Evaluation of Dodecylmaltoside as a Permeability Enhancer for Insulin Using Human Carcinoma Cells

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.

The Caco-2 Model: Modifications and enhancements to improve efficiency and predictive performance

The Caco-2 cell model has been widely used to assess the permeability of drug candidates. It has provided a high throughput in vitro platform, functionally resembling the enterocytes. Since the oral route is the most preferred for drug administration, the Caco-2 cell model acts as a very important tool to elucidate the oral "druggability" of a molecule by providing a fairly reliable estimate of its permeability through the intestinal membrane. Despite its shortcomings (the lack of a mucus layer, long cultivation period, inter-lab variability, and differences in expression of enzymes, transporters, and tight junction complexes) it remains heavily used due to its reliability, predictive performance, and wide acceptance. Various modifications have been made: co-culturing with other intestinal cells, applying biosimilar mucus, reducing culturing time, combining Caco-2 monolayer with the dissolution apparatus, enhancing protein expression, and redesigning the sampling apparatus. These modifications are intended to overcome some of the shortcomings of the Caco-2 model in order to make its use easier, quicker, economical, and more representative of the intestine. The aim of this review is to discuss such modifications to enhance this model's utility, predictive performance, and reproducibility.

Improvement of Intranasal Drug Delivery with Intravail® Alkylsaccharide Excipient as a Mucosal Absorption Enhancer Aiding in the Treatment of Conditions of the Central Nervous System

Intranasal drug administration is a commonly used route for therapeutic formulations, but there may be challenges associated with a lack of absorption and bioavailability, as well as damage to mucosal tissue. To address these issues, potential absorption enhancers that are generally nonirritating to nasal mucosal tissue have been investigated as excipients in intranasal formulations. Among those studied are alkylsaccharides, which are composed of sugars covalently coupled to at least one alkyl chain. Alkylsaccharides have been shown to be nontoxic and have been used in food products as emulsifiers. In clinical trials, alkylsaccharide excipients have demonstrated substantially increased absorption of therapeutic agents across mucosal membranes and have been shown to be applicable to a wide range of types of molecules and molecular weights. Because they are water and oil soluble, alkylsaccharide excipients can be used in formulations with both hydrophilic and hydrophobic drugs. They are also effective in safely stabilizing protein therapeutics. An example of an alkylsaccharide excipient is dodecyl maltoside (Intravail^®; 511 Da, stable long term when stored cold), which provides absorption enhancement by paracellular and transcellular routes. Dodecyl maltoside has been shown to be generally nonirritating to the nose and to promote systemic bioavailability. Dodecyl maltoside is used in US Food and Drug Administration-approved intranasal formulations of sumatriptan for migraine headaches and diazepam nasal spray for patients with epilepsy with acute seizure clusters.

A multicenter, open-label, long-term safety and tolerability study of DFN-02, an intranasal spray of sumatriptan 10 mg plus permeation enhancer DDM, for the acute treatment of episodic migraine

BACKGROUND

DFN-02 is a novel intranasal spray formulation composed of sumatriptan 10 mg and a permeation-enhancing excipient comprised of 0.2% 1-O-n-Dodecyl-β-D-Maltopyranoside (DDM). This composition of DFN-02 allows sumatriptan to be rapidly absorbed into the systemic circulation and exhibit pharmacokinetics comparable to subcutaneously administered sumatriptan. Rapid rate of absorption is suggested to be important for optimal efficacy. The objective of this study was to evaluate the safety and tolerability of DFN-02 (10 mg) in the acute treatment of episodic migraine with and without aura over a 6-month period based on the incidence of treatment-emergent adverse events and the evaluation of results of clinical laboratory tests, vital signs, physical examination, and electrocardiograms.

METHODS

This was a multi-center, open-label, repeat-dose safety study in adults with episodic migraine with and without aura. Subjects diagnosed with migraine with or without aura according to the criteria set forth in the International Classification of Headache Disorders, 2nd edition, who experienced 2 to 6 attacks per month with fewer than 15 headache days per month and at least 48 headache-free hours between attacks, used DFN-02 to treat their migraine attacks acutely over the course of 6 months.

RESULTS

A total of 173 subjects was enrolled, 167 (96.5%) subjects used at least 1 dose of study medication and were evaluable for safety, and 134 (77.5%) subjects completed the 6-month study. A total of 2211 migraine attacks was reported, and 3292 doses of DFN-02 were administered; mean per subject monthly use of DFN-02 was 3.6 doses. Adverse events were those expected for triptans, as well as for nasally administered compounds. No new safety signals emerged. Dysgeusia and application site pain were the most commonly reported treatment-emergent adverse events over 6 months (21% and 30.5%, respectively). Most of the treatment-emergent adverse events were mild. There were 5 serious adverse events, all considered unrelated to the study medication; the early discontinuation rate was 22.5% over the 6-month treatment period.

