Preparation, characterization and in vitro evaluation of insulin-PHBV nanoparticles / alginate hydrogel composite system for prolonged delivery of insulin

PURPOSE

In the present study, biodegradable poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles (NPs) containing insulin were loaded in sodium alginate/jeffamine (ALG/jeff) hydrogel for prolonged delivery of insulin. The main aim of this work was to fabricate an efficient insulin delivery system to improve patient adherence by decreasing the repetition of injections.

METHODS

Swelling and morphological properties and crosslinking efficiency of ALG/jeff hydrogel were assessed. The composite hydrogel was prepared by adding PHBV NPs to ALG/jeff hydrogel concurrently with crosslinking process. The morphology and loading capacity of composite hydrogel were analyzed.

RESULTS

Circular dichroism measurement demonstrated that insulin remains stable following fabrication process. The release profile exhibited 54.6% insulin release from composite hydrogel within 31 days with minor initial burst release equated to nanoparticles and hydrogels. MTT cell viability analysis was performed by applying L-929 cell line and no cytotoxic effect was observed.

CONCLUSIONS

Favorable results clearly introduced fabricated composite hydrogel as an excellent candidate for drug delivery systems and also paves the route for prolonged delivery systems of other proteins.

The Effectiveness of MOFs for the Removal of Pharmaceuticals from Aquatic Environments: A Review Focused on Antibiotics Removal

There is an increasing level of various pollutants and their persistence in aquatic environments. The improper use of antibiotics and their inefficient metabolism in organisms result in their release into aquatic environments. Antibiotic abuse has led to hazardous effects on human health. Thereby, efficient removal of pharmaceuticals, particularly antibiotics, from wastewater and contaminated water bodies is greatly interested in international research communities. Metal-organic framework (MOF) materials, as a hybrid group of material containing metallic center and organic linkers, offer a porous structure that is highly efficient for removing different pollutants from contaminated water and wastewater streams. This article aims to review the recent advancement in using MOF-based adsorbents and catalysts for the removal of pharmaceuticals, especially antibiotics, from polluted water. Applying MOFs-based structures for removing antibiotics using photocatalytic removal and adsorptive removal techniques will be discussed and evaluated in this review paper. Various MOF-based materials such as functionalized MOFs, MOF-based composites, magnetic MOF-based composites, MOFs templated-metal oxide catalysts for removing pharmaceuticals, personal care products, and antibiotics from contaminated aqueous media are discussed. Furthermore, effective operational parameters on the adsorption, adsorption mechanisms, adsorption isotherms, and thermodynamic parameters are explained and discussed. Finally, in the concluding remarks, the challenges and future outlooks of using MOFs-based adsorbents and catalysts for removing antibiotics are summarized.

Preparation of Mesalamine Nanoparticles Using a Novel Polyurethane- Chitosan Graft Copolymer

BACKGROUND

Chitosan nanoparticle, a potential vehicle, is used as a hydrophilic carrier system since it can deliver drugs to specific sites and also control the drug release rate. Moreover, controlled release systems are designed to minimize systemic absorption and to achieve optimum delivery of the biologically active mesalamine to the distal small intestine and the colon.

OBJECTIVE

The current study investigated the development of new nanoparticulate drug delivery systems based on polyurethane-chitosan copolymers. The copolymer shows good biodegradablity and biocompatiblity properties and thus can be considered as a potential carrier for drug delivery systems.

METHOD

In this work, Polyurethane was obtained from the condensation reaction between polypropylene glycol (PPG) as prepolymerpolyol, 1, 4-butanediol (BD) as diol, dimethylol propionic acid (DMPA) as chain extender and also isophoronediisocyanate (IPDI). The synthesized polyurethane was grafted onto the prepared chitosan through a covalent binding and preparation of nanoparticles was done further through a coprecipitation process. The particle size of the prepared samples was evaluated with dynamic light scattering (DLS) technique.

RESULTS

The obtained particle size of the samples was 80±0.05 nm. Characterization of the synthesized chitosan-polyurethane copolymer was performed by FT-IR spectroscopy, 13CNMR and 11HNMR spectroscopy. The morphology of the synthesized polyurethane-chitosan copolymers and the amount of the loaded drug were also examined using SEM images and UV-visible spectroscopy, respectively. Moreover, drug release behavior was examined in PBS (pH 7.4) at 37°C. It was concluded that the mesalamine release from polyurethane-chitosan was sustained and no initial burst release (burst effect) was observed and the percentage of mesalamine released from nanoparticles was 92.19±0.2% within 72 hrs.

