An optimized formulation of capsules containing Lansoprazole enteric-coated pellets using D-Optimal design with a polynomial statistical model were prepared by using Eudragit?L100 as an enteric coated polymer to provide resistance to simulated gastric acid dissolution in buffer media. D-Optimal experimental design was used to determine the optimal level for three coating layers that were applied to formulate the enteric-coated pellets including a drug loading layer, a sub-coating, and an outer enteric coating. Dissolution studies were performed on the prepared Lansoprazole capsules. Less than 5 percent of Lansoprazole was released in 60 minutes in an acidic dissolution medium (pH 1.2) and greater than 90 percent of active ingredient was released in the next 60 minutes in a buffer dissolution medium (pH 6.8). The Lansoprazole capsules were stable with no observable change in physico-chemical properties in accelerated and normal storage conditions for 6 and 18 months, respectively. The pharmacokinetic parameters C max, T max, AUC 0-t, and AUC 0-∞ were determined after administration of the D-Optimal design optimized capsules of LPZ to healthy beagle dogs and were statistically compared to Gastevin? capsules as a reference (KRKA, Slovenia) using the non-compartmental method with the aid of WinNonlin 5.2 software. The analysis of variance showed that the two formulations did not demonstrate bioequivalence using a 90% confidence interval range (80% - 120%) of C max, AUC 0-t, and AUC 0-∞. No significant difference in T max was found at the 0.95 significance level using the Wilcoxon signed-rank test. D-Optimal Experimental Design provided definitive direction for an optimal formulation of capsules containing enteric-coated pellets of lansoprazole loaded within the coating of pellets that provided similar bioequivalence to Gastevin.
Lansoprazole (LPZ), a proton pump inhibitor, is a lipophilic weak base with pKa values of 4.15 and 1.33, where the N-H proton in the benzimidazole ring is responsible for the acidity of the molecule (pKa 8.84). LPZ reduces gastric acidity, an important factor in healing acid-related disorders such as gastric ulcers, duodenal ulcers, and reflux esophagitis. It is used to treat gastro-oeesophageal reflux, ulcers, acid-related dyspepsia, and as an adjuvant in the eradication of Helicobacter pylori. It tends to relieve heartburn more effectively than omeprazole at therapeutic dosages [
The formulation challenge concerning a LPZ oral dosage form is the drug’s poor water solubility producing poor absorption that results in low bioavailability. Efforts to improve the solubility of LPZ by utilizing a liquid solid technique, a solid dispersion system, and by spray drying were reported. The liquid solid technique use of Tween 80 as a carrier to increase wetting of the surface area available for enhanced LPZ’s dissolution rate [
Pellets, multi-unit dosage forms, are easy to swallow while maintaining the merits of multiple units, bring about several therapeutic advantages including delayed of drug release, division of dose strength, and rapid distribution in the gastrointestinal tract when administered orally. In addition, a higher degree of flexibility in design and development during delivery of incompatible bioactive agents is also another pharmaceutical benefit of pellets [
The use of Eudragit L30D-55 as an enteric-coating polymer to formulate LPZ enteric-coated pellets, while at the same time using HPMC E5 for its role as a polymer in layering and sub-coating membrane for core pellets, the drug release from these enteric-coated pellets in 0.1 N HCl and in phosphate buffer (pH 6.8) media was 0.71% and 97.87%, respectively. The formulation was stable for 3 months at 40˚C ± 2˚C/75% RH ± 5% [
Currently, applying D-Optimal experimental design to optimize drug release from enteric-coated pellets where the coating layers are impregnated with drug for drug delivery has not been performed. The main purpose of this study was to use D-Optimal experimental design utilizing Modde 5.0 software to formulate and develop a stable, delayed release pellet formulation of LPZ with LPZ incorporated in the pellet coating, which satisfies the requirements of USP XXXV on drug dissolution in the gastrointestinal tract [
LPZ was purchased from Jai Radhe Sales (India). Eudragit®L100 was obtained as a free sample from Evonik (Germany). Lutrol F127 was provided by BASF USA (United States of America). PVA (polyvinyl alcohol) was received from Kuraray Asia Pacific Pte Ltd (Singapore). HPMC (hydroxy-propyl-methyl cellulose) E15 was obtained from Zhejiang Zhongbao (China). TEC (triethyl citrate) was purchased from Cognis (Germany). PEG (polyethylene glycol) 6000 was procured from Sino-Japan Chemical Co Ltd (Taiwan). Titanium dioxide (Titan Dioxide) was obtained from Cosmo (Republic of Korea). Sugar spheres were purchased from Colorcon Asia Pacific Pte Ltd (Singapore). Methanol (MeOH), acetonitrile, triethylamine and tert-butyl methyl ether were HPLC grade and purchased from Merck (Germany) and all other ingredients used were of analytical grade.
