Spray Freeze Dried Lyospheres® for Nasal Administration of Insulin

Trans-nasal brain delivery of anti-TB drugs by methyl-β-cyclodextrin microparticles show efficient mycobacterial clearance from central nervous system

Central nervous system tuberculosis (CNS-TB) is the most severe extra-pulmonary manifestation of tuberculosis (TB), facing significant challenges due to the limited penetration of anti-TB drugs (ATDs) across the blood-brain barrier (BBB) and their insufficient concentrations at the site of infection. This study aimed to enhance the efficacy of ATDs by encapsulating them in methyl-β-cyclodextrin (M-β-CD) microparticles (ATD-MP) using spray drying, intended for intranasal delivery to manage CNS-TB. M-β-CD microparticles loaded with isoniazid (INH) and rifampicin (RIF) exhibited spherical shapes with slightly deflated surfaces and particle sizes of 6.24 ± 0.77 μm and 5.97 ± 0.50 μm, respectively. M-β-CD improved the permeation of ATDs through RPMI-2650 cell monolayers while reducing drug cytotoxicity. Pharmacokinetic and biodistribution analysis demonstrated that intranasal administration of ATD-MP significantly enhanced the trans-nasal brain delivery of ATDs and their distribution in the brain, achieving the minimum inhibitory concentration. In a murine model of CNS-TB, intranasal insufflation of ATD-MP for four weeks led to a significant reduction (∼0.78 Log10 CFU) in mycobacterial burden in the brain compared to the untreated group (∼3.60 Log10 CFU). These preclinical results underscore the potential of intranasal administration of M-β-CD microparticles as an effective therapeutic strategy for combating brain inflammation in CNS-TB.

An overview of in vitro and in vivo techniques for characterization of intranasal protein and peptide formulations for brain targeting

The surge in neurological disorders necessitates innovative strategies for delivering active pharmaceutical ingredients to the brain. The non-invasive intranasal route has emerged as a promising approach to optimize drug delivery to the central nervous system by circumventing the blood-brain barrier. While the intranasal approach offers numerous advantages, the lack of a standardized protocol for drug testing poses challenges to both in vitro and in vivo studies, limiting the accurate interpretation of nasal drug delivery and pharmacokinetic data. This review explores the in vitro experimental assays employed by the pharmaceutical industry to test intranasal formulation. The focus lies on understanding the diverse techniques used to characterize the intranasal delivery of drugs targeting the brain. Parameters such as drug release, droplet size measurement, plume geometry, deposition in the nasal cavity, aerodynamic performance and mucoadhesiveness are scrutinized for their role in evaluating the performance of nasal drug products. The review further discusses the methodology for in vivo characterization in detail, which is essential in evaluating and refining drug efficacy through the nose-to-brain pathway. Animal models are indispensable for pre-clinical drug testing, offering valuable insights into absorption efficacy and potential variables affecting formulation safety. The insights presented aim to guide future research in intranasal drug delivery for neurological disorders, ensuring more accurate predictions of therapeutic efficacy in clinical contexts.

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.

Rivaroxaban lyospheres prepared by a dimethyl sulfoxide-based spray-freeze-drying process

Spray-freeze-drying (SFD) processes are usually using aqueous solvent systems, which however, exclude the use of SFD for poorly water-soluble drugs. Here, we evaluated dimethyl sulfoxide for its suitability in formulating SFD particles (lyospheres®). Rivaroxaban was spray-freeze-dried from DMSO solutions containing polyvinyl pyrrolidone (PVP; Kollidon® 25), vinylpyrrolidone-vinyl acetate copolymer (PVP-VA; Kollidon® VA64) or polyvinyl alcohol 4-88 (PVA) forming porous lyospheres® (median particle size 250 to 350 µm). Rivaroxaban was amorphous with all three polymers, which in combination with their high porosity resulted in rapid dissolution in vitro within 10 minutes. Consequently, this translated in lower T_max (0.5-1.0 hour) after oral administration of lyospheres® to rats (compared with T_max of 4 hours with coarse rivaroxaban). Lyosphere formulations achieved a distinct bioavailability increase (AUC_(0-inf) = 1487±657 ng*h/ml with PVP; 4426±1553 ng*h/ml with PVP-VA; 9569±3868 ng*h/ml with PVA lyospheres®; whereas 385±145 ng*h/ml with coarse rivaroxaban). These in vitro and in vivo results underlined the benefit of using DMSO in SFD that can broaden the applicability of the SFD process to much a larger repertoire of poorly water-soluble drugs.

Designing highly porous amorphous celecoxib particles by spray freeze drying leads to accelerated drug absorption in-vivo

Poorly water-soluble drugs are still a major challenge to overcome in order to achieve sufficiently high oral bioavailability. Spray freeze drying (SFD) is proposed here as an alternative for the preparation of amorphous, free-flowing porous celecoxib spheres for enhanced drug dissolution. Tertiary butyl alcohol solutions of celecoxib + excipient (povidone, hydroxypropyl methylcellulose acetate succinate (HPMC-AS) and Soluplus®) at variable ratios were sprayed into a cooled spray tower, followed by vacuum freeze drying. Final porous particles were free-flowing, highly spherical (circularity ≥ 0.96) and mean diameters ranging from 210 to 800 µm, depending on excipient and drug content. XRPD measurements showed that Celecoxib was amorphous in all formulations and remained stable during 6 months storage. Kollidon 25 and HPMC-AS combinations resulted in the highest dissolution rates as well as dissolved drug amounts (30.4 ± 1.5 µg/ml and 41.8 ± 1.7 µg/ml) which in turn was 2-fold and 1.3-fold increase compared to film casted amorphous reference formulations, respectively. This phenomenon also translated into a faster onset of the drug absorption in-vivo, with significantly lower tmax values, while AUC values were non-significantly lowered compared to amorphous references. The high porosity of SFDs led to the advantageous accelerated dissolution which also translated into faster onset of absorption in-vivo.