Once daily, high-dose mesalazine controlled-release tablet for colonic delivery: optimization of formulation variables using Box-Behnken design

Lipid-based nano-formulation platform for eplerenone oral delivery as a potential treatment of chronic central serous chorioretinopathy: in-vitro optimization and ex-vivo assessment

PURPOSE

Eplerenone (EPL) is a selective mineralocorticoid receptor antagonist used for treatment of chronic central serous chorioretinopathy which characterized by accumulation of subretinal fluid causing a localized area of retinal detachment. unfortunately, EPL suffers from poor oral bioavailability due to poor aqueous solubility in addition to high hepatic first pass metabolism.

METHOD

Aiming to improve its oral bioavailability, EPL-loaded nanostructured lipid carriers (NLCs) were prepared by the emulsification solvent evaporation method and in-vitro evaluated for particle size (PS), polydispersity index (PDI), zeta potential (ZP), and entrapment efficiency (EE%). A D-optimal design was used for study the effect of liquid lipid to solid lipid ratio, surfactant type and percentage on PS, PDI, EE%, and for data optimization. The optimized EPL-loaded NLCs system was further evaluated using in-vitro drug release and ex-vivo permeation studies through rabbit intestine in comparison to EPL aqueous suspension. The physicochemical properties of the drug in the optimized system were further examined using FT-IR and X-ray diffraction studies.

RESULTS

The resultant NLCs showed small PS (100.85-346.60 nm), homogenous distribution (0.173-0.624), negatively charged particles (ZP -20.20 to -36.75 mV), in addition to EE% (34.31-70.64%). The optimized EPL-loaded NLCs system with a desirability value of 0.905 was suggested through the Design expert® software, containing liquid to solid lipid ratio (2:1) in presence of 0.43%w/v Pluronic® F127 as a surfactant. The optimized EPL-loaded NLCs system showed a PS of 134 nm and PDI of 0.31, in addition to high EE% (76 ± 6.56%w/w), and ZP (-32.37 mV). The ex-vivo permeation study showed two-fold higher drug permeation through rabbit intestine compared to that from the aqueous drug suspension after 24 h, confirming the ability of optimized EPL-loaded NLCs system as successful oral targeting delivery carrier.

CONCLUSION

Our results pave the way for a new oral nanotherapeutic approach toward CSCR treatment. In-vivo study is currently under investigation.

Budding Multi-matrix Technology-a Retrospective Approach, Deep Insights, and Future Perspectives

The human race is consistently striving for achieving good health and eliminate disease-causing factors. For the last few decades, scientists have been endeavoring to invent and innovate technologies that can substitute the conventional dosage forms and enable targeted and prolonged drug release at a particular site. The novel multi-matrix technology is a type of matrix formulation where the formulation is embraced to have a matrix system with multiple number of matrices. The MMX technology embraces with a combination of outer hydrophilic layer and amphiphilic/lipophilic core layer, within which drug is encapsulated followed by enteric coating for extended/targeted release at the required site. In comparison to conventional oral drug delivery systems and other drug delivery systems, multi-matrix (MMX) technology formulations afford many advantages. Additionally, it attributes for targeting strategy aimed at the colon and offers modified prolonged drug release. Thus, it has emerged rapidly as a potential alternative option in targeted oral drug delivery. However, the development of this MMX technology formulations is a exigent task and also has its own set of limitations. Due to its promising advantages and colon targeting strategy over the other colon targeted drug delivery systems, premier global companies are exploiting its potential. This article review deep insights into the formulation procedures, drug delivery mechanism, advantages, limitations, safety and efficacy studies of various marketed drug formulations of MMX technology including regulatory perspectives and future perspectives.

Artificial Neural Network (ANN) Approach to Predict an Optimized pH-Dependent Mesalamine Matrix Tablet

Background

Severe bleeding and perforation of the colon and rectum are complications of ulcerative colitis which can be treated by a targeted drug delivery system.

Purpose

Development of colon-targeted delivery usually involves a complex formulation process and coating steps of pH-sensitive methacrylic acid based Eudragit^®. The current work was purposefully designed to develop dicalcium phosphate (DCP) facilitated with Eudragit-S100-based pH-dependent, uncoated mesalamine matrix tablets.

Materials and Methods

Mesalamine formulations were compressed using wet granulation technique with varying compositions of dicalcium phosphate (DCP) and Eudragit-S100. The developed formulations were characterized for physicochemical and drug release profiles. Infrared studies were carried out to ensure that there was no interaction between active ingredients and excipients. Artificial neural network (ANN) was used for the optimization of final DCP-Eudragit-S100 complex and the experimental data were employed to train a multi-layer perception (MLP) using quick propagation (QP) training algorithm until a satisfactory root mean square error (RMSE) was reached. The ANN-aided optimized formulation was compared with commercially available Masacol^®.