Animals and study products: The in vivo study utilized six healthy beagle dogs (between 10 kg and 12 kg in weight). The study protocol was approved by the ethics committee of medicine and pharmacy research at Military Medical University (Hanoi, Vietnam).
Test product: Thirty mg of enteric-coated LPZ loaded pellets in capsules of the optimized formulation were prepared. Reference product: Gastevin® 30 mg capsules were purchased from KRKA (Slovenia) containing LPZ enteric-coated pellets, manufacture date: 02/2013, expiration date: 02/2016.
Drug loading and sub-coating: The adoption of sugar spheres as the core to load a polymer coating of drug onto to formulate the LPZ pellets, and the application of the sub-coating immediately over the drug loaded core pellets after drug loading were performed as follows. The drug coating dispersion and sub coating dispersion with LPZ and other ingredients in each formulation (
Ingredients | Drug loading pellets | Subcoating |
---|---|---|
LPZ (%) | 5.70 | |
HPMC E15 (%) | 2.28 | |
PVA (%) | 0.57 | 5.00 |
PEG 6000 (%) | 1.50 | |
Dibasic sodium phosphate (%) | 5.70 | |
Lutrol F127 (%) | 0.42 | 1.00 |
Titanium dioxide (%) | 2.00 | |
Talc (%) | 2.28 | 2.00 |
pH 6.8 phosphate buffer solution (%) | 100 | 100 |
Sugar spheres (710/850 mesh, g)* | 150 | - |
Lansoprazole loaded pellets (g)* | - | 20 |
(*): Batch size for each experiment, it is not included for calculating the percentage of each ingredient. The percentage of each ingredient is compared to 100 g solvent.
mL/min, and pipe diameter of 1.2 mm for drug loading. Sub-coating was performed with the following parameters: an atomizing pressure of 1.0 bar, an inlet air temperature of 42˚C, an inlet air of 80%, a spray rate of 0.7 mL/min, and pipe diameter of 1.2 mm. The LPZ loaded pellets were coated up to 7.5% weight gain. After finishing coating, pellets were dried for 15 minutes in a fluid bed coating system and stabilized for 24 hour.
Enteric coating: The sub-coated pellets were enteric coated using Eudragit® L100 with a batch size of 20 g. A Wurster fluid bed coating apparatus was used (Caleva mini-fluidized bed coater, England) for 20 different D-Optimal experimental formulations designed by Modde 5.0 software (Umetrics Co., Sweden) for dissolution testing. Dispersions of required quantities of Eudragit®L100, TEC, talc, and titanium dioxide in specified volumes of ethanol and purified water at a ratio of 3:1 (v/v) were prepared. The prepared dispersion was stirred during enteric coating. Coating was performed with the following parameters: an atomizing pressure of 1.2 bar, an inlet air temperature of 43˚C, an inlet air of 80%, a spray rate of 0.8 mL/min, and a pipe diameter of 1.2 mm. After coating, enteric-coated pellets were dried for 15 minutes in a fluid bed coating system and stabilized for 24 hours. The optimal formulation was selected by running the dissolution data through In Form 3.1 optimization software [
Three batches of 3300 capsules (with each capsule containing 30 mg LPZ, equivalent to 1000 g pellets per batch) of the optimal formulation were prepared to evaluate the stability of capsules containing LPZ enteric-coated pellets. The LPZ enteric-coated pellets were filled in hard gelatin capsules using a HanYang HFC45 capsule filling machine (Republic of Korea). The hard gelatin capsules were packed in aluminum blisters using an Uhlmann CP250 blister packing machine (Vietnam).
