Role of Solid Dispersions in Enhancing Bioavailability of BCS Class II Drugs

Alves Rodrigue^*
*Correspondence: Alves Rodrigue, Department of Pharmaceutical Technology and Biopharmacy, University of Pennsylvania, Philadelphia, PA 19104, USA, Email:

Introduction

The bioavailability of BCS Class II drugs, characterized by high permeability but low solubility, poses significant challenges in pharmaceutical development. Solid dispersions have emerged as a promising technique to enhance the solubility and consequently the bioavailability of these drugs. This review explores the principles behind solid dispersions, their impact on the bioavailability of BCS Class II drugs and recent advancements in formulation strategies. It also discusses the challenges and future directions for research in this area.

Biopharmaceutical Classification System (BCS) Class II drugs are known for their high permeability across biological membranes but suffer from poor solubility in aqueous environments. This solubility issue leads to inadequate bioavailability, affecting the therapeutic efficacy of these drugs. Solid dispersions represent one of the most effective strategies for improving the solubility and bioavailability of BCS Class II drugs. This article reviews the role of solid dispersions in enhancing the bioavailability of these drugs, focusing on various formulation techniques, mechanisms of action and recent advancements.

Description

Solid dispersions involve the dispersion of a drug in a solid matrix, typically a polymer or a hydrophilic carrier. The primary goal is to increase the surface area of the drug, enhance its wettability and improve its dissolution rate [1]. There are several types of solid dispersions, including:

Simple physical mixtures of drug and carrier where the drug melts at a lower temperature than its melting point.

The bioavailability of BCS Class II drugs, characterized by high permeability but low solubility, poses significant challenges in pharmaceutical development. Solid dispersions have emerged as a promising technique to enhance the solubility and consequently the bioavailability of these drugs. This review explores the principles behind solid dispersions, their impact on the bioavailability of BCS Class II drugs and recent advancements in formulation strategies. It also discusses the challenges and future directions for research in this area.

Biopharmaceutical Classification System (BCS) Class II drugs are known for their high permeability across biological membranes but suffer from poor solubility in aqueous environments. This solubility issue leads to inadequate bioavailability, affecting the therapeutic efficacy of these drugs. Solid dispersions represent one of the most effective strategies for improving the solubility and bioavailability of BCS Class II drugs. This article reviews the role of solid dispersions in enhancing the bioavailability of these drugs, focusing on various formulation techniques, mechanisms of action and recent advancements [2].

Solid dispersions involve the dispersion of a drug in a solid matrix, typically a polymer or a hydrophilic carrier. The primary goal is to increase the surface area of the drug, enhance its wettability and improve its dissolution rate. There are several types of solid dispersions, including:

• Eutectic mixtures: Simple physical mixtures of drug and carrier where the drug melts at a lower temperature than its melting point.
• Co-evaporates: Drug and carrier are co-evaporated to form a solid solution.
• Melt extrusions: Drug and polymer are melted and extruded to form a homogeneous mixture.
• Spray drying: Drug and carrier are dissolved in a solvent and then spray-dried to form a solid dispersion.

The enhancement of bioavailability through solid dispersions can be attributed to several mechanisms:

• Improved dissolution rate: Solid dispersions increase the drug's surface area and wettability, leading to a faster dissolution rate in gastrointestinal fluids.
• Enhanced solubility: The drug is often molecularly dispersed in the carrier, which can significantly increase its solubility.
• Reduced particle size: The process of forming solid dispersions often reduces the particle size of the drug, leading to a larger surface area for dissolution [3].

Recent advancements in formulation strategies for solid dispersions include:

• Use of novel polymers: The development of new polymers with better solubilizing properties and compatibility with the drug.
• Nanotechnology: The application of nanotechnology to create nanoparticles and nanosuspensions that improve drug dissolution and absorption.
• Incorporation of surfactants: Surfactants can be used to enhance the wettability and solubility of the drug in the dispersion.

