A Narrative Review on Non-Invasive Drug Delivery of Teriparatide: A Ray of Hope

In the field of pharmaceutical biotechnology and formulation development, various protein and peptide-based drugs have been used for therapeutic and clinical implications. These are mainly given via parenteral routes like intravenous, subcutaneous or intramuscular delivery. Teriparatide, also known as PTH 1-34, is a U.S. Food & Drug Administartion-approved anabolic drug to treat osteoporosis is currently available in market only as subcutaneous injection. The quest for elimination of needle in case of given peptidal delivery to replace it with alternative routes like nasal, buccal, transdermal and pulmonary pathways has driven meticulous drug research. The pharmaceutical scientists are working on innovation and approaches involving new materials and methods to develop the formulations for protein and peptides by noninvasive routes. Lately, various approaches have been carried out which involve many strategies and technologies to deliver teriparatide via alternative routes. But, physicochemical instability, proteolytic degradation, low bioavailability, etc. are some obstacles to develop suitable delivery system for teriparatide. This review intends to gather the overall developments in delivery systems specific to teriparatide which meant for better convenience and avoids vulnerability of multiple subcutaneous injections. In addition, the article emphasizes on the successes to develop noninvasive technologies and devices, and new milestones for teriparatide delivery.

Anabolic Peptide-Enriched Stealth Nanoliposomes for Effective Anti-Osteoporotic Therapy

The objective of the present work was to develop PTH (1-34)-loaded stealth nanoliposomes (PTH-LPs) by employing the use of the Quality by Design (QbD) approach. Risk identification was carried out using the Ishikawa fishbone diagram. PTH-LPs were optimized using Box Behnken Design, a type of response surface methodology to examine the effect of independent variables on dependent variables such as particle size and percentage entrapment efficiency (%EE). Design space was generated for PTH-LPs to reduce interbatch variability during the formulation development process. Furthermore, a cytotoxicity assay, cell proliferation assay, calcium calorimetric assay, mineralized nodule formation, and cellular uptake assay were carried out on MG-63 osteoblast-like cells. The results obtained from these procedures demonstrated that lipid concentration had a significant positive impact on particle size and %EE, whereas cholesterol concentration showed a reduction in %EE. The particle size and %EE of optimized formulation were found to be 147.76 ± 2.14 nm and 69.18 ± 3.62%, respectively. Optimized PTH-LPs showed the sustained release profile of the drug. In vitro cell evaluation studies showed PTH-LPs have good biocompatibility with MG-63 cells. The cell proliferation study revealed that PTH-LPs induced osteoblast differentiation which improved the formation of mineralized nodules in MG-63 cells. The outcome of the present study conclusively demonstrated the potential of the QbD concept to build quality in PTH-LPs with improved osteoanabolic therapy in osteoporosis.

Chitosan-based biomaterials for the treatment of bone disorders

Bone is an alive and dynamic organ that is well-differentiated and originated from mesenchymal tissues. Bone undergoes continuous remodeling during the lifetime of an individual. Although knowledge regarding bones and their disorders has been constantly growing, much attention has been devoted to effective treatments that can be used, both from materials and medical performance points of view. Polymers derived from natural sources, for example polysaccharides, are generally biocompatible and are therefore considered excellent candidates for various biomedical applications. This review outlines the development of chitosan-based biomaterials for the treatment of bone disorders including bone fracture, osteoporosis, osteoarthritis, arthritis rheumatoid, and osteosarcoma. Different examples of chitosan-based formulations in the form of gels, micro/nanoparticles, and films are discussed herein. The work also reviews recent patents and important developments related to the use of chitosan in the treatment of bone disorders. Although most of the cited research was accomplished before reaching the clinical application level, this manuscript summarizes the latest achievements within chitosan-based biomaterials used for the treatment of bone disorders and provides perspectives for future scientific activities.

Guided bone regeneration activity of different calcium phosphate/chitosan hybrid membranes

To fulfill the properties of membrane for guided bone tissue regeneration, chitosan (CS) and calcium phosphates were blended to produce porous hybrid membranes by lyophilization. We synthesized three different calcium phosphates: calcium deficient hydroxyapatite (CDHA), biphasic calcium phosphate (BCP) and β‑tricalcium phosphate (TCP) by a reverse emulsion method followed by calcination, and compared their efficacy on bone regeneration. The CDHA/CS, BCP/CS, and TCP/CS membranes had an interconnected pore structure with porosity of 91-95% and pore size of 102-147 μm. These hybrid membranes could promote the permeability and adhesiveness to bone cells as demonstrated by in-vitro cell culture of primary osteoblast. Particularly, the CDHA/CS and BCP/CS could further increase the cell attachment and differentiation, whereas the BCP/CS and TCP/CS could enhance cell proliferation. Finally, these hybrid membranes were assessed for guided bone regeneration in the critical-size calvarial bone defects created in SD rats. Histological and histomorphometric analyses revealed that the BCP/CS membrane had the most effective bone regeneration compared to the other two hybrid membranes. At three-week post-surgery, the BCP/CS membrane could enhance new bone generation up to 57% of the original bone defect area. The BCP/CS membrane thus has the potential to be applied for guided bone regeneration.

Properties of a Stable and Sustained-Release Formulation of Recombinant Human Parathyroid Hormone (rhPTH) with Chitosan and Silk Fibroin Microparticles

Background

Parathyroid hormone (PTH) is required for the maintenance of normal bone physiology. This study describes the properties of a sustained-release formulation of recombinant human PTH (rhPTH) using chitosan and silk fibroin microparticles as carriers for drug delivery, developed using a spray-drying method.

Material/Methods

Chitosan, silk fibroin, and chitosan/silk fibroin microparticles loaded with rhPTH were studied with scanning electron microscopy (SEM) to estimate the particle size and surface morphology. The in vitro release of rhPTH was used to assess the developed formulation. The effect of the spray-drying process was assessed by powder X-ray diffraction (PXRD) of the microparticles. Quantification of the released rhPTH was performed by enzyme-linked immune sorbent assay (ELISA). Fourier-transform infrared spectroscopy (FTIR) was used to determine the differences in the absorption frequency of samples.

Results

Surface morphology of the final formulation showed the absence of pure crystals of chitosan and silk fibroin in the final formulation and FTIR demonstrated electrostatic interactions between chitosan and silk fibroin, which was supported by PXRD. The chitosan/silk fibroin microparticles loaded with rhPTH showed an entrapment efficiency (EE) that ranged from 60.36–72.99% with a 50% rhPTH release profile at pH 7.5 in 24 hours. There was no particle aggregation in blood and little hemolysis, indicating stability of the rhPTH-loaded microparticles.

Conclusions

A silk fibroin/chitosan microparticle formulation loaded with rhPTH was shown to be stable and to provide sustained-release of rhPTH, supporting a potential role of this formulation in the treatment of bone diseases including osteoporosis and bone fracture.

Electrical Signal Guided Ibuprofen Release from Electrodeposited Chitosan Hydrogel

Electrical signal guided drug release from conductive surface provides a simple and straightforward way for advanced drug delivery. In this study, we investigated the ibuprofen release from electrodeposited chitosan hydrogel by applying electrical signals. Specifically, chitosan hydrogel was electrodeposited on titanium plate and used as a matrix for ibuprofen load and release. The release of ibuprofen from the chitosan hydrogel on titanium plate was pH sensitive. By applying a positive or negative electrical potential, the release rate of ibuprofen from the electrodeposited chitosan can be facilely controlled. Thus, coupling chitosan electrodeposition and electrical signal control spurs new possibilities for biopolymeric coating and drug elution on conductive implants.