Nasal Administration and Plasma Pharmacokinetics of Parathyroid Hormone Peptide PTH 1-34 for the Treatment of Osteoporosis

Pharmacokinetics of Intranasal Drugs, Still a Missed Opportunity?

The intranasal (IN) route of administration is important for topical drugs and drugs intended to act systemically. More recently, direct nose-to-brain input was considered to bypass the blood-brain barrier.Processes related to IN absorption and nose-to-brain distribution are complex and depend, sometimes in contrasting ways, on chemico-physical and structural parameters of the compounds, and on formulation options.Due to the intricacies of these processes and despite the large number of articles published on many different IN compounds, it appears that absorption after IN dosing is not yet fully understood. In particular, at variance of the understanding and modelling approaches that are available for predicting the pharmacokinetics (PK) following oral administration of xenobiotics, it appears that there is not a similar understanding of the chemico-physical and structural determinants influencing drug absorption and disposition of compounds after IN administration, which represents a missed opportunity for this research field. This is even more true regarding the understanding of the direct nose-to-brain input. Due to this, IN administrations may represent an interesting and open research field for scientists aiming to develop PK property predictions tools, mechanistic PK models describing rate and extent of IN absorption, and translational tools to anticipate the clinical PK following IN dosing based on in vitro and in vivo non clinical experiments.This review intends to provide: i) some basic knowledge related to the physiology of PK after IN dosing, ii) a non-exhaustive list of preclinical and clinical examples related to compounds explored for the potential nose-to-blood and nose-to-brain passage, and iii) the identification of some areas requiring improvements, the understanding of which may facilitate the development of IN drug candidates.

Enhanced brain distribution of Ginsenoside F1 via intranasal administration in combination with absorption enhancers

Ginsenoside F1 (GF1) is a potential drug candidate for the treatment of Alzheimer's disease. Nevertheless, its low oral bioavailability and poor solubility limit clinical application. By utilizing either a direct or indirect approach, intranasal administration is a non-invasive drug delivery method that can deliver drugs to the brain rapidly. But large molecule drug delivered to the brain through intranasal administration may be insufficient to reach required concentration for therapeutic effect. In this study, using GF1 as a model drug, the feasibility of intranasal administration in combination with absorption enhancers to increase brain distribution of GF1 was explored. First of all, the appropriate absorption enhancers were screened by in situ nasal perfusion study. GF1-HP-β-CD inclusion complex was prepared and characterized. Thereafter, in vivo absorption of GF1 after intranasal or intravenous administration of its inclusion complex with/without absorption enhancers was investigated, and safety of the formulations was evaluated. The results showed that 2% Solutol HS 15 was a superior absorption enhancer. HP-β-CD inclusion complex improved GF1 solubility by 150 fold. Following intranasal delivery, the absolute bioavailability of inclusion complex was 46%, with drug brain targeting index (DTI) 247% and nose-to-brain direct transport percentage (DTP) 58%. Upon further addition of 2% Solutol HS 15, the absolute bioavailability was increased to 75%, with DTI 315% and DTP 66%. Both nasal cilia movement and biochemical substances (total protein and lactate dehydrogenase) leaching studies demonstrated 2% Solutol HS 15 was safe to the nasal mucosa. In conclusion, intranasal administration combining with safe absorption enhancers is an effective strategy to enhance drug distribution in the brain, showing promise for treating disorders related to the central nervous system.

A comprehensive review of advanced nasal delivery: Specially insulin and calcitonin

Peptide drugs through nasal mucous membrane, such as insulin and calcitonin have been widely used in the medical field. There are always two sides to a coin. One side, intranasal drug delivery can imitate the secretion pattern in human body, having advantages of physiological structure and convenient use. Another side, the low permeability of nasal mucosa, protease environment and clearance effect of nasal cilia hinder the intranasal absorption of peptide drugs. Researchers have taken multiple means to achieve faster therapeutic concentration, lower management dose, and fewer side effects for better nasal preparations. To improve the peptide drugs absorption, various strategies had been explored via the nasal mucosa route. In this paper, we reviewed the achievements of 18 peptide drugs in the past decade about the perspectives of the efficacy, mechanism of enhancing intranasal absorption and safety. The most studies were insulin and calcitonin. As a result, absorption enhancers, nanoparticles (NPs) and bio-adhesive system are the most widely used. Among them, chitosan (CS), cell penetrating peptides (CPPs), tight junction modulators (TJMs), soft NPs and gel/hydrogel are the most promising strategies. Moreover, two or three strategies can be combined to prepare drug vectors. In addition, spray freeze dried (SFD), self-emulsifying nano-system (SEN), and intelligent glucose reaction drug delivery system are new research directions in the future.

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.

