MedChain TN

AI + Blockchain Medical Inventory Management System for Tamil Nadu Healthcare Supply Chain

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Table of Contents

• Problem Statement
• Solution
• System Architecture
• Tech Stack
• Repository Structure
• Getting Started
• Dataset Plan
• Smart Contracts
• ML Service
• API Reference
• Mobile App
• Demo Flow

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Problem Statement

Tamil Nadu's healthcare supply chain serving 77 million people suffers from five critical failures:

Problem	Impact
No demand forecasting	Drug shortages during malaria & dengue seasons
Mutable inventory records	Stock manipulation goes undetected
No drug verification	Counterfeit medicines reach patients
Poor expiry management	~18% of batches wasted
No decision support	Reactive, manual procurement decisions

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Solution

MedChain TN combines blockchain immutability with AI intelligence to fix every layer of the supply chain.

Blockchain  →  tamper-proof batch records + ownership transfers
AI          →  demand forecasting + anomaly detection + expiry prediction
Mobile App  →  unified interface for manufacturers, distributors, patients

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System Architecture

┌─────────────────────────────────────────────┐
│           React Native Expo App             │
│  ┌──────────┬──────────────┬─────────────┐  │
│  │ Patient  │ Distributor  │Manufacturer │  │
│  │ 4 Tabs   │   4 Tabs     │   4 Tabs    │  │
│  └────┬─────┴──────┬───────┴──────┬──────┘  │
└───────┼────────────┼──────────────┼──────────┘
        └────────────┼──────────────┘
                     │ HTTPS / REST + JWT
        ┌────────────▼─────────────┐
        │    Node.js API Gateway   │
        │    JWT + RBAC Middleware │
        └──┬───────────┬───────────┘
           │           │
    ┌──────▼───┐  ┌────▼─────────┐
    │PostgreSQL│  │ Flask ML API │
    │ + Redis  │  │  3 Modules   │
    └──────────┘  └──────────────┘
           │
    ┌──────▼──────────────────┐
    │      ethers.js          │
    │         ↕               │
    │  Ganache Local Chain    │
    │  4 Solidity Contracts   │
    └─────────────────────────┘

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Tech Stack

Layer	Technology
Mobile App	React Native + Expo SDK 51
Backend	Node.js + Express
ML Service	Python + Flask
Database	PostgreSQL + Redis
Blockchain	Solidity + Hardhat + Ganache
ML Models	scikit-learn, XGBoost, Prophet, Keras
Maps	react-native-maps
Charts	victory-native
Auth	JWT + expo-secure-store

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Repository Structure

/medchain-tn
  /mobile                   ← Expo React Native app
    /app
      /_layout.tsx
      /auth/
      /(patient)/
      /(distributor)/
      /(manufacturer)/
    /components
      /shared/
      /patient/
      /distributor/
      /manufacturer/
    /hooks/
    /services/
  /backend                  ← Node.js API Gateway
    /src
      /routes/
      /controllers/
      /middleware/
      /blockchain/
      /ml/
      /db/
    app.js
  /ml-service               ← Python Flask ML API
    /data
      /raw/
      /processed/
      /synthetic/
    /models/
    /notebooks/
    /src
      /features/
      /training/
      /evaluation/
      /api/
    app.py
  /contracts                ← Solidity Smart Contracts
    /contracts/
      MedAccessControl.sol
      MedBatch.sol
      MedTransfer.sol
      MedAudit.sol
    /scripts/
    /test/
    hardhat.config.js
  /data                     ← Dataset generation
    /synthetic/
      constants.py
      generate_usage.py
      generate_movements.py
      generate_expiry.py
      generate_regional.py
      run_all.py
  /docs/
  docker-compose.yml
  README.md

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Getting Started

Prerequisites

node >= 18
python >= 3.10
docker + docker-compose
ganache (desktop or CLI)
expo-cli

1. Clone the Repository

git clone https://github.com/your-org/medchain-tn.git
cd medchain-tn

2. Set Up Environment Variables

cp .env.example .env

Fill in your .env:

# Ganache
GANACHE_RPC_URL=http://127.0.0.1:7545
GANACHE_CHAIN_ID=1337
GANACHE_MNEMONIC="your twelve word mnemonic from ganache ui"
GANACHE_PRIVATE_KEY_ADMIN=0x...
GANACHE_PRIVATE_KEY_MANUFACTURER=0x...
GANACHE_PRIVATE_KEY_DISTRIBUTOR=0x...

# PostgreSQL
POSTGRES_URL=postgresql://medchain:password@localhost:5432/medchain_tn

# Redis
REDIS_URL=redis://localhost:6379

# JWT
JWT_SECRET=your_jwt_secret_here
JWT_EXPIRES_IN=24h

# ML Service
ML_SERVICE_URL=http://localhost:5000

3. Start All Services

docker-compose up -d

This starts: Ganache · PostgreSQL · Redis · Node Backend · Flask ML Service

4. Deploy Smart Contracts

cd contracts
npm install
npx hardhat run scripts/deploy.js --network ganache
npx hardhat run scripts/seed.js --network ganache

5. Generate Datasets + Train ML Models

cd data/synthetic
pip install -r requirements.txt
python run_all.py

cd ../../ml-service
pip install -r requirements.txt
python src/training/train_all.py

6. Start the Mobile App

cd mobile
npm install
npx expo start

Scan the QR code with Expo Go on your device.

