Development and in-vivo evaluation of insulin-loaded chitosan phthalate microspheres for oral delivery

Preparation and Characterization of Novel Polyelectrolyte Liposomes Using Chitosan Succinate Layered over Chitosomes: A Potential Strategy for Colon Cancer Treatment

Chitosan succinate is distinguished by its ability to shield the loaded drug from the acidic environment, localize and keep the drug at the colon site, and release the drug over an extended time at basic pH. The current study attempts to develop polyelectrolyte liposomes (PEL), using chitosan and chitosan succinate (CSSC), as a carrier for liposomal-assisted colon target delivery of 5 fluorouracil (5FU). The central composite design was used to obtain an optimized formulation of 5FU-chitosomes. The chitosan-coated liposomes (chitosomes) were prepared by thin lipid film hydration technique. After that, the optimized formulation was coated with CSSC, which has several carboxylic (COOH) groups that produce an anionic charge that interacts with the cation NH2 in chitosan. The prepared 5FU-chitosomes formulations were evaluated for entrapment efficiency % (EE%), particle size, and in vitro drug release. The optimized 5FU-chitosomes formulation was examined for particle size, zeta potential, in vitro release, and mucoadhesive properties in comparison with the equivalent 5FU-liposomes and 5FU-PEL. The prepared 5FU-chitosomes exhibited high EE%, small particle size, low polydispersity index, and prolonged drug release. PEL significantly limited the drug release at acidic pH due to the deprotonation of carboxylate ions in CSSC, which resulted in strong repulsive forces, significant swelling, and prolonged drug release. According to a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, PEL treatment significantly decreased the viability of HT-29 cells. When compared to 5FU-liposome and 5FU-chitosome, the in vivo pharmacokinetics characteristics of 5FU-PEL significantly (p < 0.05) improved. The findings show that PEL enhances 5FU permeability, which permits high drug concentrations to enter cells and inhibits the growth of colon cancer cells. Based on the current research, PEL may be used as a liposomal-assisted colon-specific delivery.

An Insight of Naturally Occurring Phytoconstituents and Novel Approaches Towards the Treatment of Diabetes

BACKGROUND

The rising in diabetes incidents has clearly become one main worldwide health problem. Individuals suffering from diabetes are still more susceptible to many long-term and short-term side effects, which most often cause fatalities. Even though chemically synthesized anti-diabetic entities are capable of helping manage and treat, there has been significant risks related with their prolong and repetitive use. Hence, there is a requirement for safer and novel approaches that might be formed and utilized.

OBJECTIVE

Aim of the present review is to explain the naturally occurring phytochemicals and novel approach as anti-diabetic agents in the treatment of diabetes and its related issues.

METHOD

A survey of Google scholar, Research Gate, Pubmed, Science Direct, NCBI database was carried out conducted to determine a most hopeful phytochemicals and novel drug delivery systems in the management of diabetes.

RESULT

The study stressed the significance of phytomolecules and some novel approaches researched or reported in the literature for the management and cure of diabetes. It is suggested that changes in lifestyle can help patients and like nutritional support, assessment and lifestyle guidance must be individualized based on physical and functional capacity. Further evaluations and improved preventative medicine were the result of improving patient outcomes.

CONCLUSION

Conventional or synthetic drugs provide relief for short time but nanoformulations of phytomolecules offer an improved therapeutic with fewer negative side effects. Herbal medicines are rich in phytoconstituents and possess variety of health benefits. This review is compilation of phytoconstituents and novel drug delivery system of phytomolecules i.e. nanoparticles, niosomes, microsphere, microparticle and others.

