Combined mixture-process variable approach: a suitable statistical tool for nanovesicular systems optimization

Merging Experimental Design and Nanotechnology for the Development of Optimized Simvastatin Spanlastics: A Promising Combined Strategy for Augmenting the Suppression of Various Human Cancer Cells

Simvastatin (SMV) is an antihyperlipidemic agent that has been investigated as a possible anti-cancer agent. An obstacle to malignant tumor therapy using drugs is the delivery of adequate levels to the cancer cells while minimizing side effects following their systemic administration. To circumvent this challenge, the researchers directed towards the field of nanotechnology to benefit from the nano-size of the formulation in passively targeting the tumor cells. Thus, our study aimed at investigating the potential of a combined mixture-process variable design for optimization of SMV spanlastics (SMV-SPNs) with minimized particle size and maximized zeta potential to enhance the anticancer activity of the drug. The study investigated the effects of Span® 20 and Tween® 80 as mixture components and sonication time as a process variable on particle size, polydispersity index, and zeta potential as responses. SPNs were prepared using an ethanol injection method. Combining the predicted optimized variables' levels is supposed to achieve the set goals with a desirability of 0.821. The optimized spanlastics exhibited a measured globule size of 128.50 nm, PDI of 0.329, and ZP of -29.11 mV. The percentage relative error between predicted responses and the observed ones were less than 5% for the three responses, indicating the optimization technique credibility. A significant improvement in the cytotoxicity of the optimized formulation against three different cancerous cell lines was observed in comparison with SMV. The inhibitory concentration (IC50) values of MCF-7, HCT-116, and HEPG2 were found to be 0.89, 0.39, and 0.06 μM at 24 h incubation. The enhanced cytotoxicity could be assigned to the possible improved permeation and preferential build-up within the cancerous cells by virtue of the minimized size. These findings imply that SMV-SPNs could be an ideal strategy to combat cancer.

D-optimal mixture design for optimization of topical dapsone niosomes: in vitro characterization and in vivo activity against Cutibacterium acnes

This study aimed to illustrate the use of D-optimal mixture design (DOMD) for optimization of an enhancer containing Dapsone niosomal formula for acne topical treatment. Mixture components (MixCs) studied were: Span 20, Cholesterol, and Cremophor RH. Different responses were measured. Optimized formula (OF) was selected to minimize particle size and maximize absolute zeta potential and entrapment efficiency. Optimized formula gel (OF-gel) was prepared and characterized. OF-gel in vivo skin penetration using confocal laser scanning microscopy and activity against Cutibacterium acnes in acne mouse model were studied. Based on DOMD results analysis, adequate models were derived. Piepel and contour plots were plotted accordingly to explain how alteration in MixCs L-pseudo values affected studied responses and regions for different responses’ values. The OF had suitable predicted responses which were in good correlation with the actually measured ones. The OF-gel showed suitable characterization and in vivo skin penetration up to the dermis layer. In vivo acne mouse-model showed that OF-gel-treated group (OF-gel-T-gp) had significantly better recovery (healing) criteria than untreated (UT-gp) and Aknemycin^®-treated (A-T-gp) groups. This was evident in significantly higher reduction of inflammation percent observed in OF-gel-T-gp than both UT-gp and A-T-gp. Better healing in OF-gel-T-gp compared with other groups was also verified by histopathological examination. Moreover, OF-gel-T-gp and A-T-gp bacterial loads were non-significantly different from each other but significantly lower than UT-gp. Thus, DOMD was an adequate statistical tool for optimization of an appropriate enhancer containing Dapsone niosomal formula that proved to be promising for topical treatment of acne.