Spectrophotometric method: Drug content assays were performed in triplicate. An amount of coated pellets equivalent to 50 mg of LPZ was weighed and put into a dry 50-mL volumetric flask. Methanol (MeOH) was used to dissolve the drug under sonication for 15 minutes. Then the samples were centrifuged at 5000 rpm for 10 minutes to assure clarity of the sample for assay. Supernatant was collected and filtered through a 0.45 µm Teflon membrane filter. Filtrate solutions were diluted 100 times with pH 6.8 buffer solution. The assay performed on filtered drug solutions utilized a UV spectrophotometer (Hitachi U-1900, Japan) at 283 nm. The amount of LPZ contained in each formulation was determined using a standard curve prepared from known standard solutions.
HPLC method: Approximately 600 mg of enteric-coated pellets (equivalent to 60 mg of LPZ) were placed into a dry 50-mL volumetric flask where thirty mL of MeOH was added to the enteric-coated pellets to dissolve LPZ from the pellets by sonication for 15 minutes. The sample volume was made up to the mark with MeOH, then thoroughly mixed and centrifuged at 3500 rpm for 15 minutes. A 5 ml sample from the obtained supernatant filtrate solution was diluted to 50 mL with mobile phase, then shaken, filtered through a 0.45-µm Teflon membrane filter and injected into the HPLC system. Chromatographic conditions: The steel column used was RP18 (150 × 4.6 mm; 5 μm), with a steel pre-column (RP18, 4 × 3 mm). Detector PDA was set at 285 nm. The flow-rate was 1 mL/min, and the injection volume was 20 µL. The mobile phase was a mixture of 450:550:2.5 (v/v/v) acetonitrile, water and triethylamine, pH adjusted to 7.0 with phosphoric acid.
The release of LPZ from enteric-coated pellets in the simulated environment of the gastrointestinal tract was determined using the USP XXXV dissolution apparatus II (Erweka equipment with paddle at 37˚C ± 0.5˚C and 75 rpm, Germany).
Acid stage (pH 1.2): LPZ release from pellets having the equivalent of 30-mg LPZ in vessels containing 500 mL of 0.1 N HCl dissolution media was determined after 1 hour. The quantity of drug in the pellets was assayed by HPLC or spectrophotometric method as follows:
HPLC method: The medium was drained without losing the pellets; HPLC method outlined above was used for determination of remaining drug in pellets.
Spectrophotometric method: Having withdrawn a 25-mL aliquot and filtering it, the amount of drug dissolved was determined by measuring UV absorption at the wavelength of maximum absorbance at 306 nm.
Buffer stage (pH 6.8): 425 mL of buffer concentrate (4.0 L of buffer concentrate consisting of 65.4 g of monobasic sodium phosphate, 28.2 g of sodium hydroxide, 12.0 g of sodium dodecyl sulfate and water) was added to the remaining 475 mL of solution in each vessel from the acid stage. After 1 hour, the amount of drug dissolved was determined by employing HPLC or spectrophotometric method at 286 nm.
Comparison of the two drug dissolution profiles (reference versus test formulations) was performed using the similarity factor f2 which is calculated as follows (Equation (1)) [
where Rt and Tt are the percentages of drug release at time t of the reference and the test formulations, respectively; n is the number of time points. If f2 is equal to or more than 50, the two drug release profiles will be considered to be similar .
