Reference Tablets Research Articles

Enhanced bioavailability of rebamipide nanocrystal tablets: Formulation and in vitro/in vivo evaluation

The purpose of this study was to formulate rebamipide nanocrystal tablets (REB-NTs) by wet-milling technique to enhance its dissolution rate and oral bioavailability. The formulation and preparation technology were screened by single factor tests with particle size and distribution as indicators. Rebamipide nanocrystals (REB-NSs) was then achieved by freeze-dry from the prepared nanosuspensions which were characterized by differential scanning calorimetry (DSC) and x-ray powder diffraction (XRD), while the vitro dissolution and the plasma drug concentration of the nanocrystal tablets were investigated. The results indicated that the prepared nanosuspensions got an average particle size of 286 nm, PI of 0.173 and the average Zeta potential of −18.2 mv. The average particle size of obtained REB-NSs’ redispersibility was 278 nm, and the crystalline of REB-NSs was the same as the rebamipide bulk drug as shown by DSC and XRD. The drug dissolution rate of self-made nanocrystal tablets in different dissolutions was slightly faster than that from the reference tablets, REB-MTs (Mucosta®), while the Cmax and AUC0–24 of REB-NTs were 1 and 1.57 times higher than that of REB-MTs, which means the nanotechnology could significantly improve the oral bioavailability of rebamipide.

Pharmacokinetic evaluation of a newly developed piperazine dithioctate formulation in healthy volunteers.

The formulation investigated as reference contains thioctic acid which is known to be poorly soluble in water and have some instability during storage at high temperature. To overcome these limitations, a new piperazine dithioctate (PDT) tablet formulation was developed by a domestic pharmaceutical company in Korea. The aim of this clinical study was to evaluate the pharmacokinetic characteristics of PDT in healthy volunteers. This study consisted of two clinical trials. In the part 1 study, a randomized, singledose, parallel study was performed with 24 healthy volunteers. All of the subjects were administered one of the three study formulations, Thioctacid® HR (High Release) as the reference, PDT-1 or PDT-2 (each containing thioctic acid 600 mg), respectively. To determine the harmacokinetic characteristics, blood samples were serially collected at pre-dose and at pre-defined timepoints after dosing. In the part 2 study, a randomized, single-dose, two-way crossover study was conducted with 48 subjects. All of the subjects were administered both the reference and PDT-2 formulations, with a 7-day washout period between the two medications. Blood samples were collected at the same timepoints as in the part 1 study. Tolerability was evaluated throughout the study. 23 volunteers completed the part 1 study. The maximum plasma concentration (Cmax) of thioctic acid after administration of the reference tablet was 4.08 ± 2.35 μg/mL (means ± SD), and the Cmax of PDT-1 and PDT-2 was 3.53 ± 2.87 μg/mL and 4.15 ± 1.62 μg/mL, respectively. The AUClast value was 2.96 ± 1.13 μg x h/mL for the reference, 2.84 ± 1.12 μg x h/mL for PDT-1, and 3.30 ± 1.32 μg x h/mL for PDT-2. 42 volunteers completed the part 2 study. The Cmax of reference and PDT-2 was 5.59 ± 3.07 μg/mL and 5.14 ± 3.18 μg/mL, respectively. The AUClast value was 4.01 ± 1.65 μg x h/mL for the reference and 3.96 ± 1.47 μg x h/mL for PDT-2. The geometric mean ratios (PDT-2/reference) and the 90% CI for Cmax and AUClast were 0.93 (0.78 - 1.11) and 1.01 (0.94 - 1.09), respectively. Both studies suggested that the pharmacokinetic profile of the newly developed piperazine dithioctate formulation was comparable to the pharmacokinetic profile of the reference tablet. Both study tablets were well tolerated in all of the subjects.

A novel finasteride 0.25% topical solution for androgenetic alopecia: pharmacokinetics and effects on plasma androgen levels in healthy male volunteers.

