A design of experiments to optimize a new manufacturing process for high activity protein-containing submicron particles

Oromucosal delivery of macromolecules: Challenges and recent developments to improve bioavailability

Owing to their biological diversity, high potency, good tolerability, low immunogenicity, site-specific activity, and great efficacy, macromolecular drugs (i.e., proteins and peptides, antibodies, hormones, nucleic acids, vaccines, etc.) are extensively used as diagnostics, prophylactics, and therapeutics in various diseases. To overcome drawbacks associated with parenteral (invasive) delivery of macromolecules as well as to preserve their therapeutic integrity, oromucosal route (sublingual and buccal) has been proven efficient alternate port of delivery. This review aims to summarize challenges associated with oromucosal route and overtime developments in conventional delivery systems with special emphasis on most recent delivery strategies. Over the past few decades, significant efforts have been made for improving the oromucosal absorption of macromolecules by employing chemical penetration enhancers (CPE), enzyme inhibitors, chemical modification of drug structure (i.e., lipidation, PEGylation, etc.), and mucoadhesive materials in the form of buccal tablets, films (or patches), sprays, fast disintegrating tablets, and microneedles. Adaptation of adjunct strategies (e.g., iontophoresis in conjunction with CPE) has shown significant improvement in oromucosal absorption of macromolecules; however, these approaches were also associated with many drawbacks. To overcome these shortcomings and to further improve therapeutic outcomes, specialized delivery devices called "hybrid nanosystems" have been designed in recent times. This newer intervention showed promising potential for promoting oromucosal absorption and absolute bioavailability of macromolecules along with improved thermostability (cold chain free storage), enabling self-administration, site-specific activity, improving therapeutic efficacy and patient compliance. We anticipate that tailoring of hybrid nanosystems to clinical trials as well as establishing their short- and long-term safety profile would substantiate their therapeutic value as pharmaceutical devices for oromucosal delivery of macromolecules.

Risk Mitigation of Plunger-Stopper Displacement under Low Atmospheric Pressure by establishing Design Space for Filling-Stoppering Process of Prefilled Syringes: A Design of Experiment (DoE) Approach

There is a concern that low atmospheric pressure typically encountered during shipment could result in plunger-stopper displacement in prefilled syringes impacting sterility and container closure integrity (CCI) of drug product¹. In this work, following DoE principles we first investigated the impact of filling and stoppering operating parameters on creation of bubble height as performance parameters among others in nominal 1 mL and 2.25 mL Type I glass prefilled syringes (PFSs) with staked needle and rigid needle shield (RNS). Bubble height ranging from <2.0 mm to >15.0 mm were produced in syringes by filling water and vacuum stoppering at operating vacuum pressure ranging from 400 mbar to 950 mbar using a pilot scale filling-stoppering machine. We found that for a particular nominal fill volume in prefilled syringe, as the stoppering vacuum pressure increased, bubble height decreased resulting in plunger-stopper placed closer to the fill level. Subsequently, syringes with varying bubble size were exposed to reduced atmospheric pressure ranging from 628 Torr to 293 Torr bracketing the low pressure recommended by ASTM D4169 standard to qualify shipping containers for transportation of drug products. We found inverse linear correlation between bubble height and plunger-stopper displacement under low atmospheric pressure. However, plunger-stopper displacement increased exponentially as atmospheric pressure decreased. The results suggest that air bubble size in filled glass syringes should be minimized in order to mitigate sterility and container closure integrity (CCI) risk to drug product in prefilled syringes.

