Capsules For Delivery Research Articles

Small Bowel Malignancies in Patients Undergoing Capsule Endoscopy for Iron Deficiency Anemia.

Small bowel malignancies are rare and usually asymptomatic or symptoms are nonspecific. Therefore, small bowel tumors are difficult to diagnose. In patients with iron deficiency anemia (IDA) who have negative bidirectional endoscopy results, the small bowel may be considered the source of bleeding. However, in asymptomatic IDA patients with negative bidirectional endoscopy results, evidence supporting the routine use of capsule endoscopy (CE) is insufficient. CE can be considered in selected patients with recurrent or persistent IDA. The frequency of small bowel malignancies is low in patients undergoing CE for IDA, but the usefulness of CE for the diagnosis of small bowel malignancies in younger age groups with IDA has been reported. For patients with risk factors for small bowel malignancy, investigation of the small bowel should be considered. Efforts should be made to prevent adverse events, such as capsule retention or capsule aspiration, through meticulous history taking and endoscopic capsule delivery as necessary.

An Overview of Robotic Capsules for Drug Delivery to the Gastrointestinal Tract.

The introduction of capsule endoscopy two decades ago marked the beginning of the “small bowel revolution”. Since then, the rapid evolution of microtechnology has allowed the development of drug delivery systems (DDS) designed to address some of the needs that are not met by standard drug delivery. To overcome the complex anatomy and physiology of the gastrointestinal (GI) tract, several DDS have been developed, including many prototypes being designed, built and eventually produced with ingenious drug-release mechanisms and anchoring systems allowing targeted therapy. This review highlights the currently available systems for drug delivery in the GI tract and discusses the needs, limitations, and future considerations of these technologies.

Immobilization and Intracellular Delivery of Structurally Nanoengineered Antimicrobial Peptide Polymers Using Polyphenol‐Based Capsules

AbstractStructurally nanoengineered antimicrobial peptide polymers (SNAPPs) are an emerging class of antimicrobials against multidrug‐resistant bacteria. Their encapsulation in particle carriers can improve their therapeutic efficacy by preventing peptide degradation, reducing clearance, and enhancing intracellular delivery and dosage to bacteria‐infected host cells. Herein, two template‐mediated strategies are reported for immobilizing SNAPPs in microcapsules through 1) complexation of SNAPPs with tannic acid (TA) onto porous CaCO3 templates and subsequent removal of the templates (SNAPP–TA capsules) and 2) adsorption of SNAPPs onto CaCO3 templates and subsequent encapsulation within a metal–phenolic (FeIII–TA) coating and template removal (SNAPP–FeIII–TA capsules). The loading amounts of SNAPPs are 0.8 and 4.4 pg per SNAPP–TA and SNAPP–FeIII–TA capsule, respectively. At pH 7.4, there is sustained release of SNAPPs, which retain high antimicrobial activity with minimum inhibitory concentration values of ≈30 µg mL−1 in Escherichia coli. Both capsule systems are internalized by alveolar macrophages in vitro, with negligible cytotoxicity and are amenable to nebulization, remaining stable in nebulized droplets. This study demonstrates the potential of engineered polyphenol‐based capsules for peptide drug immobilization and intracellular delivery, which have prospective application in the pulmonary delivery of antimicrobials against respiratory bacterial infections (e.g., pneumonia, tuberculosis).

