Capsules For Delivery Research Articles

Collective navigation of cargo-carrying swarms

Much effort has been devoted to the study of swarming and collective navigation of micro-organisms, insects, fish, birds and other organisms, as well as multi-agent simulations and to the study of real robots. It is well known that insect swarms can carry cargo. The studies here are motivated by a less well-known phenomenon: cargo transport by bacteria swarms. We begin with a concise review of how bacteria swarms carry natural, micrometre-scale objects larger than the bacteria (e.g. fungal spores) as well as man-made beads and capsules (for drug delivery). A comparison of the trajectories of virtual beads in simulations (using different putative coupling between the virtual beads and the bacteria) with the observed trajectories of transported fungal spores implies the existence of adaptable coupling. Motivated by these observations, we devised new, multi-agent-based studies of cargo transport by agent swarms. As a first step, we extended previous modelling of collective navigation of simple bacteria-inspired agents in complex terrain, using three putative models of agent-cargo coupling. We found that cargo-carrying swarms can navigate efficiently in a complex landscape. We further investigated how the stability, elasticity and other features of agent-cargo bonds influence the collective motion and the transport of the cargo, and found sharp phase shifts and dual successful strategies for cargo delivery. Further understanding of such mechanisms may provide valuable clues to understand cargo-transport by smart swarms of other organisms as well as by man-made swarming robots.

Immobilization and Intracellular Delivery of an Anticancer Drug Using Mussel-Inspired Polydopamine Capsules

We report a facile approach to immobilize pH-cleavable polymer-drug conjugates in mussel-inspired polydopamine (PDA) capsules for intracellular drug delivery. Our design takes advantage of the facile PDA coating to form capsules, the chemical reactivity of PDA films, and the acid-labile groups in polymer side chains for sustained pH-induced drug release. The anticancer drug doxorubicin (Dox) was conjugated to thiolated poly(methacrylic acid) (PMA(SH)) with a pH-cleavable hydrazone bond, and then immobilized in PDA capsules via robust thiol-catechol reactions between the polymer-drug conjugate and capsule walls. The loaded Dox showed limited release at physiological pH but significant release (over 85%) at endosomal/lysosomal pH. Cell viability assays showed that Dox-loaded PDA capsules enhanced the efficacy of eradicating HeLa cancer cells compared with free drug under the same assay conditions. The reported method provides a new platform for the application of stimuli-responsive PDA capsules as drug delivery systems.

An in vitro study of rhBMP-2/ vancomycin/ calcium sulfate drug delivery system

Objective To study the efficacy and safety of in vitro local drug delivery capsules fabricated with the biodegradable material Osteoset(R) plus vancomycin and recombinant human bone morphogenetic protein-2 (rhBMP-2). Methods In vitro local drug delivery capsules were fabricated with the biodegradable material Osteoset(R) plus vancomycin and rhBMP-2.High-Performance Liquid Chromatography (HPLC) and bacterial inhibition tests were performed to detect the concentration and activity of vancomycin in the capsules.Enzyme-linked immunosorbent assay (ELISA) and alkaline phosphatase (ALP) tests were conducted to detect the concentration and activity of rhBMP-2 in the capsules. Results The capsules could release vancomycin above 55.8 μg/mL for up to 144 hours,with an activity of above 70％.They could release active thBMP-2 for up to 30 days,had no inhibition effects on the proliferation of mesenchymal stem cells (MSCs) and had high biological safety. Conclusion Since the capsules of Osteoset(R) plus vancomyein and rhBMP-2 can release high concentrations of active vancomycin and active rhBMP-2 with no inhibition of the proliferation of MSCs,they have good prospects for clinical use. Key words: Bone morphogenetic proteins; Vancomycin; Calcium sulfate

HP55-coated capsule containing PLGA/RS nanoparticles for oral delivery of insulin

