Durgamata Institute of Pharmacy, Dharmapuri, Parbhani, Maharashtra 431401
Oral drug delivery remains the most preferred route of administration due to its convenience, cost-effectiveness, and patient compliance. However, conventional oral dosage forms often suffer from limitations such as short gastric residence time, fluctuating plasma drug concentrations, and incomplete drug absorption. Gastro-retentive drug delivery systems (GRDDS) have emerged as a promising strategy to overcome these drawbacks. Among them, floating multiparticulate drug delivery systems (FM-DDS) represent an advanced approach that enhances gastric retention by maintaining buoyancy in gastric fluids. These systems provide controlled and sustained drug release, improve bioavailability of drugs with narrow absorption windows, and minimize side effects. This review comprehensively discusses the physiological basis of gastric retention, factors affecting gastric emptying, suitable drug candidates, classification of floating systems, formulation approaches, preparation techniques, characterization methods, advantages, limitations, applications, and future perspectives of floating multiparticulate drug delivery systems.
Oral controlled drug delivery systems have gained significant attention due to their ability to maintain therapeutic drug concentrations for extended periods. Despite numerous advancements, conventional oral dosage forms such as tablets and capsules are often associated with rapid gastric emptying, resulting in incomplete drug absorption and reduced therapeutic efficacy. [1]
The stomach presents a favorable absorption site for certain drugs, particularly those: [2]
Gastro-retentive drug delivery systems (GRDDS) are designed to prolong gastric residence time (GRT). These systems include:
Among these, floating multiparticulate systems have emerged as a superior alternative to single-unit floating systems due to reduced risk of dose dumping, uniform distribution in the gastrointestinal tract, and improved reproducibility of drug absorption. [3]
Fig: Gastro-retentive drug delivery systems
2. Physiology of the Stomach and Basis of Gastric Retention [4,5]
The stomach is anatomically divided into:
Gastric motility follows a cyclic pattern known as the Migrating Myoelectric Complex (MMC), which consists of four phases:
During the fasted state, the burst phase can rapidly empty indigestible materials from the stomach. Therefore, designing dosage forms that resist this process is critical for effective gastric retention. Floating systems achieve retention by maintaining a bulk density lower than gastric fluid (~1.004 g/cm³), enabling buoyancy over gastric contents.
3. Factors Affecting Gastric Emptying [6,7]
Gastric retention is influenced by multiple physiological and formulation-related factors:
Fig: Factors Affecting Gastric Emptying
3.1 Dosage Form Factors
3.2 Physiological Factors
3.3 Pharmacological Factors
Understanding these factors is essential for designing effective floating multiparticulate systems.
4. Suitable Drug Candidates [8,9]
Floating multiparticulate systems are ideal for:
4.1 Drugs with Narrow Absorption Window
4.2 Drugs Absorbed Mainly in Stomach/Upper GIT
4.3 Drugs Acting Locally in the Stomach
4.4 Drugs Unstable in Intestinal pH
4.5 Drugs That Disturb Colonic Flora
5. Floating Multiparticulate Drug Delivery Systems [10,11]
Multiparticulate systems consist of small discrete units such as:
Fig: Floating Multiparticulate Drug Delivery Systems
These systems distribute uniformly in the stomach and reduce the risk of localized irritation. Floating multiparticulates remain buoyant due to entrapped air, hollow core formation, or gas generation.
Advantages over single-unit systems include:
6. Classification of Floating Drug Delivery Systems [12]
Floating systems are broadly classified into:
6.1 Effervescent Systems
These systems contain gas-generating agents such as:
Upon contact with gastric fluid, carbon dioxide is released and trapped within the polymer matrix, enabling buoyancy.
Mechanism:
CO₂ generation → Entrapment in gel matrix → Reduced density → Floating
6.2 Non-Effervescent Systems
These systems rely on swellable polymers such as:
Upon hydration, polymers swell and entrap air, lowering system density.
7. Methods of Preparation of Floating Multiparticulates [13]
7.1 Solvent Evaporation Method
Advantages:
7.2 Ionotropic Gelation Method [14]
Based on cross-linking of polyelectrolytes with counter ions.
Common polymers:
Mechanism:
Polymer solution dropped into calcium chloride solution → Ionic cross-linking → Bead formation
Advantages:
7.3 Emulsion Solvent Diffusion Method [15]
Produces hollow microspheres (microballoons).
7.4 Spray Drying Method [16]
Suitable for large-scale production.
8. Characterization of Floating Multiparticulate Systems [17]
8.1 Micromeritic Properties
8.2 Particle Size and Morphology
8.3 Encapsulation Efficiency [18]
%Entrapment=Actual Drug Content Theoretical Drug Content×100\% Entrapment = \frac{Actual\ Drug\ Content}{Theoretical\ Drug\ Content} \times 100%Entrapment=Theoretical Drug Content Actual Drug Content×100
8.4 Buoyancy Studies [19]
Floating percentage calculated as:
Buoyancy (%) =WfWf+Ws×100Buoyancy (\%) = \frac{W_f}{W_f + W_s} \times 100Buoyancy(%)=Wf+WsWf×100
Where:
8.5 In-Vitro Drug Release Studies [20]
Drug release kinetics analyzed using:
8.6 In-Vivo Studies [21]
9. Advantages of Floating Multiparticulate Systems [22]
10. Limitations [23]
11. Applications [24]
11.1 Sustained Drug Delivery
Floating microspheres of NSAIDs reduce gastric irritation while maintaining therapeutic levels.
11.2 Site-Specific Delivery
Effective for drugs targeting:
11.3 Absorption Enhancement
Improves bioavailability of drugs with upper GIT absorption.
11.4 Treatment of Gastric Disorders [25]
FUTURE SCOPE
Future research focuses on:
Emerging technologies such as 3D printing may enable personalized gastro-retentive dosage forms.
CONCLUSION
Floating multiparticulate drug delivery systems represent a significant advancement in gastro-retentive drug delivery. By prolonging gastric residence time and enabling controlled drug release, these systems enhance bioavailability and therapeutic efficacy while minimizing side effects. Multiparticulate approaches provide superior performance compared to single-unit systems due to uniform distribution and reduced dose dumping risk. With continued advancements in polymer science and pharmaceutical engineering, floating multiparticulate systems are expected to play pivotal role in future oral drug delivery technologies.
REFERENCES
Rokade S. G.*, Milke U. R., Sheikh S. S., Floating Multi-particulate Drug Delivery Systems: A Comprehensive Review, Int. J. Med. Pharm. Sci., 2026, 2 (3), 335-341. https://doi.org/10.5281/zenodo.19135068
10.5281/zenodo.19135068