Stability studies were carried out using 3300 capsules from batches of the optimal formulation. The optimal formulation batches were stored at various temperatures: 15˚C - 30˚C/40 - 90% RH (room temperature) and 40˚C ± 2˚C/75% ± 5% RH (accelerated temperature) per ICH guidelines and various physico-chemical parameters (appearance, drug content, and in vitro drug release profile) were tested periodically at 3, 6, 12, and 18 months.
Drug administration and sample collection: This study was based on a single-dose, randomized, two-period crossover design. Six healthy beagle dogs were fed standardized meals for 3 days before inclusion into the study. The number of dogs in the study was determined from a pilot study of two doses and variance of data obtained. Each drug was taken after an overnight fast. In the morning of phase I, three randomly chosen dogs were given a single dose of reference product and three other dogs were given a single dose of test product with 100 mL of water. No food was allowed until 1 hour after collection of the final blood sample. Water intake was allowed after 4 hours dose administration. Phase II was conducted 72 hours after finishing the blood sample collection of phase I. The process of phase II was carried out inversely with respect to the animals and study products. Approximately 3 ml blood samples were drawn into heparinized tubes through sterile syringes from the jugular vein before LPZ administration (0 h) and at 0.5, 1.0, 1.5, 2.0, 2.25, 2.5, 2.75, 3.0, 3.5, 4.0, 6.0, 8.0, 10, 12 and 24 h after dosing for LPZ chromatographic assay. The blood samples were centrifuged at 5000 rpm/min for 7 minutes. Plasma samples were separated and kept frozen at −45˚C until assay.
Extraction of LPZ from plasma: 50-µL internal standard solution of pantoprazole (40 µg/mL) and 2-mL tert-butyl methyl ether were added to 500 µL of each plasma sample. The solution was extracted by vortex mixing for 3 minutes, followed by centrifugation at 4500 rpm/min for 10 minutes at 20˚C. A 1-mL aliquot of the supernatant obtained was transferred to a glass tube and evaporated until dry at 30˚C. The residue was dissolved in a solution containing 80-µL acetonitrile and 120-µL 0.01 M potassium dihydro phosphate buffer solution (pH adjusted to 8.0 with triethylamine) and mixed for 2 minutes. A 50-µL aliquot was subsequently injected into the HPLC system.
Chromatographic conditions: HPLC separation was carried out using a RP18 steel column (150 × 4.6 mm; 5 μm) preceded by a steel guard column (RP18, 4 × 3 mm). The detector UV used was set at 285 nm. The flow-rate was 1 mL/min, injection volume was 50 µL. The mobile phase was a mixture of 65:35 (v/v) 0.01 M potassium dihydrophosphate buffer solution (pH adjusted to 8.0 with triethylamine) and acetonitrile.
Pharmacokinetic and statistical analysis: The pharmacokinetic parameters of LPZ in beagle dogs given capsules containing enteric-coated pellets (test product) and the reference product were calculated using the noncompartmental pharmacokinetic analysis method with the aid of WinNonlin 5.2 software (Certara Inc., USA). Cmax and Tmax were obtained directly from the observed concentration-time data. The area under the curve to the last measurable concentration (AUC0−t) was calculated by the linear trapezoidal rule. The area under the curve extrapolated to infinity (AUC0−∞) was calculated by the following formula: AUC0−∞ = AUC0−t + Ct/Kel, where Ct is the last measurable concentration and Kel is the elimination rate constant. All values are expressed as the mean values ± standard deviation. For the purpose of bioequivalence analysis, Cmax, AUC0−t and AUC0−∞ were considered as primary variables. Bioequivalence was assessed using analysis of variance for crossover design and calculating standard 90% confidence intervals of the ratio test/reference. The products were considered bioequivalent if the difference between two compared parameters was found statistically insignificant (P ≥ 0.05) and 90% confidence intervals for these parameters fell within 80% - 120%.
Effects of the independent variables on the response variables: LPZ enteric- coated pellets were prepared by using Eudragit®L100 as the enteric coating polymer. The independent variables and the range of levels incorporated in to the test formulations are shown in
Factors | Lower Percentage (−) | Upper Percentage (+) |
---|---|---|
X1 | 20 | 30 |
X2 | 30 | 50 |
X3 | 25 | 35 |
X1 percentage of TEC; X2 percentage of talc; X3 weight gain of enteric-coated membrane.