Finasteride, a selective inhibitor of type 2 5-α reductase isoenzyme, inhibits the conversion of testosterone to dihydrotestosterone (DHT) and is indicated in the treatment of male androgenetic alopecia. The study objective was to evaluate a newly developed finasteride 0.25% topical solution in comparison to the marketed finasteride 1 mg tablet, with respect to finasteride pharmacokinetics and suppressive effects on plasma DHT. 24 healthy men with androgenetic alopecia were randomized in a single center, open-label, parallel-group, exploratory study, and received either multiple scalp applications of the topical solution b.i.d. or oral doses of the reference tablet o.d. for 7 days. Plasma finasteride, testosterone and DHT concentrations were determined. After multiple doses, mean (± SD) finasteride C(max) and AUC(0-t) corresponded to 0.46 ± 0.28 ng/mL and 6.64 ± 7.50 ng/mL x h for the topical solution and to 6.86 ± 1.78 ng/mL and 57.93 ± 29.38 ng/mL x h for the tablet. Plasma DHT was reduced by ~ 68 - 75% with the topical solution and by ~ 62 - 72% with the tablet. No relevant changes occurred for plasma testosterone with either treatment. No clinically significant adverse events occurred. A strong and similar inhibition of plasma DHT was found after 1 week of treatment with the topical and tablet finasteride ormulations, albeit finasteride plasma exposure was significantly lower with the topical than with the oral product (p < 0.0001).

Pharmacokinetics and bioequivalence study of three oral formulations of ambroxol 30 mg: a randomized, three-period crossover comparison in healthy volunteers.

To compare the pharmacokinetic properties of two newly developed generic ambroxol formulations with a branded innovator product in healthy Chinese male volunteers. This was a single-dose, randomized, open-label, three-period crossover study in healthy volunteers aged 18 - 45 years under fasting conditions. Subjects were assigned to receive 1 of 2 test formulations or a reference tablet of ambroxol 30 mg. Each study period was separated by a 1-week washout phase. Blood samples were collected at pre-specified times. A non-compartmental method was employed to determine pharmacokinetic properties (C(max), t(max), AUC(0-tlast), AUC(0-∞)) to test for bioequivalence. The predetermined regulatory range of 90% CI for bioequivalence was 80 - 125%. 24 subjects were enrolled in and completed the study. The geometric mean C(max) values for the test tablet, test capsule, and reference product were 82.73, 85.36, 84.56 ng/mL, and their geometric mean AUC(0-tlast) (AUC(0-∞)) were 660.87 (753.49), 678.98 (756.79), and 639.41 (712.14) ng x h/mL, respectively. For test tablet vs. reference, the 90% CIs of the least squares mean test/reference ratios of C(max), AUC(0-tlast), and AUC(0-∞) were 91.2% to 104.9%, 96.5% to 110.7%, and 98.8% to 113.4%, respectively. For test capsule, the corresponding values were 94.1% to 108.3%, 99.2% to 113.7%, and 99.2% to 113.9%, respectively. No adverse events occurred during the study. The ambroxol 30 mg tablets and capsules were considered bioequivalent to the reference formulation in accordance with predetermined regulatory criteria.

Comparison of Scaled-average, Population, and Individual Bioequivalence on 2 Tablets of Pitavastatin Calcium: A 3-Period, Reference-replicated, Crossover Study in Healthy Chinese Volunteers

BackgroundPitavastatin, a fully synthetic β-hydroxy-β-methylglutaryl–coenzyme A reductase inhibitor, is potent for the treatment of primary hyperlipidemia and mixed dyslipidemia. Recently, the original product and some generic products of pitavastatin calcium have become available in China. However, the intrasubject variability and interchangeability of this newly developed generic product and the branded innovator product have rarely been investigated in the Chinese population. PurposeThe aim of this study is to develop and compare the scaled-average, population, and individual bioequivalence (BE) of pitavastatin calcium tablets in healthy Chinese volunteers. This study will be used to allow for the interchangeability (switchability and prescribability) of the 2 products in clinical medication in China. MethodsA single-dose, reference-replicated, 3-period crossover BE study was conducted in 36 healthy male volunteers. Plasma samples were collected before and after oral administration of 2-mg test or reference tablets. A LC-MS/MS method was used to determine the concentration of pitavastatin calcium. A noncompartmental method was used to investigate the pharmacokinetic parameters. The ANOVA and 90% CIs of ln(AUC0–t) and ln(Cmax) were used for statistical analysis of scaled-average BE. A nonparametric test (Wilcoxon signed rank test) was performed to Tmax. The analyses of population BE and individual BE were used to assess the switchability and prescribability of the 2 products. FindingsThirty-six volunteers were enrolled in this clinical research; 33 volunteers completed the 3 treatment periods. The mean (SD) relative bioavailability calculated from the ratios (T/R) of AUC0–t was 101.3% (19.7%). The mean ln(AUC0–t) and ln(Cmax) were 98.64 (90% CI, 93.44–104.13) and 98.68 (90% CI, 91.88–105.99) within previously stipulated ranges recommended by the US Food and Drug Administration and the China Food and Drug Administration (CFDA). The intrasubject %CVs of AUC0–t and Cmax were 12.0% and 18.0% for the reference tablet and 13.0% and 17.0% for the test tablet. No significant differences were found among Tmax (0.742 ± 0.276, 0.674 ± 0.202, and 0.689 ± 0.226, respectively) for reference tablet 1, reference Supplemental Table II in the online version at 10.1016/j.clinthera.2014.06.21, and test tablet by a Wilcoxon test (P > 0.05). For ln(AUC0–t) and ln(Cmax), the statistical test-reference ratios were 99.13% and 98.95%, respectively. After inspecting the results for reference and mixed scaling, all the upper confidence limits were <0; therefore, population and individual BE were given. ImplicationsIn the healthy Chinese males, the generic and branded name tablets of pitavastatin calcium are bioequivalent at the rate and extent of absorption after a comparison of scaled-average, population, and individual BE and thus may be used interchangeably. Both the formulations are generally well tolerated. Chinese Clinical Trial identifier: ChiCTR-TTRCC-13003973.