In this work, we designed and developed a two-stage delivery system composed of enteric capsule and cationic nanoparticles for oral delivery of insulin. The enteric capsule was coated with pH-sensitive hydroxypropyl methylcellulose phthalate (HP55), which could selectively release insulin from nanoparticles in the intestinal tract, instead of stomach. The biodegradable poly(lactic-co-glycolic acid) (PLGA) was selected as the matrix for loading insulin. Eurdragit® RS (RS) was also introduced to the nanoparticles for enhancing the penetration of insulin across the mucosal surface in the intestine. The nanoparticles were prepared with the multiple emulsions solvent evaporation method via ultrasonic emulsification. The optimized nanoparticles have a mean size of 285nm, a positive zeta potential of 42mV. The encapsulation efficiency was up to 73.9%. In vitro results revealed that the initial burst release of insulin from nanoparticles was markedly reduced at pH 1.2, which mimics the stomach environment. In vivo effects of the capsule containing insulin PLGA/RS nanoparticles were also investigated in diabetic rat models. The oral delivered capsules induced a prolonged reduction in blood glucose levels. The pharmacological availability was found to be approximately 9.2%. All the results indicated that the integration of HP55-coated capsule with cationic nanoparticles may be a promising platform for oral delivery of insulin with high bioavailability.

Polymeric multilayer capsules for drug delivery

The advent of Layer-by-Layer (LbL) assembly to fabricate polymeric as well as hybrid multilayer thin films has opened exciting avenues for the design of multifunctional drug carriers with extreme control over their physico-chemical properties. These polymeric multilayer capsules (PMLC) are typically fabricated by sequential adsorption of polymers onto a spherical substrate with dimensions varying from 10 nm to several microns and larger. In this critical review, we give an overview of the recent advances in the field of PMLC with respect to drug delivery and point out how sophisticated capsule engineering can lead to well-defined drug carriers with unique properties (139 references).

The disintegration behaviour of capsules in fed subjects: A comparison of hypromellose (carrageenan) capsules and standard gelatin capsules

Two-piece hard shell capsules made from hypromellose (or hydroxypropyl methylcellulose, HPMC) containing carrageenan as a gelling agent have been proposed as an alternative to conventional gelatin capsules for oral drug delivery. We have previously compared the disintegration of hypromellosecarrageenan (Quali-V®) and gelatin capsules (Qualicaps) in fasted human subjects using the technique of gamma scintigraphy. This second study used the same technique with both fasted and fed human subjects. Size 0 capsules were filled with powder plugs made from lactose and did not contain croscarmellose as in the original study. The capsules were separately radiolabelled with indium-111 and technetium-99m. Both capsules were administered simultaneously with 180ml water to eight healthy male subjects following an overnight fast. Each volunteer was positioned in front of the gamma camera and sequential 60s images were acquired in a continuous manner for 30min. The mean (±S.D.) disintegration time in the fasted state for the hypromellosecarrageenan capsules was 8±2min and for gelatin 7±3min. These results were not statistically different from the data in the original study and show that the removal of the croscarmellose had no effect on the results. The mean (±S.D.) disintegration time in the fed state for the hypromellosecarrageenan capsules was 16±5min and for the gelatin capsules was 12±4min. There was no statistical difference between the hypromellosecarrageenan and gelatin capsules in either the fed or fasted state.

Pharmacokinetics of Lisdexamfetamine Dimesylate after Targeted Gastrointestinal Release or Oral Administration in Healthy Adults

The purpose of this work was to assess the pharmacokinetics and safety of lisdexamfetamine dimesylate (LDX) delivered and released regionally in the gastrointestinal (GI) tract. In this open-label, randomized, crossover study, oral capsules and InteliSite delivery capsules containing LDX (50 mg) with radioactive marker were delivered to the proximal small bowel (PSB), distal SB (DSB), and ascending colon (AC) during separate periods. Gamma scintigraphy evaluated regional delivery and GI transit. LDX and d-amphetamine in blood were measured postdose (≤72 h). Treatment-emergent adverse events (TEAEs) were assessed. Healthy males (n = 18; 18-48 years) were enrolled. Mean (S.D.) maximal plasma concentration (C(max)) was 37.6 (4.54), 40.5 (4.95), 38.7 (6.46), and 25.7 (9.07) ng/ml; area under the concentration-time curve to the last measurable time point was 719.1 (157.05), 771.2 (152.88), 752.4 (163.38), and 574.3 (220.65) ng · h · ml⁻¹, respectively, for d-amphetamine after oral, PSB, DSB, and AC delivery of LDX. Median time to C(max) was 5, 4, 5, and 8 h, respectively. Most TEAEs were mild to moderate. No clinically meaningful changes were observed (laboratory, physical examination, or electrocardiogram). LDX oral administration or targeted delivery to small intestine had similar d-amphetamine systemic exposure, indicating good absorption, and had reduced absorption after colonic delivery. The safety profile was consistent with other LDX studies.

