Potential and Applications of Nanocarriers for Efficient Delivery of Biopharmaceuticals

Purpose: Biopharmaceuticals have become clinically and commercially important due to their specificity, potency, targeting ability, and reduced side effects, but their macromolecular structure and intrinsic instability make formulation and administration challenging; parenteral delivery remains the only viable option in most cases. Nanocarriers can protect biologics from degradation, enhance plasma half-life and retention, facilitate epithelial absorption, enable site-specific delivery, and improve access to intracellular targets.

Hypothesis: No formal experimental hypothesis. Central thesis: nanocarriers—organic and inorganic—can overcome the formulation and administration challenges of biopharmaceuticals, including hormones, cytokines, nucleic acids, vaccines, antibodies, enzymes, and gene- and cell-based therapeutics, thereby improving therapeutic performance and enabling noninvasive or targeted delivery. However, clinical translation and commercialization remain limited by biological, technological, and nanotoxicological hurdles.

Aims: Highlight the clinical and commercial success of biopharmaceuticals. - Describe the major challenges in successful delivery of biopharmaceuticals. - Review applications of nanocarriers to overcome those delivery and formulation challenges. - Present effective applications of nanocarriers via invasive and noninvasive routes (oral, pulmonary, nasal, and skin). - Discuss hurdles in clinical translation and commercialization of nanocarriers.

Delivery system: Nanocarrier types: liposomes, lipid nanoparticles, polymeric nanoparticles, dendrimers, micelles, virus-like particles (VLPs), nanogels, nanocomplexes, mesoporous silica nanoparticles (MSNs), metallic nanoparticles (gold, magnetite). - Payloads: hormones (insulin, hGH, calcitonin, melatonin, estradiol), cytokines (IFN-α, IFN-β, IFN-γ, IL-2, IL-4, IL-15, GM-CSF, G-CSF), nucleic acids and nucleotides (siRNA, mRNA, antisense oligonucleotides), vaccines (HBcAg, Ebola antigen, H. pylori antigen, ovalbumin, HPV antigen, mRNA vaccines), antibodies (infliximab, anti-HER2, cetuximab, rituximab, trastuzumab, anti-EGFR), enzymes and inhibitors (α-galactosidase, β-galactosidase, cysteine proteinase type-I, tissue plasminogen activator, streptokinase), gene- and cell-based therapeutics (stem cells, salinomycin, bortezomib, placental growth factor). - Routes: parenteral, oral, pulmonary, nasal, transdermal, ocular, rectal, intravenous, subcutaneous, intraperitoneal, intramyocardial. - Surface modifications/targeting: PEGylation, folate decoration, lectin modification, chitosan coating, enteric coating (HP55), antibody conjugation, cell-penetrating peptides, Treg-cell conjugation, CD44/CD133 targeting.

Approach: Review of preclinical and clinical literature; no primary experiments. In vitro systems include Caco-2, MCF-7, HepG2, A431, BT474, Jurkat, dendritic cells, macrophages, and fibroblast cells. In vivo models include mice, rats, rabbits, and nonhuman primates, with disease contexts including diabetes, cancer, infections, autoimmune disorders, inflammatory bowel disease, osteoporosis, liver failure, myocardial infarction, and ischemia. Clinical/commercial context includes FDA-approved biopharmaceuticals from 2018–2020 and approved nanomedicines such as Doxil, DaunoXome, Abraxane, and Onpattro.

Key methods: Review-level synthesis of: - Nanoparticle characterization: particle size, PDI, zeta potential, encapsulation efficiency. - Biodistribution and pharmacokinetics: plasma levels, AUC, half-life, bioavailability. - Therapeutic efficacy: blood glucose reduction, hypocalcemic effect, tumor growth inhibition, survival, immune response. - Cellular uptake and internalization: phagocytosis, clathrin-dependent endocytosis, paracellular permeability. - Immune response: antibody titers, T cell proliferation, cytokine production, germinal center B cells. - Safety/toxicity: cytotoxicity, histopathology, blood counts, inflammatory markers.

Key results: Representative quantitative findings from cited studies: - Folate-decorated PEGylated PLGA nanoparticles for oral insulin doubled insulin bioavailability compared with subcutaneous injection. - hGH-loaded thermosensitive nanogels (~500 nm, zeta +8 mV) increased AUC 13-fold and enhanced bioavailability in hypophysectomized rats. - PLGA/Eudragit RS insulin nanoparticles: encapsulation efficiency 73.9%, size 285 nm, zeta +42 mV; enteric-coated HP55 capsules showed prolonged antidiabetic activity. - CD73-specific siRNA chitosan lactate nanoparticles: size 70–126 nm, PDI ~0.3, zeta ~19 mV, EE 50–90%; caused tumor regression via anti-angiogenic effects. - siRNA-loaded HAS nanoparticles: size <90 nm, zeta +26 mV, PDI <0.25, transfection efficiency 61.66 ± 6.8%. - Ebola lipid nanoparticle vaccine: size 117.5 ± 17.6 nm, PDI 0.18 ± 0.01, zeta −21.7 ± 1.3 mV, EE ~60%; induced germinal center B cells and polyfunctional T cells. - H. pylori PLGA oral vaccine: ~200 nm, PDI 0.228 ± 0.030, EE 79.07%; 43% of immunized mice protected from infection. - mRNA-loaded lipid nanoparticles: 110 nm, zeta 25 mV, EE 80%; strong specific T cell response and reduced tumor growth in lymphoma model. - Infliximab liposomes: size 351.3 ± 58 nm, EE 90.65 ± 2.68%, PDI 0.386, zeta ~20.8 ± 9.8 mV; reduced ocular inflammation in autoimmune uveoretinitis rats. - Bortezomib PLA nanoparticles: size 112.8 ± 2.3 nm, PDI 0.13 ± 0.1, EE 72.8%; increased targeting and tumor suppression in breast cancer.

Interpretation: Nanocarriers are promising delivery tools for biopharmaceuticals, offering protection, enhanced half-life, targeted delivery, and improved therapeutic outcomes. They have potential to enable noninvasive routes and improve patient compliance. However, clinical translation and commercialization remain uncertain due to biological, technological, and nanotoxicological hurdles. The authors conclude that nanocarrier-based biopharmaceutical delivery has great potential for treating cancers, autoimmune disorders, and other diseases, but requires scale-up, quality control, and safety assessment.

Limitations: Review article; no primary data. - Most examples are preclinical; clinical translation of nanocarrier-biopharmaceutical combinations is limited. - Biological hurdles: controlling in vivo fate, species differences, interpatient variability, target expression, and dose-dependent pathological conditions. - Technological hurdles: large-scale manufacturing, reproducibility, stability, high-throughput screening, and prediction of clinical outcomes. - Nanotoxicological hurdles: ADME profiles, unintended biological interactions, chronic exposure to nonbiodegradable materials, and safety of synthetic components, ligands, and coatings. - PEGylation can cause anti-PEG antibodies and accelerated blood clearance upon repeated administration. - Need for extensive safety and biodistribution profiling before clinical use. - Computational and theoretical models are needed but not yet sufficient for predicting clinical outcomes.