GastroPlus

GastroPlus® is the leading physiologically based pharmacokinetic (PBPK) and physiologically based biopharmaceutics modeling (PBBM) software platform developed by Simulations Plus. Designed to support researchers and modelers across the full drug development lifecycle — from early internal research through regulatory filings — GastroPlus enables mechanistic simulation of drug absorption, bioavailability, pharmacokinetics, and pharmacodynamics across multiple routes of administration and species.

The platform is built for both new and experienced modelers, combining a user-friendly interface with advanced capabilities including an AI-powered chatbot (GastroPlusGPT™), an embedded model assessment assistant, and REST API and R/Python script integration to streamline complex workflows. GastroPlus predictions are consistently ranked number one in independent comparisons, reflecting the platform's commitment to implementing best-in-class scientific theories and novel modeling approaches.

Supported Routes of Administration and Simulation Capabilities

• Intravenous, oral, oral cavity, ocular, inhalation, dermal, subcutaneous, and intramuscular absorption
• Biopharmaceutics, pharmacokinetics, and pharmacodynamics modeling in humans and animals
• Simulation of different dosing scenarios to anticipate and avoid costly surprises during development
• Generation of model outputs that can potentially support waivers for expensive regulatory studies

Key Platform Features

• Simple, intuitive user interface suitable for modelers at all experience levels
• Model customization to accommodate unique research needs
• High-quality, publication-ready plots and figures for reporting
• Embedded assistant for real-time model assessment and optimization suggestions
• GastroPlusGPT™ AI-powered chatbot for instant answers to technical and operational questions
• REST API and R/Python script support to automate and streamline custom or complex workflows with a single click
• Integrated AI/ML technologies to support model development and operational assistance
• Flexible licensing models including options for incubators and biotech startups
• Thriving online GastroPlus User Group for community support and sharing of best practices
• Excellent customer support and multiple learning journeys available

Available Modules

• Additional Dosage Routes — extending simulation beyond standard oral and IV administration
• ADMET Predictor® integration — use top-rated QSAR models to define PBPK and PBBM inputs
• AssessmentsPlus™ — embedded model assessment capabilities
• Biologics — modeling support for biologic drug candidates
• Drug-Drug Interaction (DDI) — predict and analyze DDI scenarios
• GastroPlusGPT™ — AI-powered chatbot for real-time modeling assistance
• IVIVCPlus™ — in vitro–in vivo correlation modeling
• Metabolism & Transporter — nonlinear metabolism and transport modeling
• Optimization — parameter and formulation optimization tools
• Orchestrator — workflow automation and orchestration
• PBPKPlus™ — advanced PBPK modeling capabilities
• PDPlus™ — pharmacodynamic modeling
• PKPlus™ — compartmental pharmacokinetic modeling
• P-PSD — particle size distribution modeling

On-Demand Training and Courses

• GastroPlus® X Tutorial Series II — an 8-module free introductory series covering absorption, ACAT, bioequivalence, compartmental PK, DDI, IVIVC, metabolism and transporter, PBPK, PDPlus™, PK/PD, and PKPlus™
• Introduction to DDDPlus™ — a 2-module course covering solubility versus pH, particle size effects, biorelevant solubility, precipitation modeling, extended-release formulations, surfactant media dissolution, and disintegration or solubilizer constants
• Introduction to DDI Predictions Bundle — a 3-module course covering basic software use, nonlinear metabolism and transport, and drug-drug interaction predictions with hands-on exercises

Ecosystem Integrations

• ADMET Predictor® for QSAR-based input definition for PBPK and PBBM models
• DDDPlus™ and MembranePlus™ for strengthening in vitro–in vivo extrapolation of dissolution and absorption inputs
• DILIsym® and NAFLDsym® for quantitative systems pharmacology and toxicology models predicting drug-induced liver injury (DILI), non-alcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH)

GastroPlus supports regulatory submissions and has been applied across a broad range of drug development contexts, with an extensive body of peer-reviewed publications demonstrating its scientific credibility. The platform is actively developed with regular updates, and Simulations Plus participates in major scientific meetings and webinars to keep the user community informed of the latest advances in PBPK and PBBM modeling.