Bioavailability assessment of hydroxymethylglutaryl coenzyme A reductase inhibitor utilizing pulsatile drug delivery system: a pilot study

Chronotherapy or pulsatile drug delivery system could be achieved by increasing drug plasma concentration exactly at the time of disease incidence. Cholesterol synthesis shows a circadian rhythm being high at late night and early in the morning. Simvastatin (SIM) inhibits hydroxymethylglutaryl coenzyme A reductase, which is responsible for cholesterol synthesis. In this study, SIM lipid-based formulation filled in gelatin capsules and coated with aqueous Eudragit® S100 dispersion was prepared for chronotherapeutic treatment of hypercholesterolemia. The pharmacokinetic parameters of SIM capsules were studied in human volunteers after a single oral dose and compared with that of Zocor® tablets as a reference in a randomized cross-over study. Pharmacokinetic parameters such as AUC0–∞, Cmax, Tmax, t1/2 and elimination rate constant were determined from plasma concentration-time profile for both formulations. The tested formulation had the ability to delay drug absorption and provide higher drug concentrations from 3 up to 10 h after oral administration compared to that of commercial tablets. The data in this study revealed that the prepared formulation could be effective in chronotherapeutic treatment of hypercholesterolemia. Moreover, the tested formulation was found to enhance SIM bioavailability by 29% over the reference tablets.

A NOVEL APPROACH TO EXTEND STANDBY BATTERY LIFE FOR MOBILE DEVICES

Mobile devices are an essential need for most of us in this modern world. Current generation of mobile devices, such as smartphones and tablets are equipped with high speed multi core processors with advanced features to uplift the user experience. However, advances in battery technology continue to lag with the advancement of mobile technology, especially for the compact form-factor devices. Cutting down energy consumption is one of the most crucial design factors for a mobile device. This paper will emphasize on a new power optimization technique and focus on the expected power saving by theoretical calculations. Analysis of the actual power saving by experimenting on a reference tablet platform and highlight the results of power saving achieved by optimization on the reference tablet.

Formulation development for the orexin receptor antagonist almorexant: assessment in two clinical studies.

Almorexant, a dual orexin receptor antagonist, was investigated for the treatment of insomnia. The following observations initiated further formulation development: the active pharmaceutical ingredient (API) was sticking to the apparatus used during tablet compression; almorexant has an absolute bioavailability of 11.2%; and almorexant modestly decreased the latency to persistent sleep by 10.4 minutes in patients. Two randomized crossover studies were performed to investigate the pharmacokinetics of several new formulations in healthy subjects. In study I, the old “sticky” tablet was compared to two new formulations developed to prevent sticking: a qualitatively similar tablet but with a larger API crystal size and a tablet with 30% more excipients as well as a larger API crystal size. This latter formulation was available in two strengths. The geometric mean ratios and 90% confidence interval of the area under the curve (AUC) were within the bioequivalence range of 0.80–1.25 for the different comparisons between formulations. In study II, 100 mg of the reference tablet was compared to 25 and 50 mg of a liquid-filled hard gelatin capsule developed to increase the bioavailability of almorexant. The geometric mean ratios of the maximum concentration and AUC comparing the new 25 and 50 mg capsule formulations to the reference tablet did not exceed 0.25 and 0.50, respectively, indicating that the new capsule formulation did not increase the maximum concentration of or the total exposure to almorexant. In conclusion, a new tablet was developed but formulation development aimed at increasing the bioavailability of almorexant failed.