CONCLUSION

DFN-02 was shown to be well tolerated when used over 6 months to treat episodic migraine acutely.

A Randomized Trial Comparing the Pharmacokinetics, Safety, and Tolerability of DFN-02, an Intranasal Sumatriptan Spray Containing a Permeation Enhancer, With Intranasal and Subcutaneous Sumatriptan in Healthy Adults

OBJECTIVE/BACKGROUND

Intranasal sumatriptan (Imitrex^® ) may be an alternative for patients who refuse injections and cannot tolerate oral agents, but due to low bioavailability and slow absorption, the clinical utility of the currently marketed formulation is limited, highlighting an unmet need for an effective non-oral migraine medication with a rapid onset of action. To overcome the slow absorption profile associated with intranasal administration, we evaluated the impact of 1-O-n-Dodecyl-β-D-Maltopyranoside (DDM, Intravail A-3™), a permeation enhancer, on sumatriptan's pharmacokinetic profile by comparing the pharmacokinetic characteristics of two commercial sumatriptan products, 4 mg subcutaneous and 6 mg subcutaneous in healthy adults, with DFN-02 - a novel intranasal agent comprised of sumatriptan 10 mg plus 0.20% DDM. We also determined the pharmacokinetic characteristics of DDM and evaluated its safety and tolerability.

METHODS

We conducted two studies: a randomized, three-way crossover study comparing monodose and multidose devices for delivery of single doses of DFN-02 with commercially available intranasal sumatriptan 20 mg in 18 healthy, fasted adults, and an open-label, randomized, single-dose, three-way crossover bioavailability study comparing DFN-02 with 4 mg and 6 mg subcutaneous sumatriptan in 78 healthy, fasted adults. In the study comparing DFN-02 with IN sumatriptan, subjects received a single dose of DFN-02 (sumatriptan 10 mg plus DDM 0.20%) via monodose and multidose delivery systems with at least 5 days between treatments. In the comparison with SC sumatriptan, subjects received a single dose of each treatment with at least 3 days between treatments. In both studies, blood was sampled for pharmacokinetic evaluation of sumatriptan and DDM through 24 hours post-dose; safety and tolerability were monitored throughout.

RESULTS

In the comparison with commercially available intranasal sumatriptan 20 mg, DFN-02 had a more rapid absorption profile; t_max was 15 minutes for DFN-02 monodose, 10.2 minutes for DFN-02 multidose, and 2.0 hours for commercially available intranasal sumatriptan 20 mg. Compared with 4 and 6 mg subcutaneous sumatriptan, DFN-02's median t_max (10 minutes) was significantly earlier (15 minutes; P < .0001). Mean sumatriptan exposure metrics were similar for DFN-02 and 4 mg sumatriptan: AUC_0-2 : 35.12 and 44.82 ng*hour/mL, respectively; AUC_0-∞ : 60.70 and 69.21 ng*hour/mL, respectively; C_max : 51.79 and 49.07 ng/mL, respectively. With 6 mg subcutaneous sumatriptan, these exposure metrics were about 50% larger (AUC_0-2 : 67.17 ng*hour/mL; AUC_0-∞ : 103.78 ng*hour/mL; C_max : 72.75 ng/mL). Inter-subject variability of AUC_0-2 , AUC_0-∞ , and C_max was 42-58% for DFN-02, 15-22% for 4 mg subcutaneous sumatriptan, and 15-25% for 6 mg subcutaneous sumatriptan. DDM exposure was low (mean C_max : 1.63 ng/mL), t_max was 30 minutes, and it was undetectable by 4 hours. There were no serious adverse events, discontinuations due to adverse events, or remarkable findings for vital signs, physical examinations (including nasal and injection site examinations), or clinical laboratory assessments. The overall incidence of adverse events was comparable across treatments, and all treatment-related events were mild in severity. Adverse events occurring in ≥10% of subjects were dysgeusia (19%), headache (18%), nausea (15%), paresthesia (15%), and dizziness (12%).