Pea protein-based capsules for probiotic and prebiotic delivery

Summary Capsule design for entrapping Bifidobacterium adolescentis and fructoligosacchardes within a pea protein isolate–alginate matrix was investigated as a function of total biopolymer concentration (2.5–6.5%), fructoligosacchardes levels (0–3.0%) and needle gauge (G; 20 vs. 27) by extrusion. Capsules were accessed based on the levels of entrapped fructoligosacchardes and protein, size, swelling and probiotic survival within simulated gastric juice (SGJ) and release properties within simulated intestinal fluids (SIF). All designs offered sufficient protection to B. adolescentis during challenge experiments and showed evidence of burst and prolonged release within SIF. Capsule size was found to depend on needle gauge, with diameter of 2.17 and 1.75 mm for those produced by the 20 and 27 G needles, respectively. All designs were found to shrink once immersed in SGJ. Encapsulation of probiotics using plant-based materials could play a role in food applications and as a feed/pet food supplement.

Chemical surface modification of parylene C for enhanced protein immobilization and cell proliferation

To introduce the adhesion site of proteins and/or cells on parylene C (PC)-coated medical devices that can be used as implantable biosensors or drug delivery capsules, the PC surfaces were initially modified by the Friedel–Crafts acylation reaction to generate active chlorines. These chlorines were then employed to initiate the atom transfer radical polymerization of tert-butyl acrylate (TBA) and form a polymer brush layer of polyTBA on PC; the acrylate groups in the polymer brushes were hydrolyzed to carboxylic acid groups and further activated into succinimidyl ester groups via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide coupling reaction. The PC surface grafted with polymer brushes and activated by succinimide showed efficient attachment of proteins, including gelatin, contortrostatin (CN) and bovine serum albumin (BSA), all at high density on the PC surface. The CN density on the surface was evaluated for both monolayer and polymer brush-based coatings. Based on fluorescence measurements, the polymer brush gives a 60-fold higher surface protein density than the monolayer-based system. Gelatin was used as a model protein and covalently coated onto the modified PC surface for cell culture study. Substrates with gelatin coating showed a significantly higher cell attachment and proliferation in 7 days cultures as compared to the uncoated substrates. In addition, a conventional photolithography technique was coupled with the surface chemistry to successfully pattern the BSA labeled with fluorescein isothiocyanate on the modified PC surfaces.

Physiological modeling and assessments of regional drug bioavailability of danoprevir to determine whether a controlled release formulation is feasible

Danoprevir, a potent, selective inhibitor of HCV NS3/4A protease, has a short half-life in humans. Therefore, the feasibility of a controlled release (CR) formulation to allow less frequent dosing was investigated using experimental approaches and physiological modeling to examine whether danoprevir is absorbed in the colon. Danoprevir absorption was studied in portal-vein-cannulated monkeys and in monkeys surgically modified to make intraduodenal, intrajejunal, intracolonic and oral administration possible. In portal-vein-cannulated monkeys, absorption was apparent up to 24 h after administration. The observed relative bioavailability from intracolonic delivery in the monkey was approximately 30% relative to oral administration, consistent with the model prediction of 40%. Human relative bioavailability for a tablet delivered to the colon compared with an immediate release (IR) formulation was predicted to be 4-28%. Preclinical data and modeling suggested that CR development would be challenging for this Biopharmaceutics Classification System Class IV compound. Therefore, a confirmative study in healthy volunteers was conducted to investigate the relative bioavailability of danoprevir in various regions of the gastrointestinal tract. In a randomized, open-label, crossover study, subjects received 100 mg danoprevir IR soft gel capsule, 100 mg danoprevir solution delivered to the distal small bowel and colon via an Enterion™ capsule (a remotely activated capsule for regional drug delivery) and 100 mg danoprevir powder to the colon via an Enterion™ capsule. The relative bioavailability of danoprevir (compared with IR) delivered to the colon was 6.5% for a solution and 0.6% for a powder formulation, indicating that a CR formulation is not feasible.