Comparative Fasting Bioavailability of 2 Bepotastine Formulations in Healthy Male Chinese Volunteers: An Open-Label, Randomized, Single-Dose, 2-Way Crossover Study

BackgroundBepotastine is a second-generation histamine1 receptor antagonist that is used in the treatment of allergic rhinitis, urticaria, and pruritus associated with skin disease. A new generic formulation of bepotastine has been developed in China, and information concerning bioavailability and pharmacokinetic properties in the Chinese population has not been reported. ObjectiveThe aim of the present study was to compare the bioavailability and pharmacokinetic properties of 2 tablet formulations of bepotastine, the 10-mg generic formulation (test) and a branded formulation (reference), in healthy male Chinese volunteers to obtain registration approval of the test formulation. MethodsA single-center, open-label, randomized, 2-way crossover study with a 1-week washout period was conducted in 24 healthy male volunteers. Blood samples were collected for 16 hours after a single dose of the 10-mg bepotastine test formulation or the reference formulation. Plasma bepotastine concentrations were determined using a validated LC-MS/MS method. Cmax, Tmax, AUC0–t, AUC0–∞, and t½ were determined using noncompartmental analysis. The formulations were considered bioequivalent if the 90% CIs for the log-transformed Cmax and AUC values were within the predetermined interval of 75% to 133% and 80% to 125%, respectively, according to the guidelines of the China Food and Drug Administration. ResultsNo significant differences were found in mean (SD) pharmacokinetic parameters between the test and reference drugs, including Cmax (74.81 [9.91] ng/mL vs 78.60 [29.58] ng/mL), AUC0–t (295.55[115.29] ng·h/mL vs 299.17[109.29] ng·h/mL), and AUC0-∞ (305.28 [118.50] ng·h/mL vs 310.90 [112.20] ng·h/mL). The mean (SD) t½ values of the test and reference formulations were 2.53 (0.50) hours and 2.62 (0.41) hours, respectively. The 90% CIs of the treatment ratios for the logarithmic transformed values of Cmax, AUC0–t, and AUC0–∞ were 86.96% to 101.80%, 93.22% to 104.13%, and 92.66% to 103.30%, respectively. All values were within the predetermined bioequivalence range. Two adverse events were reported as neutropenia (1 volunteer [4.2%]) and neutrophilia (1 volunteer [4.2%]). Both adverse events were transient and considered mild by physicians. ConclusionThe test and reference tablets met the regulatory criteria for bioequivalence as defined by the China Food and Drug Administration. Both formulations were well tolerated. Chinese Clinical Trials Registry identifier: ChiCTR-TTRCC-13003723.

Formulation and Release Characteristics of Zidovudine-Loaded Solidified Lipid Microparticles

Purpose: To formulate and determine the release profile of zidovudine (AZT)-loaded solidified lipid microparticles (SLMs). Methods: Different concentrations (0, 1, 2, 3 and 5 %w/w) of zidovudine (AZT) were formulated into microparticles in melt dispersion of Phospholipon ® 90H and goat fat in the ratio 1:1, 2:1, 2:3 and 1:3 followed by lyophilization. They were characterized for particle size, yield, entrapment efficiency (EE) and loading capacity (LC). In vitro release kinetics and mechanism of release were assessed sequentially in simulated gastric fluid (SGF, pH 1.2)and simulated intestinal fluid (SIF, pH 7.2). Results : The ratio 1: 1 formulation was the most stable in terms of physical observation.. Particle size analysis indicated that the particles were irregular in shape with size ranging from 5.10 ± 0.10 to 13.40 ± 2.20 μm. Yield decreased with increase in drug concentrations in the SLMs formulations. EE data showed that the microparticles containing 1 % w/w of AZT had the highest entrapment efficiency of 74.0 ± 0.03 %. LC also decreased with increase in concentration of AZT. AZT tablet released most of its content within 5 min with a sharp decrease in the concentration but the SLMs maintained its release for 8 to 12 h in different batches Conclusion: The results show that drug content has influence on drug release from the SLMs, but not on the mechanism of release. Furthermore, dose dumping was avoided and drug release mechanism was mostly non-Fickian while for the reference (commercial) tablet, it was Fickian. Keywords: Phospholipon ® 90H, Solidified lipid microparticles, Solidified reverse micellar microparticle, Zidovudine.