Recent insights in the use of nanocarriers for the oral delivery of bioactive proteins and peptides

Bioactive proteins and peptides have been used with either prophylactic or therapeutic purposes, presenting inherent advantages as high specificity and biocompatibility. Nanocarriers play an important role in the stabilization of proteins and peptides, offering enhanced buccal permeation and protection while crossing the gastrointestinal tract. Moreover, preparation of nanoparticles as oral delivery systems for proteins/peptides may include tailored formulation along with functionalization aiming bioavailability enhancement of carried proteins or peptides. Oral delivery systems, namely buccal delivery systems, represent an interesting alternative route to parenteric delivery systems to carry proteins and peptides, resulting in higher comfort of administration and, therefore, compliance to treatment. This paper outlines an extensive overview of the existing publications on proteins/peptides oral nanocarriers delivery systems, with special focus on buccal route. Manufacturing aspects of most commonly used nanoparticles for oral delivery (e.g. polymeric nanoparticles using synthetic or natural polymers and lipid nanoparticles) advantages and limitations and potential applications of nanoparticles as proteins/peptides delivery systems will also be thoroughly addressed.

Encapsulation of albumin in self-assembled layer-by-layer microcapsules: comparison of co-precipitation and adsorption techniques

OBJECTIVE

The objective of this study is to prepare and characterize polymeric self-assembled layer-by-layer microcapsules (LbL-MC) to deliver a model protein, bovine serum albumin (BSA). The aim is to compare the BSA encapsulation in LbL-MC using co-precipitation and adsorption methods.

MATERIALS AND METHODS

In co-precipitation method, BSA was co-precipitated with growing calcium carbonate particles to form a core template. Later, poly(styrene sulfonate) and poly(allylamine hydrochloride) were sequentially adsorbed onto the CaCO3 templates. In adsorption method, preformed LbL-MC were incubated with BSA and encapsulation efficiency is optimized for pH and salt concentration. Free and BSA-encapsulated LbL-MC were characterized using Zetasizer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and differential scanning calorimeter. Later, in vitro release studies were performed using dialysis membrane method at pH 4, 7.4 and 9.

RESULTS AND DISCUSSION

Results from Zetasizer and SEM showed free LbL-MC with an average size and zeta-potential of 2.0 ± 0.6 μm and 8.1 ± 1.9 mV, respectively. Zeta-potential of BSA-loaded LbL-MC was (-)7.4 ± 0.7 mV and (-)5.7 ± 1.0 mV for co-precipitation and adsorption methods, respectively. In adsorption method, BSA encapsulation in LbL-MC was found to be greater at pH 6.0 and 0.2 M NaCl. Co-precipitation method provided four-fold greater encapsulation efficiency (%) of BSA in LbL-MC compared with adsorption method. At pH 4, the BSA release from LbL-MC was extended up to 120 h. Polyacrylamide gel electrophoresis showed that BSA encapsulated in LBL-MC through co-precipitation is stable toward trypsin treatment.

CONCLUSION

In conclusion, co-precipitation method provided greater encapsulation of BSA in LbL-MC. Furthermore, LbL-MC can be developed as carriers for pH-controlled protein delivery.

Protein-coated nanoparticles embedded in films as delivery platforms

Objectives

This work aimed to evaluate the performance of nanoparticle-loaded films based on matrices of polymethacrylates and hydroxypropylmethylcellulose (HPMC) intended for delivery of macromolecules.

Methods

Lysozyme (Lys)-loaded nanoparticles were manufactured by antisolvent co-precipitation. After size, loading efficiency and stability characterization, the selected batch of particles was further formulated into films. Films were characterized for mechanical properties, mucoadhesion, Lys release and activity after manufacture.

Key findings

We found that protein-coated nanoparticles could be obtained in USP phosphate buffer pH 6.8. Particles obtained at pH 6.8 had a z-average of 347.2 nm, a zeta-potential of 21.9 mV and 99.2% remaining activity after manufacture. This formulation was further studied for its application in films for buccal delivery. Films loaded with nanoparticles that contained Eudragit RLPO (ERL) exhibited excellent mechanical and mucoadhesive properties. Due to its higher water-swelling and solubility compared with ERL, the use of HPMC allowed us to tailor the release of Lys from films. The formulation composed of equal amounts of ERL and HPMC revealed a sustained release over 4 h, with Lys remaining fully active at the end of the study.

Conclusions

Mucoadhesive films containing protein-coated nanoparticles are promising carriers for the buccal delivery of proteins and peptides in a stable form.