D-Optimal Mixture Design: Optimization of Ternary Matrix Blends for Controlled Zero-Order Drug Release From Oral Dosage Forms

D-optimal mixture design optimized solid formulation containing fruits extracts of Momordica charantia and Abelmoschus esculentus

Fruit extracts of Momordica charantia L. (Cucurbitaceae) and Abelmoschus esculentus (L.) Moench (Malvaceae) have shown promising antidiabetic activities in clinical trials. However, they remain underutilized due to insufficient standardization and lack of formulation containing their mixture. This study’s overall purpose was to develop and optimize a capsule dosage form containing dried fruit extracts of M. charantia and A. esculentus. The design of the experiment involved two steps; first, response surface methodology (RSM) with a five-level two-factor central composite rotatable design (CCRD) was employed to determine the optimal dose of a mixture of extracts for adequate glycemic control. The extract of M. charantia and A. esculentus were the independent variables while fasting plasma glucose (FPG) was the dependent factor. In the second step, a D-optimal mixture design was applied to study the interaction effect of the optimal dose and selected excipients on granules flowability and capsules’ disintegration time. Moreover, a second-order quadratic model determined the interrelationship of excipients and the desired capsules’ quality attributes. The validity of the predicted models was confirmed. The findings indicated that a combined dose of 175 A. esculentus and 281 M. charantia (mg/kg) significantly reduced the FPG level compared to vehicle at day 14 (mean difference -2.7 ± 0.21, p < 0.001). This dose was used to make a 600 mg capsule (DM083) with 76% drug loading. The DM083 had 40.4 ± 0.62 mg GAE/gDW total polyphenols, 12 peaks HPLC fingerprint, and 26.6 ± 4.75 min average disintegration time. Together, these findings showed that a mixture of M. charantia and A. esculentus fruit extracts could be formulated in a stable capsule dosage form with acceptable quality standards. Further biological studies such as toxicity assays and long-term efficacy studies of the developed capsules could be carried out before large-scale commercial production.

Multiple-reaction monitoring (MRM) LC-MS/MS quantitation of venlafaxine and its O-desmethyl metabolite for a preclinical pharmacokinetic study in rabbits

Preclinical pharmacokinetic (PK) studies in animal models during the formulation development phase give preliminary evidence and near clear picture of the PK behavior of drug and/or its dosage forms before clinical studies on humans and help in the tailoring of the dosage form according to the expected and requisite clinical behavior. The present work reports a first of its kind preclinical PK study on extended-release (ER) solid oral dosage forms of venlafaxine (VEN) in New Zealand White rabbits. The VEN is a highly prescribed and one of the safest and most effective therapeutic agents used in the treatment of different types of depression disorders worldwide. The multiple-reaction monitoring (MRM) LC–MS/MS method developed for this purpose demonstrated enough reliability in simultaneously quantitating VEN and its equipotent metabolite O-desmethylvenlafaxine (ODV) in rabbit plasma. The method described uses solid-phase extraction for sample preparation followed by an ultrafast LC–MS/MS analysis. The chromatographic separation was achieved isocratically with a predominantly polar mobile phase by employing RPLC. The triple quadrupole LC/MS/MS system operated in MRM mode used an ESI probe as an ion source in positive polarity. The validation results are within the permissible limits of US FDA recommendations and acceptance criteria for bioanalytical method validation.

Supersaturated LFCS type III self-emulsifying delivery systems of sorafenib tosylate with improved biopharmaceutical performance: QbD-enabled development and evaluation