No | X3 (%) | X1 (%) | X2 (%) | Y1 (%) | Y2 (%) |
---|---|---|---|---|---|
N1 | 25.34 | 20.00 | 30.00 | 9.70 | 81.14 |
N2 | 34.47 | 20.00 | 30.00 | 5.32 | 85.60 |
N3 | 35.09 | 20.00 | 50.00 | 3.08 | 87.31 |
N4 | 26.97 | 20.00 | 36.67 | 4.55 | 87.96 |
N5 | 32.14 | 20.00 | 50.00 | 1.52 | 92.25 |
N6 | 29.48 | 20.00 | 50.00 | 7.92 | 84.26 |
N7 | 25.88 | 20.00 | 43.33 | 9.17 | 78.95 |
N8 | 24.79 | 23.33 | 50.00 | 9.78 | 77.49 |
N9 | 34.70 | 25.00 | 40.00 | 8.16 | 86.08 |
N10 | 33.44 | 20.00 | 40.00 | 6.38 | 85.96 |
N11 | 33.44 | 25.00 | 30.00 | 11.91 | 72.64 |
N12 | 29.94 | 25.00 | 40.00 | 8.49 | 85.20 |
N13 | 30.61 | 25.00 | 40.00 | 6.69 | 87.81 |
N14 | 29.40 | 25.00 | 40.00 | 6.47 | 82.69 |
N15 | 30.54 | 25.00 | 40.00 | 8.30 | 83.14 |
N16 | 26.04 | 30.00 | 50.00 | 8.49 | 73.79 |
N17 | 24.23 | 30.00 | 30.00 | 14.54 | 70.50 |
N18 | 34.15 | 30.00 | 30.00 | 6.58 | 90.37 |
N19 | 25.56 | 26.67 | 50.00 | 8.48 | 84.10 |
N20 | 34.89 | 30.00 | 50.00 | 4.69 | 83.08 |
Optimization of the formulation of LPZ enteric-coated pellets: Based on the experimental dissolution data, the range of optimal conditions for dependent variables are as follows: the percentages of drug released in acid pH 1.2 medium (0% ≤ Y1 ≤ 10%), and the percentages of drug released in buffer pH 6.8 medium (80% ≤ Y2 ≤ 100%) were identified. Running In Form 3.1 optimization software program, the optimal formulation of enteric coating was extrapolated and shown in
The optimal formulation of enteric coating was prepared at the batch size of 150 g (n = 3) using Diosna spray coater (Germany). The enteric membrane was coated on the subcoating core pellets containing LPZ. The physico-chemical properties of enteric-coated pellets for optimal formulation were evaluated and shown in
The dissolution profiles of optimal formulation pellets were the same as that of Gastevin® 30 mg with f2 equal to 56.62 (
Ingredients | Percentage (%) |
---|---|
TEC* | 20.00 |
Talc* | 46.14 |
Titan dioxide* | 20.00 |
Weight gain of enteric-coating membrane | 35.09 |
(*): percent per enteric polymer, using the mixture of ethanol/purified water (3:1) as solvent for coating; Titanium Oxide was held constant to amount of the Enteric-coated polymer used in the study.
