Systematic implementation of quality-by-design (QbD) to develop NSAID-loaded nanostructured lipid carriers for ocular application: preformulation screening studies and statistical hybrid-design for optimization of variables

From Preformulative Design to In Vivo Tests: A Complex Path of Requisites and Studies for Nanoparticle Ocular Application. Part 1: Design, Characterization, and Preliminary In Vitro Studies

Ocular pathologies are widely diffused worldwide, and their effective treatment, combined with a high patient compliance, is sometimes challenging to achieve due to the barriers of the eye; in this context, the use of nanoparticles for topical ophthalmic application could represent a successful strategy. Aiming to develop nanoplatforms with potential clinical applications, great attention has to be paid to their features, in relation to the route of administration and to the pharmacopoeial requirements. This review (part 1) thus embraces the preliminary steps of nanoparticle development and characterization. At the beginning, the main barriers of the eye and the different administration routes are resumed, followed by a general description of the advantages of the employment of nanoparticles for ocular topical administration. Subsequently, the preformulative steps are discussed, deepening the choice of raw materials and determining the quantitative composition. Then, a detailed report of the physicochemical and technological characterization of nanoparticles is presented, analyzing the most relevant tests that should be performed on nanoparticles to verify their properties and the requisites (both mandatory and suggested) demanded by regulatory agencies. In conclusion, some preliminary noncellular in vitro evaluation methods are described. Studies from in vitro cellular assays to in vivo tests will be discussed in a separate (part 2) review paper. Hence, this overview aims to offer a comprehensive tool to guide researchers in the choice of the most relevant studies to develop a nanoplatform for ophthalmic drug administration.

Design of Experiments-Driven Optimization of Spray Drying for Amorphous Clotrimazole Nanosuspension

This study employed a Quality by Design (QbD) approach to spray dry amorphousclotrimazole nanosuspension (CLT-NS) consisting of Soluplus® and microcrystallinecellulose. Using the Box-Behnken Design, a systematic evaluation was conducted toanalyze the impact of inlet temperature, % aspiration, and feed rate on the criticalquality attributes (CQAs) of the clotrimazole spray-dried nanosuspension (CLT-SDNS). In this study, regression analysis and ANOVA were employed to detect significantfactors and interactions, enabling the development of a predictive model for the spraydrying process. Following optimization, the CLT-SD-NS underwent analysis using Xraypowder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), Dynamic Scanning Calorimetry (DSC), and in vitro dissolution studies. The resultsshowed significant variables, including inlet temperature, feed rate, and aspiration rate,affecting yield, redispersibility index (RDI), and moisture content of the final product. The models created for critical quality attributes (CQAs) showed statistical significanceat a p-value of 0.05. XRPD and DSC confirmed the amorphous state of CLT in theCLT-SD-NS, and FTIR indicated no interactions between CLT and excipients. In vitrodissolution studies showed improved dissolution rates for the CLT-SD-NS (3.12-foldincrease in DI water and 5.88-fold increase at pH 7.2 dissolution media), attributed torapidly redispersing nanosized amorphous CLT particles. The well-designed studyutilizing the Design of Experiments (DoE) methodology.

Quality-by-Design-Driven Nanostructured Lipid Scaffold of Apixaban: Optimization, Characterization, and Pharmacokinetic Evaluation

Apixaban, an anticoagulant, is limited in its efficacy due to poor solubility, low bioavailability, and extensive metabolism. This study investigates the application of nanostructured lipid carriers (NLCs) to enhance the bioavailability of Apixaban. NLCs were prepared using the high-pressure homogenization method. The influence of independent variables, viz., the amount of Tween 80, HPH pressure, and the number of HPH cycles, were studied using a 23 factorial design. The average particle size, PDI, zeta potential, and entrapment efficiency of the optimized NLCs were found to be 232 ± 23 nm, with 0.514 ± 0.13 PDI and zeta potential of about -21.9 ± 2.1 mV, respectively. Additionally, concerning the thermal and crystallographic properties of the drug, the NLCs showed drug entrapment without altering its potency. The in-vitro drug release studies revealed an immediate release pattern, followed by sustained release for up to 48 h. In-vivo pharmacokinetic experiments demonstrated that Apixaban-loaded NLCs exhibited higher values of t1/2 (27.76 ± 1.18 h), AUC0-∞ (19,568.7 ± 1067.6 ng·h/mL), and Cmax (585.3 ± 87.6 ng/mL) compared to free drugs, indicating improved bioavailability. Moreover, a decrease in the elimination rate constant (Kel) reflected the sustained effect of Apixaban with NLCs. NLCs offer improved oral absorption rates and enhanced therapeutic impact compared to free drugs, potentially reducing dose frequency and improving patient outcomes.