Pharmacokinetic Properties and Bioequivalence of 2 Formulations of Valsartan 160-mg Tablets: A Randomized, Single-Dose, 2-Period Crossover Study in Healthy Korean Male Volunteers

BackgroundThe solubility of valsartan is dependent on pH and thus may cause patient variability in drug absorption and failure in bioequivalence studies; thus, increasing the solubility and release of valsartan at low pH has been suggested for a more favorable pharmacokinetic profile. However, due to this pH dependence, the change in the formulation process could alter the disintegration and/or dissolution profile of the drug, possibly making the results of bioequivalence studies misleading. ObjectiveThe aim of this study was to assess the bioavailability and tolerability of a newly developed oral formulation of valsartan 160 mg (wet-granulation tablet) in healthy Korean male volunteers. MethodThis study was performed with the subjects under fasted conditions, using a randomized, single-dose, 2-period crossover design. Subjects were assigned to receive, in randomized order, a single dose of the test formulation and a reference formulation (valsartan 160-mg dry-granulation tablet), with a washout period of 7 days between the administrations. Blood samples were collected up to 24 hours after dosing, and pharmacokinetic parameters were determined after the plasma valsartan concentration was analyzed using UPLC-MS/MS. The dissolution studies of both formulations were conducted using USP apparatus 2 at 50 rpm with 1000 mL of phosphate buffer solution (pH, 6.8) at 37°C ± 0.5°C. Bioequivalence was defined per Korean Food and Drug Administration’s regulatory criteria as 90% CIs of the geometric mean test/reference ratios of AUC0–t and Cmax within the range of 0.8 to 1.25. Tolerability was assessed using physical examination and subject interviews. ResultsSixty subjects were enrolled (mean [SD] age [range], 23.6 [2.4] years [21–31]; height, 173.7 [6.6] cm [161–190]; and weight, 68.0 [8.7] kg [54–85]). The mean AUC0–∞ values with the test and reference tablets were 31,784 (13,844) and 32,714 (14,512) ng·h/mL, respectively; Cmax, 5094 (2061) and 5064 (1864) ng/mL; Tmax, 2.92 (1.04) and 3.08 (1.01) hours. The 90% CIs for the geometric mean test/reference ratios of AUC0–t and Cmax were 0.9295 to 1.0546 and 0.9190 to 1.0848, respectively, which met the criteria for bioequivalence. The most frequently reported adverse event was dizziness after blank blood sampling, recorded in 4 subjects, 2 cases each with the test and reference formulations. ConclusionsIn this study in healthy Korean male volunteers, the test and reference formulations of 160-mg valsartan met the Korean Food and Drug Administration’s regulatory criteria for bioequivalence despite the difference in formulation (wet granulation vs dry granulation). Both formulations were well tolerated, with no serious adverse events reported.

Formulation development and evaluation of the anti-malaria properties of sustained release artesunate-loaded solid lipid microparticles based on phytolipids

Contexts: Artemisinins and its derivatives are considered the basis in the treatment of Plasmodium falciparum malaria due to their high potency and rapid action. However, they have short half life, low solubility, and poor oral bioavailability, hence the need to formulate sustained release lipid particulate dosage form of these drugs.Objectives: To formulate and evaluate artesunate-loaded solid lipid microparticles (SLMs) based on structured lipid matrices consisting of soybean oil and dika wax.Materials and methods: The lipid matrices were characterized by differential scanning calorimetry (DSC), small-angle X-ray diffraction (SAXD), and wide-angle X-ray diffraction (WAXD). The SLMs were prepared by hot melt-homogenization. Time-dependent particle size analysis, time-dependent pH stability studies, encapsulation efficiency (EE%), and in vitro drug release were carried out on the SLMs. In vivo anti-malarial studies were performed using a modified Peter’s 4-day suppressive protocol using Plasmodium berghei infected mice.Results and discussion: Thermograms of the lipid matrices showed modifications in the microstructure of dika wax as a result of inclusion of soybean oil. SAXD and WAXD diffractograms showed that the lipid matrices were found to be non-lamellar. Particle size of SLM increased with time, while the pH was almost constant. The SLMs had maximum EE% of 80.6% and sustained the release of artesunate more than the reference tablet. In vivo pharmacodynamic studies showed that the SLMs had significant (p < 0.05) reduction in parasitaemia compared with reference tablet.Conclusion: Artesunate-loaded SLMs could be used once daily in the treatment of malaria.