Pellet characteristics | ||||||
---|---|---|---|---|---|---|
Shape | Particle size distribution (mm) | Moisture (%) | Bulk density (g/mL) | Flow rate (g/s) | Friability (%) | Drug content (%) |
Spherical and smooth uniformity | 0.85 - 1.2 | 3.58 ± 0.78 | 0.81 ± 0.04 | 11.8 ± 0.42 | 0.05 | 8.26 ± 0.35 |
The scanning electron microscopy (SEM) of the optimal formulation shows that prepared enteric-coated pellets have a good coating with three individual layers including a drug loading, a subcoating, and an enteric coating (
Stability studies: Triple batches of 3300 capsules containing the optimal formulation of LPZ enteric-coated pellets were prepared by the same method. The results of dissolution and drug content from the stability study in accelerated and room conditions are summarized in
The mean concentration-time profiles of the LPZ 30-mg test and reference capsules are depicted in
Time (months) | Sample | Drug content (%) (n = 3) | Percent of LPZ release (n = 6) | ||
---|---|---|---|---|---|
Y1 | Y2 | ||||
t = 0 | B1 | 102.93 ± 1.02 | 3.09 ± 0.48 | 96.94 ± 1.96 | |
B2 | 102.45 ± 1.27 | 3.49 ± 0.20 | 98.92 ± 1.70 | ||
B3 | 101.98 ± 2.11 | 3.39 ± 0.07 | 97.26 ± 1.63 | ||
t = 3 | B1 | rc | 101.84 ± 0.61 | 2.91 ± 0.46 | 96.41 ± 1.85 |
B1 | ac | 101.29 ± 1.32 | 3.10 ± 0.30 | 98.68 ± 1.60 | |
B2 | rc | 100.09 ± 0.29 | 3.08 ± 0.24 | 98.93 ± 1.62 | |
B2 | ac | 100.99 ± 1.76 | 3.64 ± 0.40 | 99.59 ± 1.27 | |
B3 | rc | 101.60 ± 2.63 | 3.07 ± 0.22 | 99.66 ± 2.18 | |
B3 | ac | 101.69 ± 1.03 | 3.57 ± 0.39 | 99.42 ± 1.35 | |
t = 6 | B1 | rc | 101.50 ± 1.09 | 2.98 ± 0.38 | 96.00 ± 1.26 |
B1 | ac | 99.52 ± 1.18 | 3.67 ± 0.28 | 98.58 ± 1.19 | |
B2 | rc | 99.93 ± 0.52 | 3.45 ± 0.23 | 98.08 ± 1.26 | |
B2 | ac | 101.96 ± 0.10 | 3.92 ± 0.24 | 98.84 ± 1.88 | |
B3 | rc | 101.94 ± 2.53 | 3.43 ± 0.12 | 98.54 ± 1.92 | |
B3 | ac | 99.48 ± 1.09 | 3.75 ± 0.43 | 98.62 ± 0.78 | |
t=12 | B1 | rc | 102.21 ± 0.81 | 3.31 ± 0.27 | 98.85 ± 1.15 |
B2 | rc | 101.93 ± 1.03 | 3.38 ± 0.34 | 99.33 ± 1.14 | |
B3 | rc | 99.77 ± 1.82 | 3.35 ± 0.28 | 98.92 ± 0.89 | |
t = 18 | B1 | rc | 100.32 ± 0.93 | 4.08 ± 0.21 | 94.72 ± 1.32 |
B2 | rc | 100.75 ± 1.25 | 4.96 ± 0.38 | 93.63 ± 1.59 | |
B3 | rc | 99.25 ± 1.08 | 4.18 ± 0.58 | 95.85 ± 1.36 |
rc = room condition, ac = accelerated condition; B1 = batch 1, B2 = batch 2, B3 = batch 3.
Animal no. | Cmax (µg/mL) | Tmax (h) | AUC0−t (ng/mL/h) | AUC0−∞ (ng/mL/h) | ||||
---|---|---|---|---|---|---|---|---|
R | T | R | T | R | T | R | T | |
1 | 1.0515 | 1.4823 | 2.25 | 2.75 | 3194.9 | 3627.4 | 3330.4 | 3660.4 |
2 | 0.7851 | 1.0238 | 2.25 | 2.00 | 1866.0 | 1518.1 | 2021.4 | 1543.7 |
3 | 0.7111 | 0.4310 | 2.50 | 2.00 | 1998.0 | 784.2 | 2120.3 | 889.2 |
4 | 0.4320 | 0.8134 | 2.00 | 2.75 | 450.8 | 2040.1 | 474.6 | 2158.4 |
5 | 1.2963 | 1.1512 | 2.75 | 2.50 | 1651.5 | 2964.1 | 1939.5 | 3457.5 |
6 | 0.5251 | 0.6540 | 2.25 | 2.25 | 1031.9 | 2537.8 | 1069.6 | 3359.4 |
Mean | 0.8002 | 0.9260 | 2.33 | 2.37 | 1698.8 | 2245.2 | 1825.9 | 2511.4 |
SD | 0.3252 | 0.3746 | 0.25 | 0.34 | 933.8 | 1021.5 | 979.7 | 1151.2 |
R = reference product; T = test product.
