Design And Development Of Nanoparticulate Dosage Form For Treatment Of Cystic Fibrosis

Cystic Fibrosis is a life-threatening autosomal recessive disorder caused by mutations in the CFTR gene, leading to impaired chloride ion transport and the production of thick, viscous mucus in various organs, particularly the lungs.¹ This abnormal mucus accumulation results in chronic respiratory infections, inflammation, and progressive lung damage, significantly affecting patient morbidity and mortality. Despite advances in diagnosis and management, cystic fibrosis continues to pose a substantial global health burden, with increasing prevalence reported across different populations, including India. The disease is associated with multiple mutations, among which the ΔF508 mutation is the most common, affecting the structure and function of the CFTR protein.²

The pathophysiology of cystic fibrosis involves disrupted ion transport across epithelial cells, leading to dehydration of airway surfaces, reduced mucociliary clearance, and persistent bacterial infections, particularly by Pseudomonas aeruginosa. Clinically, patients present with respiratory complications, pancreatic insufficiency, malabsorption, and reduced quality of life. Current treatment strategies focus on symptom management, including airway clearance, antimicrobial therapy, anti-inflammatory agents, and CFTR modulators such as Ivacaftor, which enhances chloride channel function in specific mutations. However, limitations such as poor drug solubility, systemic side effects, and inadequate pulmonary targeting restrict the therapeutic effectiveness of conventional dosage forms.^3-5

Pulmonary drug delivery has emerged as a promising approach for the treatment of respiratory diseases due to its ability to deliver drugs directly to the site of action, providing rapid onset, improved bioavailability, and reduced systemic exposure. The unique anatomical and physiological characteristics of the lungs, including large surface area and high permeability, make them an attractive route for drug administration. In this context, nanoparticulate drug delivery systems have gained significant attention due to their ability to enhance drug solubility, provide controlled release, and improve targeted delivery.^6-7

Polymeric nanoparticles, particularly those prepared using biodegradable polymers such as PLGA, PLA, and chitosan, offer several advantages including enhanced stability, protection of drug molecules, and prolonged residence time in the pulmonary system. These nanoscale carriers can be engineered to optimize particle size, surface properties, and drug release profiles, thereby improving therapeutic outcomes. The incorporation of poorly soluble drugs like Ivacaftor into polymeric nanoparticles can significantly enhance their dissolution behavior and bioavailability.⁸

Therefore, the present study focuses on the design and development of Ivacaftor-loaded polymeric nanoparticles for pulmonary delivery as an innovative strategy to improve drug delivery efficiency and therapeutic efficacy in cystic fibrosis. This approach aims to overcome the limitations of conventional therapies and provide a targeted, sustained, and effective treatment option for better disease management.^9-10

MATERIALS AND METHODS:

MATERIALS:

Ivacaftor, a selective CFTR potentiator used for the treatment of Cystic Fibrosis, was selected as the active pharmaceutical ingredient (API) for the present study. Biodegradable and biocompatible polymers, including chitosan, poly (lactic-co-glycolic acid) (PLGA), and polylactic acid (PLA), were employed for the preparation of polymeric nanoparticles due to their proven suitability in controlled drug delivery systems. Polyethylene glycol (PEG) was utilized as a surface-modifying and coating agent to enhance nanoparticle stability, reduce aggregation, and improve pulmonary compatibility.

Various analytical-grade solvents were used during formulation and characterization processes. Organic solvents such as methanol, ethanol, dichloromethane, and dimethyl sulfoxide (DMSO) were employed for dissolving the drug and polymers, while distilled water was used as the aqueous phase during nanoparticle preparation. All chemicals and reagents used in the study were of analytical grade and were used without further purification.