Development of a Versatile Nanostructured Lipid Carrier (NLC) Using Design of Experiments (DoE)-Part II: Incorporation and Stability of Butamben with Different Surfactants

Nanostructured lipid carriers (NLCs) are typically composed of liquid lipids, solid lipids, and surfactants, enabling the encapsulation of lipophilic drugs. Butamben is a Class II anesthetic drug, according to the Biopharmaceutical Classification System (BCS); it has a log P of 2.87 and is considered a 'brick dust' (poorly water-soluble and poorly lipid-soluble) drug. This characteristic poses a challenge for the development of NLCs, as they are not soluble in the liquid lipid present in the NLC core. In a previous study, we developed an NLC core consisting of a solid lipid (CrodamolTM CP), a lipophilic liquid with medium polarity (SRTM Lauryl lactate), and a hydrophilic excipient (SRTM DMI) that allowed the solubilization of 'brick dust' types of drugs, including butamben. In this study, starting from the NLC core formulation previously developed we carried out an optimization of the surfactant system and evaluated their performance in aqueous medium. Three different surfactants (CrodasolTM HS HP, SynperonicTM PE/F68, and CroduretTM 40) were studied and, for each of them, a 23 factorial design was stablished, with total lipids, % surfactant, and sonication time (min) as the input variables and particle size (nm), polydispersity index (PDI), and zeta potential (mV) as the response variables. Stable NLCs were obtained using CrodasolTM HS HP and SynperonicTM PE/F68 as surfactants. Through a comparison between NLCs developed with and without SRTM DMI, it was observed that besides helping the solubilization of butamben in the NLC core, this excipient helped in stabilizing the system and decreasing particle size. NLCs containing CrodasolTM HS HP and SynperonicTM PE/F68 presented particle size values in the nanometric scale, PDI values lower than 0.3, and zeta potentials above |10|mV. Concerning NLCs' stability, SBTB-NLC with SynperonicTM PE/F68 and butamben demonstrated stability over a 3-month period in aqueous medium. The remaining NLCs showed phase separation or precipitation during the 3-month analysis. Nevertheless, these formulations could be freeze-dried after preparation, which would avoid precipitation in an aqueous medium.

A Study of Microemulsion Systems for Transdermal Delivery of Risperidone Using Penetration Enhancers

The aim of this study was to develop and characterize microemulsion formulations using penetration enhancers as potential transdermal delivery systems for risperidone. Initially, a simple formulation of risperidone in Propylene Glycol (PG) was prepared as a control formulation, together with formulations incorporating various penetration enhancers, alone and/or in combination, and also microemulsion formulations with various chemical penetration enhancers, were prepared and all were evaluated for risperidone transdermal delivery. An ex-vivo permeation study was carried out using human cadaver skin and vertical glass Franz diffusion cells to compare all the microemulsion formulations. The microemulsion prepared from oleic acid as the oil (15%), Tween 80 (15%) as the surfactant and isopropyl alcohol (20%) as the co-surfactant, and water (50%) showed higher permeation with a flux value of 32.50±3.60 ug/hr/sq.cm, a globule size of 2.96±0.01 nm, a polydispersity index of 0.33±0.02 and pH of 4.95. This novel in vitro research disclosed that an optimized microemulsion formulated using penetration enhancers was able to increase permeation of risperidone by 14-fold compared to the control formulation. The data suggested that microemulsions may be useful in the delivery of risperidone via the transdermal route.

