Gastrointestinal-Targeted Drug Delivery Systems

CD Bioparticles offers a comprehensive platform for the design, synthesis, ligand conjugation, modification, and evaluation of drug delivery carriers based on nano-carriers for Gastrointestinal tract targeting. Our professional carrier construction, combined with in vivo and in vitro analysis and characterization, enables us to provide a range of products and services that meet the unique needs of Gastrointestinal tract targeted drug delivery systems. We provide full support for early development, leveraging the specific characteristics of the Gastrointestinal tract to ensure optimal efficacy.

Introduction to GI-Targeted Drug Delivery Systems

The gastrointestinal (GI) tract is composed of four major compartments that play a critical role in drug release and absorption: the mouth, stomach, small intestine, and large intestine. Each section of the GI tract has distinct biochemical, acidic, fluid, and enzyme characteristics that pose targeting challenges for orally administered drugs. In Figure 1, the pH characteristics of the gastrointestinal tract are presented (alongside the controlled release attributes of a typical pH-responsive material). When drugs have poor solubility, stability, and bioavailability, treating diseases through oral administration can be especially difficult. Various approaches have been explored to overcome these limitations, with the nano-delivery system gaining particular attention. Drug-loaded nano-carriers such as polymeric nanoparticles, lipid nanoparticles, inorganic nanoparticles, micelles, nano-emulsions, and liposomes have been developed to improve drug dispersion, solubility, and stability. These methods also offer potential for gastrointestinal absorption of peptide drugs and vaccines. Local treatments for gastrointestinal diseases like gastritis, Crohn's disease, gastrointestinal cancer, and systemic diseases like diabetes, neurological disease, and vaccines require efficient drug delivery systems to overcome the gastrointestinal biological barrier and enhance local targeting[1].

Schematic model of gastrointestinal tract. Each segment has different pH values and epithelial characteristics.Figure 1. Schematic model of gastrointestinal tract. Each segment has different pH values and epithelial characteristics.

The Specific Features of GI-targeted Drug Delivery Systems:

Different drugs target different sites based on the physiological characteristics of those sites. Table 1 below highlights some of these features:

Table 1. Features for gastrointestinal response.

Gastrointestinal parts Features Function
Gastric response Acid resistant (stability), slow release (long duration of action), less irritating to the gastric mucosa, not easily cleared by the stomach Prolong gastric retention time and release drugs continuously to improve local treatment
Small intestinal response Acid resistance, high bioavailability and stability, so as not to be destroyed by digestive juices such as stomach acid and bile. Targeted (targeted action on small intestinal tissue) Intestinal absorption of biodegradable drugs;
Absorption of drugs for systemic diseases;
Deliver drugs to the appropriate intestinal absorption site to reduce dose and improve safety.
Colon response Intestinal flora can be used, such as the use of biodegradable materials; targeting and specificity, biocompatibility and low toxicity (does not affect the intestinal flora) Sustained release and slow absorption of gastrointestinal degradable drugs;
Delivery of local therapeutic drugs to the colon.
Mucus response Remain in mucus or penetrate mucus, control the slow release of drugs, and target specific factors. Enhance retention time and the local drug concentration to improve local treatment or systemic absorption. Or reach the epithelial intactly and avoid being cleared rapidly to improve local treatment or systemic absorption.

The Applications of GI-targeted Drug Delivery Systems:

Targeted drug delivery systems have been developed to improve the efficiency and efficacy of drug delivery in different parts of the gastrointestinal tract.

  • In the stomach, gastro-retentive devices such as floating systems and pH-dependent adhesion have been used to prolong drug retention and achieve sustained drug release. High molecular weight materials such as Eudragit are a series of acrylic resins that have been widely used as coating materials for gastrointestinal controlled release preparations.
  • In the mucus layer, materials such as PEG and Poloxamer/Pluronic have been used for mucus-penetrating or mucus-interacting systems.
  • The small intestine, with its large surface area and rich villi, provides a suitable environment for absorption, and safe oral formulations have been successfully used to improve the bioavailability of easily degraded peptide drugs.
  • For colon-targeted drug delivery, biodegradable polymers that are specifically degraded by microflora in the colon have been used.

All of these targeted drug delivery systems have the potential to improve the efficacy and safety of drug treatments for various diseases[2].

Our Featured Services:

  • Design and synthesis: Our services include selection and synthesis of carriers such as dendrimers, polymer nanoparticles, liposomes and lipid nanoparticles depend on the different therapeutic purposes and positions including the mucus, epithelium and segments of the stomach and intestines.
  • Ligand conjugation and chemical modification: CD Bioparticles provides conjugation services for a variety of molecules including synthetic polymer, small molecular compound, proteolytic enzyme, natural polysaccharide, natural protein, etc. Table 2 lists some typical materials reported for the modification of nano-carriers (Incomplete, located at the bottom of this page.)
  • Analysis and characterization: We offer analysis and characterization services for size, surface properties, encapsulation efficiency, gene expression efficiency, purity, and more.
  • Cell toxicity, dose determination, pharmacokinetic assessment, and off-target effect evaluation.

