValue: string; bodyWeight: string }; // Volume of distribution (L)
   foodEffect: { enabled: boolean; tmaxDelay: string }; // hours
   urinePh: { mode: 'normal' | 'acidic' | 'alkaline' }; // pH effect on elimination
   fOral: string; // bioavailability fraction
@@ -138,8 +137,7 @@ export const getDefaultState = (): AppState => ({
       absorptionHalfLife: '0.7' // Updated from 0.9 for better ~1h Tmax of prodrug
     },
     advanced: {
-      standardVd: { preset: 'adult', customValue: '377' }, // Adult: 377L (Roberts 2015), Child: ~150-200L
-      weightBasedVd: { enabled: false, bodyWeight: '70' }, // kg, adult average
+      standardVd: { preset: 'adult', customValue: '377', bodyWeight: '70' }, // Adult: 377L (Roberts 2015), Child: ~150-200L, Weight-based: ~5.4 L/kg
       foodEffect: { enabled: false, tmaxDelay: '1.0' }, // hours delay
       urinePh: { mode: 'normal' }, // 'normal' (6-7.5), 'acidic' (<6), 'alkaline' (>7.5)
       fOral: String(DEFAULT_F_ORAL), // 0.96 bioavailability

src/hooks/useAppState.ts

@@ -52,6 +52,38 @@ export const useAppState = () => {
               }
             }
           }
+
+          // Migrate weightBasedVd from old {enabled, bodyWeight} to new standardVd structure
+          const oldWeightBasedVd = (migratedPkParams.advanced as any).weightBasedVd;
+          if (oldWeightBasedVd && typeof oldWeightBasedVd === 'object' && 'enabled' in oldWeightBasedVd) {
+            // Old format detected: {enabled: boolean, bodyWeight: string}
+            if (oldWeightBasedVd.enabled) {
+              // Convert to new weight-based preset
+              migratedPkParams.advanced.standardVd = {
+                preset: 'weight-based',
+                customValue: migratedPkParams.advanced.standardVd?.customValue || '377',
+                bodyWeight: oldWeightBasedVd.bodyWeight || '70'
+              };
+            } else {
+              // Keep existing standardVd, but ensure bodyWeight is present
+              if (!migratedPkParams.advanced.standardVd?.bodyWeight) {
+                migratedPkParams.advanced.standardVd = {
+                  ...migratedPkParams.advanced.standardVd,
+                  bodyWeight: oldWeightBasedVd.bodyWeight || '70'
+                };
+              }
+            }
+            // Remove old weightBasedVd property
+            delete (migratedPkParams.advanced as any).weightBasedVd;
+          }
+
+          // Ensure bodyWeight exists in standardVd (for new installations or old formats)
+          if (!migratedPkParams.advanced.standardVd?.bodyWeight) {
+            migratedPkParams.advanced.standardVd = {
+              ...migratedPkParams.advanced.standardVd,
+              bodyWeight: '70'
+            };
+          }
         }
 
         // Validate numeric fields and replace empty/invalid values with defaults

src/locales/de.ts

@@ -79,11 +79,13 @@ export const de = {
   advancedSettings: "Erweiterte Einstellungen",
   advancedSettingsWarning: "⚠️ Diese Parameter beeinflussen die Simulationsgenauigkeit und können von Bevölkerungsdurchschnitten abweichen. Nur anpassen, wenn spezifische klinische Daten oder Forschungsreferenzen vorliegen.",
   standardVolumeOfDistribution: "Verteilungsvolumen (Vd)",
-  standardVdTooltip: "Definiert wie sich der Wirkstoff im Körper verteilt. Erwachsene: 377L (Roberts 2015), Kinder: ~150-200L. Beeinflusst alle Konzentrationsberechnungen. Nur für pädiatrische oder spezialisierte Simulationen ändern. Standard: {{standardVdValue}}L ({{standardVdPreset}}).",
+  standardVdTooltip: "Definiert wie sich der Wirkstoff im Körper verteilt. Erwachsene: 377L (Roberts 2015), Kinder: ~150-200L. Gewichtsbasierte Skalierung: ~5,4 L/kg (für Erwachsene >18 Jahre basierend auf [Populations-Pharmakokinetik](https://pmc.ncbi.nlm.nih.gov/articles/PMC5572767/)). Beeinflusst alle Konzentrationsberechnungen. Nur für pädiatrische oder spezialisierte Simulationen ändern. Standard: {{standardVdValue}}L ({{standardVdPreset}}).",
   standardVdPresetAdult: "Erwachsene (377L)",
   standardVdPresetChild: "Kinder (175L)",
   standardVdPresetCustom: "Benutzerdefiniert",
+  standardVdPresetWeightBased: "Gewichtsbasiert (~5,4 L/kg)",
   customVdValue: "Benutzerdefiniertes Vd (L)",
+  weightBasedVdInfo: "Gewichtsbasiertes Vd passt Plasmakonzentrationen basierend auf Körpergewicht an (~5,4 L/kg). Leichtere Personen → höhere Spitzen, schwerere → niedrigere Spitzen. Diese Option ist für Erwachsene (>18 Jahre) basierend auf der Populations-PK-Studie vorgesehen. Für pädiatrische Patienten verwenden Sie die Voreinstellung 'Kinder'.",
   xAxisTimeFormat: "Zeitformat",
   xAxisFormatContinuous: "Fortlaufend",
   xAxisFormatContinuousDesc: "Endlose Sequenz (0h, 6h, 12h...)",