Establishing postprandial bio-equivalency and IVIVC for generic metformin sustained release small sized tablets

The objective of current study was to develop metformin hydrochloride modified release small sized tablets, and to evaluate its bioequivalence when compared with the reference product (Glucophage® SR). The physicochemical properties of the formulated and reference tablets were determined and compared. The in vitro dissolution profiles of formulated tablets were obtained using bio-relevant media and IVIVC was established. Bioequivalence investigation was carried out in 32 healthy male volunteers who received a single dose 1,000 mg of both test and reference products in a randomized two-way crossover design in postprandial conditions. After dosing, serial blood samples were collected for a period of 48 h. Metformin concentration was assayed by using a validated LC–MS/MS method. The log-transformed Cmax and AUC were statistically compared by analysis of variance, and the 90 % confidence intervals (CI) of the ratio of the log-transformed Cmax and AUC between the most promising developed formulation and the reference product were determined. It was deduced that the dissolution rate profile of the formulated modified release small sized tablets was similar to the reference product employed in the study. Their similarity and difference factors were found to be well within the established limits. In the bioequivalence study, the difference in Cmax, AUClast and AUCinf between the test and reference product was not statistically significant, with the 90 % CI of 100.73–116.20, 86.16–97.37 and 87.12–96.99 %, respectively. The results suggested that the metformin small tablets formulated with reduced quantity of controlled release polymer were found to be bioequivalent in the postprandial state. For these small tablets, pH 5.5 acetate buffer as a bio-relevant dissolution media for the development of IVIVC.

Pharmacokinetic and Bioequivalence Studies of Oral Cefuroxime Axetil 250 mg Tablets in Healthy Human Subjects

The objective of this study was to determine the bioequivalence of two Cefuroxime oral 250 mg tablet formulation. One was the innovators brand (Zinnat®), was taken as reference brand (REF) and the other was a newly developed, optimized and cost effective formulation (TEST). A single dose, open, random sequence, cross over, two treatment study with a one week washout period in between was carried out in 12 healthy male Pakistani young volunteers. Reference and Test tablets were administered to these volunteers with 150 mL of water after an overnight fast. Blood samples were drawn 15 min prior to the administration of dose and at 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7 and 8 hours post dose. The cefuroxime concentrations in the plasma were determined by a modified, simple HPLC method in which the mobile phase was 10 mM solution of ammonium acetate and acetonitrile, pH was adjusted to 5 ± 0.2 with glacial acetic acid. The wavelength of detection was 254 nm having a flow rate of 1ml/min and the retention time of 5.8 min. The method was validated as per the ICH requirements. Both compartmental and non-compartmental methods were used to determine the various PK parameters such as Cmax. Tmax, AUC0-t, AUC0-∞ , AUMC, MRT, t1/2, Kel, Vd and Cl using Kinetica® ver 4.4.1 The bioequivalence between the REF and TEST cefuroxime axetil 250mg formulations was established as the Latin square design of ANOVA does not show any significant difference with a p≥0.05 for period and the 90% confidence interval lies within the acceptable range (80-125%) for the log transformed data of Cmax, Tmax, AUC0-t, AUC0-∞, t1/2, AUMC, MRT, Vd and Cl, showing a comparable plasma profiles generated by both the formulations. It is, thus concluded that both the formulations were bioequivalent.

Comparative Bioavailability of Two Extemporaneous Solid Formulations of Carbamazepine against the Innovator in Mexican Healthy Subjects

Extemporaneous or off-label prescribing is not illegal and may sometimes be clinically and economically appropriate. However it is associated with a number of clinical, safety and ethical issues. Bioequivalence of these products must be proven before they are used in place of patent medicines. In the present study, a single-center, open, randomized, single-dose, 2-period crossover, 2-sequences pilot assay (two subgroups with n=6) was carried out to evaluate the bioavailability of two extemporaneous capsule of carbamazepine (200 mg): A-Formula® (A); and Formule® (B) in comparison to a tablet of the innovator product Tegretol® (C). Twelve healthy volunteers were randomly assigned to one of two arms to receive one test/reference formulation and following a two week wash-out period they received the other compound. Blood sampling was performed over 72 hours after dosing and levels of carbamazepine were determined by HPLC. Main findings of the study include that peak of plasma carbamazepine was faster following the extemporaneous capsules as compared to reference (Tmax: A: 6.58 h; B: 4.83 h vs 8.25-10.00 h, respectively), although no changes was observed in Cmax (A: 3.32 μg/mL; B: 3.10 μg/mL vs C: 3.14-2.85 μg/mL) neither in AUC0-t (A: 116.34 μg*h/mL; B: 145.66 μg*h/mL vs C: 123.18-138.37 μg*h/mL). The elimination half-life that ranged between 38.64-61.29 h but not difference were observed between all formulations. By using bioequivalence statistics it appears that A-Formula® or Formule® is bioequivalent to Tegretol® in terms of AUC0-t but not regarding Cmax. In conclusion, we demonstrated that two extemporaneous capsules of carbamazepine, A-Formula® and Formule® show similar concentration-time profiles to the reference tablet of immediate Tegretol®, however further studies with longer sample size are needed to confirm its bioequivalence and interchangeability.