CONCLUSIONS

In healthy subjects, DFN-02, an intranasal spray containing 10 mg sumatriptan plus DDM, had a more rapid absorption profile than commercially available intranasal sumatriptan 20 mg, and systemic exposure from a single-dose administration of DFN-02 was similar to 4 mg SC sumatriptan and two-thirds that of 6 mg SC sumatriptan. With DFN-02, plasma sumatriptan peaked 5 minutes earlier than with both subcutaneous formulations. Systemic exposure to sumatriptan was similar with DFN-02 and 4 mg subcutaneous sumatriptan; both yielded lower systemic exposure than 6 mg subcutaneous sumatriptan. Systemic exposure to DFN-02's excipient DDM was short-lived. DFN-02's safety and tolerability appear to be comparable to subcutaneous sumatriptan. Addition of a permeation enhancer improved the absorption profile compared with commercially available intranasal sumatriptan 20 mg.

Excipients with specialized functions for effective drug delivery

INTRODUCTION

There is a growing need for the development of pharmaceutical excipients that could improve product performance and overcome the shortcomings of new drug moieties, such as their poor solubility and membrane permeability, as well as to aid with modern manufacturing processes.

AREAS COVERED

Different types of functional excipients are discussed in this paper, in terms of their roles in modern dosage forms to optimize drug delivery and manufacturability. Functions of specialized excipients that are covered in this article include the enhancement of drug membrane permeability, the improvement of drug solubility and stability, the regulation of drug release in response to feedback mechanisms and assistance with the production of dosage forms.

EXPERT OPINION

Modern drug delivery systems rely on sophisticated excipients with multiple functions to improve overall product performance. The excipient market is expected to grow substantially with emerging trends in the development of these advanced drug delivery systems.

Role of 99mTc-mannitol and 99mTc-PEG in the assessment of paracellular integrity of cell monolayers

AIM

To assess the role of 99mTc-mannitol and 99mTc-polyethylene glycol 4000 in the evaluation of paracellular integrity of Caco-2 and Madine-Darby canine kidney (MDCK) cell monolayers, and confirm it in the presence of absorption promoters.

METHODS

Radiolabelling of mannitol and polyethylene glycol was performed by a simple reduction method. Transepithelial electrical resistance values were measured to gain information regarding the integrity of tight junctions of Caco-2 and MDCK cell monolayers. Permeabilities of 99mTc-mannitol/99mTc-polyethylene glycol across cell monolayers were studied in the absence and presence of absorption promoters, namely dimethyl-beta-cyclodextrin, chitosan hydrochloride and sodium lauryl sulfate, and during recovery studies to assess paracellular integrity.

RESULTS

Values for the apparent permeability coefficient (Papp) of Tc-mannitol were found to be 0.286 x 10 cm x s(-1) and 0.507 x 10 cm x s(-1) in Caco-2 and MDCK cell monolayers, respectively, whereas corresponding values for 99mTc-polyethylene glycol were 0.046 x 10 cm x s(-1) and 0.065 x 10 cm x s(-1). The insignificant Papp values of the marker molecules demonstrated the paracellular integrity of the cell monolayers. Significant increases in the Papp values in the presence of absorption promoters and their combinations due to opening of paracellular pathways and a return of Papp values to almost baseline values during recovery studies confirm the role of these marker molecules in the assessment of paracellular integrity of cell monolayers.

CONCLUSION

99mTc-labelled marker molecules can be attractive, useful and viable alternatives to the conventionally used markers in the assessment of paracellular integrity because of the absence of tissue-damaging corpuscular radiation and the ease of production of radiochemically pure and stable molecules at a reasonable cost.

Disruption of epithelial tight junctions by yeast enhances the paracellular delivery of a model protein

PURPOSE

The aim of this study was to investigate the effect of heat-killed yeast cells on the integrity of epithelial tight junctions in vitro.

METHODS

Changes in barrier potential of Caco-2 cell monolayers were assessed by transepithelial electrical resistance (TEER) measurements and by an increasing permeability to a marker protein, horse-radish peroxidase (HRP). Visualisation of tight junction disruption was carried out directly through electron microscopy and indirectly through fluorescence confocal microscopy and immunoblotting of the tight junction-associated proteins zonula occludens ZO-1, occludin and actin.

RESULTS

Yeast cells opened tight junctions in a reversible dose- and time-dependent manner, as shown by a decrease in TEER and an increase in HRP permeability. These changes to barrier potential were shown not to be due to cytotoxic effects but due to modulation of the tight junctions. ZO-1, actin and occludin proteins were demonstrated to be involved in yeast-induced tight junction opening through the use of confocal microscopy and western blotting. Electron microscopy confirmed a direct opening of tight junctions after application of yeast.

CONCLUSION

Yeast modulated epithelial tight junctions in a reversible manner by contraction of the actin cytoskeleton and shift of ZO-1 and occludin tight junction proteins from the membrane to cytoskeletal areas of the cell.