Development of pH-sensitive pectinate/alginate microspheres for colon drug delivery

Delivery system for grape seed extract based on biodegradable pectin-Zn-alginate gel particles

Pectin-Zn-alginate gel particles from callus culture pectin with increased linearity and decreased rhamnogalacturonan I branching and degree of methylesterification had a higher gel strength and encapsulation capacity. An increase of the alginate concentration led to an increase in the particle gel strength. The grape seed extract (GSE) loaded and empty particles swelled slightly in the simulated gastric fluid (SGF) and gradually in the intestinal (SIF) fluid. The swelling degrees of the GSE-loaded and empty particles in the simulated colonic fluids (SCF) were decreased in the range SCF-7.0 (pH 7.0 + pectinase) > SCF-5.3 (pH 5.3 + pectinase) > SCF-2.3 (pH 2.3 + pectinase). The FTIR spectra indicated that GSE was embedded in the composite particles. Negligible leakage of GSE in SGF was shown. The increase in GSE release in SIF was due to the decrease in particle gel strength and increased swelling degree. The GSE release in fluids simulating the colon inflammation (SCF-2.3 and SCF-5.3) was similar, and it was lower than that in the SCF-7.0 simulating a healthy colon due to the increased gel strength. The percentage release of GSE increased slightly after exposure to different pH. Pectin-Zn-alginate hydrogel systems may be promising candidates for colon-targeted GSE delivery systems.

Advances in Bio-Based Polymers for Colorectal CancerTreatment: Hydrogels and Nanoplatforms

Adenocarcinoma of the colon is the most common malignant neoplasia of the gastrointestinal tract and is a major contributor to mortality worldwide. Invasiveness and metastatic behavior are typical of malignant tumors and, because of its portal drainage, the liver is the closest capillary bed available in this case, hence the common site of metastatic dissemination. Current therapies forecast total resection of primary tumor when possible and partial liver resection at advanced stages, along with systemic intravenous therapies consisting of chemotherapeutic agents such as 5-fluorouracil. These cures are definitely not exempt from drawbacks and heavy side effects. Biocompatible polymeric networks, both in colloids and bulk forms, able to absorb large quantities of water and load a variety of molecules-belong to the class of innovative drug delivery systems, thus suitable for the purpose and tunable on each patient can represent a promising alternative. Indeed, the implantation of polymeric scaffolds easy to synthesize can substitute chemotherapy and combination therapies scheduling, shortening side effects. Moreover, they do not require a surgical removal thanks to spontaneous degradation and guarantees an extended and regional cargo release, maintaining high drug concentrations. In this review, we focus our attention on the key role of polymeric networks as drug delivery systems potentially able to counteract this dramatic disease.

Physicochemical and swelling properties of composite gel microparticles based on alginate and callus cultures pectins with low and high degrees of methylesterification

Composite gel microparticles based on alginate and callus culture pectins with low and high degrees of methylesterification or apple pectin were produced. By varying the chemical composition of the pectic samples and the ratio of alginate to pectin, the gel strength, morphology, and swelling properties of composite microparticles can be altered. The inclusion of increasing concentrations of alginate in gel formulations promoted an increase in the microparticle gel strength and the formation of a smoother surface microrelief independently of the pectin chemical composition. Microparticles based on the pectin with a low degree of methylesterification (DM) and a higher concentration of alginate exhibited an increased swelling degree in the simulated digestive fluids. Microparticles based on the pectin with high DM and low alginate concentration were destroyed in the simulated intestinal fluid within 1 h due to the low Ca²⁺ content, gel strength, and grooved and rough surface of these microparticles. An increase in alginate concentration of gel formulations based on pectin with high DM led to increased stability of the microparticles in the simulated intestinal and colonic fluids due to increased Ca²⁺ content, microparticle gel strength and degree of crosslinking.