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📊 Dataset Plan

Three datasets covering Tamil Nadu's pharmaceutical supply chain across 10 districts, 12 drugs, 3 facility types, 24 months.

Dataset	Rows	Purpose
Drug Usage History	~3,500	Demand Forecasting
Stock Movement Log	~5,000	Anomaly Detection
Batch Expiry & Wastage	~2,000	Expiry Prediction

Districts Covered

Chennai · Coimbatore · Madurai · Trichy · Salem
Tirunelveli · Vellore · Erode · Thoothukudi · Kanchipuram

Drugs Covered

Paracetamol · Amoxicillin · Metformin · Ibuprofen · Omeprazole
Amlodipine · Artemether · Ciprofloxacin · Insulin · Salbutamol
Ondansetron · Chloroquine

Disease Season Flags (Tamil Nadu)

Dengue / Vector-borne   Oct–Jan   → Paracetamol, Ciprofloxacin
Malaria                 Jun–Sep   → Artemether, Chloroquine
Respiratory             Dec–Feb   → Salbutamol, Amoxicillin
Gastroenteritis         May–Jun   → Ondansetron, Omeprazole
Diabetes                Oct–Nov   → Metformin, Insulin

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⛓️ Smart Contracts

Contracts Overview

Contract	Responsibility
MedAccessControl.sol	Role management (Admin, Manufacturer, Distributor, Patient)
MedBatch.sol	Drug batch registration + QR hash storage
MedTransfer.sol	Ownership transfer between supply chain participants
MedAudit.sol	Expiry tracking + immutable audit trail

Network Configuration

Development:   Ganache local   (port 7545, chainId 1337)
Testing:       Polygon Amoy Testnet
Production:    Polygon PoS Mainnet

Key Contract Functions

// MedBatch.sol
registerBatch(drugName, region, quantity, expiryDate, qrHash)
getBatch(batchId)
verifyBatch(batchId) → isValid, status

// MedTransfer.sol
initiateTransfer(batchId, to, quantity, toRegion)
acceptTransfer(transferId)
getTransferHistory(batchId)

// MedAudit.sol
getAuditTrail(batchId)
getExpiringBatches(withinDays)

Running Tests

cd contracts
npx hardhat test --network ganache

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ML Service

3 Intelligence Modules

Module 1 — Demand Forecasting

Models:    Random Forest · XGBoost · Facebook Prophet
Endpoint:  POST /predict/demand
Output:    predicted_qty_30d, predicted_qty_60d, predicted_qty_90d,
           confidence_interval, reorder_recommendation

Module 2 — Anomaly Detection

Models:    Isolation Forest · Autoencoder (Keras) · Z-Score
Endpoint:  POST /anomaly/detect
Output:    is_anomaly, anomaly_type, confidence_score,
           flagged_features, recommended_action

Module 3 — Expiry Waste Prediction

Models:    Gradient Boosting · Logistic Regression · Survival Analysis
Endpoint:  POST /predict/expiry
Output:    expiry_risk, probability_of_waste,
           redistribution_recommendation

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API Reference

Auth

POST  /auth/login
POST  /auth/logout
GET   /auth/me

Drugs

GET   /drugs
GET   /drugs/:id
POST  /drugs

Blockchain

POST  /batch/register
GET   /batch/:batchId
GET   /batch/verify/:qrHash
POST  /transfer/initiate
POST  /transfer/accept
POST  /transfer/reject
GET   /audit/:batchId

ML Predictions

GET   /predict/demand
POST  /anomaly/detect
POST  /predict/expiry

Alerts

GET   /alerts
PATCH /alerts/:id/resolve

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Mobile App

User Roles & Tab Structure

Patient (4 Tabs)

Home          ← drug search + availability + stock status
Scan QR       ← verify drug authenticity via blockchain
Prescriptions ← track active + past prescriptions
Notifications ← low stock alerts for prescribed medicines

Distributor (4 Tabs)

Inventory     ← stock levels, batch breakdown, incoming shipments
Transfers     ← initiate + accept + track batch transfers
Forecast      ← AI demand predictions 30/60/90 days
Chain History ← full blockchain transaction log

Manufacturer (4 Tabs)

Add Batch     ← register drug batch on blockchain + generate QR
Supply Chain  ← map view of all batches + regional distribution
Distributors  ← activity, stock levels, demand vs supply gaps
Alerts        ← anomaly feed + expiry warnings + resolve actions

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Demo Flow

End-to-end demo in 5 steps:

Step 1 — Manufacturer registers a Artemether batch
         → batch written to Ganache chain
         → QR code generated

Step 2 — Manufacturer transfers batch to Madurai distributor
         → transfer pending on-chain

Step 3 — Distributor accepts transfer
         → ownership updated on-chain
         → inventory dashboard reflects new stock

Step 4 — Patient scans QR code
         → app queries blockchain
         → authenticity confirmed: manufacturer, expiry, chain of custody shown

Step 5 — Anomaly alert fires
         → ML service flags unusual stock drop on Insulin batch
         → manufacturer sees alert with confidence score 0.91
         → alert escalated for investigation

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Security

✓ JWT required on all non-public endpoints
✓ RBAC middleware checks role before every write operation
✓ Private keys never exposed to mobile app
✓ All blockchain writes go through Node backend server wallet
✓ Patient role is read-only — zero write access to chain
✓ Anomaly alerts auto-escalate at confidence score > 0.85
✓ Ganache --deterministic flag keeps wallet addresses stable across restarts

Built for Tamil Nadu. Designed for every healthcare supply chain.