Progress in the Development of Chitosan Based Insulin Delivery Systems: A Systematic Literature Review

Diabetes mellitus is a chronic disease that is considered a worldwide epidemic, and its control is a constant challenge for health systems. Since insulin had its first successful use, scientists have researched to improve the desired effects and reduce side-effects. Over the years, the challenge has been to increase adherence to treatment and improve the quality of life for diabetics by developing an insulin delivery system. This systematic review (SR) analyses experimental articles from 1998 to 2018 related to the development of the chitosan/insulin delivery system (CIDS). Automated support: Start tool was used to perform part of these activities. The search terms “insulin”, “delivery or release system”, and “chitosan” were used to retrieve articles in PubMed, Science Direct, Engineering Village, and HubMed. A total of 55 articles were selected. The overview, phase, model, way of administration, and the efficiency of CIDS were analyzed. According to SR results, most of the articles were published from 2010 onwards, representing 72.7% of the selected papers, and research groups from China publicized 23.6% of the selected articles. According to the SR, 51% of the studies were carried out in vivo and 45% in vitro. Most of the systems were nanoparticle based (54.8%), and oral administration was proposed by 60.0% of the selected articles. Only 36.4% performed loaded capacity and encapsulation efficiency assays, and 24 h (16.4%), 12 h (12.7%), and 6 h (11.0%) were the most frequent insulin release times. Chitosan’s intrinsic characteristics, which include biodegradability, biocompatibility, adhesiveness, the ability to open epithelial tight junctions to allow an increase in the paracellular transport of macromolecular drugs, such as insulin, and the fact that it does not result in allergic reactions in the human body after implantation, injection, topical application or ingestion, have contributed to the increase in research of CIDS over the years. However, the number of studies is still limited and the use of an alternative form of insulin administration is not yet possible. Thus, more studies in this area, aiming for the development of an insulin delivery system that can promote more adherence to the treatment and patient comfort, are required.

Microparticles, microcapsules and microspheres: A review of recent developments and prospects for oral delivery of insulin

Diabetes mellitus is a chronic metabolic health disease affecting the homeostasis of blood sugar levels. However, subcutaneous injection of insulin can lead to patient non-compliance, discomfort, pain and local infection. Sub-micron sized drug delivery systems have gained attention in oral delivery of insulin for diabetes treatment. In most of the recent literature, the terms "microparticles" and "nanoparticle" refer to particles where the dimensions of the particle are measured in micrometers and nanometers respectively. For instance, insulin-loaded particles are defined as microparticles with size larger than 1 μm by most of the research groups. The size difference between nanoparticles and microparticles proffers numerous effects on the drug loading efficiency, aggregation, permeability across the biological membranes, cell entry and tissue retention. For instance, microparticulate drug delivery systems have demonstrated a number of advantages including protective effect against enzymatic degradation, enhancement of peptide stability, site-specific and controlled drug release. Compared to nanoparticulate drug delivery systems, microparticulate formulations can facilitate oral absorption of insulin by paracellular, transcellular and lymphatic routes. In this article, we review the current status of microparticles, microcapsules and microspheres for oral administration of insulin. A number of novel techniques including layer-by-layer coating, self-polymerisation of shell, nanocomposite microparticulate drug delivery system seem to be promising for enhancing the oral bioavailability of insulin. This review draws several conclusions for future directions and challenges to be addressed for optimising the properties of microparticulate drug formulations and enhancing their hypoglycaemic effects.

Oral insulin delivery: existing barriers and current counter-strategies

Objectives

The chronic and progressive nature of diabetes is usually associated with micro- and macrovascular complications where failure of pancreatic β-cell function and a general condition of hyperglycaemia is created. One possible factor is failure of the patient to comply with and adhere to the prescribed insulin due to the inconvenient administration route. This review summarizes the rationale for oral insulin administration, existing barriers and some counter-strategies trialled.

Key findings

Oral insulin mimics the physiology of endogenous insulin secreted by pancreas. Following the intestinal absorption of oral insulin, it reaches the liver at high concentration via the portal vein. Oral insulin on the other hand has the potential to protect pancreatic β-cells from autoimmune destruction. Structural modification, targeting a particular tissue/receptor, and the use of innovative pharmaceutical formulations such as nanoparticles represent strategies introduced to improve oral insulin bioavailability. They showed promising results in overcoming the hurdles facing oral insulin delivery, although delivery is far from ideal.