Tumoral Acidic pH-Responsive cis-Diaminodichloroplatinum-Incorporated Cy5.5-PEG- g-A-HA Nanoparticles for Targeting Delivery of CDDP against Cervical Cancer

Cisplatin (CDDP) has been considered as one of the most effective anticancer drugs against cervical cancer, but the lack of selectivity of CDDP to tumor tissues often leads to serious toxic side effects. In this study, CDDP-incorporated Cy5.5-PEG- g-A-HA nanoparticles were prepared to endue CDDP the ability to selectively target tumors and fluorescence imaging in vivo. The nanoparticles exhibited a spherical shape with particle sizes between 216.4 and 281.5 nm and had a pH and Cl^- concentration dependence on controlled and sustained CDDP release, which was favorable for nanoparticles to release more drugs at acidic tumor microenvironment. Cell biology experiments demonstrated that the nanoparticles had good biocompatibility and tumor targeting; the nanoparticles could selectively bind and internalize into HeLa cells and induce apoptosis, but lead to less cytotoxicity on NIH3T3 cells. What is more, the nanoparticles could be clearly fluorescent-imaged in vivo and showed an effective accumulation at the tumor site. Antitumor test in vivo displayed that the nanoparticles had good antitumor efficiency and low systemic toxicity which improved the life quality of mice. Hence, the CDDP-incorporated Cy5.5-PEG- g-A-HA nanoparticles were a potential delivery system for targeting delivery of CDDP against cervical cancer.

Pectin and Pectin-Based Composite Materials: Beyond Food Texture

Pectins are plant cell wall natural heteropolysaccharides composed mainly of α-1-4 d-galacturonic acid units, which may or may not be methyl esterified, possesses neutral sugars branching that harbor functional moieties. Physicochemical features as pH, temperature, ions concentration, and cosolute presence, affect directly the extraction yield and gelling capacity of pectins. The chemical and structural features of this polysaccharide enables its interaction with a wide range of molecules, a property that scientists profit from to form new composite matrices for target/controlled delivery of therapeutic molecules, genes or cells. Considered a prebiotic dietary fiber, pectins meetmany regulations easily, regarding health applications within the pharmaceutical industry as a raw material and as an agent for the prevention of cancer. Thus, this review lists many emergent pectin-based composite materials which will probably palliate the impact of obesity, diabetes and heart disease, aid to forestall actual epidemics, expand the ken of food additives and food products design.

Fabrication of high specificity hollow mesoporous silica nanoparticles assisted by Eudragit for targeted drug delivery

Hollow mesoporous silica nanoparticles (HMSNs) are one of the most promising carriers for effective drug delivery due to their large surface area, high volume for drug loading and excellent biocompatibility. However, the non-ionic surfactant templated HMSNs often have a broad size distribution and a defective mesoporous structure because of the difficulties involved in controlling the formation and organization of micelles for the growth of silica framework. In this paper, a novel "Eudragit assisted" strategy has been developed to fabricate HMSNs by utilising the Eudragit nanoparticles as cores and to assist in the self-assembly of micelle organisation. Highly dispersed mesoporous silica spheres with intact hollow interiors and through pores on the shell were fabricated. The HMSNs have a high surface area (670 m(2)/g), small diameter (120 nm) and uniform pore size (2.5 nm) that facilitated the effective encapsulation of 5-fluorouracil within HMSNs, achieving a high loading capacity of 194.5 mg(5-FU)/g(HMSNs). The HMSNs were non-cytotoxic to colorectal cancer cells SW480 and can be bioconjugated with Epidermal Growth Factor (EGF) for efficient and specific cell internalization. The high specificity and excellent targeting performance of EGF grafted HMSNs have demonstrated that they can become potential intracellular drug delivery vehicles for colorectal cancers via EGF-EGFR interaction.

Hyaluronan-cisplatin conjugate nanoparticles embedded in Eudragit S100-coated pectin/alginate microbeads for colon drug delivery

Hyaluronan–cisplatin conjugate nanoparticles (HCNPs) were chosen as colon-targeting drug-delivery carriers due to the observation that a variety of malignant tumors overexpress hyaluronan receptors. HCNPs were prepared by mixing cisplatin with a hyaluronan solution, followed by dialysis to remove trace elements. The cells treated with HCNPs showed significantly lower viability than those treated with cisplatin alone. HCNPs were entrapped in Eudragit S100-coated pectinate/alginate microbeads (PAMs) by using an electrospray method and a polyelectrolyte multilayer-coating technique in aqueous solution. The release profile of HCNPs from Eudragit S100-coated HCNP-PAMs was pH-dependent. The percentage of 24-hour drug release was approximately 25.1% and 39.7% in pH 1.2 and pH 4.5 media, respectively. However, the percentage of drug released quickly rose to 75.6% at pH 7.4. Moreover, the result of an in vivo nephrotoxicity study demonstrated that Eudragit S100-coated HCNP-PAMs treatment could mitigate the nephrotoxicity that resulted from cisplatin. From these results, it can be concluded that Eudragit S100-coated HCNP-PAMs are promising carriers for colonspecific drug delivery.