In Vitro and In Vivo Analysis of a Biodegradable Poly(lactide-co-glycolide) Copolymer Capsule and Collagen Composite System for Antibiotics and Bone Cells Delivery

The authors investigated poly(lactide-co-glycolide) (PLGA) capsule and collagen composite system for antibiotics and bone cells delivery to treat infected bone defects. Poly(lactide-co-glycolide) was mixed with vancomycin and hot compressing molded to form an antibiotic capsule. Rabbit mesenchymal stem cells (MSCs) were entrapped in collagen gel phase and dispersed throughout the void volume of capsule. In vitro study, the composite systems were cultured in complete or osteogenic medium for 21 days. The profiles of vancomycin released from the systems were evaluated using the high-performance liquid chromatography method. Relative activity of vancomycin against Staphylococcus aureus was determined by an antibiotic disk diffusion method. The expression of osteogenic gene was determined by reverse-transcription polymerase chain reaction. The alkaline phosphatase activity and calcium level of the MSCs were assessed. Analytical results demonstrated that the concentrations of vancomycin eluted from the composite system were above the minimal inhibitory concentration for 21 days. Sample inhibition zone was 10 to 24 mm, and the relative activity was 17.6% to 100%. mRNA of Cbfa1 and osteocalcin were detected, and increased alkaline phosphatase activity and calcium levels were noted. In in vivo investigation, the PKH 26-labeled MSCs and composite systems were implanted in the distal femoral cavities of four rabbits. The local concentration of vancomycin was above the minimal inhibitory concentration for 56 days. Sample inhibition zone was 9 mm to 24 mm, and the relative activity was 11.8% to 100%. Implanted PKH 26-labeled MSCs were identified in the newly formed bony trabeculae in specimens at 2 and 4 months after implantation. The results offer a potential approach to meet clinical requirements in the treatment of infected bone defects.

Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. The optic nerve can be accessed within the orbit of the eye and completely transected (axotomized), cutting the axons of the entire RGC population. Optic nerve transection is a reproducible model of apoptotic neuronal cell death in the adult CNS 1-4. This model is particularly attractive because the vitreous chamber of the eye acts as a capsule for drug delivery to the retina, permitting experimental manipulations via intraocular injections. The diffusion of chemicals through the vitreous fluid ensures that they act upon the entire RGC population. Moreover, RGCs can be selectively transfected by applying short interfering RNAs (siRNAs), plasmids, or viral vectors to the cut end of the optic nerve 5-7 or injecting vectors into their target, the superior colliculus 8. This allows researchers to study apoptotic mechanisms in the desired neuronal population without confounding effects on other bystander neurons or surrounding glia. An additional benefit is the ease and accuracy with which cell survival can be quantified after injury. The retina is a flat, layered tissue and RGCs are localized in the innermost layer, the ganglion cell layer. The survival of RGCs can be tracked over time by applying a fluorescent tracer (3% Fluorogold) to the cut end of the optic nerve at the time of axotomy, or by injecting the tracer into the superior colliculus (RGC target) one week prior to axotomy. The tracer is retrogradely transported, labeling the entire RGC population. Because the ganglion cell layer is a monolayer (one cell thick), RGC densities can be quantified in flat-mounted tissue, without the need for stereology. Optic nerve transection leads to the apoptotic death of 90% of injured RGCs within 14 days postaxotomy 9-11. RGC apoptosis has a characteristic time-course whereby cell death is delayed 3-4 days postaxotomy, after which the cells rapidly degenerate. This provides a time window for experimental manipulations directed against pathways involved in apoptosis.

Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. The optic nerve can be accessed within the orbit of the eye and completely transected (axotomized), cutting the axons of the entire RGC population. Optic nerve transection is a reproducible model of apoptotic neuronal cell death in the adult CNS (1-4). This model is particularly attractive because the vitreous chamber of the eye acts as a capsule for drug delivery to the retina, permitting experimental manipulations via intraocular injections. The diffusion of chemicals through the vitreous fluid ensures that they act upon the entire RGC population. Moreover, RGCs can be selectively transfected by applying short interfering RNAs (siRNAs), plasmids, or viral vectors to the cut end of the optic nerve (5-7) or injecting vectors into their target, the superior colliculus (8). This allows researchers to study apoptotic mechanisms in the desired neuronal population without confounding effects on other bystander neurons or surrounding glia. An additional benefit is the ease and accuracy with which cell survival can be quantified after injury. The retina is a flat, layered tissue and RGCs are localized in the innermost layer, the ganglion cell layer. The survival of RGCs can be tracked over time by applying a fluorescent tracer (3% Fluorogold) to the cut end of the optic nerve at the time of axotomy, or by injecting the tracer into the superior colliculus (RGC target) one week prior to axotomy. The tracer is retrogradely transported, labeling the entire RGC population. Because the ganglion cell layer is a monolayer (one cell thick), RGC densities can be quantified in flat-mounted tissue, without the need for stereology. Optic nerve transection leads to the apoptotic death of 90% of injured RGCs within 14 days postaxotomy (9-11). RGC apoptosis has a characteristic time-course whereby cell death is delayed 3-4 days postaxotomy, after which the cells rapidly degenerate. This provides a time window for experimental manipulations directed against pathways involved in apoptosis.