In vitro and in vivo correlation of disintegration and bitter taste masking using orally disintegrating tablet containing ion exchange resin-drug complex

Although the taste-masking of bitter drug using ion exchange resin has been recognized, in vitro testing using an electronic tongue (e-Tongue) and in vivo bitterness test by human panel test was not fully understood. In case of orally disintegrating tablet (ODT) containing bitter medicine, in vitro and in vivo disintegration is also importance for dosage performance. Donepezil hydrochloride was chosen as a model drug due to its bitterness and requires rapid disintegration for the preparation of ODT. In this study, ion exchange resin drug complex (IRDC) at three different ratios (1:2, 1:1, 2:1) was prepared using a spray-drying method and then IRDC-loaded ODT containing superdisintegrants (crospovidone, croscarmellose sodium, and sodium starch glycolate) were prepared by the direct compression method. The physical properties and morphologies were then characterized by scanning electron microscopy (SEM), X-ray powder diffraction (PXRD) and electrophoretic laser scattering (ELS), respectively. The in vitro taste-masking efficiency was measured with an electronic tongue (e-Tongue). In vivo bitterness scale was also evaluated by human volunteers and then we defined new term, "bitterness index (BI)" to link in vitro e-Tongue. There was a good correlation of IRDC between in vitro e-Tongue values and in vivo BI. Furthermore, IRDC-loaded ODT showed good in vitro/in vivo correlation in the disintegration time. The optimal IRDC-loaded ODTs displayed similar drug release profiles to the reference tablet (Aricept(®) ODT) in release media of pH 1.2, pH 4.0, pH 6.8 and distilled water but had significantly better palatability in vivo taste-masking evaluation. The current IRDC-loaded ODT according to the in vitro and in vivo correlation of disintegration and bitter taste masking could provide platforms in ODT dosage formulations of donepezil hydrochloride for improved patient compliances.

Bioequivalence of a new liquid formulation of benazepril compared with the reference tablet product

To compare the bioequivalence and 'switchability' of two formulations of benazepril (tablet and liquid) after oral administration. Randomised cross-over design, followed by parallel comparison. Twelve mixed-breed dogs were administered either a tablet (Group A) or liquid formulation (Group B) of benazepril orally at 0.45 mg/kg daily for 4 days. With no washout period, the dogs then received the alternative treatment at the same dose for a further 4 days. Blood samples taken prior to treatment and serially after treatment were analysed for plasma concentrations of benazepril and benazeprilat and the activity and concentration of angiotensin-converting enzyme (ACE). The calculated percentage inhibition of ACE was defined as the primary outcome variable. No statistically significant differences were found between groups A and B for any variable evaluated. The mean (± SD) percentage of ACE inhibition was 85.5 ± 7.04% for the liquid formulation and 85.9 ± 6.66% for the tablet formulation. The mean of the ratios was 1.00 (80% confidence interval 0.96-1.04). No evaluated effect term (sequence, formulation or period) had any statistical effect on any outcome variable. This study supports a conclusion that, based on pharmacodynamic response, the liquid formulation of benazepril is bioequivalent to the reference tablet formulation. Further, the lack of a sequence effect supports the switchability of these two formulations.

Comparative evaluation of in vitro efficacy of colesevelam hydrochloride tablets

Context: Colesevelam hydrochloride is used as an adjunct to diet and exercise to reduce elevated low-density lipoprotein (LDL) cholesterol in patients with primary hyperlipidemia as well as to improve glycemic control in patients with type 2 diabetes. This is likely to result in submission of abbreviated new drug applications (ANDA).Objective: This study was conducted to compare the efficacy of two tablet products of colesevelam hydrochloride based on the in vitro binding of bile acid sodium salts of glycocholic acid (GC), glycochenodeoxycholic acid (GCDA) and taurodeoxycholic acid (TDCA).Methods: Kinetic binding study was carried out with constant initial bile salt concentrations as a function of time. Equilibrium binding studies were conducted under conditions of constant incubation time and varying initial concentrations of bile acid sodium salts. The unbound concentration of bile salts was determined in the samples of these studies. Langmuir equation was utilized to calculate the binding constants k1 and k2.Results: The amount of the three bile salts bound to both the products reached equilibrium at 3 h. The similarity factor (f2) was 99.5 based on the binding profile of total bile salts to the test and reference colesevelam tablets as a function of time. The 90% confidence interval for the test to reference ratio of k2 values were 96.06–112.07 which is within the acceptance criteria of 80–120%.Conclusion: It is concluded from the results that the test and reference tablets of colesevelam hydrochloride showed a similar in vitro binding profile and capacity to bile salts.