Effect of Different Absorption Enhancers on the Nasal Absorption of Nalmefene Hydrochloride

The purpose of this work is to explore the effects of novel absorption enhancers on the nasal absorption of nalmefene hydrochloride (NMF). First, the influence of absorption enhancers with different concentrations and types and drug concentrations on the nasal absorption of NMF was investigated in vivo in rats. The absorption enhancers studied include n-dodecyl-β-D-maltoside (DDM), hydroxypropyl-β-cyclodextrin (HP-β-CD), and polyethylene glycol (15)-hydroxy Stearate (Solutol®HS15). At the same time, the in situ toad palate model and rat nasal mucosa model were used to assess the cilia toxicity. The results showed that all the absorption enhancers investigated significantly promote the nasal absorption of NMF, but with different degrees and trends. Among them, the 0.5% (w/v) DDM had the strongest enhancement effect, followed by 0.5% (w/v) Solutol®HS15, 0.25% (w/v) DDM, 0.25% (w/v) Solutol®HS15, 0.1% (w/v) Solutol®HS15, 0.1% (w/v) DDM, and 0.25% (w/v) HP-β-CD, with absolute bioavailability of 76.49%, 72.14%, 71.00%, 69.46%, 60.41%, 59.42%, and 55.18%, respectively. All absorption enhancers exhibited good safety profiles in nasal ciliary toxicity tests. From the perspective of enhancing effect and safety, we considered DDM to be a promising nasal absorption enhancer. And in addition to DDM, Solutol®HS15 can also promote intranasal absorption of NMF, which will provide another option for the development of nalmefene hydrochloride nasal spray.

Nanotechnologies for the delivery of biologicals: Historical perspective and current landscape

Biological macromolecule-based therapeutics irrupted in the pharmaceutical scene generating a great hope due to their outstanding specificity and potency. However, given their susceptibility to degradation and limited capacity to overcome biological barriers new delivery technologies had to be developed for them to reach their targets. This review aims at analyzing the historical seminal advances that shaped the development of the protein/peptide delivery field, along with the emerging technologies on the lead of the current landscape. Particularly, focus is made on technologies with a potential for transmucosal systemic delivery of protein/peptide drugs, followed by approaches for the delivery of antigens as new vaccination strategies, and formulations of biological drugs in oncology, with special emphasis on mAbs. Finally, a discussion of the key challenges the field is facing, along with an overview of prospective advances are provided.

Evaluation of the Pharmacokinetics of Intranasal Drug Delivery for Targeting Cervical Lymph Nodes in Rats

A well-developed lymphatic network is located under the nasal mucosa, and a few drugs that permeate the nasal mucosa are absorbed into the lymphatic capillaries. Lymph from the nasal cavity flows to the cervical lymph nodes (CLNs). In this study, we evaluated the pharmacokinetics of the direct transport of intranasally administered drugs to CLNs through the nasal mucosa of Wistar rats using methotrexate as a model drug. The drug targeting index, which was calculated based on the areas under the concentration–time curves after intravenous and intranasal administration, was 3.78, indicating the benefits of nasal delivery of methotrexate to target CLNs. The direct transport percentage, which was indicative of the contribution of the direct nose–CLN pathway of methotrexate after intranasal administration, was 74.3%. The rate constant of methotrexate from the nasal cavity to CLNs was 0.0047 ± 0.0013 min⁻¹, while that from systemic circulation to CLNs was 0.0021 ± 0.0009 min⁻¹. Through pharmacokinetic analysis, this study demonstrated that the direct nasal–CLN pathway contributed more to the transport of methotrexate to the CLNs than the direct blood–CLN pathway.

Target specific tight junction modulators

Intercellular tight junctions represent a formidable barrier against paracellular drug absorption at epithelia (e.g., nasal, intestinal) and the endothelium (e.g., blood-brain barrier). In order to enhance paracellular transport of drugs and increase their bioavailability and organ deposition, active excipients modulating tight junctions have been applied. First-generation of permeation enhancers (PEs) acted by unspecific interactions, while recently developed PEs address specific physiological mechanisms. Such target specific tight junction modulators (TJMs) have the advantage of a defined specific mechanism of action. To date, merely a few of these novel active excipients has entered into clinical trials, as their lack in safety and efficiency in vivo often impedes their commercialisation. A stronger focus on the development of such active excipients would result in an economic and therapeutic improvement of current and future drugs.

Role of bone-forming agents in the management of osteoporosis

Recent evidence confirms the superiority of osteoanabolic therapy compared to anti-remodeling drugs for rapid improvement in bone density and fracture risk reduction, providing strong justification for the use of these anabolic agents as the initial therapy in high-risk patients, to be followed by anti-remodeling therapy. This review will highlight the results of recent studies and define the current status of osteoanabolic therapy for osteoporosis.