Methods for Experimental Manipulations after Optic Nerve Transection in the Mammalian CNS

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. The optic nerve can be accessed within the orbit of the eye and completely transected (axotomized), cutting the axons of the entire RGC population. Optic nerve transection is a reproducible model of apoptotic neuronal cell death in the adult CNS (1-4). This model is particularly attractive because the vitreous chamber of the eye acts as a capsule for drug delivery to the retina, permitting experimental manipulations via intraocular injections. The diffusion of chemicals through the vitreous fluid ensures that they act upon the entire RGC population. Viral vectors, plasmids or short interfering RNAs (siRNAs) can also be delivered to the vitreous chamber in order to infect or transfect retinal cells (5-12). The high tropism of Adeno-Associated Virus (AAV) vectors is beneficial to target RGCs, with an infection rate approaching 90% of cells near the injection site (6, 7, 13-15). Moreover, RGCs can be selectively transfected by applying siRNAs, plasmids, or viral vectors to the cut end of the optic nerve (16-19) or injecting vectors into their target the superior colliculus (10). This allows researchers to study apoptotic mechanisms in the injured neuronal population without confounding effects on other bystander neurons or surrounding glia. RGC apoptosis has a characteristic time-course whereby cell death is delayed 3-4 days postaxotomy, after which the cells rapidly degenerate. This provides a window for experimental manipulations directed against pathways involved in apoptosis. Manipulations that directly target RGCs from the transected optic nerve stump are performed at the time of axotomy, immediately after cutting the nerve. In contrast, when substances are delivered via an intraocular route, they can be injected prior to surgery or within the first 3 days after surgery, preceding the initiation of apoptosis in axotomized RGCs. In the present article, we demonstrate several methods for experimental manipulations after optic nerve transection.

Cells as Factories for Humanized Encapsulation

Biocompatibility is of paramount importance for drug delivery, tumor labeling, and in vivo application of nanoscale bioprobes. Until now, biocompatible surface processing has typically relied on PEGylation and other surface coatings, which, however, cannot minimize clearance by macrophages or the renal system but may also increase the risk of chemical side effects. Cell membranes provide a generic and far more natural approach to the challenges of encapsulation and delivery in vivo. Here we harness for the first time living cells as "factories" to manufacture cell membrane capsules for encapsulation and delivery of drugs, nanoparticles, and other biolabels. Furthermore, we demonstrate that the built-in protein channels of the new capsules can be utilized for controlled release of encapsulated reagents.

Self-standing nanoparticle membranes and capsules

We perform coarse-grained molecular dynamics simulations of self-standing nanoparticle membranes observed in recent experiments (K. E. Mueggenburg et al., Nat. Mater., 2007, 6, 656). In order to make our simulations feasible, we model 2-3 times smaller gold nanoparticles (core radius of r(core) ≈ 0.8 nm) covered with alkanethiol ligands (length of l(ligand) ≈ 0.5-2.6 nm). We study the structure, stability, and mechanical properties of these membranes and show that these characteristics are controlled by the ratio of R(LC) = l(ligand)/r(core). For R(LC) ≈ 0.6, the ligated nanoparticles form well ordered monolayers with hexagonal packing, in agreement with the experiments (R(LC) ≈ 0.44). For R(LC) ≈ 1.6, the nanoparticles form less organized multilayers, which are more stable and flexible. We show that these membranes could potentially form stable capsules for molecular storage and delivery.