Results

Compressed tablets met the desirability criteria in terms of thickness, hardness, weight variation, friability, and content uniformity, ie, 5.34 mm, 7.7 kg/cm^2, 585±5 mg (%), 0.44%, and 103%, respectively. In-vitro dissolution study of commercially available mesalamine and optimized formulation was carried out and the former showed 100% release at 6 h while the latter released only 12.09% after 2 h and 72.96% after 12 h which was fitted to Weibull release model with b value of 1.3, indicating a complex release mechanism.

Conclusion

DCP-Eudragit-S100 blend was found explicative for mesalamine release without coating in gastric and colonic regions. This combination may provide a better control of ulcerative colitis.

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Desirability Based Optimization of New Mesalazine Modified Release Formulations: Compression Coated Tablets and Mini Tablets in Capsules

Background:

Mesalazine (5-aminosalicylic acid, 5-ASA) is a drug substance with an antiinflammatory activity, which is mainly used in the symptomatic treatment of diseases, such as Ulcerative Colitis, the Crohn's disease and the idiopathic inflammatory bowel disease. Mesalazine exerts its effect locally in the inflamed area of the intestine and not through systematic absorption, therefore the investigation of its release characteristics from solid pharmaceutical formulations is of great importance.

Objective:

The development of novel mesalazine modified release formulations with improved properties, regarding drug release in the gastrointestinal tract, by utilisation of the Design of Experiments (DoE) approach.

Methods:

D-optimal experimental design was applied. A Simplex Lattice mixture design was used for the development of suitable capsules containing 4 mini tablets and a D-optimal mixture design was used for compression-coated tablets, with the following characteristics: ≤10% release in 2 h, to minimize its degradation in the upper gastrointestinal tract, 20-40% release in 5 h for mesalazine administration in the small intestine, and quantitative release in 12 h for colonic delivery. The dissolution experiments were conducted in gastrointestinal-like fluids and pectinases to simulate the pectinolytic enzymes present in the colon.

Results:

The optimal compositions were reached via the desirability function, as a compromise to the different responses. The optimal solutions for both formulations led to colon-specific delivery of the active substance with minimal 5-ASA release in the upper gastrointestinal tract and appeared to conform with the pre-determined characteristics. Hard gelatin capsules, when filled with mini-tablets led to the aimed modified release profile, having sigmoidal characteristics and compression coated tablets led to colonic delivery.

Conclusion:

Two novel mesalazine formulations were developed with the desirable colonic release, by conducting a minimal number of experiments, as suggested by DoE experimental design.

A novel concept of overcoming the skin barrier using augmented liquid nanocrystals: Box-Behnken optimization, ex vivo and in vivo evaluation

Agomelatine suffers from extensive inactivation through 1^st pass effect with a limited oral bioavailability (5%). The aim of this study was to formulate and optimize liquid nanocrystals (LNC) containing agomelatine to enhance the transdermal permeation of the drug. The independent factors of the employed Box-Behnken design were the Pluronic F127, deoxycholic acid sodium salt and propylene glycol percentages. On the other hand, particle size, polydispersity index, zeta potential, entrapment efficiency, cumulative amount permeated at certain time intervals and permeation enhancement ratio were considered as dependent responses. The optimized formulation was composed of 1.5% Pluronic F127 and 1.5% deoxycholic acid sodium salt and it was found to have significantly higher AUC_0-24h, AUC_0-∞ and elimination t_1/2 than that of the employed reference indicating the enhancement of the drug permeation. The obtained findings indicated the ability of the optimized LNC formulation to improve the drug bioavailability after its transdermal application.

Formulation and Characterization of Fast-Dissolving Sublingual Film of Iloperidone Using Box-Behnken Design for Enhancement of Oral Bioavailability