Table 2 Typical materials for the nano-carriers

Category Typical Carrier-surface Material / Decoration Main mechanism
Mucus adhesive Synthetic polymer Poly (lactic acid) (PLA), Poly (sebacic acid) (PSA), Poly (lacticacid-glycolic acid) (PLGA), Poly (acrylic acid) (PAA), Carbopol, Polycarbophil, Copolymer of methylvinylether and methacrylic acid, and their Derivatives Hydrogen bonding, Electrostatic interaction, Long-chain entanglement
Cellulose derivative Carboxy methyl cellulose (CMC), Thiolated carboxy methyl cellulose (TCMC), Sodium carboxy methyl cellulose (SCMC), Hydroxyethyl cellulose (HEC), Hydroxypropyl cellulose (HPC), Methyl hydroxyethyl cellulose (MHPC), Methyl cellulose (MC), Hydroxypropyl methyl- cellulose (HPMC) Hydrogen bonding, Electrostatic interaction, Long-chain entanglement
Natural polysaccharide Chitosan, Gelatin, Hyaluronic acid, Carrageenan, Pectin, Sodium alginate and their derivatives Hydrogen bonding, Electrostatic interaction, Long-chain entanglement
Natural protein Keratose, Kerateine Hydrogen bonding, Electrostatic interaction, Covalent disulfide bond
Sulfhydrylation agent Cysteine, Thioglycolic Acid (TGA), 4-Thiobuthylamidine (TBA), N-acetyl-cysteine, Isopropyl-S-acetyl thioacetimidate, Glutathione Covalent disulfide bond
Mucus penetration Synthetic polymer Polyethylene glycol (PEG), Pluronic F127 (PF127), Poly(2-hydroxypropyl) methacrylamide (PHPMA), Polysarcosine (PSAR), Poly(vinyl alcohol) (PVA), Poly(2-alkyl-2-oxazoline) (PAOXA), Hydroxyl-containing non-ionic water-soluble polymers, Zwitterionic polymers (polybetaines) Shielding electrostatic and hydrophobic interactions
Small molecular compound N-acetylcysteine, 2-mercapto-N-octylacetamide, N-dodecyl-4-mercaptobutylamide Destroying mucin disulfide bond
Proteolytic enzyme Papain, Bromelain, Trypsin Hydrolyzed mucin
Promote transcellular transport Penetration
Nonionic surfactants (such as Pluronic P123, F68 and F127) Alter cell membrane fluidity Decrease transepithelial
resistance; Inhibit the effect of P-glycoprotein efflux
Bile salts and derivatives Alter cell membrane fluidity; Interact with bile acid transporter to induce endocytosis and uptake
Medium-chain fatty acids and derivatives Alter cell membrane fluidity; Decrease transepithelial resistance
charged polymer
Chitosan and derivatives Reversible decrease of the transepithelial resistance; Electrostatic interaction with cell surface prolongs absorption time
Cell penetrating
HIV-1 Tat, penetratin, oligoarginine, MAP and R8 Assist carriers enter directly into cells through lipid membrane or be internalized by endocytosis.
Broad enterocyte surface targeting ligand IgG (for Neonatal Fc receptor (FcRn, FCGRT)); Lactoferrin (for Lactoferrin receptor (ITLN-1)); Vitamin B12 (for Vitamin B12–intrinsic factor receptor (CUBN, AMN)) Trigger transcytosis mechanism of receptors in cell membrane
M cell targeting ligand Lectin (UEA-1, WGA, TL and LTA) Combine with cell surface glycoproteins and sugar esters to prolong absorption and promote endocytosis
HA recombinant proteins whose C terminus are introduced with CPE30 (the terminal 30 amino acids of Clostridium Perfringens enterotoxin) Bound to claudin-4 receptor that is highly expressed in M cells
RGD and LDV peptidomimetics Bound to integrins on the apical surface
of M cells
Promote paracellular transport Penetration
Nonionic surfactants, bile salts, medium-chain fatty acids and their derivatives Irreversibly dissolve cell membrane components Combine with extracellular Ca2+ to induce redistribution of target proteins of calmodulin
charged polymer
Chitosan and derivatives Possible mechanism is reversible interaction with tight junction proteins
Peptide ADT-6 HAV-6 C-CPE 7-mer(FDFWITP or PN-78) AT-1002 PN159(KLAL or MAP) Interacting with occludin and claudins to regulate the tight junction opening
Myosin light chain phosphatase (MLCP) inhibitory peptides 640 and 250 (synthetic peptides emulating interfacial contacts involving MLCP regulatory proteins CPI-17 and MYPT) Inhibit dephosphorylation catalyzed by MLCP to prevent reversion of opened tight junction
Bacterial protein Clostridium perfringens enterotoxin (CPE) Binding to claudins to regulate the tight junction opening
Metal chelating agent Citrate Combine with extracellular Ca to induce redistribution of target proteins of calmodulin

Quotations and Ordering

Quotations and Ordering


  1. Wang W, Yan X, Li Q, Chen Z, Wang Z, Hu H: Adapted nano-carriers for gastrointestinal defense components: surface strategies and challenges. Nanomedicine 2020, 29:102277.
  2. Subramanian DA, Langer R, Traverso G: Mucus interaction to improve gastrointestinal retention and pharmacokinetics of orally administered nano-drug delivery systems. J Nanobiotechnology 2022, 20(1):362.
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