Oral delivery of insulin using chitosan capsules cross-linked with phytic acid

Phytic acid (PA) was used as a cross-linking agent for encapsulation of insulin in a chitosan matrix for oral delivery of insulin. PA-chitosan capsules were compared with tripolyphosphate (TPP)-chitosan capsules for stable oral delivery of insulin. During 2 h incubation in simulated gastric fluid, PA-chitosan capsules prepared using pH 6, 6% PA solutions showed better stability than TPP-chitosan capsules prepared using pH 7, 6% TTP solution. PA-chitosan capsules released less than 60% of their encapsulated insulin after 24 h incubation in simulated gastrointestinal fluids. TPP-chitosan capsules showed burst release and virtually the entire insulin content was released in 12 h. Both capsule types were tested in vivo via oral drug administration using diabetic mice. PA-chitosan capsules significantly decreased blood glucose levels while TPP-chitosan capsules caused a lesser reduction. The relative pharmacological bioactivity of PA-chitosan capsules prepared was 6.4% while that of TPP-chitosan capsules was 1.1%. PA-chitosan capsules appeared to have good potential for use in oral delivery of insulin for sustained control of the blood glucose level.

A Novel Drug Delivery Capsule based Magnetic Technique for GI Tract

This paper proposes a novel detachable drug delivery capsule to realize diagnosis application inside human body. The proposed capsule, with dimensions of 7mm×34mm, is enclosed with two neodymium-iron-boron (NdFeB) magnetic shells (8mm×2mm) outside its surface. The magnetic shells can be used for tracking capsule's position and assisting to detach capsule. Using the magnetic position and orientation technique, the real-time position and orientation can be obtained by the external magnetic array sensors. When detecting the specific position, the capsule will be actuated to disassemble into two parts by the external magnetic field. For this kind of capsule, there are many aspects to be solved. Here, we only focus on the position and orientation techniques for the whole drug delivery capsule and the two detached parts. The position tracking results are given in this paper.

Efficacy of oral colon-specific delivery capsule of low-molecular-weight heparin on ulcerative colitis

Low-molecular-weight heparin has the potential for the treatment of ulcerative colitis, and targeted drug delivery to the colon is important for topical treatment of this disease, so low-molecular-weight heparin oral colon-specific delivery capsule was prepared, and the in vitro and in vivo drug release behavior was investigated. The macroscopical and histological scoring systems, wet colon mass index and myeloperoxidase activity were assessed to evaluate the efficacy of the capsule after administered orally to experimental colitis mice. Serum levels, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and a link factor of blood coagulation and inflammation factor Xa (FXa) were assayed by enzyme-linked immunosorbent assay. The expression of Musashi-1 (as an intestinal stem cell marker) in the colons was assessed by immunohistochemical analysis. The in vitro and in vivo drug release studies clearly indicated that the specific coated capsules were capable of protecting low-molecular-weight heparin from releasing in stomach and small intestine, while specifically delivering at colon. The oral colon-specific delivery capsule of low-molecular-weight heparin could attenuate macroscopic and histological features of colitis. The results showed that low-molecular-weight heparin oral colon-specific delivery capsule significantly decreased the serum levels of TNF-α, IL-6 as well as FXa, while increased the expression of Musashi-1 in colon compared with acetic acid-induced ulcerative colitis model group. The results showed that low-molecular-weight heparin oral colon-specific delivery capsule had the potential for treatment of inflammatory bowel disease.

A Critical Look at Multilayered Polymer Capsules in Biomedicine: Drug Carriers, Artificial Organelles, and Cell Mimics

AbstractThis Feature Article discusses utility of multilayered polymer capsules in biomedicine, specifically in drug delivery and in design of artificial organelles and cells. We provide a critical view on recent successes and identified shortcomings of these capsules in delivery of therapeutic cargo and outline plausible further developments of capsules as candidate drug carriers. A special emphasis is placed on poly(methacrylic acid) hydrogel capsules as successful carriers used in delivery of anticancer drugs and protein and peptide vaccines. We further present a novel biomedical approach whereby the same vessel acts first as a microreactor and then as a carrier for de novo synthesized therapeutic cargo. Finally, utility of polymer capsules in design of cell mimics is discussed with an emphasis on assembly and performance of capsosomes, polymer capsules with liposomal subcompartments. This presentation of capsules in biomedicine aims to provide an overview of past achievements and existing challenges associated with these candidate vessels and to stimulate further research interest from a broad scientific audience.