Iloperidone is a second-generation antipsychotic drug which is used for the treatment of schizophrenia and has very low aqueous solubility and bioavailability. This drug also undergoes first-pass metabolism. The aim of this work is to formulate fast-dissolving sublingual films of iloperidone to improve its bioavailability. Sublingual films were prepared by solvent casting method. Hydroxypropyl methyl cellulose E5, propylene glycol 400, and transcutol HP were optimized using Box-Behnken three-level statistical design on the basis of disintegration time and folding endurance of films. Iloperidone:hydroxypropyl-β-cyclodextrin kneaded complex was used in films instead of plain drug due to its low solubility. Optimized film was further evaluated for drug content, pH, dissolution studies, ex vivo permeation studies, and pharmacokinetic studies in rats. The optimized film disintegrated within 30 s. The in vitro dissolution of the film showed 80.3 ± 3.4% drug dissolved within first 5 min. In ex vivo permeation studies using sublingual tissue, flux achieved within first 15 min by film was around 117.1 ± 0.35 (mcg/cm²/h) which was ten times more than that of plain drug. This formulation showed excellent uniformity. AUC and C_max of film were significantly higher (p < 0.001) as compared to plain drug and relative bioavailability of the films was 148% when compared to the plain drug. Thus, this study showed optimized fast-dissolving sublingual film to improve permeation and bioavailability of iloperidone. Fast-dissolving films will be customer-friendly approach for geadiatric schizophrenic patients.

Transdermal agomelatine microemulsion gel: pyramidal screening, statistical optimization and in vivo bioavailability

Agomelatine is a new antidepressant having very low oral drug bioavailability less than 5% due to being liable to extensive hepatic 1st pass effect. This study aimed to deliver agomelatine by transdermal route through formulation and optimization of microemulsion gel. Pyramidal screening was performed to select the most suitable ingredients combinations and then, the design expert software was utilized to optimize the microemulsion formulations. The independent variables of the employed mixture design were the percentages of capryol 90 as an oily phase (X1), Cremophor RH40 and Transcutol HP in a ratio of (1:2) as surfactant/cosurfactant mixture 'Smix' (X2) and water (X3). The dependent variables were globule size, optical clarity, cumulative amount permeated after 1 and 24 h, respectively (Q1 and Q24) and enhancement ratio (ER). The optimized formula was composed of 5% oil, 45% Smix and 50% water. The optimized microemulsion formula was converted into carbopol-based gel to improve its retention on the skin. It enhanced the drug permeation through rat skin with an enhancement ratio of 37.30 when compared to the drug hydrogel. The optimum ME gel formula was found to have significantly higher Cmax, AUC 0-24 h and AUC0-∞ than that of the reference agomelatine hydrogel and oral solution. This could reveal the prosperity of the optimized microemulsion gel formula to augment the transdermal bioavailability of agomelatine.

Optimizing Prednisolone Loading into Distiller's Dried Grain Kafirin Microparticles, and In vitro Release for Oral Delivery

Kafirin microparticles have potential as colon-targeted delivery systems because of their ability to protect encapsulated material from digestive processes of the upper gastrointestinal tract (GIT). The aim was to optimize prednisolone loading into kafirin microparticles, and investigate their potential as an oral delivery system. Response surface methodology (RSM) was used to predict the optimal formulation of prednisolone loaded microparticles. Prednisolone release from the microparticles was measured in simulated conditions of the GIT. The RSM models were inadequate for predicting the relationship between starting quantities of kafirin and prednisolone, and prednisolone loading into microparticles. Compared to prednisolone released in the simulated gastric and small intestinal conditions, no additional drug release was observed in simulated colonic conditions. Hence, more insight into factors affecting drug loading into kafirin microparticles is required to improve the robustness of the RSM model. This present method of formulating prednisolone-loaded kafirin microparticles is unlikely to offer clinical benefits over commercially available dosage forms. Nevertheless, the overall amount of prednisolone released from the kafirin microparticles in conditions simulating the human GIT demonstrates their ability to prevent the release of entrapped core material. Further work developing the formulation methods may result in a delivery system that targets the lower GIT.

Optimization of high pressure machine decocting process for Dachengqi Tang using HPLC fingerprints combined with the Box-Behnken experimental design

Using Dachengqi Tang (DCQT) as a model, high performance liquid chromatography (HPLC) fingerprints were applied to optimize machine extracting process with the Box–Behnken experimental design. HPLC fingerprints were carried out to investigate the chemical ingredients of DCQT; synthetic weighing method based on analytic hierarchy process (AHP) and criteria importance through intercriteria correlation (CRITIC) was performed to calculate synthetic scores of fingerprints; using the mark ingredients contents and synthetic scores as indicators, the Box–Behnken design was carried out to optimize the process parameters of machine decocting process under high pressure for DCQT. Results of optimal process showed that the herb materials were soaked for 45 min and extracted with 9 folds volume of water in the decocting machine under the temperature of 140 °C till the pressure arrived at 0.25 MPa; then hot decoction was excreted to soak Dahuang and Mangxiao for 5 min. Finally, obtained solutions were mixed, filtrated and packed. It concluded that HPLC fingerprints combined with the Box–Behnken experimental design could be used to optimize extracting process of traditional Chinese medicine (TCM).