Formulation, characterization, optimization, and in-vivo performance of febuxostat self-nano-emulsifying system loaded sublingual films

Febuxostat (FXS) is a potent antigout drug with poor water solubility and relative high first-pass effect leading to moderate oral bioavailability (<49%). This study aimed to increase FXS solubility and bioavailability by optimizing sublingual fast-dissolving films (SFs) containing a selected FXS self-nano-emulsifying system (s-SNES) previously prepared by our team. The s-SNES was loaded into SFs by solvent casting technique. A full factorial design (3²) was applied to study the effects of polymer and plasticizer types on mechanical characteristics and the dissolution profile of FXS from the SFs. Numerical optimization was performed to select the SF having highest desirability according to predetermined characteristics. The optimized SF (O-SF) contained 1 g of s-SNES, polyvinylpyrrolidone K30 (6%w/v), polyethylene glycol 300 (20%w/w of polymer wt.), and Avicel PH101 (0.5%w/v). O-SF showed good permeation of FXS through sheep sublingual tissue. Storage of O-SF for three months showed no significant change in the FXS dissolution profile. In-vivo performance of O-SF in rabbits was compared to that of oral marketed tablets (Staturic^® 80 mg). A cross-over design was applied and pharmacokinetic parameters were calculated after ensuring absence of sequence effect. Statistical analysis revealed better performance for O-SF with significantly higher C_max, AUC_0–24, AUC_0–∞, apparent t_1/2 together with lower t_max, and apparent k_el than marketed tablets. Relative bioavailability of O-SF compared to the marketed tablet was found to be 240.6%. This confirms the achievement of the study aims of improving dissolution rate and bioavailability of FXS using a patient-wise convenient formula.

Liver targeting of ledipasvir via galactosylated chitosan-coated spanlastics: chemical synthesis, statistical optimization, in vitro, and pharmacokinetic evaluation

INTRODUCTION

Ledipasvir is an effective direct acting antiviral agent used in the treatment of hepatitis C virus. The high price of ledipasvir was a reason for its limited provision to wide population of HCV patients.

OBJECTIVES

Our objective is the formulation of liver targeted drug delivery system that can increase the amount of ledipasvir delivered to liver and prolong its liver residence in an attempt to reduce its recommended dose and its costing in the treatment of HCV.

METHODS

Different ledipasvir-loaded spanlastic formulations were prepared using the ethanol injection method and evaluated with respect to the particle size, zeta potential, polydispersity index, and entrapment efficiency %. Using Design-Expert ® software, the optimum spanlastics formulation was selected; then, it was coated by synthesized galactosylated chitosan. A pharmacokinetic study was carried out to evaluate the ability of the prepared galactosylated chitosan-coated spanlastics formulation to enhance ledipasvir liver bioavailability when it was administrated via the oral route.

RESULTS

The pharmacokinetic study revealed that the optimized galactosylated chitosan-coated spanlastics exhibited significantly higher liver peak concentration (Cmax) and area under liver concentration versus time curve (AUC0-72 h) and significant prolongation in the liver terminal half life (t½) and mean residence time (MRT) compared to the free ledipasvir dispersion with values of 6270 ng/g, 61,706.3 ng.h/g, 15.85 h, and 24.66 h, respectively.

CONCLUSIONS

Enhanced liver bioavailability of ledipasvir has been accomplished using the developed galactosylated chitosan-coated spanlastics which can be a base for probable reduction in the required dose of ledipasvir in HCV treatment.

Effects of ionic interactions on protein stability prediction using solid-state hydrogen deuterium exchange with mass spectrometry (ssHDX-MS)

Deuterium incorporation in solid-state hydrogen deuterium exchange with mass spectrometry (ssHDX-MS) has been correlated with protein aggregation on storage in sugar-based solid matrices. Here, the effects of sucrose, arginine and histidine buffer on the rate of aggregation of a lyophilized monoclonal antibody (mAb) were assessed using design of experiments (DoE) and response surface methodology. Lyophilized formulations were characterized using ssHDX-MS and Fourier transform infrared spectroscopy (ssFTIR) to assess potential correlation with stability in solid state. The samples were subjected to storage stability at 5 °C and stressed stability at 40 °C/75% RH for 6 months, and the aggregation rate was measured using size exclusion chromatography (SEC). Different levels of arginine had no significant effect on deuterium uptake in ssHDX-MS, although stability studies showed that aggregation rate decreased with increasing arginine concentration. Similarly, when histidine buffer was replaced with phosphate buffer at the same pH and molarity, ssHDX-MS showed no differences in deuterium uptake, but storage stability studies showed a significant increase in aggregation rate. The results suggest that proteins can be stabilized in amorphous solids by ionic interactions which ssHDX-MS does not detect, an important indication of the limitations of the method.