Formulation and evaluation of pH activated dosage form as minitablets in capsule for delivery of fesoterodine

ObjectivesIn the present study, an attempt is made to develop novel multifunctional sustained-release minitablets in a capsule system by film coating Fesoterodine for the treatment of urinary incontinence (increased urinating frequency). MethodologyThe direct compression technique was used to formulate the minitablets, and coating was applied using hydroxypropyl methylcellulose (HPMC) phthalate. The pre-formulation study was performed using tools like differential scanning calorimetry (DSC), infrared spectroscopy (IR) and post-formulation parameters such as hardness, thickness, weight variation, uniformity, and drug release. Drug release kinetics were studied for the formulations F1–F11. ResultsAll the pre- and post-formulation parameters were found to be within the limits. F1 and F2 result in burst release of the drug within 30 minutes. For the F3, F4, and F5 formulations, HPMC phthalate-coated minitablets show almost 100% drug release in 3, 4, and 5 hours, respectively. F6, F7, and F8 (2.5%, 5%, and 10% formaldehyde-coated minitablets, respectively) show drug releases in the small intestine, and the release was prolonged for 24 hours, whereas F9, F10, and F11 (2.5%, 5%, and 10% glutaraldehyde-coated minitablets, respectively) release in the small intestine, but drug release takes more than 20 hours. ConclusionFilm-coated minitablets were satisfactorily developed in terms of various post-compression parameters like hardness, thickness, friability, weight variation, and content uniformity. IR and DSC studies revealed no significant drug excipient interactions. HPMC phthalate-coated minitablets released in the buffer, and it was supposed that the drug releases in the intestine, which leads to better absorption and follows Korsmeyer-Peppas release kinetics.

Effect of inner physical properties on powder adhesion in inhalation capsules in case of a high resistance device.

The inhalation performance of a dry powder inhaler (DPI) depends on the inhalation patterns of patients, inhalation particle characteristics and inhalation devices. In capsule-based DPIs, the capsule plays an important role in the dispersion of inhalation particles. The present study investigated the effects of inner physical properties of capsules on drug release from capsules-based DPIs with high resistance device. Atomic force microscopy (AFM) was used to evaluate the capsule physical properties, such as the capsule inner structure and surface potential, of three capsules with different compositions (G-Cap, PEG/G-Cap, and HPMC-Cap). As a model dry powder for capsule-based DPIs, the dry powder in Spiriva® Inhalation Capsules containing tiotropium bromide was used. Inhalation performance was evaluated using a twin-stage liquid impinge and Handihaler® (flow rate 30 l/min). The results indicated that the capsule inner surface presented with numerous valleys and mountains, regardless of the capsule type. Furthermore, the valley and mountain areas on the capsule inner surface showed a significantly higher or lower surface potential. Following inhalation of capsule-based DPIs, the drug remained in the valleys on the capsule inner surface; however, no significant difference was observed in the drug release from capsule and lung drug delivery. Therefore, inhalation performance in capsule-based DPIs when a high resistance device, such as Handihaler®, is used at an appropriately flow rate is not markedly affected by the physical properties of the capsule inner surface due to capsule composition.

Abstract 280: Sub-30-nm capsules for drug delivery

Abstract Systemic treatment of cancer using long-circulating nanomedicines is promising due to their passive tumor targeting ability to achieve higher and more selective accumulation in tumors with irregular vascularization, a phenomenon known as extended permeation and retention (EPR) effect.1,2 Clinical use of nanometer-sized carriers, such as Doxil and Abraxane, to deliver chemotherapeutics to solid tumors is proven effective in highly vascularized tumors such as breast cancer, ovarian cancer, multiple myeloma, and Kaposi's sarcoma.3-5 Most nanomedicines that are being developed or approved so far have a diameter of around 100-200 nm for prolonged retention in highly angiogenic and densely vascularized tumors,6 however, they suffer from limited accumulation and poor penetration to the inner core of avascular or hypovascular tumors (such as prostate and pancreatic cancer),7-9 therefore nanomedicines small than 100 nm are more preferred for improved tumor penetration.10,11 Here we present our strategy to form cyclodextrin-based sub-30-nm nanocarriers, which allows easy drug encapsulation, and successful delivery of therapeutics to human tumor xenografts with significantly reduced tumor growth rates and improved survival rates. Citation Format: Xiaowei Ma, Ping Zhang, Chao Cui, Chang-Chun Ling, Lina Cui. Sub-30-nm capsules for drug delivery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 280.