Self-Assembled Micelles Improve the Oral Bioavailability of Dihydromyricetin and Anti-Acute Alcoholism Activity

Dihydromyricetin (DMY) is highly effective in counteracting acute alcohol intoxication. However, its poor aqueous solubility and permeability lead to the low oral bioavailability and limit its clinic application. The aim of this work is to use Solutol®HS15 (HS 15) as surfactant to develop novel micelle to enhance the oral bioavailability of DMY by improving its solubility and permeability. The DMY-loaded Solutol®HS15 micelles (DMY-Ms) were prepared by the thin-film hydration method. The particle size of DMY-Ms was 13.97 ± 0.82 nm with an acceptable polydispersity index of 0.197 ± 0.015. Upon entrapped in micelles, the solubility of DMY in water was increased more than 25-fold. The DMY-Ms had better sustained release property than that of pure DMY. In single-pass intestinal perfusion models, the absorption rate constant (Ka) and permeability coefficient (Papp) of DMY-Ms were 5.5-fold and 3.0-fold than that of pure DMY, respectively. The relative bioavailability of the DMY-Ms (AUC_0-∞) was 205% compared with that of pure DMY (AUC_0-∞), indicating potential for clinical application. After administering DMY-Ms, there was much lower blood alcohol level and shorter duration of the loss of righting relax (LORR) in drunk animals compared with that treated by pure DMY. In addition, the oral administration of DMY-Ms greatly reduced oxidative stress, and significantly defended liver and gastric mucosa from alcoholic damages in mice with alcohol-induced tissue injury. Taken together, HS 15-based micelle system greatly improves the bioavailability of DMY and represents a promising strategy for the management of acute alcoholism. Graphical abstract.

Development and in vivo evaluation of intranasal formulations of parathyroid hormone (1-34)

For efficient intranasal transport of parathyroid hormone (1-34) [PTH(1-34)], there is a great medical need to investigate permeation enhancers for intranasal formulations. In this study, the development of PTH(1-34) intranasal formulations was conducted. Based on conformation and chemical stability studies, the most preferable aqueous environment was determined to be 0.008 M acetate buffer solution (ABS). Subsequently, citric acid and Kolliphor^® HS·15 were compared as permeation enhancers. The mechanisms of action of citric acid and Kolliphor^® HS·15 were investigated using an in vitro model of nasal mucosa, and Kolliphor^® HS·15 led to higher permeability of fluorescein isothiocyanate-labeled PTH(1-34) (FITC-PTH) by enhancing both the transcellular and paracellular routes. Moreover, citric acid showed severe mucosal toxicity resulting in cilia shedding, while Kolliphor^® HS·15 did not cause obvious mucosa damage. Finally, Kolliphor^® HS·15 was studied as a permeation enhancer using a liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The results showed that 5% and 10% Kolliphor^® HS·15 increased the bioavailability of PTH(1-34) to 14.76% and 30.87%, respectively. In conclusion, an effective and biosafe PTH(1-34) intranasal formulation was developed by using 10% Kolliphor^® HS·15 as a permeation enhancer. Intranasal formulations with higher concentrations of Kolliphor^® HS·15 for higher bioavailability of PTH(1-34) could be further researched.

A Novel Synthetic Interfering Peptide Tat-3L4F Attenuates Olanzapine-Induced Weight Gain Through Disrupting Crosstalk Between Serotonin Receptor 2C and Protein Phosphatase and Tensin Homolog in Rats

BACKGROUND

Accompanied with profound efficacy, atypical antipsychotics (AAPs) contribute to metabolic adverse effects with few effective strategies to attenuate. Serotonin 5-HT2C receptor (HTR2C) plays a critical role in hyperphagia and weight gain induced by AAPs, and expression of phosphatase tensin homolog (PTEN) in the hypothalamus also affects feeding behavior and weight change. Moreover, PTEN has a physical crosstalk between PTEN and a region in the third intracellular loop (3L4F) of the HTR2C. Tat-3L4F has the property to disrupt crosstalk between PTEN and HTR2C. This is the first study to our knowledge to investigate the effect of Tat-3L4F on olanzapine-induced metabolic abnormalities and PTEN/ phosphatidylinositol 3-kinase/protein kinase B expression in the hypothalamus in rats.

METHODS

The effects of Tat-3L4F were investigated through measuring body weight, food intake, and blood glucose. In addition, PTEN/phosphatidylinositol 3-kinase/protein kinase B level in the hypothalamus was detected by immunofluorescence assay and western blot. Metabolites in the liver tissue were detected by liquid chromatography-mass spectrometry and analyzed by multivariate analyses and pairwise comparison.

