Peptide Engraftment on PEGylated Nanoliposomes for Bone Specific Delivery of PTH (1-34) in Osteoporosis

Bone-specific functionalization strategies on liposomes are promising approaches to delivering the drug in osteoporotic conditions. This approach delivers the drug to the bone surface specifically, reduces the dose and off-target effects of the drug, and thereby reduces the toxicity of the drug. The purpose of the current research work was to fabricate the bone-specific peptide conjugated pegylated nanoliposomes to deliver anabolic drug and its physicochemical evaluations. For this, a bone-specific peptide (SDSSD) was synthesized, and the synthesized peptide was conjugated with a linker (DSPE-PEG2000-COOH) to obtain a bone-specific conjugate (SDSSD-DSPE). Purified SDSSD-DSPE was characterized by HPLC, Maldi-TOF, NMR, and Scanning Electron Microscope/Energy Dispersive Spectroscopy (SEM/EDS). Further, peptide-conjugated and anabolic drug-encapsulated liposomes (SDSSD-LPs) were developed using the ethanol injection method and optimized by Central Composite Design (CCD) using a statistical approach. Optimized SDSSD-LPs were evaluated for their physicochemical properties, including surface morphology, particle size, zeta potential, in vitro drug release, and bone mineral binding potential. The obtained results from these studies demonstrated that SDSSD-DSPE conjugate and SDSSD-LPs were optimized successfully. The particle size, % EE, and zeta potential of SDSSD-LPs were observed to be 183.07 ± 0.85 nm, 66.72 ± 4.22%, and −25.03 ± 0.21 mV, respectively. SDSSD-LPs demonstrated a sustained drug release profile. Further, the in vitro bone mineral binding assay demonstrated that SDSSD-LPs deliver the drug to the bone surface specifically. These results suggested that SDSSD-LPs could be a potential targeting approach to deliver the anabolic drug in osteoporotic conditions.