Inhomogeneous Large Deformation Study on Magneto-Thermal Sensitive Hydrogels

Due to the incorporation of magnetic nanoparticles (MNPs), magnetically tuneable hydrogels have attracted considerable attention recently due to their ability to undergo remotely controlled large deformation. This work investigates the mechanics of the large deformation from the thermodynamics perspective for magneto-thermal sensitive hydrogels. The chemical thermodynamics of a temperature sensitive gel is first recapped before moving on to the thermodynamics of magnetism. Furthermore, an explicit energy form for the magneto-thermal sensitive hydrogel is adopted. The proposed field theory is implemented in a finite element method through the UHYPER subroutine. The finite element simulation results have been validated with analytical solutions at various temperatures and magnetic field strengths for MNPs entrapped PNIPAM hydrogel. We also utilize the numerical models to explain the interesting phenomena, including micro valves, bifurcation, and the opening of gel capsule for drug release delivery. The numerical deformation pattern for bifurcation is consistent with the experimental pattern, thus illustrating our theory and numerical method can provide future perspectives for device design of magneto-thermal sensitive hydrogel.

A Descriptive Analysis of Capsule Endoscopy Events in the FDA Manufacturer and User Facility Device Experience (MAUDE) Database.

The malfunction of capsule endoscopy (CE) devices is a significant reason for the failure of CE procedures, which could hinder and prevent diagnosis. Unfortunately, malfunction-related adverse events (AEs) caused by CE devices are rarely reported in publications. Although most malfunction-related AEs could not lead to physical harm, they could reduce the efficiency of medical care and increase medical costs. The manufacturer and user facility device experience (MAUDE) database, a publicly accessible resource for patient safety, contains not only the common complications of CE but also valuable malfunction-related AEs, which have been underutilized. Therefore, the study aims to discover and analyze the possible AEs associated with CE and demonstrate the utility of the MAUDE reports to promote patient safety. We acquired MAUDE reports of CE systems from January 01, 2008, to July 31, 2020, through a systematic search strategy. We utilized the manufacturers, brand names, and product codes as search terms from which medical device reports including structured data and narrative texts were extracted, followed by a manual review of the narrative texts, reporter occupation, device involved, event type and the phase of the event; finally, patient outcomes were recorded and analyzed as per CE categories and characteristics. A total of 377 CEs medical device reports were retrieved, and 342 reports were included after reviewing. There were 327 mandatory reports (96%) and 15 voluntary reports (4%). These reports referred to capsule endoscope (n = 213), sensing system (n = 66), patency capsule (n = 38), and capsule delivery device (n = 26). A total of 349 CE-related AEs were identified, including complications (n = 228), malfunction-related AEs (n = 109), and other events (n = 12). The composition of AEs was not the same for the CE devices. Complications were major AEs of capsule endoscope and patency capsule, but malfunction-related AEs were the most common in AEs of sensing systems and capsule delivery devices. MAUDE serves as an invaluable data source for investigating malfunction-related AEs. In addition to common complications, malfunction of CE devices could threaten patient safety in CE procedures. Improving awareness of the malfunction of CE devices and raising adequate training for staff working in gastrointestinal (GI) endoscopic units could be critical and beneficial in preventing malfunction-related AEs.

Exogenous proteases from seafood processing waste as functional additives in rainbow trout aquaculture