The current studies investigate the application of quality by design-enabled type III self-emulsifying delivery system (Type III-SEDDS) of sorafenib tosylate (SFN) in improving its biopharmaceutical attributes. Initially, lipidic and emulsifying excipients were selected by carrying out solubility and phase titration experiments. After screening studies using Taguchi OA design, Type III-SEDDS were further optimised using D-optimal mixture design. The prepared formulations were assessed for globule size, zeta potential and percent of drug release. Following graphical optimisation, the optimum formulation was earmarked and further supersaturated to form saturated Type III-SEDDS (Sat-Type III-SEDDS) using a combination of HPMC and PVP to improve the stability of the formulation for a prolonged period. In vitro drug release of Type III-SEDDS study indicated approximately 8-fold improvement in dissolution rate over the pure powder drug. Cell uptake studies demonstrated higher uptake of dye-loaded Type III-SEDDS formulations in Caco-2 cells vis-à-vis plain dye. Cytotoxicity assay on Hep G2 cells revealed significant reduction in cell growth with Type III- and Sat-Type III-SEDDS vis-à-vis the pure drug. Furthermore, in situ permeation studies carried out using Wistar rats exhibited nearly 8.3- to 10.2-fold augmentation in permeation and absorption parameters of the drug from the Type III- and Sat-Type III-SEDDS, respectively, vis-à-vis the pure drug. Pharmacokinetic studies indicated nearly 3.98- and 3.62-fold improvement in AUC_0-72, and 8.01- and 5.42-fold in C_max, along with 0.25-fold decrease in T_max of the drug from Type III- and Sat-Type III-SEDDS, respectively, in comparison with the SFN suspension. Furthermore, high degree of level A linear correlation was established between fractions of drug dissolved (in vitro) and of drug absorbed (in vivo) at the corresponding time points for Sat-Type III-SEDDS and pure drug, whereas the Type III-SEDDS exhibited a nonlinear relationship. Stability studies indicated the robustness of Sat-Type III-SEDDS, when stored at 25 °C for 3 months. Overall, the manuscript documents the successful systematic development of SFN-loaded Sat-Type III-SEDDS with distinctly improved biopharmaceutical performance. Graphical abstract.

Design and optimization of a probiotic tablet for gastrointestinal tolerance by a simplex-centroid mixture

In this study, a simplex-centroid mixture design using design of experiment (DOE) software was implemented to evaluate the effect of biopolymers as excipients, which are hydroxypropyl methylcellulose, and alginate, on the gastrointestinal tolerance of probiotic tablet containing Saccharomyces boulardii. Microbial viability and dissolution time were used to evaluate the ideal formulation made using 39.01% carboxymethylcellulose and 60.99% alginate as excipients, which protected the probiotics from the acidic condition in the stomach with good dissolution time. The formulated probiotic tablet is more stable in terms of viability when stored at 4 °C compared to room temperature. However, the viability remains above 10⁶ CFU/tablet after six months of storage at room temperature. This study shows that the simplex-centroid mixture design is valid and can be used to formulate probiotic tablets that possess gastrointestinal tolerance. This study can lead to the development of commercial production of probiotic yeast tablets with gastrointestinal tolerance.

Optimization of maize-millet based soy fortified composite flour for preparation of RTE extruded products using D-optimal mixture design

Formulation of composite flour comprising of maize (MF), finger millet (FM), defatted soy (DS) and elephant foot yam (YP) was carried out for the preparation of extruded product. The proportion of three major ingredients was varied as maize: 40-55%, finger millet: 20-30%, defatted soy: 10-25% and that of YP was kept constant as 10%. In all 16 experiments were conducted by D-optimal mixture design keeping the upper and lower values of ingredients in the range given above. Extruded products were developed by using twin screw extruder (BTPL lab model) at barrel temperature 100 °C, screw speed 300 rpm and feed moisture content 15% (wb). Physical and functional properties like expansion ratio (ER), bulk density (BD), hardness, water absorption index (WAI) and water solubility index (WSI) of extruded products were analyzed. Composite flour was optimized on the basis of physical and functional properties of extruded products. The values of ER, BD, hardness, WAI and WSI of extruded products were in the range of 2.42-3.30, 0.14-0.26 g cm^-3, 11.15-18.67 N, 5.57-6.87 g g^-1 and 14.42-19.95%, respectively. Variations in proportion of ingredients in the composite blend significantly affected ER, BD, hardness, WAI and WSI of the product. The regression models for ER, BD, hardness, WAI and WSI were developed to explain the effect of ingredients on the response variables. A blend of ingredients in the ratio of 40:30:20:10 (MF:FM:DS:YP) was found to be optimum with a desirability function of 0.82 which resulted extrudate attributes of ER 3.29, BD 0.14 g cm^-3, hardness 11.94 N, WAI 6.13 g g^-1 and WSI 17.07%.

