Concept of Orodispersible or Mucoadhesive “Tandem Films” and Their Pharmaceutical Realization

Orodispersible or mucoadhesive films as a patient-oriented dosage form for low-dosed drugs are usually produced using solvent casting. This paper presents a modification of the solvent casting technique that aimed to divide oral films into two or more compartments. The proposed objectives and fields of applications include improved handling properties and safety of application, the optimization of drug release kinetics and the enhancement of long-term stability when combining two or more active pharmaceutical ingredients into one oral film. A feasibility study for the combination of different film-forming polymers to generate the so-called tandem films was performed. As examples of practical implementation, orodispersible applicator films consisting of a drug-loaded section and a handheld piece were cast, and mucoadhesive buccal tandem films were cast to optimize the dissolution rate of the films.

Development of Bilayer Tablet Containing Saxagliptin Immediate Release and Metformin Sustained Release Using Quality by Design Approach

Objective:

Adequate glycemic control in diabetes patients requires oral combination therapy. Saxagliptin is a dipeptidyl peptidase-4 inhibitor having fewer adverse effects, and metformin is the first-line medicine for diabetes treatment. The aim of this research work is to develop a bilayer tablet of saxagliptin and metformin in fixed-dose combination (FDC) using quality by design (QbD) to acquire the immediate release of saxagliptin and sustained release of metformin from bilayer tablet to ultimately achieve superior patient compliance.

Methods:

The development of the bilayer tablet was done in four stages using QbD. In the first step, quality target product profile (QTPP) of bilayer tablet was defined, and critical quality attributes (CQAs) were identified by risk estimation matrix and taguchi design; an immediate release saxagliptin layer was optimized in the second step, optimization of sustained-release metformin layer was carried out in the third step, and in the final step, bilayer tablet was prepared and characterized. The effect of independent parameters, i.e., magnesium stearate level (X1), kneading time (X2) and lubrication time (X3) on Carr’s Index (Y1), percentage relative standard deviation of content uniformity (Y2) and drug release at 30 minutes (Y3), were estimated for optimization of immediate release saxagliptin layer using Box-Behnken design (BBD). The effect of independent parameters, i.e., hydroxypropyl methylcellulose level (X4), compritol level (X5) and magnesium stearate level (X6) on Carr’s Index (Y4), drug release at 2 h (Y5), drug release at 5 h (Y6) and drug release at 10 h (Y7) were estimated for optimization of sustained-release metformin layer using BBD.

Results:

The optimized composition of immediate release saxagliptin layer estimated using numerical optimization by Design expert was 0.88% (X1), 15 minutes (X2) and 3.85 minutes (X3) with predicted variables, i.e., 10.59% (Y1), 3.16% (Y2) and 85% (Y3). The optimized composition of sustained- release saxagliptin layer predicted through numerical optimization was 30% (X4), 3.36% (X5) and 0.9% (X6) having 10.89% (Y4), 43.44% (Y5), 60% (Y6) and 85.14% (Y7). In-vitro dissolution study of bilayer tablet showed immediate release of Saxagliptin (approximately 85% in 30 minutes) and sustained release of metformin illustrating 43.21±1.21, 60.86±2.96 and 86.26±1.38% drug release at 2, 5 and 10 h, respectively. The release exponent for the Korsmeyer-Peppas model for Saxagliptin and metformin was 0.237 (<0.45) and 1.536 (n>0.85), indicating Fickian and super case II transport drug release behavior, respectively.

Conclusion:

By QbD approach, bilayer tablet containing saxagliptin and metformin was successfully developed, and influence of various formulation parameters on CQAs of drug products was understood with fewer experiments. This leads to the conclusion that cost can be reduced using QbD in the development of FDC for improving patient compliance.

Impact of Insoluble Separation Layer Mechanical Properties on Disintegration and Dissolution Kinetics of Multilayer Tablets

Dissolution and disintegration of solid dosage forms such as multiple-layer tablet with different active ingredients depend on formulation and properties used in the formulations, and it may sometimes result in counterintuitive release kinetics. In this manuscript, we investigate the behavior of combined acetylsalicylic acid and mefenamic acid bi- and triple-layer formulations. We show that the simulation model with a cellular automata predicted the impact of the inert layer between the different active ingredients on each drug release and provide a good agreement with the experimental results. Also, it is shown that the analysis based on the Noyes–Whitney equation in combination with a cellular automata-supported dissolution and disintegration numerical solutions explain the nature of the unexpected effects. We conclude that the proposed simulation approach is valuable to predict the influence of material attributes and process parameters on drug release from multicomponent and multiple-layer pharmaceutical tablets and to help us develop the drug product formulation.