Previous studies about enzyme additives for salmonids employed commercial proteases from bacteria, but research obtaining such enzymes from other organisms are scarce. We aimed to increase digestive protease activity in Oncorhynchus mykiss, by analysing potential sources of exogenous proteases generated from different seafood processing waste. To date, there is no information regarding the influences that exogenous enzymes have on the activity and integrity of endogenous enzymes in salmonids. The compatibility and interaction between endogenous and exogenous proteases were evaluated through protein hydrolysis and electrophoresis. We also evaluated the capacity of two types of microcapsules (Alginate–Chitosan and Alginate–Chitosan–Bentonite) to protect the protease activity after being exposed to the gastric environment of trout. The seafood wastes had activities around 0.23–2.53 U/ml at 15°C. Among all the exogenous proteases evaluated, P. granulosa's extract showed the best performance, followed by L. santolla's extract. Such extracts increased the protein hydrolysis to equal or higher levels than the commercial protease and did not alter the integrity of trout proteases. The optimal catalytic function at low temperatures of these extracts might be linked to the habitat of these arthropods. Alginate–Chitosan–Bentonite microcapsules are recommended in preference to Alginate–Chitosan capsules for delivery of enzymes in salmonids because they ensure the activity of exogenous proteases for longer in acid pH (6 vs. 4 h). This research promotes a re-evaluation of seafood processing wastes through the production of a potentially functional additive that may improve trout protein digestion.

Assembly of responsive metal-phenolic network capsules for drug delivery

Assembly of responsive metal-phenolic network capsules for drug delivery

Assessment of different formulations of Trichoderma for their shelf life

Eleven formulations of Trichoderma asperellum were evaluated in present investigation, among these four types of tablets formulation viz. talc tablets, charcoal tablets, lignite tablets, fly ash tablets, six capsules formulations viz. talc capsule, alginate capsules, gelatin capsules, alginate + charcoal capsules, gelatin + fly ash capsules and T. asperellum frozen culture mass along with medium disc capsules and one sorghum grains formulation as a control were used and observation on shelf life up to 270 days from date of manufacturing at regular intervals of 30 days were taken. Maximum cfu/g (42.00 x 107) was obtained in Trichoderma treatment frozen culture mass along with medium disc capsule and least cfu/g was recorded in T. asperellum lignite tablet (11.33 × 107 cfu/g) upto 270 days of storage. In the present study tablet and capsule delivery system of various formulations was tried by using jaggery treatment. Maximum population of T. asperellum obtained (45.00 × 107 cfu/ml) in T. asperellum frozen culture mass along with medium disc capsule and minimum were obtained in T. asperellum lignite tablets, (8.33 × 107cfu/ml).

Innovative delivery methods for Trichoderma formulations

The present investigation was carried out to evaluate the shelf life in T. asperellum tablets and capsules. Four types of tablets viz. T1 (T. asperellum talc tablet), T2 (T. asperellum charcoal tablet), T3 (T. asperellum lignite tablet), T4 (T. asperellum flyash tablet) and Six types of capsules viz. T5 (T. asperellum talc capsule), T6 (T. asperellum gelatin capsule), T7 (T. asperellum alginate capsule), T8 (T. asperellum alginate + charcoal capsule), T9 (T. asperellum gelatin + flyash capsule), T10 (T. asperellum Frozen culture mass along with disc capsule) were prepared and compaired with sorghum grains based carrier as control T11. Then observe the shelf life upto 180 days from the date of manufacturing at regular interval of 30 days. The study revealed that the desired minimum count i.e. 1 x 107 was noticed in all the formulations upto 180 days storage. Maximum cfu/g (76.33 x 107) was obtained inT10 i.e. frozen culture mass along with medium disc capsule followed by T4, T. asperellum fly ash tablet (39 × 107cfu/g). However, least cfu/g recorded in T9 T. asperellum alginate + charcoal capsules (20 × 107cfu/g). In the present study tablet and capsule delivery system of various formulations was also tried by using jaggery treatment and maximum population of T. asperellum obtained (77.66 × 107cfu/ml) in T10,T. asperellum Frozen culture mass along with medium disc capsule followed by (53 × 107cfu/ml) in T7, T. asperellum alginate capsule.

Oral Fecal Microbiota Transplant Capsules Are Safe and Effective for Recurrent Clostridioides difficile Infection: A Systematic Review and Meta-Analysis.