Summary

The use of advanced pharmaceutical technologies and further research in particulate carrier system delivery predominantly nanoparticle utilization would offer useful tools in delivering insulin via the oral route which in turn would potentially improve diabetic patient compliance to insulin and the overall management of diabetes.

Development of acid-resistant alginate/trimethyl chitosan nanoparticles containing cationic β-cyclodextrin polymers for insulin oral delivery

In this study, the use of trimethylchitosan (TMC), by higher solubility in comparison with chitosan, in alginate/chitosan nanoparticles containing cationic β-cyclodextrin polymers (CPβCDs) has been studied, with the aim of increasing insulin uptake by nanoparticles. Firstly, TMCs were synthesized by iodomethane, and CPβCDs were synthesized within a one-step polycondensation reaction using choline chloride (CC) and epichlorohydrine (EP). Insulin-CβCDPs complex was prepared by mixing 1:1 portion of insulin and CPβCDs solutions. Then, nanoparticles prepared in a three-step procedure based on the iono-tropic pregelation method. Nanoparticles screened using experimental design and Placket Burman methodology to obtain minimum size and polydispercity index (pdI) and the highest entrapment efficiency (EE). CPβCDs and TMC solution concentration and pH and alginate and calcium chloride solution concentrations are found as the significant parameters on size, PdI, and EE. The nanoparticles with proper physicochemical properties were obtained; the size, PdI, and EE% of optimized nanoparticles were reported as 150.82 ± 21 nm, 0.362 ± 0.036, and 93.2% ± 4.1, respectively. The cumulative insulin release in intestinal condition achieved was 50.2% during 6 h. By SEM imaging, separate, spherical, and nonaggregated nanoparticles were found. In the cytotoxicity studies on Caco-2 cell culture, no significant cytotoxicity was observed in 5 h of incubation, but after 24 h of incubation, viability was decreased to 50% in 0.5 mμ of TMC concentration. Permeability studies across Caco-2 cells had been carried out, and permeability achieved in 240 min was 8.41 ± 0.39%, which shows noticeable increase in comparison with chitosan nanoparticles. Thus, according to the results, the optimized nanoparticles can be used as a new insulin oral delivery system.

Preparation, statistical optimization, and in vitro characterization of insulin nanoparticles composed of quaternized aromatic derivatives of chitosan

The aim of this study was the preparation, optimization, and in vitro characterization of insulin nanoparticles composed of methylated N-(4-N,N-dimethylaminobenzyl), methylated N-(4-pyridinyl), and methylated N-(benzyl) chitosan. Three types of derivatives were synthesized by the Schiff base reaction followed by quaternization. Nanoparticles were prepared by the polyelectrolyte complexation method. Experimental design D-optimal response surface methodology was used for the optimization of the nanoparticles. Independent variables were pH of polymer solution, concentration ratio of polymer/insulin, and also polymer type. Dependent variables include size, zeta potential, polydispersity index (PdI), and entrapment efficiency (EE%). Optimized nanoparticles were studied morphologically by transmission electron microscopy (TEM), and in vitro release of insulin from nanoparticles were determined under phosphate buffer (pH = 6.8) condition. Although a quadratic model has been chosen to fit the responses for size, PdI, and EE%, the zeta potential of the particles has been best fitted to 2-FI model. The optimized nanoparticles were characterized. The size of the particles were found to be 346, 318, and 289 nm; zeta potentials were 28.5, 27.7, and 22.2 mV; PdI of particles were 0.305, 0.333, and 0.437; and calculated EE% were 70.3%, 84.5%, and 69.2%, for methylated (aminobenzyl), methylated (pyridinyl), and methylated (benzyl) chitosan nanoparticles, respectively. TEM images show separated and non-aggregated nanoparticles with sub-spherical shapes and smooth surfaces. An in vitro release study of the prepared nanoparticles showed that the cumulative percentage of insulin released from the nanoparticles were 47.1%, 38%, and 68.7% for (aminobenzyl), (pyridinyl), and (benzyl) chitosan, respectively, within 300 min.