Challenges in technology of bilayer and multi-layer tablets: a mini-review

Bilayer and multi-layer tablets are enjoying growing popularity among original drug and generic product manufacturers. Multi-layer tablets have many key benefits compared to classic immediate-release tablets. The use of such solid oral dosage forms simplifies dosing regimens in combination therapy, and thus improves patient compliance. However, the technology of multilayer tablets is demanding and requires precise choice of excipients and production parameters with regard to each technological step. The main benefits of multi-layer tablets, certain aspects of their production and the challenges encountered during the compression process are reviewed in this paper.

Interfacial bonding in formulated bilayer tablets

To take full advantage of the drug delivery benefits offered by bilayer tablets, the common issue of weak interfacial bonding strength (IBS) with manufacturing must be overcome. This work seeks to characterize the effects of composition in individual layers and compaction pressure on the IBS. Mixtures of MCC and lactose in different ratios with and without HPMC were used where the first layer was compacted with two different pressures (20 and 100 MPa) followed by a second layer compaction pressure of 200 MPa. After identifying the failure mode as either at the interface or within a layer, the complex trends of bilayer tablet IBS as a function of MCC content were explained by considering the interplay between particle bonding strength and bonding area at the interface.

Optimized chronomodulated dual release bilayer tablets of fexofenadine and montelukast: quality by design, development, and in vitro evaluation

Background

The conventional oral dosage forms are not effective in dealing with chronopathological conditions, such as nocturnal asthma. Therefore, there is an unmet need to develop a delivery system that can deliver drug as per the chronopharmacology of the diseases. The purpose of the study is to use quality by design (QbD) technique and pulsatile principles for the development of Eudragit-coated dual release bilayer tablets. The dual layer consists of immediate release layer of fexofenadine HCl and sustained release layer of montelukast sodium.

Results

The quality target product profile of the formulation was developed, and the critical quality attributes were identified. Three-level, three-factor Box-Behnken design was used for the optimization of the bilayer tablets. Based on the design, a total of 13 formulation combinations (F1–F13 and M1–M13) were made having acceptable micromeritic properties. The developed immediate and sustained release layers were evaluated for physicochemical properties. Depending upon the value of the diffusion exponent, the Fickian diffusion mechanism is dominant among immediate and sustained release tablet layers. Response curve for immediate release layer showed that concentrations of sodium starch glycolate and sodium bicarbonate had a negative effect on disintegration time and a positive effect on drug release. For sustained release tablet layer, concentrations of HPMC E 5 LV and magnesium stearate had a significant effect on drug release. The ANOVA and diagnostic plots confirmed the significance and goodness of fit of the used model. Based on desirability plot values, optimized formulation was developed and coated with Eudragit coat. The coated bilayer tablet showed met the requirement of providing an immediate release during the first hour and a sustained release action for a period of more than 8 h after passing the gastric region.

Conclusions

The formulation can be fruitful in curbing the menace of nocturnal asthma and providing a high degree of patient compliance as the patient will not have to wake up at night to take the medication.

Bilayer Tablet Dissolution Kinetics Based on a Degassing Cyclic Flow UV-Vis Spectroscopy with Chemometrics

Dissolution kinetics of a bilayer direct compress tablet was evaluated by using degassing cyclic flow UV-visible (Vis) spectroscopy with chemometrics. The model bilayer nicotinamide (NA)-pyridoxine hydrochloride (PH) 100.0 mg tablets were prepared via the dual compress method. The fast diffusion layer of the bilayer tablet contained nicotinamide, microcrystal cellulose, beta-lactose, magnesium stearate, and croscarmellose sodium. The slow release layer contained pyridoxine hydrochloride and carnauba wax. The monolayer direct compress tablets were prepared as dual ingredient (API)s formulation tablets. The degassing cyclic flow UV-Vis spectroscopy dissolution test was carried out using the prepared tablets. The dissolution test conditions were as follows: time, 60 min; temperature, 37°C; paddle method, 50 rpm, and UV-Vis spectra measurement 1 time/min. The UV-Vis spectra of the flow solution were measured in the range of 240-380 nm. API concentration was predicted by partial least squares (PLS) regression models based on UV-Vis spectra. The dissolution kinetics of the bilayer and monolayer tablets were evaluated based on the UV-Vis spectra with the predicted API concentration profile. The degassing flow system could prevent air bubbles in the flow cell at 1800 min. Therefore, simultaneous determination of NA and PH concentration based on the PLS regression was suggested to have high accuracy. PLS regression has advantages over the conventional λ_max absorbance method of simultaneous determination. We found that the kinetics of the separated bilayer tablet can be evaluated by the same kinetic analysis method used for the single layer model tablet.