We performed a systematic review with meta-analysis to examine the efficacy and safety of oral fecal microbiota transplantation (FMT) capsules for recurrent Clostridioides difficile infection (rCDI). FMT through colonoscopy is established as effective and safe in treating multiple recurrences of CDI, but consensus has not been established on delivery through oral capsules. A systematic literature search was performed with multiple databases including MEDLINE and EMBASE to identify original studies including at least 10 patients that investigated the role of oral FMT capsules to treat rCDI. Cure rates were pooled by a random effects model and publication bias was assessed with the Egger test. Secondary analyses assessed for differences between capsule preparation (frozen vs. lyophilized stool) and delivery modality (capsule vs. colonoscopy). Fifteen studies (12 case series and 3 randomized controlled trials) encompassing 763 patients were identified for inclusion. Significant variability existed in baseline patient characteristics and protocols. Meta-analysis of proportions showed efficacy of oral FMT capsules to be 0.821 (95% confidence interval: 0.762-0.874). No evidence for publication bias was found (P=0.51). Secondary analyses did not find significant differences in efficacy. Fourteen adverse events leading to death or hospitalization were noted, none of which were attributed to FMT. Oral FMT capsules for rCDI are promising because of ease of administration and noninvasive delivery. We found an overall efficacy of 82.1% with a low rate of serious adverse events. Further studies are needed to optimize protocols and outcomes.

HPMC Capsules for Moisture Sensitive and Hygroscopic Products

<i>Background</i>: Moisture content varies in capsules made from different materials. Gelatin capsules contain 13-16% moisture. HPMC (Hydroxypropyl methyl cellulose or Hypromellose) capsules may contain moisture 2- 8%. Usual HPMC capsules have inherently low moisture content which allows for the encapsulation of ingredients that are sensitive to moisture and are hygroscopic in nature. This has greatly broadened the scope of capsules in drug delivery. Moisture content of HPMC capsules can be reduced as low as 2%. HPMC capsules lower moisture content is better for moisture sensitive and hygroscopic products. <i>Objective</i>: Low moisture content of HPMC capsules help to improve stability of moisture sensitive active pharmaceutical and active nutraceutical active ingredients. This is illustrated with examples. Different properties of HPMC capsules helps targeted delivery. It offers some special advantages for nutraceutical products. It also helps to improve physical stability of capsules. Liquid filled hard capsules provide many options and are commonly used for nutraceutical products.

Efficient Synthesis of Folate-Conjugated Hollow Polymeric Capsules for Accurate Drug Delivery to Cancer Cells.

This study presents an efficient and systematic approach to synthesize bioapplicable porous hollow polymeric capsules (HPCs). The hydroxyl-functionalized nanoporous polymers with hollow capsular shapes could be generated via the moderate Friedel-Crafts reaction without using any hard or soft template. The numerous primitive hydroxyl groups on these HPCs were further converted to carboxyl groups. Owing to the abundance of highly branched carboxyl groups on the surface of the HPCs, biomolecules [such as folic acid (FA)] could be covalently decorated on these organic capsules (FA-HPCs) for drug delivery applications. The intrinsic hollow porosities and specific targeting agent offered a maximum drug encapsulation efficiency of up to 86% and drug release of up to 50% in 30 h in an acidic environment. The in vitro studies against cancer cells demonstrated that FA-HPCs exhibited a more efficient cellular uptake and intracellular doxorubicin release than bare HPCs. This efficient approach to fabricate carbonyl-functionalized hollow organic capsules may open avenues for a new type of morphological-controlled nanoporous polymers for various potential bioengineering applications.