Multivariate Statistical Optimization of Tablet Formulations Incorporating High Doses of a Dry Herbal Extract

The development of oral tablet formulation for herbal medicines has been restricted by large drug loadings and the poor physicochemical and mechanical properties of dry herbal extracts (DHEs). Herein, statistical experimental designs were applied to herbal tablet formulation development and optimization using Wuzi Yanzong dry extract (WYE). The tablet disintegration time and hardness were identified as the critical quality attributes (CQAs) of the product. The tablet formulation was designed to achieve a high drug loading (50% or higher of WYE), shorter tablet disintegration time (less than 30 minutes), and suitable hardness (6.0 to 7.5 kp). A D-optimal mixture design was used to evaluate the effects of excipients on CQAs to minimize the risk compression failure and improve the tabletability in formulations containing WYE at 50% and 65% by weight. A partial least squares model was used to elucidate the multivariate relationships between a large number of formulation variables and product CQAs, and determine the maximum possible WYE loading. From overlaid plots of the effects of formulation variables on CQAs, it was found that a maximum WYE loading of 67% in tablet formulation satisfied the acceptance criteria of CQAs. In conclusion, this study shows that multivariate statistical tools are useful for developing tablet formulations containing high doses of herbal extracts and establishing control strategies that ensure product quality.

A Modified Particle Swarm Optimization Technique for Finding Optimal Designs for Mixture Models

Particle Swarm Optimization (PSO) is a meta-heuristic algorithm that has been shown to be successful in solving a wide variety of real and complicated optimization problems in engineering and computer science. This paper introduces a projection based PSO technique, named ProjPSO, to efficiently find different types of optimal designs, or nearly optimal designs, for mixture models with and without constraints on the components, and also for related models, like the log contrast models. We also compare the modified PSO performance with Fedorov's algorithm, a popular algorithm used to generate optimal designs, Cocktail algorithm, and the recent algorithm proposed by [1].

Combined application of mixture experimental design and artificial neural networks in the solid dispersion development

This study for the first time demonstrates combined application of mixture experimental design and artificial neural networks (ANNs) in the solid dispersions (SDs) development. Ternary carbamazepine-Soluplus®-poloxamer 188 SDs were prepared by solvent casting method to improve carbamazepine dissolution rate. The influence of the composition of prepared SDs on carbamazepine dissolution rate was evaluated using d-optimal mixture experimental design and multilayer perceptron ANNs. Physicochemical characterization proved the presence of the most stable carbamazepine polymorph III within the SD matrix. Ternary carbamazepine-Soluplus®-poloxamer 188 SDs significantly improved carbamazepine dissolution rate compared to pure drug. Models developed by ANNs and mixture experimental design well described the relationship between proportions of SD components and percentage of carbamazepine released after 10 (Q10) and 20 (Q20) min, wherein ANN model exhibit better predictability on test data set. Proportions of carbamazepine and poloxamer 188 exhibited the highest influence on carbamazepine release rate. The highest carbamazepine release rate was observed for SDs with the lowest proportions of carbamazepine and the highest proportions of poloxamer 188. ANNs and mixture experimental design can be used as powerful data modeling tools in the systematic development of SDs. Taking into account advantages and disadvantages of both techniques, their combined application should be encouraged.

Comparative evaluation of drug release from aged prolonged polyethylene oxide tablet matrices: effect of excipient and drug type

Polyethylene oxide (PEO) undergoes structural adjustments caused by elevated temperatures, which results in loss of its stability within direct compression tablets. The aim of this study was to evaluate the influence of filler solubility on the drug delivery process of matrix tablets containing drugs with different water-solubility properties and stored at elevated temperature. The results demonstrated that in the case of propranolol HCl (highly water-soluble) tablet matrices, soluble lactose promoted drug release, whereas, a stable release of drug was observed with insoluble DCP. A drug release pattern similar to the propranolol HCl formulation containing DCP was obtained for hydrophilic matrix tablets containing either lactose or DCP for the less water-soluble drug, zonisamide. In the case of the partially water-soluble drug, theophylline, formulated with lower molecular weight PEO 750, drug release increased considerably in the presence of both fillers with increasing storage time, however a stable release rate (similar to fresh samples) was observed in the case of higher molecular weight PEO 303 tablet matrices containing theophylline with either lactose or DCP. The hydration properties (e.g. solubility) of the diluents had a considerable effect on drug release behavior from various model matrices; this effect was dependent on both molecular weight of PEO and solubility of drug.

Curcumin-loaded solid lipid nanoparticles with Brij78 and TPGS improved in vivo oral bioavailability and in situ intestinal absorption of curcumin

PURPOSE

The present study was to formulate curcumin solid lipid nanoparticles (Cur-SLNs) with P-gp modulator excipients, TPGS and Brij78, to enhance the solubility and bioavailability of curcumin.

METHODS

The formulation was optimized by Plackett-Burman screening design and Box-Behnken experiment design. Then physiochemical properties, entrapment efficiency and in vitro release of Cur-SLNs were characterized. In vivo pharmacokinetics study and in situ single-pass intestinal perfusion were performed to investigate the effects of Cur-SLNs on the bioavailability and intestinal absorption of curcumin.