METHODOLOGY:

Preformulation Studies

Preformulation studies were carried out to evaluate the physicochemical properties of Ivacaftor and its compatibility with selected excipients to ensure the development of a stable and effective nanoparticulate dosage form for Cystic Fibrosis. The drug was characterized for physical appearance, color, odor, and nature using standard descriptive methods. The melting point was determined using a capillary method to confirm purity and identity. Solubility studies were performed in various solvents to assess the drug’s dissolution behavior and select suitable formulation media.^11-13

Fourier Transform Infrared (FT-IR) spectroscopy

Fourier Transform Infrared (FT-IR) spectroscopy was conducted to identify characteristic functional groups and evaluate drug–excipient compatibility.¹⁴

Analytical Method

Quantitative analysis of Ivacaftor was performed using UV-visible spectrophotometry. A stock solution was prepared in ethanol and further diluted to obtain working concentrations. The solution was scanned in the wavelength range of 200–400 nm, and the maximum absorbance (λmax) was found to be 215 nm. A calibration curve was constructed using concentrations of 1–5 µg/ml, and absorbance was measured at 215 nm to establish linearity for drug quantification.¹⁵

Method of Preparation of Nanoparticles (Solvent Evaporation Method)

Ivacaftor polymeric nanoparticles were prepared by the solvent evaporation method using different polymers and solvent systems. Accurately weighed quantities of Ivacaftor, polymers, and PEG were dissolved in 10 mL of respective organic solvent systems to obtain a clear organic phase. Among all formulations, formulation F5 containing 10 mg of Ivacaftor, 25 mg of PLGA, 25 mg of PLA, and 10 mg of PEG dissolved in ethanol was selected as the optimized batch.

Separately, 50 mL of purified water containing Tween 80 was prepared as the aqueous phase. The organic phase was added dropwise into the aqueous phase under continuous magnetic stirring at 1200 rpm to form an oil-in-water emulsion. The emulsion was further homogenized at 11,000 rpm for 13 minutes to obtain uniform nanoparticles. The formulation was then stirred continuously at room temperature for complete evaporation of the organic solvent, resulting in the formation of polymeric nanoparticles entrapping Ivacaftor.

The nanoparticle dispersion was centrifuged at 15,000 rpm for 25 minutes and the obtained pellet was washed twice with distilled water to remove unentrapped drug and excess surfactant. The purified nanoparticles were redispersed in distilled water and spray dried using mannitol as cryoprotectant to obtain dry free-flowing nanoparticulate powder suitable for inhalable delivery.^16-20

Evaluation Parameters of Nanoparticles

The prepared Ivacaftor-loaded polymeric nanoparticles were evaluated for various physicochemical and performance characteristics to assess their suitability for pulmonary delivery in Cystic Fibrosis.^21-30

Particle size and polydispersity index (PDI)

Particle size and polydispersity index (PDI) were determined using a zeta sizer to evaluate the average size and uniformity of the nanoparticle dispersion. The nanoparticle yield was assessed by comparing the amount of nanoparticles recovered after preparation with the total amount of materials used, indicating the efficiency of the formulation process.

Drug content and entrapment efficiency

Drug content and entrapment efficiency were determined using an indirect method. The nanoparticle suspension was centrifuged at 5000 rpm for 30 minutes at 4 °C to separate the unentrapped drug. The supernatant was collected, suitably diluted, and analyzed using a UV spectrophotometer at 215 nm to estimate the amount of free drug, from which drug loading and entrapment efficiency were determined.

Zeta potential

Zeta potential was measured using a zeta sizer to evaluate the surface charge and stability of the nanoparticles. Morphological characteristics were examined using transmission electron microscopy (TEM), which provided detailed information on particle shape and surface features. Optical microscopy was also employed to observe the size, distribution, and aggregation behavior of nanoparticles under 100 × magnifications.

In-vitro drug release studies

In-vitro drug release studies were performed using a Franz diffusion cell with a dialysis membrane separating the donor and receptor compartments. The receptor compartment contained phosphate buffer (pH 6.8) maintained under constant stirring and temperature conditions. Samples were withdrawn at predetermined intervals over 24 hours and analyzed using UV spectrophotometry at 215 nm.