src/locales/en.ts

@@ -78,11 +78,13 @@ export const en = {
   advancedSettings: "Advanced Settings",
   advancedSettingsWarning: "⚠️ These parameters affect simulation accuracy and may deviate from population averages. Adjust only if you have specific clinical data or research references.",
   standardVolumeOfDistribution: "Volume of Distribution (Vd)",
-  standardVdTooltip: "Defines how drug disperses in body. Adult: 377L (Roberts 2015), Child: ~150-200L. Affects all concentration calculations. Change only for pediatric or specialized simulations. Default: {{standardVdValue}}L ({{standardVdPreset}}).",
+  standardVdTooltip: "Defines how drug disperses in body. Adult: 377L (Roberts 2015), Child: ~150-200L. Weight-based scaling: ~5.4 L/kg (intended for adults >18 years based on [population PK analysis](https://pmc.ncbi.nlm.nih.gov/articles/PMC5572767/)). Affects all concentration calculations. Change only for pediatric or specialized simulations. Default: {{standardVdValue}}L ({{standardVdPreset}}).",
   standardVdPresetAdult: "Adult (377L)",
   standardVdPresetChild: "Child (175L)",
   standardVdPresetCustom: "Custom",
+  standardVdPresetWeightBased: "Weight-Based (~5.4 L/kg)",
   customVdValue: "Custom Vd (L)",
+  weightBasedVdInfo: "Weight-based Vd adjusts plasma concentrations based on body weight (~5.4 L/kg). Lighter persons → higher peaks, heavier → lower peaks. This option is intended for adults (>18 years) based on the population PK study. For pediatric patients, use the 'Child' preset.",
   xAxisTimeFormat: "Time Format",
   xAxisFormatContinuous: "Continuous",
   xAxisFormatContinuousDesc: "Endless sequence (0h, 6h, 12h...)",

src/utils/exportImport.ts

@@ -242,7 +242,7 @@ export const validateImportData = (data: any): ImportValidationResult => {
 
   // Validate advanced settings
   if (importData.advancedSettings !== undefined) {
-    const validCategories = ['standardVd', 'weightBasedVd', 'foodEffect', 'urinePh', 'fOral', 'steadyStateDays', 'ageGroup', 'renalFunction'];
+    const validCategories = ['standardVd', 'foodEffect', 'urinePh', 'fOral', 'steadyStateDays', 'ageGroup', 'renalFunction'];
     const importedCategories = Object.keys(importData.advancedSettings);
     const unknownCategories = importedCategories.filter(c => !validCategories.includes(c));
     if (unknownCategories.length > 0) {

src/utils/pharmacokinetics.ts

@@ -186,13 +186,13 @@ export const calculateSingleDoseConcentration = (
     }
   }
 
-  // Weight-based Vd scaling (OVERRIDES preset if enabled)
+  // Weight-based Vd scaling (selected as 'weight-based' preset)
   // Research Section 8.1: Vd_damph ≈ 5.4 L/kg body weight
   // Lighter person → smaller Vd → higher concentration
   // Heavier person → larger Vd → lower concentration
   let effectiveVd_damph = baseVd_damph;
-  if (pkParams.advanced.weightBasedVd.enabled) {
-    const bodyWeight = parseFloat(pkParams.advanced.weightBasedVd.bodyWeight);
+  if (pkParams.advanced.standardVd && pkParams.advanced.standardVd.preset === 'weight-based') {
+    const bodyWeight = parseFloat(pkParams.advanced.standardVd.bodyWeight);
     if (!isNaN(bodyWeight) && bodyWeight > 0) {
       effectiveVd_damph = bodyWeight * 5.4; // L/kg factor from literature
     }