In vitro and in vivo evaluation of a self-microemulsifying drug delivery system for the poorly soluble drug fenofibrate

Fenofibrate is indicated in hypercholesterolemia and hypertriglyceridemia alone or combined (types IIa, IIb, III, IV, and V dyslipidemias). However, due to its low solubility in water, it has low bioavailability after oral administration. In order to improve the dissolution rate, fenofibrate was formulated into a self-microemulsifying drug delivery system (SMEDDS). We used pseudoternary phase diagrams to evaluate the area of microemulsification, and an in vitro dissolution test was used to investigate the dissolution rate of fenofibrate. The optimized formulation for in vitro dissolution and bioavailability assessment consisted of propylene glycol laurate (Lauroglycol FCC) (60%), macrogol-15-hydroxystearate (Solutol HS 15) (27%), and diethylene glycol monoethyl ether (Transcutol-P) (13%). The mean droplet size of the oil phase in the microemulsion formed by the SMEDDS was 131.1nm. The dissolution rate of fenofibrate from SMEDDS was significantly higher than that of the reference tablet. In vivo pharmacokinetics study of fenofibrate in beagles administered SMEDDS-A form resulted in a 3.7-fold increase in bioavailability as compared with the reference drug. Our studies suggested that the fenofibrate containing SMEDDS composition can effectively increase the solubility and oral bioavailability of poorly water-soluble drugs.

Pharmacokinetic Interactions of Valsartan and Hydrochlorothiazide: An Open-Label, Randomized, 4-Period Crossover Study in Healthy Egyptian Male Volunteers

BackgroundCo-administration of valsartan (VAL) and hydrochlorothiazide (HCT) has been used to regulate blood pressure. Compliance with a multiple medication regimen can be difficult for some patients; therefore, a combination of VAL + HCT tablets may be a suitable alternative. ObjectiveThis study was conducted to compare the rate and extent of absorption of VAL and HCT after oral administration as a fixed-dose combination (FDC) tablet and concomitant administration of the individual drugs under fasting conditions in healthy Egyptian subjects. The study was extended to investigate any potential interaction between VAL and HCT. MethodsThis study was conducted as an open-label, randomized study with 2 parts (parts I and II), with each part consisting of 4 single-dose treatment periods with a crossover design and 2-week washout periods. Blood samples were collected up to 48 hours postdose, and plasma was analyzed for VAL and HCT concentrations by using HPLC. The pharmacokinetic properties of each drug after co-administration of VAL and HCT were compared with those of each drug administered alone. Tolerability was assessed by physical examination and verbally questioning subjects regarding their well-being and any feelings of discomfort. All events reported by the subjects were recorded in adverse-event forms. ResultsForty-eight healthy subjects were enrolled (24 in each part), and all subjects completed the study. None of the participants showed any sign of adverse drug reactions during or after the completion of the study. Statistical analysis confirmed that the 90% CIs for AUC and Cmax of VAL/HCT FDC and VAL + HCT were within the commonly accepted bioequivalence range of 0.8 to 1.25. As a result, from an in vivo pharmacokinetic perspective, 1 FDC tablet could be considered interchangeable in medical practice with the 2 individual reference tablets. However, the 90% CIs between VAL alone and when administered with HCT, either as FDC or concomitantly, indicated the presence of an interaction between VAL and HCT, which would significantly decrease the systemic exposure and intensity of VAL absorption. The co-administration of HCT with VAL decreased the AUC and Cmax of HCT nonsignificantly compared with administration of HCT alone. ConclusionsBoth VAL/HCT FDC and VAL + HCT were well tolerated. The safety/efficacy profile of VAL + HCT co-administration therapy could be extended to the VAL/HCT FDC tablet. The interaction of HCT with other angiotensin-receptor blockers should be investigated to determine whether this interaction is limited to VAL or if other angiotensin-receptor blockers have the same pharmacokinetic interactions. Further studies are necessary to determine the role of efflux and influx transporters on VAL and HCT disposition and pharmacokinetics.