Stability studies

Stability studies were conducted according to ICH guidelines by storing the formulations at room temperature (approximately 20 °C) and refrigerated conditions (4 °C) for a period of six months. Samples were evaluated at regular intervals for changes in particle size, zeta potential, and physical appearance, including sedimentation, to assess formulation stability.

RESULTS AND DISCUSSION:

Pre-formulation Studies:

Pre-formulation studies of Ivacaftor were performed to evaluate its physicochemical properties for the development of a nanoparticulate system intended for Cystic Fibrosis. The drug was identified as a white to off-white, odorless crystalline powder, confirming its purity and suitability for formulation. The melting point (281–284 °C) closely matched reported values, indicating high purity, crystalline nature, and good thermal stability.

Solubility studies revealed that Ivacaftor is practically insoluble in aqueous media but highly soluble in organic solvents such as methanol, ethanol, and DMSO. This behavior confirms its hydrophobic nature and supports the need for nanoparticle-based delivery to enhance solubility and pulmonary bioavailability. Overall, the results demonstrate that Ivacaftor is suitable for incorporation into polymeric nanoparticles.

FT-IR Spectroscopy

FT-IR spectral analysis was performed to confirm the identity of Ivacaftor and to evaluate its compatibility with selected excipients used in nanoparticle formulation for Cystic Fibrosis. The FT-IR spectrum of Ivacaftor exhibited characteristic peaks corresponding to key functional groups, including C–H stretching, C=O stretching, C=N stretching, and aromatic C=C vibrations, confirming the structural integrity of the drug.

Similarly, the spectra of polymers such as PLGA, chitosan, and PEG showed their respective characteristic peaks, indicating their chemical identity. Importantly, comparison of the drug and excipient spectra revealed no significant shifts, disappearance, or formation of new peaks. This indicates the absence of chemical interaction between Ivacaftor and the selected excipients.

Overall, the FT-IR results confirm that the drug is compatible with the formulation components, supporting their suitability for the development of stable polymeric nanoparticles.

 

Figure 1: FTIR Spectra of Ivacaftor

 

Figure 2: FTIR Spectra of Physical Mixture

 

Figure 3: Maximum wavelength detection of Ivacaftor

 

Figure 4: Standard Curve for Ivacaftor

Figure 5: Particle Size of Ivacaftor Nanoparticles

Figure 6: Entrapment Efficiency of Ivacaftor Nanoparticles

 

Figure 7: Zeta Potential of Ivacaftor Nanoparticles

 

Figure 8: In-vitro Drug Release Profile of Ivacaftor Nanoparticles (pH 6.8)

Overall, the optimized ivacaftor nanoparticles remained physically stable for 6 months under both conditions, with refrigerated storage providing better stability, as evidenced by minimal changes in particle size, zeta potential, and absence of sedimentation.

CONCLUSION:

The present study successfully developed Ivacaftor-loaded polymeric nanoparticles using the solvent evaporation method for potential pulmonary drug delivery in cystic fibrosis. Preformulation, FT-IR, and DSC studies confirmed the identity, thermal stability, and compatibility of Ivacaftor with the selected formulation components. Among the developed formulations, F5 was identified as the optimized batch, exhibiting a particle size of 198.3 ± 3.2 nm, low PDI, high nanoparticle yield, 85.6 ± 0.9% entrapment efficiency, and a favorable zeta potential of −31.6 ± 1.0 mV. The optimized formulation demonstrated spherical morphology and a biphasic sustained-release profile, with approximately 98% drug release over 24 h. Six-month stability studies further confirmed acceptable physical stability, with superior stability observed under refrigerated conditions. Overall, the developed Ivacaftor-loaded nanoparticles represent a promising platform for sustained pulmonary drug delivery. However, further studies involving aerodynamic characterization, aerosolization performance, in-vivo pulmonary deposition, pharmacokinetics, and pharmacodynamic evaluation are necessary to establish their suitability for clinical application in cystic fibrosis.

CONFLICTS OF INTERESTS:

All authors declared that the there is no conflict of interest.

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