RESULTS

Our results showed that hyperphagia and weight gain were evident in the olanzapine alone-fed rats but was attenuated after Tat-3L4F treatment. In addition, oral glucose tolerance test indicated blood glucose at 120 minutes was higher in the olanzapine alone-treated group than in groups treated with vehicle and olanzapine + Tat-3L4F (10 μmol kg-1 per day). Furthermore, compared with olanzapine alone treatment, treatment with Tat-3L4F (10 μmol kg-1 per day) significantly inhibited PTEN expression in the hypothalamus. The olanzapine alone-treated group had the highest bile acid level, followed by the olanzapine with Tat-3L4F (1 μmol kg-1) group, olanzapine with Tat-3L4F (10 μmol kg-1) group, and vehicle group.

CONCLUSIONS

Our present results reveal that Tat-3L4F is a potential pharmacological strategy for suppressing hyperphagia and weight gain induced by olanzapine, which acts through disrupting crosstalk between HTR2C and PTEN as a result of PTEN downregulation in the hypothalamus.

Role of Ca²⁺ in Inhibiting Ischemia-Induced Apoptosis of Parathyroid Gland Cells in New Zealand White Rabbits

Background

Hypoparathyroidism is a common complication after thyroidectomy. Calcium supplementation can relieve these symptoms, but it is not clear whether it can protect the parathyroid glands. This study aimed to verify whether Ca²⁺ inhibits the apoptosis of parathyroid cells following ischemic injury.

Material/Methods

A rabbit model of parathyroid gland ischemic injury was established. The blood calcium concentrations were measured by colorimetry. The parathyroid hormone (PTH) levels were measured by enzyme-linked immunosorbent assay (ELISA). The parathyroid tissues were observed by hematoxylin and eosin (H&E) staining and the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Western blotting was used to quantify the levels of the following proteins: caspase-3 and p38 MAP Kinase (p38 MAPK).

Results

This study demonstrates that apoptosis can be a part of the pathological changes associated with parathyroid ischemic injury. Calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury. There were no significant differences among the serum calcium levels from the Sham operation (Sham), the Control group (CG), or the Calcium supplementation group (CSG) after 24 h, 72 h, and 168 h of treatment. PTH levels in the CG were significantly higher than in the CSG at 24 h and 72 h after treatments. The apoptosis rate of parathyroid cells from rabbits in the CSG was significantly lower than that of those from rabbits in the CG at 24 h and 72 h after the treatment. Calcium supplementation inhibited p38 MAPK and caspase-3 expression.

Conclusions

This study demonstrates that calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury.

New Targets and Emergent Therapies for Osteoporosis

The 11 existing FDA-approved osteoporosis drug treatments include hormone replacement therapy, 2 SERMs (raloxifene and bazedoxifene), 5 inhibitors of bone-resorbing osteoclasts (4 bisphosphonates and anti-RANKL denosumab), 2 parathyroid hormone analogues (teriparatide and abaloparatide), and 1 WNT signaling enhancer (romosozumab). These therapies are effective and provide multiple options for patients and physicians. As the genomic revolution continues, potential novel targets for future drug development are identified. This review takes a wide perspective to describe potentially rewarding topics to explore, including knowledge of genes and pathways involved in bone cell metabolism, the utility of animal models, targeting drugs to bone, and ongoing advances in drug design and delivery.

Pharmacokinetic Study of Bioactive Glycopeptide from Strongylocentrotus droebachiensis After Intranasal Administration to Rats Using Biomarker Approach

A glycopeptide fraction (GPF) from internal organs of green sea urchins (Strongylocentrotus droebachiensis Müller, Strongylocentrotidae) has been reported to be an effective bronchitis treatment. In this study, we evaluated the pharmacokinetic and tissue distribution of GPF, following single and repeated intranasal (i/n) administration over the course of seven days in rats. The method measuring lactate dehydrogenase as biomarker was used to analyse the plasma and tissue concentrations of GPF. GPF appears in the plasma 15 min after single i/n administration (100 µg/kg) and reaches its maximum at 45 min. The area under the curve (AUC)0-24 and Cmax were similar using both i/n and intravenous administration, while mean residence time (MRT) and T1/2 after i/n administration were significantly higher compared with intravenous (i/v) administration. The absolute bioavailability of GPF after i/n administration was 89%. The values of tissue availability (ft) provided evidence about the highest concentration of GPF in the nose mucosa (ft = 34.9), followed by spleen (ft = 4.1), adrenal glands (ft = 3.8), striated muscle (ft = 1.8), kidneys (ft = 0.5), and liver (ft = 0.3). After repeated dose administration, GPF exhibited significantly higher AUC0-24 and MRT, indicating its accumulation in the plasma.