RESULTS

The optimized formulations showed an average size of 135.3 ± 1.5 nm with a zeta potential value of -24.7 ± 2.1 mV and 91.09% ± 1.23% drug entrapment efficiency, meanwhile displayed a sustained release profile. In vivo pharmacokinetic study showed AUC0→t for Cur-SLNs was 12.27-folds greater than curcumin suspension and the relative bioavailability of Cur-SLNs was 942.53%. Meanwhile, Tmax and t(1/2) of curcumin for Cur-SLNs were both delayed comparing to the suspensions (p < 0.01). The in situ intestinal absorption study revealed that the effective permeability (Peff) value of curcumin for SLNs was significantly improved (p < 0.01) comparing to curcumin solution.

CONCLUSION

Cur-SLNs with TPGS and Brij78 could improve the oral bioavailability and intestinal absorption of curcumin effectively.

Optimization of primaquine diphosphate tablet formulation for controlled drug release using the mixture experimental design

A tablet formulation based on hydrophilic matrix with a controlled drug release was developed, and the effect of polymer concentrations on the release of primaquine diphosphate was evaluated. To achieve this purpose, a 20-run, four-factor with multiple constraints on the proportions of the components was employed to obtain tablet compositions. Drug release was determined by an in vitro dissolution study in phosphate buffer solution at pH 6.8. The polynomial fitted functions described the behavior of the mixture on simplex coordinate systems to study the effects of each factor (polymer) on tablet characteristics. Based on the response surface methodology, a tablet composition was optimized with the purpose of obtaining a primaquine diphosphate release closer to a zero order kinetic. This formulation released 85.22% of the drug for 8 h and its kinetic was studied regarding to Korsmeyer-Peppas model, (Adj-R(2) = 0.99295) which has confirmed that both diffusion and erosion were related to the mechanism of the drug release. The data from the optimized formulation were very close to the predictions from statistical analysis, demonstrating that mixture experimental design could be used to optimize primaquine diphosphate dissolution from hidroxypropylmethyl cellulose and polyethylene glycol matrix tablets.

Process optimization and evaluation of novel baicalin solid nanocrystals

The objective of this study was to prepare baicalin solid nanocrystals (BCN-SNS) to enhance oral bioavailability of baicalin. A Box–Behnken design approach was used for process optimization. The physicochemical properties and pharmacokinetics of the optimal BCN-SNS were investigated. Multiple linear regression analysis for process optimization revealed that the fine BCN-SNS was obtained wherein the optimal values of homogenization pressure (bar), homogenization cycles (cycles), amount of TPGS to drug (w/w), and amount of MCCS to drug (w/w) were 850 bar, 25 cycles, 10%, and 10%, respectively. Transmission electron microscopy and scanning electron microscopy results indicated that no significant aggregation or crystal growth could be observed in the redispersed freeze-dried BCN-SNS. Differential scanning calorimetry and X-ray diffraction results showed that BCN remained in a crystalline state. Dissolution velocity of the freeze-dried BCN-SNS powder was distinctly superior compared to those of the crude powder and physical mixture. The bioavailability of BCN in rats was increased remarkably after oral administration of BCN-SNS (P < 0.05), compared with those of BCN or the physical mixture. The SNS might be a good choice for oral administration of poorly soluble BCN, due to an improvement of the bioavailability and dissolution velocity of BCN-SNS.

Development and optimization of solid lipid nanoparticle formulation for ophthalmic delivery of chloramphenicol using a Box-Behnken design

The purpose of the present study was to optimize a solid lipid nanoparticle (SLN) of chloramphenicol by investigating the relationship between design factors and experimental data using response surface methodology. A Box-Behnken design was constructed using solid lipid (X₁), surfactant (X₂), and drug/lipid ratio (X₃) level as independent factors. SLN was successfully prepared by a modified method of melt-emulsion ultrasonication and low temperature-solidification technique using glyceryl monostearate as the solid lipid, and poloxamer 188 as the surfactant. The dependent variables were entrapment efficiency (EE), drug loading (DL), and turbidity. Properties of SLN such as the morphology, particle size, zeta potential, EE, DL, and drug release behavior were investigated, respectively. As a result, the nanoparticle designed showed nearly spherical particles with a mean particle size of 248 nm. The polydispersity index of particle size was 0.277 ± 0.058 and zeta potential was −8.74 mV. The EE (%) and DL (%) could reach up to 83.29% ± 1.23% and 10.11% ± 2.02%, respectively. In vitro release studies showed a burst release at the initial stage followed by a prolonged release of chloramphenicol from SLN up to 48 hours. The release kinetics of the optimized formulation best fitted the Peppas–Korsmeyer model. These results indicated that the chloramphenicol-loaded SLN could potentially be exploited as a delivery system with improved drug entrapment efficiency and controlled drug release.