A pH-sensitive nanocomposite microsphere based on chitosan and montmorillonite with in vitro reduction of the burst release effect

OBJECTIVE

The aim of this study was to prepare pH-sensitive ofloxacin (OFL)/montmorillonite (MMT)/chitosan (CTS) nanocomposite microspheres that improve the burst release effect of the drug by the solution intercalation technique and emulsification cross-linking techniques.

METHODS

First, OFL/MMT hybrids were prepared through the solution intercalation technique. Then, OFL/MMT-intercalated OFL/MMT/CTS nanocomposite microspheres were obtained through emulsification cross-linking technology. The intercalated nanocomposite was confirmed by Fourier-transform infrared spectroscopy and X-ray diffraction. Finally, in vitro release of OFL from the microspheres was performed in simulated gastric fluids and simulated intestinal fluids. The effect of MMT content on drug encapsulation efficiency and the drug release of the nanocomposite microspheres were investigated.

RESULTS

The results showed that the release rate of OFL from the nanocomposite microspheres at pH 7.4 was higher than that at pH 1.2. Compared with pure CTS microspheres, the incorporation of certain amount of MMT in the nanocomposite microspheres can enhance the drug encapsulation efficiency and reduce the burst release.

CONCLUSION

A sustained release particulate system can be obtained by incorporating MMT into the nanocomposite microspheres and can improve the burst release effect of the drug.

Development and validation of an improved Bradford method for determination of insulin from chitosan nanoparticulate systems

CONTEXT

Blank chitosan nanoparticles are currently used as reference for the calibration curve, which fails to resolve the supernatant of the nanoparticles in the interference of Coomassie Brilliant Blue G-250 reagent; supernatants are generated at different chitosan nanoparticulate prescriptions, which have different interferences. There are notable errors in the experimental results, and the method is not feasible.

OBJECTIVE

In this study, an improved, rapid, and economic Bradford method was developed and validated.

MATERIALS AND METHODS

The pH of the supernatant of blank chitosan nanoparticles was adjusted to 7-9 through adding saturated NaOH. The precipitation (free chitosan) in the solution was separated by centrifuging for about 10 min (4000 r/min).

RESULTS

The method eliminated the interference of free chitosan of different prescriptions. The results showed that the method presented a linearity in the range of 50-300 microg/mL (R(2) = 0.9992), and possessed a good inter-day and intra-day precision based on relative standard deviation values (less than 3.10%). Recovery of the supernatant of blank chitosan nanoparticles was between 98.30 and 99.93%, and the recovery of blank chitosan nanoparticles was between 95.57 and 100.27%.

DISCUSSION AND CONCLUSION

The method was further tested for determination of the association efficiency of insulin to nanoparticulate carriers composed of chitosan. Encapsulant release under simulated gastrointestinal fluids was evaluated.

Modified chitosans for oral drug delivery

The cationic polysaccharide chitosan has been extensively studied for oral drug delivery. In recent years, chemically modified chitosans developed in order to improve the properties of chitosan for oral drug delivery have gained increasing attention. Representatives of these novel polymers are trimethyl-chitosans, thiolated chitosans, carboxymethyl chitosan and derivatives, hydrophobic chitosans, chitosan succinate and phthalate, PEGylated chitosans and chitosan-enzyme inhibitor conjugates. Besides their use for oral delivery of therapeutic peptides and proteins, they have recently been evaluated regarding their potential for the delivery of other substance classes, including genes and efflux pump substrates. Within the current review, various modified chitosan derivatives, their properties and synthesis are discussed.