Dependent | Hypothesis | DF | SS | MS | F_stat | P_value |
---|---|---|---|---|---|---|
Ln(Cmax) | Sequence | 1 | 0.0478 | 0.0478 | 0.14 | 0.7284 |
Ln(Cmax) | Sequence Subject | 4 | 1.3774 | 0.3443 | 3.83 | 0.1107 |
Ln(Cmax) | Formulation | 1 | 0.0590 | 0.0590 | 0.66 | 0.4630 |
Ln(Cmax) | Period | 1 | 0.0326 | 0.0326 | 0.36 | 0.5792 |
Ln(AUC0−t) | Sequence | 1 | 0.1809 | 0.1809 | 0.41 | 0.5574 |
Ln(AUC0−t) | Sequence Subject | 4 | 1.7703 | 0.4426 | 3.43 | 0.1299 |
Ln(AUC0−t) | Formulation | 1 | 0.3267 | 0.3267 | 2.53 | 0.1868 |
Ln(AUC0−t) | Period | 1 | 1.3394 | 1.3394 | 10.38 | 0.0322 |
Ln(AUC0−∞) | Sequence | 1 | 0.0948 | 0.0948 | 0.21 | 0.6740 |
Ln(AUC0−∞) | Sequence Subject | 4 | 1.8481 | 0.4620 | 4.03 | 0.1030 |
Ln(AUC0−∞) | Formulation | 1 | 0.4008 | 0.4008 | 3.49 | 0.1350 |
Ln(AUC0−∞) | Period | 1 | 1.5275 | 1.5275 | 13.31 | 0.0218 |
The pharmacokinetic data were transformed into natural logarithm (Ln); DF = degrees of freedom; SS = sum of squares; MS = mean square.
Animal no. | Tmax (h) | Difference | Ranked difference | |
---|---|---|---|---|
R | T | |||
1 | 2.25 | 2.75 | −0.5 | 3.5 (3 - 4) |
2 | 2.25 | 2.00 | +0.25 | 1.5 (1 - 2) |
3 | 2.50 | 2.00 | +0.5 | 3.5 (3 - 4) |
4 | 2.00 | 2.75 | −0.75 | 5 |
5 | 2.75 | 2.50 | +0.25 | 1.5 (1 - 2) |
6 | 2.25 | 2.25 | 0 |
Cmax and Tmax: The mean Cmax was 0.800 ± 0.325 and 0.926 ± 0.374 µg/mL for reference and test products, respectively. 90% confidence interval ranges between the reference and test products fell within 79.56% - 166.40%. At the 0.95 significance level, ANOVA did not show any significant differences between the two products on all effects. For example, the effects of sequence on Cmax, the observed P value was 0.728 while the P value was 0.110 for the influence of study subjects on Cmax. In terms of treatment, no significant differences were seen, (the observed P value was 0.463) and the period effects with the observed P value were 0.579.
For Tmax, the sum of the ranks of the scores with positive and negative values were 6.5 and 8.5, respectively. Therefore, the smaller sum was 6.5 and the number of differences was 5. Using the table of Wilcoxon signed-rank, no significant difference was recorded at the 0.95 significance level (P > 0.05). With the value of Tmax obtained and dissolution data in acidic medium, the LPZ 30-mg test capsules showed delayed release in gastrointestinal tract on 6 beagle dogs in this in vivo study.