CONCLUSION

The results of the drug loaded nanoparticles showed that the drug loading process was performed successfully. As a result, polyurethane-chitosan copolymer can be a good candidate for drug delivery systems.

Plateau waves and baroreflex sensitivity in patients with head injury: a case study

The study aimed to investigate baroreceptor reflex sensitivity in a patient with head injury for whom plateau waves of intracranial pressure (ICP) were recorded. Baroreflex sensitivity index was separately estimated on top of plateau waves and during intermediate intervals between two consecutive waves. The EuroBaVar data set was utilized to verify and validate the results. A very high baroreflex sensitivity associated with dominant parasympathetic activity was observed spontaneous to the acute elevations of ICP. The high vagal afferent discharge was found to be suggestive for the high firing rate of carotid baroreceptors and probably an active Cushing reflex mechanism during plateau waves.

Pulse wave velocity in patients with severe head injury a pilot study

The study aimed to determine the potential of pulse wave velocity measurements to reflect changes in compliant cerebral arteries/arterioles in head injured patients. The approach utilizes the electrocardiogram and intracranial pressure signals to measure the wave transit time between heart and cranial cavity. Thirty five clinical records of nineteen head injured patients, with different levels of cerebrovascular pressure-reactivity response, were investigated through the study. Results were compared with magnitude of normalized transfer function at the fundamental cardiac frequency. In patients with intact cerebrovascular pressure-reactivity, magnitude of normalized transfer function at the fundamental cardiac component was found to be highly correlated with pulse wave transit time.

Normalized power transmission between ABP and ICP in TBI

A new approach to study the pulse transmission between the cerebrovascular bed and the intracranial space is presented. In the proposed approach, the normalized power transmission between ABP and ICP has got the main attention rather than the actual power transmission. Evaluating the gain of the proposed transfer function at any single frequency can reveal how the percentage of contribution of that specific frequency component has been changed through the cerebrospinal system. The gain of the new transfer function at the fundamental cardiac frequency was utilized to evaluate the state of the brain in three TBI patients. Results were assessed using the reference evaluations achieved by a novel CT scan-based scoring scheme. In all three study cases, the gain of the transfer function showed a good capability to follow the trend of the CT scores and describe the brain state. Comparing the new transfer function with the traditional one and also the index of compensatory reserve, the proposed transfer function was found more informative about the state of the brain in the patients under study.

[Ossicular reconstruction with autograft in type III]

OBJECTIVE

The prostheses known as biocompatible are usually proposed for columellar repair in absence of stapes but at which cost and which long-term tolerance? It appeared useful to study the possibilities of autograft ossicular reconstruction (incus and cortical bone) in absence of suprastructure of the stapes.

MATERIAL AND METHODS

Retrospective study for 82 operated patients for cholesteatoma with lysis of the cruras of the stapes. Columellar repair was obtained by prosthesis, columella of cortical mastoid bone, and more often autograft of incus (54 cases). The technique of Autogreffe Tympanum-Cartilage-Os-Platinum (ATCOP) (Autograft Tympanum-Cartilage-Bone-Footplate is described: tympanic repair by fascia and cartilage from the concha is made at the first surgical step. Type III ossiculoplasty is performed at the second look. The distance tympanum-footplate is then lower than 6 mm and the body of the incus, preserved as a spare ossicle in the mastoid, has a sufficient length to be interposed in between new drum and footplate.

RESULTS

78% of the patients have final air bone gap less or equal than 30 decibels. The average post op air bone gap is 23 decibels with incus while it was 42 decibels before surgery. Average gain is 19 decibels. The cost of autograft is null and tolerance is excellent.

CONCLUSION

Patient's incus is usable in type III ossiculoplasty thanks to a cartilage graft of the tympanic membrane. Patient's ossicle is a material of choice for columellar repair even in absence of the suprastructure of the stapes. Prostheses in biomaterial appear justified in case of absent or destroyed incus.