Prolonged hypocalcemic effect by pulmonary delivery of calcitonin loaded poly(methyl vinyl ether maleic acid) bioadhesive nanoparticles

Noninvasive and Microinvasive Nanoscale Drug Delivery Platforms for Hard Tissue Engineering

Bone tissue plays a crucial role in protecting internal organs and providing structural support and locomotion of the body. Treatment of hard tissue defects and medical conditions due to physical injuries, genetic disorders, aging, metabolic syndromes, and infections is more often a complex and drawn out process. Presently, dealing with hard-tissue-based clinical problems is still mostly conducted via surgical interventions. However, advances in nanotechnology over the last decades have led to shifting trends in clinical practice toward noninvasive and microinvasive methods. In this review article, recent advances in the development of nanoscale platforms for bone tissue engineering have been reviewed and critically discussed to provide a comprehensive understanding of the advantages and disadvantages of noninvasive and microinvasive methods for treating medical conditions related to hard tissue regeneration and repair.

Spatiotemporally controlled calcitonin delivery: Long-term and targeted therapy of skeletal diseases

Bone is a connective tissue that support the entire body and protect the internal organs. However, there are great challenges on curing intractable skeletal diseases such as hypercalcemia, osteoporosis and osteoarthritis. To address these issues, calcitonin (CT) therapy is an effective treatment alternative to regulate calcium metabolism and suppress inflammation response, which are closely related to skeletal diseases. Traditional calcitonin formulation requires frequent administration due to the low bioavailability resulting from the short half-life and abundant calcitonin receptors distributed through the whole body. Therefore, long-term and targeted calcitonin delivery systems (LCDS and TCDS) have been widely explored as the popular strategies to overcome the intrinsic limitations of calcitonin and improve the functions of calcium management and inflammation inhibition in recent years. In this review, we first explain the physiological effects of calcitonin on bone remodeling: (i) inhibitory effects on osteoclasts and (ii) facilitated effects on osteoblasts. Then we summarized four strategies for spatiotemporally controlled delivery of calcitonin: micro-/nanomedicine (e.g. inorganic micro-/nanomedicine, polymeric micro-/nanomedicine and supramolecular assemblies), hydrogels (especially thermosensitive hydrogels), prodrug (PEGylation and targeting design) and hybrid biomaterials. Subsequently, we discussed the application of LCDS and TCDS in treating hypercalcemia, osteoporosis, and arthritis. Understanding and analyzing these advanced calcitonin delivery applications are essential for future development of calcitonin therapies toward skeletal diseases with superior efficacy in clinic.

Calcitonin-loaded octamaleimic acid-silsesquioxane nanoparticles in hydrogel scaffold support osteoinductivity in bone regeneration

Novel osteoinductive scaffolds fabricated using the benefits of tissue engineering techniques accompanied by utilizing drugs can accelerate bone regeneration. The purpose of this study was to load salmon calcitonin (sCT) in octamaleimic acid-silsesquioxane (OMA-POSS) nanoparticles and enrich the hydrogel scaffold based on hydroxyapatite, Gelrite® and platelet-rich plasma (PRP) for use in bone tissue engineering. The loading efficiency, release percentage, particle size and zeta potential of the nanoparticles were evaluated. The proliferation of seeded MG-63 osteoblast cells on the designed scaffold, its cytotoxicity and osteo-conductivity were studied by alkaline phosphatase measurement and Alizarin red staining. The expression of cellular osteogenic markers such as collagen 1 (COL1A1), osteocalcin (BGLAP) and osteopontin (SPP1) was examined using reverse transcription polymerase chain reaction. The results revealed that the particle size of the nanoparticles varied between 94.2 and 199.2 nm and their negative surface charge increased after drug conjugation. The osteoblast cell proliferation and calcium granule production in the optimum formulation were significantly higher in comparison with the control group (p < 0.05). Osteogenic markers increased significantly after a specific number of days of cell culture compared to the control group (p < 0.05). The results also showed the potential of the designed scaffold in bone tissue engineering.

Optimization of Poly(methyl vinyl ether-co-maleic acid) Electrospun Nanofibers as a Fast-Dissolving Drug Delivery System

Background:

Poly(methyl vinyl ether-maleic acid) (PMVEMA) is a water-soluble, biodegradable polymer used for drug delivery. The aim of the present study was to prepare nanofibers of this polymer as a fast-dissolving carrier for montelukast.

Materials and Methods:

Polymeric nanofibers were spun by electrospinning method using different ratios of biodegradable polymer of PMVEMA. The processing variables including voltage, distance of the needle to rotating screen, and flow rate of the solution were optimized based on the diameter of the nanofibers, drug content, and release efficiency by a Taguchi design. The morphology, diameter, and diameter distribution of the nanofibers were studied by scanning electron microscopy (SEM). Drug loading and its release rate from the nanofibers were analyzed spectrophotometrically. The possible molecular between the polymer and the drug was characterized with Fourier-transform-infrared spectroscopy.

Results:

The results showed the best situation for electrospinning of the polymer obtained at the polymer concentration of 37%, the distance of the needle to rotating screen of 19 cm, the voltage of 120 kV, and the rate of injection of 0.2 ml/h. In these situations, the fiber diameter and drug loading efficiency percentage were 273 nm and 83%, respectively. These nanofibers released the total loaded drug within 1–3 s with no residue in the dissolution medium. SEM results showed that the optimized nanofibers were quite smooth and without beads.

Conclusions:

The results indicated that the nanofibers of PMVEMA could dissolve the drug very rapidly and can be adopted for fast-dissolving dosage forms.

Luteinizing hormone-releasing hormone targeted poly(methyl vinyl ether maleic acid) nanoparticles for doxorubicin delivery to MCF-7 breast cancer cells

The purpose of this study was to design a targeted anti-cancer drug delivery system for breast cancer. Therefore, doxorubicin (DOX) loaded poly(methyl vinyl ether maleic acid) nanoparticles (NPs) were prepared by ionic cross-linking method using Zn(2+) ions. To optimise the effect of DOX/polymer ratio, Zn/polymer ratio, and stirrer rate a full factorial design was used and their effects on particle size, zeta potential, loading efficiency (LE, %), and release efficiency in 72 h (RE72, %) were studied. Targeted NPs were prepared by chemical coating of tiptorelin/polyallylamin conjugate on the surface of NPs by using 1-ethyl-3-(3-dimethylaminopropyl) carboiimid HCl as cross-linking agent. Conjugation efficiency was measured by Bradford assay. Conjugated triptorelin and targeted NPs were studied by Fourier-transform infrared spectroscopy (FTIR). The cytotoxicity of DOX loaded in targeted NPs and non-targeted ones were studied on MCF-7 cells which overexpress luteinizing hormone-releasing hormone (LHRH) receptors and SKOV3 cells as negative LHRH receptors using Thiazolyl blue tetrazolium bromide assay. The best results obtained from NPs prepared by DOX/polymer ratio of 5%, Zn/polymer ratio of 50%, and stirrer rate of 960 rpm. FTIR spectrum confirmed successful conjugation of triptorelin to NPs. The conjugation efficiency was about 70%. The targeted NPs showed significantly less IC50 for MCF-7 cells compared to free DOX and non-targeted NPs.