Subconjunctival Delivery of Sorafenib-Tosylate-Loaded Cubosomes for Facilitated Diabetic Retinopathy Treatment: Formulation Development, Evaluation, Pharmacokinetic and Pharmacodynamic (PKPD) Studies

Diabetic retinopathy (DR) is a microvascular complication associated with vascular endothelial growth factor (VEGF) overexpression. Therapeutic delivery to the retina is a challenging phenomenon due to ocular biological barriers. Sorafenib tosylate (ST) is a lipophilic drug with low molecular weight, making it ineffective at bypassing the blood-retinal barrier (BRB) to reach the target site. Cubosomes are potential nanocarriers for encapsulating and releasing such drugs in a sustained manner. The present research aimed to compare the effects of sorafenib-tosylate-loaded cubosome nanocarriers (ST-CUBs) and a sorafenib tosylate suspension (ST-Suspension) via subconjunctival route in an experimental DR model. In this research, ST-CUBs were prepared using the melt dispersion emulsification technique. The distribution of prepared nanoparticles into the posterior eye segments was studied with confocal microscopy. The ST-CUBs were introduced into rats' left eye via subconjunctival injection (SCJ) and compared with ST-Suspension to estimate the single-dose pharmacokinetic profile. Streptozotocin (STZ)-induced diabetic albino rats were treated with ST-CUBs and ST-Suspension through the SCJ route once a week for 28 days to measure the inhibitory effect of ST on the diabetic retina using histopathology and immunohistochemistry (IHC) examinations. Confocal microscopy and pharmacokinetic studies showed an improved concentration of ST from ST-CUBs in the retina. In the DR model, ST-CUB treatment using the SCJ route exhibited decreased expression levels of VEGF, pro-inflammatory cytokines, and adhesion molecules compared to ST-Suspension. From the noted research findings, it was concluded that the CUBs potentially enhanced the ST bioavailability. The study outcomes established that the developed nanocarriers were ideal for delivering the ST-CUBs via the SCJ route to target the retina for facilitated DR management.

Strategizing Spray Drying Process Optimization for the Manufacture of Redispersible Indomethacin Nanoparticles Using Quality-by-Design Principles

The present study adopted a Quality by Design (QbD) approach to spray dry indomethacin nanosuspension (IMC-NS) consisting of HPC-SL, poloxamer 407, and lactose monohydrate. The Box-Behnken Design was used to systematically evaluate the effects of inlet temperature, aspiration rate, and feed rate on the critical quality attributes (CQAs) [redispersibility index (RDI; minimize), % yield (maximize), and % release at 15 min (maximize)] of the indomethacin spray dried nanosuspension (IMC-SD-NS). To identify significant main and quadratic effects, two-way interactions, and create a predictive model for the spray drying process, regression analysis and ANOVA were utilized. Following optimization, the IMC-SD-NS was analyzed for its physicochemical properties using X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), and in vitro dissolution studies. Statistical analysis revealed significant independent variables, including inlet temperature, feed rate, and aspiration rate, that critically impacted the solidified end product's RDI, % yield, and % release at 15 min. The models developed for critical quality attributes (CQAs) were significant at a p-value of 0.05. The crystalline state of IMC was maintained in the solidified product, as confirmed by XRPD, and no interactions were observed between IMC and the excipients as evaluated by FTIR. In vitro dissolution studies showed improved dissolution rate for the IMC-SD-NS (3.82-fold increase in overall drug release), which may be attributed to the readily redispersible nanosized drug particles. The implementation of a well-designed study, utilizing Design of Experiments (DoE) methodology, played a crucial role in the development of a highly effective spray drying process.

Loteprednol-Loaded Nanoformulations for Corneal Delivery by Quality-by-Design Concepts: Optimization, Characterization, and Anti-inflammatory Activity

Loteprednol etabonate (LE) is a topical corticosteroid that uses inflammatory conditions of the eye. It has a low ocular bioavailability and side effects such as corneal disorder, eye discharge, and ocular discomfort. Therefore, it was decided to select the delivery systems, which are solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and nanoemulsion (NE). Design of experiments (DoE) of SLN, NLC, and NE formulations were formulated by using the quality by design (QbD) approach. Precirol® ATO 5 and oleic acid were used as solid and liquid lipids, respectively, in SLN, NLC, and NE formulations. Physiochemical characterization was performed on the formulations. The optimized formulations' inflammatory effects have been appraised on human corneal epithelial cells employing the ELISA test. Physicochemical characterization studies and inflammatory effects were appraised. The sizes of optimized formulations of SLN, NLC, and NE were 86.19 nm, 82.38 nm, and 126.35 nm, respectively, with minimum polydispersity. The release behavior of the formulations is composed of both diffusion and erosion. ELISA test results proved that the formulations significantly reduced IL-1 and IL-6 levels (p < 0.05). D-optimal mixture experimental design allowed us to develop the most precise formulations of SLN, NLC, and NE. Furthermore, the optimized formulations could be promising candidates for treating an inflammation-based corneal disease of the eye.