Optimization by Response Surface Methodology of Confluent and Aligned Cellular Monolayers for Nerve Guidance

Anisotropic tissue structures provide guidance for navigating neurons in vitro and in vivo. Here we optimized the generation of comparable anisotropic monolayers of astrocytes, endothelial cells, and Schwann cells as a first step toward determining which properties of anisotropic cells are sufficient for nerve guidance. The statistical experimental design method Design of Experiments and the experimental analysis method Response Surface Methodology were applied to improve efficiency and utility. Factors investigated included dimensions of microcontact printed protein patterns, cell density, and culture duration. Protein patterning spacing had the strongest influence. When cells initially aligned at borders and proliferated to fill in spaces, space between stripes was most effective when it was comparable to cell size. Maximizing the area of adhesive molecule coverage was also important for confluence of these types of cells. When cells adhered and aligned over the width of a stripe and broadened to fill spaces, space width about half the cell width was most effective. These findings suggest that if the mechanism of alignment, alignment at borders or over the width of the stripe, is predetermined and the cell size determined, the optimal size of the micropatterning for aligned monolayers of other cell types can be predicted. This study also demonstrates the effective use of DOE and RSM to probe cellular responses to various and multiple factors toward determination of optimal conditions for a desired cellular response.

Development and optimization of a sublingual tablet formulation for physostigmine salicylate

This study is aimed to design and optimize a sublingual tablet formulation of physostigmine salicylate, an effective drug in Alzheimer's disease and nerve gas poisoning, by means of the D-optimal experimental design methodology. Polyvinyl pyrrolidone, lactose, starch 1500 and sodium starch glycolate were used in the formulations as independent variables. Tablets were prepared by the direct compression method and evaluated for their physical properties (tablet hardness, disintegration time and friability), which were regarded as responses in a D-optimal design. Due to the significance of the special cubic model for data fitted, compared to other models, it was used to examine the obtained results. Response surface plots were plotted to study the tablet properties and the optimized overlay plot was generated based on the results and targets considered for the responses. After verification of the optimum checkpoint formulations, an optimized formulation was chosen due to its desirable physical properties and closely observed and predicted values. Drug assay, content uniformity of the dosage unit, drug dissolution and accelerated stability studies were done on the optimum formulation as further experiments. All the obtained results complied with the requirements of a sublingual tablet formulation.

Fluid bed coating: the utility of dual programmable pumps for controlled gradient drug deposition on pellets

The objective of this study was to demonstrate the potential use of dual programmable pumps in a fluid bed coating process to manufacture pellets coated with gradient layers of a drug. To achieve this goal, two matrix forming dispersions with an equivalent amount of solids, one containing verapamil HCl as a model drug, and the other without the drug, were forced in a gradient pattern into a fluid bed coater using two pumps joined at Y junction. The two pumps were operated at opposing flow rates via a computer guided program to maximize drug concentration in the inner layers around the core. The difference between gradient and non-gradient drug coating was demonstrated by dissolution studied. Depending on the drug to polymer ratio, verapamil HCl release from gradient layered pellets was delayed over an extended period of time and was significantly different from the non-gradient coated pellets.

A novel texture-probe for the simultaneous and real-time measurement of swelling and erosion rates of matrix tablets

In this note, a novel probe fitted to a texture analyzer was described. This probe has the ability to simultaneously measure, in real-time, dimensional changes in the swollen layer and the glassy core of hydrophilic matrices when exposed to aqueous dissolution media. The utility of this probe was demonstrated on directly compressed tablets containing polymer blends, a water soluble additive, and theophylline as a model drug. Both the erosion and swelling fronts were measured for the same tablet every hour for 12 h. The probe provided accurate thickness data of the swollen region and the glassy core, and was able to demonstrate the swelling and subsequent erosion of the tablet with time. With this method, it is possible to simultaneously measure the swelling rate of the rubbery region and the erosion rate of the glassy core without operator intervention, which provides many advantages over the conventional approaches frequently reported in the literature.