Improved Dissolution of an Insoluble Drug Using a 4-Fluid Nozzle Spray-Drying Technique

Clofazimine Inhalation Suspension Demonstrates Promising Toxicokinetics in Canines for Treating Pulmonary Nontuberculous Mycobacteria Infection

Pulmonary nontuberculous mycobacteria (NTM) infection is recognized as a major global health concern due to its rising prevalence worldwide. As an opportunistic pathogen with increasing antibiotics resistance, prolonged systemic dosing with multiple antibiotics remains the primary treatment paradigm. These prolonged treatments, administered predominantly by oral or parenteral routes, often lead to systemic toxicity. A novel inhaled formulation of clofazimine may finally resolve issues of toxicity, thereby providing for improved NTM therapy. Clofazimine inhalation suspension was evaluated in canines to determine toxicity over 28 days of once-a-day dosing. The good laboratory practice (GLP) repeat dosing study evaluated low, mid, and high dosing (2.72 mg/kg and 2.95 mg/kg; 5.45 mg/kg and 5.91 mg/kg; and 10.87 mg/kg and 10.07 mg/kg, average male versus female dosing) of nebulized clofazimine over 30, 60, and 120 min using a jet nebulizer. Toxicokinetic analyses were performed on study days 29, 56, and 84. All three dose levels showed significant residual drug in lung tissue, demonstrating impressive lung loading and long lung residence. Drug concentrations in the lung remained well above the average NTM MIC at all time points, with measurable clofazimine levels at 28 and 56 days postdosing. In contrast, plasma levels of clofazimine were consistently measurable only through 14 days postdosing, with measurements below the limit of quantitation at 56 days postdosing. Clofazimine inhalation suspension may provide an effective therapy for the treatment of NTM infections through direct delivery of antibiotic to the lungs, overcoming the systemic toxicity seen in oral clofazimine treatment for NTM.

Effect of Storage Humidity on Physical Stability of Spray-Dried Naproxen Amorphous Solid Dispersions with Polyvinylpyrrolidone: Two Fluid Nozzle vs. Three Fluid Nozzle

In a spray drying operation, a two-fluid nozzle (2FN) with a single channel is commonly used for atomizing the feed solution. However, the less commonly used three-fluid nozzle (3FN) has two separate channels, which allow spray drying of materials in two incompatible solution systems. Although amorphous solid dispersions (ASDs) prepared using a 3FN have been reported to deliver comparable drug dissolution performance relative to those prepared using a 2FN, few studies have systematically examined the effect of 3FN on the physical stability. Therefore, the goal of this work is to systematically study the physical stability of ASDs that are spray-dried using a 3FN compared to those prepared using the traditional 2FN. For the 2FN, a single solution of naproxen and polyvinylpyrrolidone (PVP) was prepared in a mixture of acetone and water at a 1:1 volume ratio because 2FN allows for only one solution inlet. For the 3FN, naproxen and PVP were dissolved individually in acetone and water, respectively, because 3FN allows simultaneous entry of two solutions. Upon storage of the formulated ASDs at different humidity levels (25%, 55% and 75% RH), naproxen crystallized more quickly from the 3FN ASDs as compared with the 2FN ASDs. 3FN ASDs crystallized after 5 days of storage at all conditions, whereas 2FN ASDs did not crystallize even at 55% RH for two months. This relatively higher crystallization tendency of 3FN ASDs was attributed to the inhomogeneity of drug and polymers as identified by the solid-state Nuclear Magnetic Resonance findings, specifically due to poor mixing of water- and acetone-based solutions at the 3FN nozzle. When only acetone was used as a solvent to prepare drug-polymer solutions for 3FN, the formulated ASD was found to be stable for >3 months of storage (at 75% RH), which suggests that instability of the 3FN ASD was due to the insufficient mixing of water and acetone solutions. This study provides insights into the effects of solvent and nozzle choices on the physical stability of spray-dried ASDs.

Improvement in Dissolution of Bosentan Monohydrate by Solid Dispersions Using Spray Drying Technique

Background:

Bosentan monohydrate (BM), a dual endothelin receptor antagonist, is indicated for the treatment of patients with pulmonary arterial hypertension (PAH). It is poorly soluble in water, and having absolute bioavailability of 50%.

