Intrinsic dissolution rate (IDR) refers to the rate at which a pure drug substance dissolves under controlled conditions. It specifically measures the speed of the drug releasing from its solid form into a solution. More specifically, it is the dissolution rate of pure substances under the condition of constant surface area. The dissolution rate and bioavailability of a drug substance are influenced by extrinsic factors, such as hydrodynamics and test conditions (pH, temperature, fluid viscosity and buffer strength in the case of ionizable compounds.) By exposing the surface area of a material to an appropriate dissolution medium while maintaining constant temperature, stirring rate, and pH, the IDR can be determined. Typically, IDR is expressed in terms of mg per minute per cm2.
The intrinsic dissolution rate (IDR) of active pharmaceutical ingredients (API) is a key property that aids in early drug development, especially selecting formulation strategies to improve dissolution and thereby drug absorption in the intestine. Intrinsic dissolution rate is a fundamental concept in pharmaceutical research and development, particularly in the context of oral solid dosage forms.
The IDR is an important parameter in pharmaceutical development because it can help predict the bioavailability and pharmacokinetic properties of a drug. For example, a drug with a high IDR may be more likely to be absorbed quickly and efficiently, while a drug with a low IDR may be more likely to be absorbed slowly.
Intrinsic dissolution rate is also used to predict the performance of different formulations, such as tablets and capsules. By measuring the IDR of a drug, researchers can predict how well the drug will dissolve in different formulations and how it will affect the overall performance of the product.
There are several factors that can influence the IDR of a drug, including:
1. Solubility: The intrinsic solubility of the drug in the solvent can affect its IDR.
2. Particle size: The size of the drug particles can affect their surface area and, therefore, their IDR.
3. Surface roughness: The surface roughness of the drug particles can affect their IDR.
4. pH: The pH of the solvent can affect the ionization state of the drug and its IDR.
5. Temperature: The temperature of the solvent can affect the kinetic energy of the molecules and, therefore, their IDR.
Pion’s Rainbow Dynamic Dissolution Monitoring system is a useful tool for measuring intrinsic dissolution rates in real-time. When coupled with low-volume accessories such as our MicroDISS for volumes from 2-20ml, intrinsic dissolution rates may be evaluated from small amounts of sample to understand how a drug will release in the body so you may abandon or optimize lead compounds with confidence. Lastly, our BEE brand homogenizers are heavily used to reduce particle size (micronization) to impact intrinsic dissolution rates when developing new drugs.
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