S0217 Twitter Interactions Around Fecal Microbiota Transplantation Have Increased Over Time

INTRODUCTION: Fecal Microbiota Transplantation (FMT) has been shown to be a safe and efficacious treatment for C. difficile infections (CDI) and is being studied for other indications associated with dysbiosis. Within the medical community and lay public, awareness of FMT and interest around other potential applications has increased over time, as has willingness to perform or undergo the procedure. Twitter, a social-media platform, has increasingly become a major source of news and information. With 71% of internet users accessing a social media site monthly and 330 million monthly active Twitter Users, Twitter has been heavily studied by consumer brands and data scientists to understand the attitudes and feelings of the general public. METHODS: This study retrospectively investigates the public’s interest in and opinions about FMT. Twitter’s Full Archive was searched for “Fecal Microbiota Transplantation” from 3/21/06 to 3/14/20. Tweets were stored on a SQLite database and analyzed with Python and Microsoft Excel. RESULTS: Of the 13,810 Tweets about “Fecal Microbiota Transplantation,” 7,925 (57%) were retweets and 5,885 (33%) were original Tweets. The total number of Tweets increased yearly, with a doubling of retweets and tripling of favorites from 2017 to 2018. There were 7,410 unique users who Tweeted about FMT. The sum of followers of all of these accounts tops 30 million. The number of exposures of FMT or times someone saw a Tweet about FMT nears 90 million. The average polarity of Tweets was 0.1, on a scale of −1 most negative to +1 most positive. The average polarity stayed fairly neutral over time. FMT had many associations on Twitter. CDI came up the most frequently with 6,800 mentions and peak discussion in 2018. Next most frequent was ulcerative colitis with 3,120 mentions, peaking in 2019. Tweets about route of FMT peaked in 2017, coinciding with the publication of a randomized control trial looking at capsule vs. colonoscopic FMT. That year, there was consistently greater discussion about capsule delivery than colonoscopy. Furthermore, the polarity for capsule (0.28) vs. colonoscopy (0.11) was twice as positive. From Twitter analysis, it can be determined that there was strong, positive public interest for capsule over colonoscopy.Figure 1.: Total number of original Tweets, retweets, replies, and favorites for “Fecal Microbiota Transplantation” each year.CONCLUSION: Increased Twitter interactions amongst a large audience has contributed to greater public awareness around FMT over time.Figure 2.: Average polarity of Tweets each year on a scale of -1 as the most negative to +1 as the most positive. Polarity of Tweet calculated with Python’s natural language toolkit.Figure 3.: The total number of “Fecal Microbiota Transplantation” Tweets on colonoscopy and capsule each year.

Crack self-healing of thermo-responsive shape memory polymers with application to control valves, filtration, and drug delivery capsule

Fracture behavior of Shape Memory Polymers (SMPs) and their self-healing property is one of the up-to-date subjects through the literature, where only a few researches have been conducted. Nowadays, because of the exceptional properties of SMPs and their implementation in 4D printing, they are most taken into attention. In this study, thermomechanical coupling effect on 3D fracture analysis of SMPs in large deformation regime has been investigated. Firstly, a thermo-visco-hyperelastic model is implemented to model the thermomechanical cycle of the SMP in the stress-free strain-recovery as well as the fixed-strain-stress-recovery processes. Motivated by fracture analysis and self-healing properties of SMPs, both 2D and 3D fracture analysis are conducted through various feasibility applications, such as flow control valve, pressure control valve, filtration and drug delivery capsule. Moreover, the ability of the analysis is shown through examining different parameters could affect the SMP response, such strain rate (or applied strain), temperature rate and memory recovery. Finally, the results show the ability of the numerical modeling in the aforesaid applications to design, analyze, and fabricate these applications.

Prodigiosin-loaded electrospun nanofibers scaffold for localized treatment of triple negative breast cancer.