Developing a Formulation Strategy Coupled with PBPK Modeling and Simulation for the Weakly Basic Drug Albendazole

Albendazole (ABZ) is a weakly basic drug that undergoes extensive presystemic metabolism after oral administration and converts to its active form albendazole sulfoxide (ABZ_SO). The absorption of albendazole is limited by poor aqueous solubility, and dissolution is the rate-limiting step in the overall exposure of ABZ_SO. In this study, PBPK modeling was used to identify formulation-specific parameters that impact the oral bioavailability of ABZ_SO. In vitro experiments were carried out to determine pH solubility, precipitation kinetics, particle size distribution, and biorelevant solubility. A transfer experiment was conducted to determine the precipitation kinetics. A PBPK model for ABZ and ABZ_SO was developed using the Simcyp™ Simulator based on parameter estimates from in vitro experiments. Sensitivity analyses were performed to assess the impact of physiological parameters and formulation-related parameters on the systemic exposure of ABZ_SO. Model simulations predicted that increased gastric pH significantly reduced ABZ absorption and, subsequently, ABZ_SO systemic exposure. Reducing the particle size below 50 µm did not improve the bioavailability of ABZ. Modeling results illustrated that systemic exposure of ABZ_SO was enhanced by increasing solubility or supersaturation and decreasing the drug precipitation of ABZ at the intestinal pH level. These results were used to identify potential formulation strategies to enhance the oral bioavailability of ABZ_SO.

Development and Optimization of Imiquimod-Loaded Nanostructured Lipid Carriers Using a Hybrid Design of Experiments Approach

Background

Imiquimod (IMQ) is an immunomodulating drug that is approved for the treatment of superficial basal cell carcinoma, actinic keratosis, external genital warts and perianal warts. However, IMQ cream (Aldara^®) has several drawbacks including poor skin permeation, local toxicity, and compromised patient compliance as a topical pharmacological option.

Methods

Our research aimed to develop and optimize nanostructured lipid carriers (NLCs) containing IMQ for the first time using a hybrid design of experiments approach. The optimized formulation was then incorporated into a matrix-type topical patch as an alternative dosage form for topical application and evaluated for IMQ deposition across different skin layers in comparison to the performance of the commercial product. Additionally, our work also attempted to highlight the possibility of implementing environment-friendly practices in our IMQ-NLCs formulation development by reviewing our analytical methods and experimental designs and reducing energy and solvent consumption where possible.

Results

In this study, stearyl alcohol, oleic acid, Tween^® 80 (polysorbate 80), and Gelucire^® 50/13 (Stearoyl polyoxyl-32 glycerides) were selected for formulation development. The formulation was optimized using a 2^k factorial design and a central composite design. The optimized formulation achieved the average particle size, polydispersity index, and zeta potential of 75.6 nm, 0.235, and - 30.9 mV, respectively. Subsequently, a matrix-type patch containing IMQ-NLCs was developed and achieved a statistically significant improvement in IMQ deposition in the deeper skin layers. The IMQ deposition from the patch into the dermis layer and receptor chamber was 3.3 ± 0.9 µg/cm² and 12.3 ± 2.2 µg/cm², while the commercial cream only deposited 1.0 ± 0.8 µg/cm² and 1.5 ± 0.5 µg/cm² of IMQ, respectively.

Conclusion

In summary, IMQ-NLC-loaded patches represent great potential as a topical treatment option for skin cancer with improved patient compliance.

Optimized L-SNEDDS and spray-dried S-SNEDDS using a linked QbD-DM3 rational design for model compound ketoprofen