Objective:

The aim of the present work is to develop and evaluate the solid dispersions (SD) of a poorly water soluble drug bosentan monohydrate (BM).

Method:

Solid dispersions (SDs) systems of BM were prepared with Hydroxy propyle β-cyclodextrin (HPβ-CD) and Polyethylene glycol (PEG-4000) polymers using a spray drying technique.

Result:

The significant rise in a saturation solubility 174.23±1.36 mg/mL; and drug dissolution 95.11±1.22%; was observed with optimized formulation (SD 6). The solid state characterization of optimized formulation (SD 6) by SEM, DSC, and XRPD revealed the absence of crystalline nature of BM in solid dispersion. High dissolution rate of solid dispersion (SD 6) compared with pure drug indicated the increase in dissolution characteristics.

Conclusion:

In conclusion, our studies illustrated that spray drying technique could be useful large scale producing method to prepare the solid dispersion of bosentan with HP β-CD, which can improve the solubility as well as stability of the formulation.

Spray drying formulation of amorphous solid dispersions

Spray drying is a well-established manufacturing technique which can be used to formulate amorphous solid dispersions (ASDs) which is an effective strategy to deliver poorly water soluble drugs (PWSDs). However, the inherently complex nature of the spray drying process coupled with specific characteristics of ASDs makes it an interesting area to explore. Numerous diverse factors interact in an inter-dependent manner to determine the final product properties. This review discusses the basic background of ASDs, various formulation and process variables influencing the critical quality attributes (CQAs) of the ASDs and aspects of downstream processing. Also various aspects of spray drying such as instrumentation, thermodynamics, drying kinetics, particle formation process and scale-up challenges are included. Recent advances in the spray-based drying techniques are mentioned along with some future avenues where major research thrust is needed.

Pharmaceutical spray freeze drying

Pharmaceutical spray-freeze drying (SFD) includes a heterogeneous set of technologies with primary applications in apparent solubility enhancement, pulmonary drug delivery, intradermal ballistic administration and delivery of vaccines to the nasal mucosa. The methods comprise of three steps: droplet generation, freezing and sublimation drying, which can be matched to the requirements given by the dosage form and route of administration. The objectives, various methods and physicochemical and pharmacological outcomes have been reviewed with a scope including related fields of science and technology.

A user-friendly model for spray drying to aid pharmaceutical product development

The aim of this study was to develop a user-friendly model for spray drying that can aid in the development of a pharmaceutical product, by shifting from a trial-and-error towards a quality-by-design approach. To achieve this, a spray dryer model was developed in commercial and open source spreadsheet software. The output of the model was first fitted to the experimental output of a Büchi B-290 spray dryer and subsequently validated. The predicted outlet temperatures of the spray dryer model matched the experimental values very well over the entire range of spray dryer settings that were tested. Finally, the model was applied to produce glassy sugars by spray drying, an often used excipient in formulations of biopharmaceuticals. For the production of glassy sugars, the model was extended to predict the relative humidity at the outlet, which is not measured in the spray dryer by default. This extended model was then successfully used to predict whether specific settings were suitable for producing glassy trehalose and inulin by spray drying. In conclusion, a spray dryer model was developed that is able to predict the output parameters of the spray drying process. The model can aid the development of spray dried pharmaceutical products by shifting from a trial-and-error towards a quality-by-design approach.

Selection of excipient, solvent and packaging to optimize the performance of spray-dried formulations: case example fenofibrate

CONTEXT

Along with other options, solid dispersions prepared by spray drying offer the possibility of formulating poorly soluble drugs in a rapidly dissolving format. As a wide range of potential excipients and solvents is available for spray drying, it is usually necessary to carry out a comprehensive array of studies to arrive at an optimal formulation.

OBJECTIVE

To study the influence of formulation parameters such as co-sprayed excipients, solvents and packaging on the manufacture, in vitro performance and stability of spray-dried oral drug products using fenofibrate as a model drug.