Despite their benefits, solid dispersions face several challenges:

• Stability issues: Solid dispersions can suffer from physical and chemical instability over time.
• Manufacturing difficulties: The production of solid dispersions can be complex and expensive.
• Scale-up problems: Translating lab-scale formulations to commercial production can be challenging.

Future research in solid dispersions may focus on:

• Development of more effective carriers: Finding carriers that provide better solubility and stability for a wider range of drugs.
• Advanced processing techniques: Exploring new processing methods that improve the efficiency and scalability of solid dispersion production.
• Personalized medicine: Tailoring solid dispersion formulations to individual patient needs based on genetic and physiological factors [4].

The enhancement of bioavailability through solid dispersions can be attributed to several mechanisms:

• Improved dissolution rate: Solid dispersions increase the drug's surface area and wettability, leading to a faster dissolution rate in gastrointestinal fluids.
• Enhanced solubility: The drug is often molecularly dispersed in the carrier, which can significantly increase its solubility.
• Reduced particle size: The process of forming solid dispersions often reduces the particle size of the drug, leading to a larger surface area for dissolution.

Recent advancements in formulation strategies for solid dispersions include:

• Use of novel polymers: The development of new polymers with better solubilizing properties and compatibility with the drug.
• Nanotechnology: The application of nanotechnology to create nanoparticles and nanosuspensions that improve drug dissolution and absorption.
• Incorporation of surfactants: Surfactants can be used to enhance the wettability and solubility of the drug in the dispersion.

Despite their benefits, solid dispersions face several challenges:

• Stability issues: Solid dispersions can suffer from physical and chemical instability over time.
• Manufacturing difficulties: The production of solid dispersions can be complex and expensive.
• Scale-up problems: Translating lab-scale formulations to commercial production can be challenging.

Future research in solid dispersions may focus on:

• Development of more effective carriers: Finding carriers that provide better solubility and stability for a wider range of drugs.
• Advanced processing techniques: Exploring new processing methods that improve the efficiency and scalability of solid dispersion production.
• Personalized medicine: Tailoring solid dispersion formulations to individual patient needs based on genetic and physiological factors [5].

Conclusion

Solid dispersions play a crucial role in overcoming the solubility challenges associated with BCS Class II drugs. Through various formulation techniques and advancements in technology, solid dispersions have significantly enhanced the bioavailability of these drugs, thereby improving their therapeutic efficacy. Continued research and innovation in this field are essential to address existing challenges and optimize the benefits of solid dispersions for better patient outcomes.

Acknowledgement

None.

Conflict of Interest

None.

References

1. McGhie, Tony K. and Michaela C. Walton. "The bioavailability and absorption of anthocyanins: towards a better understanding."Mol Nutr Food Res51 (2007): 702-713.

   Google Scholar, Crossref, Indexed at

2. Wallace, Taylor C. and M. Monica Giusti. "Anthocyanins."Adv Nutr 6 (2015): 620.

   Google Scholar, Crossref, Indexed at

3. Krga, Irena and Dragan Milenkovic. "Anthocyanins: From sources and bioavailability to cardiovascular-health benefits and molecular mechanisms of action."J Agric Food Chem67 (2019): 1771-1783.

   Google Scholar, Crossref, Indexed at

4. Cooper, Jason P., C. Patrick Reynolds, Hwangeui Cho and Min H. Kang. "Clinical development of fenretinide as an antineoplastic drug: Pharmacology perspectives."Exp Biol Med242 (2017): 1178-1184.

   Google Scholar, Crossref, Indexed at

5. Orienti, Isabella, Federica Francescangeli, Maria Laura De Angelis and Katia Fecchi, et al. "A new bioavailable fenretinide formulation with antiproliferative, antimetabolic and cytotoxic effects on solid tumors."Cell Death Dis10 2019): 529.

   Google Scholar, Crossref, Indexed at