A QbD-DM³ strategy was used to design ketoprofen (KTF) optimized liquid (L-SNEDDS) and solid self-nanoemulsifying drug delivery systems (S-SNEDDS). Principal component analysis was used to identify the optimized L-SNEDDS containing Capmul® MCM NF, 10 % w/w; Kolliphor® ELP, 60 % w/w; and propylene glycol, 30 % w/w. The S-SNEDDS was manufactured by spray-drying a feed dispersion prepared by dissolving the optimized KTF-loaded L-SNEDDS in an ethanol-Aerosil® 200 dispersion. A Box Behnken design was employed to evaluate the effect of drug concentration (DC), Aerosil® 200 concentration (AC) and feed rate (FR) on maximizing percent yield (PY) and loading efficiency (LE). The optimal levels of DC, AC, and FR were 19.9 % w/w, 30.0 % w/w, and 15.0 %, respectively. The optimized S-SNEDDS was amorphous, and its dissolution showed a 2.37-fold increase in drug release compared to KTF in 0.1 HCl. An optimized independent spray-dried S-SNEDDS verification batch showed that the predicted and observed PY and LE were 70.49 % and 92.49 %, and 70.02 % and 91.27 %, respectively. The optimized L-SNEDDS and S-SNEDDS also met their quality target product profile criteria for globule size <100 nm, polydispersity index < 0.400, emulsification time < 30 s, and KTF L-SNEDDS solubility 100-fold greater than its water solubility.

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

Corticosteroids, although highly effective for the treatment of both anterior and posterior ocular segment inflammation, still nowadays struggle for effective drug delivery due to their poor solubilization capabilities in water. This research work aims to develop nanostructured lipid carriers (NLC) intended for periocular administration of dexamethasone acetate to the posterior segment of the eye. Pre-formulation studies were initially performed to find solid and liquid lipid mixtures for dexamethasone acetate solubilization. Pseudoternary diagrams at 65 °C were constructed to select the best surfactant based on the macroscopic transparency and microscopic isotropy of the systems. The resulting NLC, obtained following an organic solvent-free methodology, was composed of triacetin, Imwitor® 491 (glycerol monostearate >90%) and tyloxapol with Z-average = 106.9 ± 1.2 nm, PDI = 0.104 ± 0.019 and zeta potential = -6.51 ± 0.575 mV. Ex vivo porcine sclera and choroid permeation studies revealed a considerable metabolism in the sclera of dexamethasone acetate into free dexamethasone, which demonstrated higher permeation capabilities across both tissues. In addition, the NLC behavior once applied onto the sclera was further studied by means of multiphoton microscopy by loading the NLC with the fluorescent probe Nile red.

Quality by design based development of nanostructured lipid carrier: a risk based approach

The aim of this review is to discuss the development of nanostructured lipid carrier (NLC) by the application of quality by design (QbD). QbD started with the evolution of the quality concept and slow adaptation of quality guidelines, which has now become a regulatory requirement. In this review, brief history and elements of QbD including risk assessment (RA) have been discussed followed by the design of experiments (DoEs) that acts as a tool to analyze the input whose variation can optimize the output with the desired goal. NLC is a versatile delivery system as researchers widely use it to administer therapeutics with different physicochemical properties. The surface of NLC can be modified, making it a suitable delivery system with targeting potential for therapeutics. Implementation of QbD provides a high-quality robust formulation that can consistently meet the patient’s requirement throughout its life cycle without compromising the safety and effectiveness of the drug and delivery system. This review discusses QbD concepts followed by the systematic development of NLC by the application of DoE. Process analytical technology (PAT) and six sigma concepts have also been included which can benefit in the development of optimized NLC.

Neither too little nor too much: Finding the ideal proportion of excipients using confocal Raman and chemometrics

The applications of Raman imaging in pharmaceutical field are ever-increasing due its ability to obtain spatial and spectral information simultaneously, once it allows determine the chemical distribution of compounds. In this sense, it is used to study homogeneity, of paramount importance during the development of pharmaceutical formulations due to its relation to stability, safety and efficacy. Commonly, just surface is analyzed, but confocal Raman spectroscopy can also characterize the inner part of samples, allowing to determine phase separation in the early stages. In this sense, confocal 3D Raman microscopy was crucial to obtain the optimal proportion of Apifil®, Capryol® 90 and Transcutol® to promote controlled release of the local anesthetic butamben (BTB). 3D chemical maps were obtained by classical least squares (CLS) using pure compound spectra as S matrix, showing that chemical distribution throughout the material was different. Knowing that the composition of samples affects the homogeneity parameter, standard deviation and distributional homogeneity index (DHI) were used in mixture experimental design (DoE). From this analysis, it was revealed that a correct amount of Capryol® 90 enhances both miscibility and solubility. Furthermore, suitable miscibility was observed in two ratio proportions of excipients with a desirability of 0.783 and 0.742. These results unequivocally demonstrated that confocal Raman microscopy combined to DoE can bring pharmaceutical development to a higher level.