Hybrid composite nanofibers, with the potential to enhance cell adhesion while improving sustained drug release profiles, were fabricated by the blend electrospinning of poly(d,l-lactic-co-glycolic acid) (PLGA), gelatin, pluronic F127 and prodigiosin (PG). Scanning Electron Microscopy (SEM) images of the nanofibers revealed diameters of 1.031 ± 0.851 μm and 1.349 ± 1.264 μm, corresponding to PLGA/Ge-PG and PLGA/Ge-F127/Ge, respectively. The Young's moduli were also determined to be 1.446 ± 0.496 kPa and 1.290 ± 0.617 kPa, while the ultimate tensile strengths were 0.440 ± 0.117 kPa and 0.185 ± 0.480 kPa for PLGA/Ge-PG and PLGA/Ge-F127/Ge, respectively. In-vitro drug release profiles showed initial (burst) release for a period of 1 h to be 26.000 ± 0.004% and 16.000 ± 0.015% for PLGA/Ge and PLGA/Ge-F127 nanofibers, respectively. This was followed by 12 h of sustained release, and subsequent slow sustained release of PG from the composite nanofibers. The cumulative release of PG (for three days) was determined to be 82.0 ± 0.1% for PLGA/Ge and 49.7 ± 0.1% for PLGA/Ge-F127 nanofibers. The release exponents (n) show that both nanofibers exhibit diffusion-controlled release by non-Fickian (zeroth order) and quasi-Fickian diffusion in the initial and sustained release regimes, respectively. The suitability of the composite nanofibers for supporting cell proliferation and viability, as well as improving sustained release of the drug were explored. The in-vitro effects of cancer drug (PG) release were also studied on breast cancer cell lines (MCF-7 and MDA-MB-231 cells). The implications of the results are discussed for the potential applications of drug-nanofiber scaffolds as capsules for localized delivery of chemotherapeutic drugs for the treatment of triple negative breast cancer.

Injection Molded Capsules for Colon Delivery Combining Time-Controlled and Enzyme-Triggered Approaches.

A new type of colon targeting system is presented, combining time-controlled and enzyme-triggered approaches. Empty capsule shells were prepared by injection molding of blends of a high-amylose starch and hydroxypropyl methylcellulose (HPMC) of different chain lengths. The dissolution/erosion of the HPMC network assures a time-controlled drug release, i.e., drug release starts upon sufficient shell swelling/dissolution/erosion. In addition, the presence of high-amylose starch ensures enzyme-triggered drug release. Once the colon is reached, the local highly concentrated bacterial enzymes effectively degrade this polysaccharide, resulting in accelerated drug release. Importantly, the concentration of bacterial enzymes is much lower in the upper gastrointestinal tract, thus enabling site-specific drug delivery. The proposed capsules were filled with acetaminophen and exposed to several aqueous media, simulating the contents of the gastrointestinal tract using different experimental setups. Importantly, drug release was pulsatile and occurred much faster in the presence of fecal samples from patients. The respective lag times were reduced and the release rates increased once the drug started to be released. It can be expected that variations in the device design (e.g., polymer blend ratio, capsule shell geometry and thickness) allow for a large variety of possible colon targeting release profiles.

Molecular recognition of isovanillin crosslinked carrageenan biocomposite for drug delivery application

This work aims to evaluate carrageenan as a potential biocomposite for hard capsule in the drug delivery application. The interaction between carrageenan and isovanillin was studied by modeling their molecule electronic surface potential and enthalpy. Simulation results showed that the physical crosslinking is established at two points: hydroxyl (isovanillin)-sulfate (carrageenan) and aldehyde (isovanillin)-hydroxyl (carrageenan) with strong hydrogen bonds (H-bond) lengths of 1.74–1.79 Å. FTIR showed that isovanillin addition increased the intermolecular H-bond up to 57% as the OH-stretching is shifted from 3376 to 3356 cm−1. At 3 wt.% isovanillin concentration, the tensile strength of the biocomposite film increased to 49% and the hard capsule developed from the formulation solution disintegrated in 9 min. Upon contact with water, the H-bonds broke and caused the carrageenan fragments to dissolve in deionized water. The disintegration and mechanical properties of the crosslinked carrageenan biocomposite film made from renewable and low price materials facilitate the application of the film as hard capsules for drug delivery.