MATERIALS AND METHODS

Solid dispersions of fenofibrate with different amorphous polymers were manufactured from two solvent systems by spray drying. These were characterized in terms of physicochemical properties, crystalline content and dissolution behavior in biorelevant media upon production and after storage in two packaging systems (Glass and Activ-Vials(™)).

RESULTS AND DISCUSSION

Spray drying the same formulation from two different solvents led to different physicochemical properties, dissolution behavior and long-term stability. The dissolution behavior and long-term stability also varied significantly among excipients. The viscosity of the polymer and the packaging material proved to be important to the long-term stability.

CONCLUSION

For spray-dried products containing fenofibrate, the excipients were ranked according to dissolution and stability performance as follows: PVP derivatives >> HPMC 2910/15, HPMCAS-MF, HP-β-CD >> PVP:PVA 2:8. EtOH 96% proved superior to acetone/water for spray drying with polymers. The results were used to propose a general approach to developing spray-dried formulations of poorly soluble drugs.

Clofazimine: current status and future prospects

Clofazimine, a lipophilic riminophenazine antibiotic, possesses both antimycobacterial and anti-inflammatory activities. However, its efficacy has been demonstrated only in the treatment of leprosy, not in human tuberculosis, despite the fact that this agent is impressively active in vitro against multidrug-resistant strains of Mycobacterium tuberculosis. Recent insights into novel targets and mechanisms of antimicrobial and anti-inflammatory activity coupled with the acquisition of innovative drug delivery technologies have, however, rekindled interest in clofazimine as a potential therapy for multidrug- and extensively multidrug-resistant tuberculosis in particular, as well as several autoimmune diseases. The primary objective of this review is to critically evaluate these recent developments and to assess their potential impact on improving the therapeutic efficacy and versatility of clofazimine.

Characterization and Physical Stability of Tolfenamic Acid-PVP K30 Solid Dispersions

Obtaining a stable formulation with high bioavailability of a poorly water-soluble drug often presents a challenge to the formulation scientist. Transformation of the drug into its more soluble high-energy amorphous form is one method used for improving the dissolution rate of such compounds. The present study uses the spray-drying technique for preparation of solid dispersions (SDs) of tolfenamic acid (TA) and polyvinylpyrrolidone K-30 (PVP). The SDs and TA in the form of a spray-dried powder were initially characterized and compared with a physical mixture and starting materials. Stability of the SDs was monitored over 12 weeks at 25 degrees C and 60% RH. XRPD studies revealed changes in solid state during the formation of the SDs and indicated the presence of TA in the amorphous state. FTIR, together with TGA, suggested molecular interactions (hydrogen-bonding) in the SDs. Dissolution studies proved an increase in the dissolution rate of TA from all SDs. The SDs with higher content of PVP retained TA in the amorphous state throughout the stability study. However, SDs with lower content showed recrystallization of TA after 1 week. Thus, this study reveals the possibility of preparing stable SDs of amorphous TA in PVP with improved dissolution rate.

Scaling up the spray drying process from pilot to production scale using an atomized droplet size criterion

PURPOSE

The purpose of this study was to investigate the possibility of producing identical powders in pilot and production scale spray drying equipment by matching the droplet size distributions produced by two differently sized atomizers.

METHODS

Particles were prepared by spray drying solutions of acetaminophen and polyvinylpyrrolidone K-30. The success of the up-scaling was evaluated by comparing the powders in terms of particle size distribution (laser diffraction), crystallinity (XPRD) and morphology (SEM). Furthermore, the influence of process parameters on other product characteristics such as stability and residual volatile content was also evaluated.

RESULTS

The spray drying experiments resulted in spherical, amorphous particles with volumetric median diameters of typically 4-10 microm for pilot scale and 4-30 microm for production scale. The results showed that particles with similar morphology and crystallinity could be produced in the two applied spray dryers. However, scale-up based purely on matching droplet size distributions was not feasible.

CONCLUSIONS

The scale-up criterion did not account for the differences between the droplet-drying gas mixing and residence time distribution within the two spray dryers. Therefore, production scale experiments are required in order to obtain similar product characteristics as in pilot scale.