Combinatorial delivery of Ribociclib and Green tea extract mediated nanostructured lipid carrier for oral delivery for the treatment of breast cancer synchronizing in silico, in vitro, and in vivo studies

Purpose: The current research investigated the development and evaluation of dual drug-loaded nanostructure lipidic carriers (NLCs) of green tea extract and Ribociclib.Method: In silico study were performed to determine the effectiveness of combinational approach. The prepared NLCs were subjected to in vitro drug release, lipolysis, haemolysis and cell line studies to assess their in vivo prospect.Results: In silico study was done to get docking score of EGCG (-8.98) close to Ribociclib (-10.78) in CDK-4 receptors. The prepared NLCs exhibited particle size (175.80 ± 3.51 nm); PDI (0.571 ± 0.012); and %EE [RBO (80.91 ± 1.66%) and GTE 75.98 ± 2.35%)] respectively. MCF-7 cell lines were used to evaluate the MTT assay, cellular uptake and antioxidant (ROS and SOD) of prepared NLCs. In vitro drug release showed the controlled release up to 72 h. In vitro lipolysis and in vitro haemolysis studies showed the availability of drugs at absorption sites and the greater in vivo prospects of NLCs respectively. Pharmacokinetic study revealed a 3.63-fold and 1.53-fold increment in RBO and GTE bioavailability in female Wistar rats respectively.Conclusion: The prominent potential of green tea extract and RBO-loaded NLCs in enhancing their therapeutic efficacy for better treatment of breast cancer.

Lipid Nanoparticles for the Posterior Eye Segment

This review highlights the application of lipid nanoparticles (Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, or Lipid Drug Conjugates) as effective drug carriers for pathologies affecting the posterior ocular segment. Eye anatomy and the most relevant diseases affecting the posterior segment will be summarized. Moreover, preparation methods and different types and subtypes of lipid nanoparticles will also be reviewed. Lipid nanoparticles used as carriers to deliver drugs to the posterior eye segment as well as their administration routes, pharmaceutical forms and ocular distribution will be discussed emphasizing the different targeting strategies most recently employed for ocular drug delivery.

Understanding the Impact of Multi-factorial Composition on Efficient Loading of the Stable Ketoprofen Nanoparticles on Orodispersible Films Using Box-Behnken Design

The purpose of the present study was to prepare Orodispersible films (ODFs) loaded with ketoprofen nanoparticles (KT-NP). The Box-Behnken design was constructed in developing and optimizing the KTF-NP-ODFs. The effect of independent variables: Soluplus® concentration (X₁, stabilizer), Tween 80 concentration (X₂, surfactant), and KTF concentration (X₃, drug) were studied on the dependent variables: particle size (PS, Y₁), zeta potential (ZP, Y₂), and the polydispersity index (PDI, Y₃) of the NPs, as well as on the tensile strength (TS, Y₄) and permeability coefficient (PC, Y₅) of the KTF-NP-ODFs. Hydroxypropyl methylcellulose (HPMC E15) and polyethylene glycol (PEG 400) were used as the film former polymer and plasticizer, respectively, and their concentrations were kept constant for all formulations. KTF-NPs were prepared by antisolvent precipitation technology. This was followed by the addition of HPMC E15 and PEG 400 to prepare the ODFs using the solvent-casting method. The PS, PDI, and ZP for all the formulations were found in the range of 94 nm to 350 nm, 0.09 to 0.438, and -21.83 mV to -8.03 mV, respectively. The TS and PC of the prepared KTF-NP-ODFs were found between 1.21 MPa to 3.93 MPa and 3.12 × 10^-4 cm/h to 34.23 × 10^-4 cm/h, respectively. The amorphous nature of the KTF-NP in the ODFs was confirmed by the absence of characteristic crystalline peaks and endothermic events of KTF in X-ray diffraction (XRD) and modulated differential scanning calorimetry (mDSC), respectively. The optimized formulation showed ̴ 4 times higher permeability as compared to the pure KTF. In addition, the dissolution of pure KTF and the optimized KTF-NP-ODF in pH 1.2 at the end of 60 min was found to be ̴ 30% and ̴ 95%, respectively. Conclusively, KTF-NP-ODFs can be a promising drug delivery system to counter the issues related to dysphagia and bypass the common side effects, such as the gastric irritation associated with NSAIDs like KTF.