Sustained Release Bilayer Tablet of Ibuprofen and Phenylephrine Hydrochloride: Preparation and Pharmacokinetics in Beagle Dogs

Cold is a global common infectious disease accompanied by symptoms such as headache and stuffy nose. Ibuprofen (IBU) and phenylephrine hydrochloride (PE) were commonly used for common cold due to their different effects in relieving fever and the main symptoms such as nasal congestion and high sinus pressure. However, the commercial tablets of IBU and PE have to be administered 2 to 3 times per day due to their short half-life, with inconvenience for patient and fluctuations of plasma concentration. Bilayer tablet technology was utilized to design the IBU-PE sustained release tablets because of the significantly different solubility of IBU and PE in release media. The formulations of IBU layer and PE layer contain different viscosity grades of hydroxypropyl methylcellulose (HPMC) as sustained-release matrix, hydrophilic diluent, and traditional glidant and lubricant. The sustained release bilayer tablet exhibited satisfying sustained release performance with the mechanisms of diffusion and matrix erosion. Compared with the conventional tablets, the IBU-PE sustained release bilayer tablet expressed significantly sustained-release behavior with decreased C_max and prolonged T_max in fasted conditions for IBU and PE. Though IBU of IBU-PE sustained release bilayer tablet was bioequivalent to the commercial IBU tablet, the relative bioavailability of PE from the bilayer tablets was 87.49 ± 20.00% (90% confidence interval was 72.3 to 102.5%), indicating bioinequivalence probably due to the "first pass" effect.

Oral drug delivery systems comprising altered geometric configurations for controlled drug delivery

Recent pharmaceutical research has focused on controlled drug delivery having an advantage over conventional methods. Adequate controlled plasma drug levels, reduced side effects as well as improved patient compliance are some of the benefits that these systems may offer. Controlled delivery systems that can provide zero-order drug delivery have the potential for maximizing efficacy while minimizing dose frequency and toxicity. Thus, zero-order drug release is ideal in a large area of drug delivery which has therefore led to the development of various technologies with such drug release patterns. Systems such as multilayered tablets and other geometrically altered devices have been created to perform this function. One of the principles of multilayered tablets involves creating a constant surface area for release. Polymeric materials play an important role in the functioning of these systems. Technologies developed to date include among others: Geomatrix(®) multilayered tablets, which utilizes specific polymers that may act as barriers to control drug release; Procise(®), which has a core with an aperture that can be modified to achieve various types of drug release; core-in-cup tablets, where the core matrix is coated on one surface while the circumference forms a cup around it; donut-shaped devices, which possess a centrally-placed aperture hole and Dome Matrix(®) as well as "release modules assemblage", which can offer alternating drug release patterns. This review discusses the novel altered geometric system technologies that have been developed to provide controlled drug release, also focusing on polymers that have been employed in such developments.

Preparation of lovastatin matrix sustained-release pellets by extrusion-spheronization combined with microcrystal dispersion technique

The poorly water-soluble drug lovastatin (LVA) is an inhibitor of 3-hydroxy-3-methylglutarylcoenzyme A reductase and has a slow dissolution rate. In this study, a microcrystal dispersion (MCD) technique was used in the preparation of LVA to increase its dissolution rate and then combining with an extrusion-spheronization method, microcrystalline cellulose (MCC) matrix sustained-release pellets containing LVA-MCD were developed and characterized in vitro. Photomicrographs indicated that LVA-MCD existed as fine crystals, of which the mean particle size was reduced from 65.75 μm to 3.97 μm and the dried LVA-MCD powders released completely within 2 hours. SEM results during the release process showed that pellets possessed a matrix structure and after the dissolution test, this matrix structure became loose and porous. The release of LVA was fast and complete, and accumulated release by the optimal formulation was: 0.5 h (20.23 ± 3.40%), 2 h (56.87 ± 2.85%), 4 h (78.71 ± 3.42%), and 8 h (96.81 ± 3.30%). The 3 months accelerating test at 40°C and 75% RH demonstrated that drug release of pellets was not changed and drug degradation was less than 1%. Thus, a novel MCD process with MCC matrix was feasible and effective to get complete release without a lag time for the poorly water soluble drug, LVA, with high stability.