AUC0−t and AUC0−∞: The mean AUC0−t were 1698.8 ± 933.8 and 2245.2 ± 1021.5 ng/mL/h for reference and test products, respectively. 90% confidence interval range between the reference and test products fell within 89.38 - 216.46%. At the 0.95 significance level, ANOVA did not show any significant differences between the two products on the effects of sequence on AUC0−t, (P value = 0.557), the effects of subject (P value = 0.129), and the effects of treatment (P value = 0.186). However, there was a statistically significant difference between the test and reference products on period effects (P value < 0.05). The same results were obtained for AUC0−∞.
To evaluate the bioavailability of prepared LPZ 30-mg enteric capsules, the in vivo study was conducted based on a single-dose, randomized, two-period crossover design per FDA guidelines. The mean concentration-time profiles of the LPZ 30-mg test and reference capsules showed their delayed-release characteristics in gastrointestinal tract on experimental dogs. With the obtained values of Cmax, AUC0−t, and AUC0−∞ by utilizing the noncompartmental method, the lack of bioequivalence outcome was given between the test and reference products whereas Tmax of both formulations was equivalent. Although the in vitro dissolution profiles of the two products were similar with f2 value at 56.62, but the obtained in vivo results were not equivalent which might be caused by the low f2 and the small number of subjects in the in vivo study. The pharmacokinetic parameters of the two compared capsules were appropriate to the results of previous research [
LPZ is characterized by low solubility and low stability. In this study, the drug layering method was selected to prepare the core pellets containing LPZ. The results also show that the solubility and stability of LPZ increased considerably by layering and including alkaline salts, similarly seen in previous research [
As is shown in many earlier studies, some enteric polymers and aqueous dispersions such as HPMCP, HPMCAS, Eudragit®L30D-55, Acrylcoat®L30D have been used for coating derivatives of benzimidazoles [
D-Optimal was chosen as the approach to create the experimental design for the study as it uses a simpler model in its design, which aims to minimize the variance of factor-effect estimates to create test formulations to study to obtain an optimized formulation. Other experimental design methods such as I-Optimal are available and provide better prediction performance with their experimental designs as it aims to minimize the average variance of prediction over the region of experimentation [
The pharmacokinetic parameters Cmax, Tmax, AUC0−t, and AUC0−∞ were determined for the D-Optimal design optimized capsules of LPZ given to healthy beagle dogs and were statistically compared to Gastevin® capsules as a reference (KRKA, Slovenia) using the non-compartmental method with the aid of WinNonlin 5.2 software. The analysis of variance showed that the two formulations did not demonstrate bioequivalence using a 90% confidence interval range (80 - 120%) for Cmax, AUC0−t, and AUC0−∞. However, no significant difference in Tmax was found at the 0.95 significance level using the Wilcoxon signed-rank test.
The prepared capsules containing LPZ enteric-coated pellets were stable for 18 months at room conditions and 6 months in accelerated conditions. The use of D-Optimal to experimentally design an optimal dosage form was quite satisfactory. The experimental design yielded an optimal formulation that produced similar bioequivalence to the commercially available reference lansoprazole product. The stability study results have important significance for this formulation in zone IV, which includes Vietnam as well as other countries in South-East Asia.
Appreciation and acknowledgement are given to the Vietnam Ministry of Health for their support to conduct this research.
The study protocol was approved by the ethics committee of medicine and pharmacy research at Military Medical University (Hanoi, Vietnam).
The authors declare that there is no conflict of interest regarding the publication of this research paper.
Luong, A.Q., Vu, T.N., Nguyen, D.H., Alshahrani, S.M., Chri- stensen, J.M. and Nguyen, C.N. (2017) Formulation Optimization Utilizing D-Optimal Experimental Design of Oral Capsules Containing Enteric-Coated Pellets of Lansoprazole and In Vivo Bioequivalence. Pharmacology & Pharmacy, 8, 153-171. https://doi.org/10.4236/pp.2017.85011