Solutol HS15 based binary mixed micelles with penetration enhancers for augmented corneal delivery of sertaconazole nitrate: optimization, in vitro, ex vivo and in vivo characterization

Keratomycosis is a serious corneal disease that can cause a permanent visual disability if not treated effectively. Sertaconazole nitrate (STZ), a novel broad spectrum antifungal drug, was suggested as a promising treatment. However, its utility in the ocular route is restricted by its poor solubility, along with other problems facing the ocular delivery like short residence time, and the existing corneal barrier. Therefore, the objective of this study was to formulate STZ loaded binary mixed micelles (STZ-MMs) enriched with different penetration enhancers using thin-film hydration method, based on a 3¹.2² mixed factorial design. Different formulation variables were examined, namely, type of auxiliary surfactant, type of penetration enhancer, and total surfactants: drug ratio, and their effects on the solubility of STZ in MMs (S_M), particle size (PS), polydispersity index (PDI), and zeta potential (ZP) were evaluated. STZ-MMs enhanced STZ aqueous solubility up to 338.82-fold compared to free STZ. Two optimized formulations (MM-8 and MM-11) based on the desirability factor (0.891 and 0.866) were selected by Design expert^® software for further investigations. The optimized formulations were imaged by TEM which revealed nanosized spherical micelles. Moreover, they were examined for corneal mucoadhesion, stability upon dilution, storage effect, and ex vivo corneal permeation studies. Finally, both in vivo corneal uptake and in vivo corneal tolerance were investigated. MM-8 showed superiority in the ex vivo and in vivo permeation studies when compared to the STZ-suspension. The obtained results suggest that the aforementioned STZ loaded mixed micellar system could be an effective candidate for Keratomycosis-targeted therapy.

Sustained ocular delivery of Dorzolamide-HCl via proniosomal gel formulation: in-vitro characterization, statistical optimization, and in-vivo pharmacodynamic evaluation in rabbits

Glaucoma is the second cause of blindness worldwide. Frequent administration of traditional topical dosage forms may lead to patient incompliance and failure of treatment. Our study aims to formulate proniosomal gel formulations that sustain the release of the water-soluble anti-glaucoma drug Dorzolamide-HCl (Dorz). Proniosomal gel formulations were prepared using coacervation phase separation method according to a 5² full factorial design. The effects of Cholesterol and surfactant (Span 40) amounts (independent variables) on the percentage entrapment efficiency (EE%), particle size (PS), and the percent of drug released after 8 h (Q8h) (dependent variables (DVs)) were investigated. An optimized formulation (OF) was chosen based on maximizing EE% and Q8h and minimizing PS. An intraocular pressure (IOP) pharmacodynamic study was performed in rabbits to evaluate the in-vivo performance of the OF-gel compared to the marketed Trusopt^® eye drops. The results showed that the independent variables studied significantly affected EE%, PS, and Q8h. OF was the one containing 60 mg Cholesterol and 540 mg Span 40. It had desirability of 0.885 and its actually measured DVs deviated from the predicted ones by a maximum of 4.8%. The in-vivo pharmacodynamic study showed that OF could result in higher reduction in IOP, significantly sustain that reduction in IOP and increase Dorz bioavailability compared to Trusopt^® eye drops. Thus the OF-gel is very promising for being used in glaucoma treatment.