Lipid-Based Nanocarriers for Ophthalmic Administration: Towards Experimental Design Implementation

Nanotherapeutics based on biocompatible lipid matrices allow for enhanced solubility of poorly soluble compounds in the treatment of ophthalmic diseases, overcoming the anatomical and physiological barriers present in the eye, which, despite the ease of access, remains strongly protected. Micro-/nanoemulsions, solid lipid nanoparticles (SLN) or nanostructured lipid carriers (NLC) combine liquid and/or solid lipids with surfactants, improving drug stability and ocular bioavailability. Current research and development approaches based on try-and-error methodologies are unable to easily fine-tune nanoparticle populations in order to overcome the numerous constraints of ocular administration routes, which is believed to hamper easy approval from regulatory agencies for these systems. The predictable quality and specifications of the product can be achieved through quality-by-design (QbD) implementation in both research and industrial environments, in contrast to the current quality-by-testing (QbT) framework. Mathematical modelling of the expected final nanoparticle characteristics by variation of operator-controllable variables of the process can be achieved through adequate statistical design-of-experiments (DoE) application. This multivariate approach allows for optimisation of drug delivery platforms, reducing research costs and time, while maximising the understanding of the production process. This review aims to highlight the latest efforts in implementing the design of experiments to produce optimised lipid-based nanocarriers intended for ophthalmic administration. A useful background and an overview of the different possible approaches are presented, serving as a starting point to introduce the design of experiments in current nanoparticle research.

Hybridized nanoamorphous micellar dispersion using a QbD-DM3 linked rational product design strategy for ritonavir: A BCS IV drug

A QbD-DM³ linked rational product design strategy was adopted to create a hybridized ritonavir (RTV, BCS Class IV) nanoamorphous micellar dispersion (RTV-NAD). A DM³ research strategy was employed in conjunction with the quality-by-design spaces, and quality target product profile to link the critical material attributes and critical process parameters to the quality target product profile's critical product attributes QbD elements. A Box-Behnken design and multivariate analysis using multiple linear regression and partial least squares provided data analysis. The hybridized strategy leveraged three different mechanisms to increase RTV's solubility and four mechanisms to increase its dissolution rate. Statistically significant models were generated for critical product attributes: particle size (p = 0.0000, R² adjusted = 0.9513), polydispersity index (p = 0.0002, R² adjusted = 0.6398), zeta potential (p = 0.0000, R² adjusted = 0.9744), and drug loading on a dry basis (p = 0.0000, R² adjusted = 0.9951). The impact of drug concentration, Soluplus® concentration, and solvent:antisolvent ratio, their interactions and square effects on the critical product attributes were assessed by multivariate analysis. The QbD optimal formulation was determined for RTV-NAD. Multiple linear regression and partial least squares computational predictability was evaluated using three verification batches. The prediction error for critical product attributes was <5%. RTV-NAD and ritonavir microsuspension were characterized by x-ray diffraction and in-vitro dissolution studies. X-ray diffraction confirmed the amorphous nature of the RTV-NAD. RTV-NAD exhibited a 'spring-hover' dissolution profile at pH 4.5. At pH 6.8, a classic 'spring-parachute' dissolution behavior was observed.

Nanocarriers for ocular drug delivery: current status and translational opportunity

Ocular diseases have a significant effect on vision and quality of life. Drug delivery to ocular tissues is a challenge to formulation scientists. The major barriers to delivering drugs to the anterior and posterior segments include physiological barriers (nasolacrimal drainage, blinking), anatomical barriers (static and dynamic), efflux pumps and metabolic barriers. The static barriers comprise the different layers of the cornea, sclera, and blood-aqueous barriers whereas dynamic barriers involve conjunctival blood flow, lymphatic clearance and tear drainage. The tight junctions of the blood-retinal barrier (BRB) restrict systemically administered drugs from entering the retina. Nanocarriers have been found to be effective at overcoming the issues associated with conventional ophthalmic dosage forms. Various nanocarriers, including nanodispersion systems, nanomicelles, lipidic nanocarriers, polymeric nanoparticles, liposomes, niosomes, and dendrimers, have been investigated for improved permeation and effective targeted drug delivery to various ophthalmic sites. In this review, various nanomedicines and their application for ophthalmic delivery of therapeutics are discussed. Additionally, scale-up and clinical status are also addressed to understand the current scenario for ophthalmic drug delivery.