Dual thermal stabilizing effects of xanthan gums via glycosylation and hydrogen bonding and in vivo human bioavailability of desmopressin in orodispersible film.

Desmopressin acetate (DDAVP), a nonapeptide drug, is easily destroyed by heat in the manufacturing process of orodispersible film (ODF). A new challenging study was conducted to improve thermal stability through glycosylation and hydrogen bonding using carbohydrate gums (agar, arabic gum, carrageenan, xanthan gum) using the solvent casting method. Among gum types, xanthan gum strongly showed dual stabilizing effects of DDAVP via covalent glycosylation and hydrogen bonding, minimizing total impurities and optimizing physicochemical properties of ODF under accelerated conditions for six months. The optimized ODF formulation (O-DDAVP ODF) at a DDAVP and xanthan gum ratio of 1:1.5 had a pharmaceutically equivalent dissolution profile as compared with a commercial 0.2 mg commercial Minirin® tablet in four different media: pH 1.2, pH 4.0, and pH 6.8 buffers and deionized water. Furthermore, O-DDAVP ODF showed in vivo bioequivalence to Minirin® tablets in healthy human volunteers. Glycosylation-oriented stabilization of peptide drug using pharmaceutically active excipients against thermal denaturation could be challenged to design patient-friendly ODF.

Pharmacokinetic comparison between tablet of varenicline tartrate and orally disintegrating film of varenicline salicylate in healthy subjects.

OBJECTIVE: Varenicline is an efficacious aid for smoking cessation. In this study, the pharmacokinetics and safety were compared between film-coated tablets of varenicline tartrate (reference drug) and the newly developed orally disintegrating films of varenicline salicylate (test drug), both of them contained 1 mg of varenicline. MATERIALS AND METHODS: A randomized, open-label, single-dose, two-sequence, two-period crossover study was conducted in healthy male subjects. Serial blood samples were obtained for up to 72 hours in each period, with a washout period of 7 days or more. The pharmacokinetic parameters were calculated using the noncompartmental method. Safety profiles were assessed throughout the study. RESULTS: A total of 28 subjects completed the study. The plasma varenicline concentration-time profiles were similar for the two study drugs. The maximum plasma varenicline concentration (Cmax) was 5,768.95 ng/L (mean) and 5,780.55 ng/L for the test drug and reference drug, respectively. The areas under the concentration-time curve from time 0 to the last measurable time point (AUC0-t) were 94,086.30 h×ng/L and 89,958.55 h×ng/L for the test drug and reference drug, respectively. The geometric mean ratios (90% confidence intervals) of the test drug to the reference drug for Cmax and AUC0-t were 0.9955 (0.9488 - 1.0444) and 1.0449 (0.9848 - 1.1088), respectively, which fell within the bioequivalence range of 0.8 - 1.25. There was no difference in safety between the study drugs. CONCLUSION: The pharmacokinetics and safety profiles were similar between the two study drugs. The orally disintegrating film of varenicline salicylate can be an alternative to varenicline tartrate tablets.

Pharmacokinetics of a new orally soluble film formulation of sildenafil administered without water.

OBJECTIVE: To compare the pharmacokinetic profiles and to assess bioequivalence of a newly developed orally soluble film formulation of sildenafil, taken without water, with those of a conventional formulation of sildenafil. METHODS: This study was conducted in a population of healthy subjects as an open-label, randomized sequence, two-period, two-formulation, single-dose, crossover design. The subjects were randomly assigned to 1 of 2 sequences of the two formulations: an orally soluble film (OSF) of 50 mg sildenafil as the test drug and a film-coated tablet (FCT) of 50 mg sildenafil as the reference drug. Blood samples were collected at intervals from 0 to 24 hours after administration. Plasma concentrations of sildenafil and its active metabolite N-desmethyl sildenafil were analyzed using a liquid chromatography/tandem mass spectrometry method. RESULTS: 48 healthy male subjects completed the study. The geometric mean (CV%) for Cmax in the OSF and FCT formulations were 267.21 (4.68%) ng/mL and 285.97 (5.32%) ng/mL, respectively. The geometric mean for AUClast in the OSF and FCT formulations were 664.48 (4.40%) ng x h/mL and 647.96 (4.63%) ng x h/mL, respectively. The geometric mean for AUCinf in the OSF and FCT formulations were 685.65 (4.37%) ng x h/mL and 666.28 (4.60%) ng x h/ mL, respectively. The 90% confidence intervals of the ratios of the geometric means of the Cmax, AUClast, and AUCinf were 0.844 - 1.030, 0.961 - 1.091, and 0.965 - 1.093, respectively. CONCLUSIONS: The OSF sildenafil formulation exhibited no significant differences in its pharmacokinetics compared with those of the FCT formulation. Therefore this convenient OSF sildenafil formulation, which can be taken without the need for water or chewing, offers physicians a novel and attractive treatment option for men with erectile dysfunction. *These authors contributed equally to this work.

Solid dispersion formulations of megestrol acetate with copovidone for enhanced dissolution and oral bioavailability.

In order to enhance the dissolution profile and oral bioavailability of megestrol acetate (MA), solid dispersions of MA (MASDs) were formulated with copovidone and crystal sugar as a hydrophilic polymeric carrier and an inert core bead, respectively. Solvent evaporation method and fluidized bed coating technique were employed. MASDs were categorized as crystalline solid dispersion by the characterization of differential scanning calorimetry and X-ray diffraction. The mass-median diameters of MASDs were in a range of 1.4 to 2.6 µm. Based on drug to polymer ratio, MASD (1:1) and (1:2) were considered as optimized formulations, resulting in a smooth-surfaced homogeneously coated layer with enhanced dissolution rate. Dissolution of MASD was gradually increased up to 15 min, after which it reached a plateau. For the initial period, dissolution rates were in the decreasing order of MASD (1:2) ≥ MASD (1:1) > MASD (1:3) > MASD (1:5) > MASD (1:0.5) > MA powder. In the comparative pharmacokinetic study with Megace OS, a reference drug product, MASD (1:1) showed improved bioavailability of over 220% with 2-fold higher C(max) and 30% faster T(max). We conclude that MASD (1:1) is a good candidate for the development of oral solid dosage forms.