Resolution V fractional factorial design for screening of factors affecting weakly basic drugs liposomal systems

This study aims to investigate factors affecting weakly basic drugs liposomal systems. Resolution V fractional factorial design (2_V^5-1) is used as an example of screening designs that would better be used as a wise step before proceeding with detailed factors effects or optimization studies. Five factors probable to affect liposomal systems of weakly basic drugs were investigated using Amisulpride as a model drug. Factors studied were; A: Preparation technique B: Phosphatidyl choline (PhC) amount (mg) C: Cholesterol: PhC molar ratio, D: Hydration volume (ml) and E: Sonication type. Levels investigated were; Ammonium sulphate-pH gradient technique or Transmembrane zinc chelation-pH gradient technique, 200 or 400 mg, 0 or 0.5, 10 or 20 ml and bath or probe sonication for A, B, C, D and E respectively. Responses measured were Particle size (PS) (nm), Zeta potential (ZP) (mV) and Entrapment efficiency percent (EE%). Ion selective electrode was used as a novel method for measuring unentrapped drug concentration and calculating entrapment efficiency without the need for liposomal separation. Factors mainly affecting the studied responses were Cholesterol: PhC ratio and hydration volume for PS, preparation technique for ZP and preparation technique and hydration volume for EE%. The applied 2_V^5-1 design enabled the use of only 16 trial combinations for screening the influence of five factors on weakly basic drugs liposomal systems. This clarifies the value of the use of screening experiments before extensive investigation of certain factors in detailed optimization studies.

Enhanced transdermal delivery of ondansetron using nanovesicular systems: Fabrication, characterization, optimization and ex-vivo permeation study-Box-Cox transformation practical example

This study aimed to formulate suitable nanovesicles (NVs) for transdermal delivery of Ondansetron. It also illustrated a practical example for the importance of Box-Cox transformation. A 2³ full factorial design was used to enable testing transfersomes, ethosomes, and transethosomes of Ondansetron simultaneously. The independent variables (IVs) studied were sodium taurocholate amount, ethanol volume in hydration medium and sonication time. The studied dependent variables (DVs) were: particle size (PS), zeta potential (ZP) and entrapment efficiency (EE). Polynomial equations were used to study the influence of IVs on each DV. Numerical multiple response optimization was applied to select an optimized formula (OF) with the goals of minimizing PS and maximizing ZP absolute value and EE. Box-Cox transformation was adopted to enable modeling PS raised to the power of 1.2 with an excellent prediction R² of 1.000. ZP and EE were adequately represented directly with prediction R² of 0.9549 and 0.9892 respectively. Response surface plots helped in explaining the influence of IVs on each DV. Two-sided 95% prediction interval test and percent deviation of actual values from predicted ones proved the validity of the elucidated models. The OF was a transfersomal formula with desirability of 0.866 and showed promising results in ex-vivo permeation study.

Tri-block co-polymer nanocarriers for enhancement of oral delivery of felodipine: preparation, in vitro characterization and ex vivo permeation

This study aimed to prepare, optimize and characterize novel felodipine-loaded polymeric nanomicelles, using a pluronic mixture of F127 and P123. Thin-film hydration method was adopted for the preparation of different polymeric nanomicelles (T1-T12) according to a 4¹.3¹ full factorial design. Factors studied were: Pluronic®:drug ratio (P:D ratio) (10, 20, 30 and 40 w/w) and percent of hydrophilic polymer (F127%) (33.33%, 50% and 66.67% w/w). Optimization criteria were to maximize transmittance percent (T%) and entrapment efficiency percent (EE%) and to minimize particle size (PS) and polydispersity index (PDI). The optimized formulation was further characterized by DSC, FTIR and ¹H NMR studies. It was also subjected to stability testing and ex vivo permeation using rabbit intestines. Spherical nanomicelles of particle size ranging from 26.18 to 87.54 nm were successfully obtained. The optimized formulation was found to be the already prepared formulation T12 (P:D ratio of 40 and 66.67% F127) with suitable T% and EE% of 95.12% and 91.75%, respectively. DSC, FTIR and ¹H NMR studies revealed felodipine (FLD) incorporation within T12 nanomicelles. T12 enhanced the ex vivo intestinal permeation of FLD when compared to a drug suspension and showed good stability. Therefore, pluronic nanomicelles could be promising for improved oral delivery of FLD.