Preparation and in vitro/in vivo evaluation of metformin hydrochloride rectal dosage forms for treatment of patients with type II diabetes.

Background: Metformin hydrochloride (MtHCL) is an oral antidiabetic drug and has many other therapeutic benefits. It has poor bioavailability, narrow absorption window and extensive liver metabolism. Moreover, children and elders face difficulty to swallow the commercial oral tablets.

In vitro and in vivo permeation of vitamin E and vitamin E acetate from cosmetic formulations.

Objective: To investigate the ability of α-tocopherol acetate (TA) and α-tocopherol (T), widely used ingredients in cosmetics, to cross the epidermal barrier using the neonatal rat as a model.

Materials And Methods: The content of T and TA in four marketed products (A-D) and two experimental formulations (F1, F2) was investigated by HPLC. An in vitro permeation study was performed in neonatal rat epidermis using diffusion cells.

Analysis of vitamin E in commercial cosmetic preparations by HPLC.

A specific HPLC method, with an RP-C-18 column and a UV detector, for simultaneous determination of vitamin E (tochopherol, T)/T acetate (TA) in four commercial and two experimental cosmetic products is described. Three solvent systems for extraction of T/TA were assessed: isopropyl alcohol; 10:90 v/v hexane-methanol mixture (method 1); and methanol alone (method 2). The procedure was accurate, as indicated by high recovery (97.

Physicochemical characterization of gliclazide-macrogol solid dispersion and tablets based on optimized dispersion.

Background: This study investigated the physical interaction of gliclazide (GLC) with a hydrophilic carrier, that is, macrogol [polyethylene glycol (PEG)]. Different molecular weights of PEG (4000, 10,000, and 20,000) were used in different drug : carrier weight ratios (1 : 1, 1 : 2, 1 : 5, and 1 : 10).

Method: Preliminary screening was done by phase solubility studies to characterize the liquid state interaction between the drug and the carrier.

Comparison between lipolysis and compendial dissolution as alternative techniques for the in vitro characterization of alpha-tocopherol self-emulsified drug delivery systems (SEDDS).

In vitro characterization of alpha-tocopherol SEDDS formulations was performed by (1) lipolysis in bio-relevant media, and (2) physical assessment by dissolution, particle size, and turbidity analyses. Both methods were statistically correlated using a 25-run, five-factor multiple-level d-optimal mixture design. Independent variables were SEDDS composition [vitamin E (12.

Bioavailability assessment of vitamin A self-nanoemulsified drug delivery systems in rats: a comparative study.

Objectives: To assess and compare the bioavailability of three different oral dosage forms of vitamin A in rats. The formulations included vitamin A self-nanoemulsified drug delivery (SNEDD) optimized formulation-filled capsule (F1), vitamin A SNEDD optimized formulation compressed tablet (F2) and vitamin A oily solution-filled capsules without any additives (control, F3).

Materials And Methods: Bioavailability was assessed after a single oral dose of the three formulations using three groups of rats, each group comprising 6 rats.

Response surface methodology to obtain beta-estradiol biodegradable microspheres for long-term therapy of osteoporosis.

The purpose of this work was to evaluate the main and interaction effects of formulation factors on the drug encapsulation efficiency of beta-estradiol biodegradable microspheres by applying response surface methodology. A secondary purpose was to obtain an optimized formula for long-term therapy of osteoporosis. A three factor, three level Box-Behnken experimental design was used to get 15 experimental runs.

Biodegradable microparticulates of beta-estradiol: preparation and in vitro characterization.

Beta-estradiol has been recommended for the long-term therapy of osteoporosis and its oral formulations are subjected to intensive first pass metabolism. The present investigation was aimed at preparing and characterizing biodegradable microparticles of beta-estradiol with polymers such as PLA, PLGA 85/15, PLGA 75/25, and their mixtures. The microparticles were prepared by solvent evaporation method using methylene chloride as a solvent and polyvinyl alcohol as a surfactant.

Pulmonary absorption of insulin mediated by tetradecyl-beta-maltoside and dimethyl-beta-cyclodextrin.

Purpose: To determine if tetradecyl-beta-maltoside (TDM) and dimethyl-beta-cyclodextrin (DMbetaCD) enhance pulmonary absorption of insulin and to investigate if they do so by a reversible action on respiratory epithelium.

Methods: Insulin formulated with saline, TDM, or DMbetaCD was administered intratracheally, after laryngoscopic visualization, as a spray to anesthetized rats. Reversibility studies were conducted in intact rats by administering insulin at different time points after administration of TDM or DMbetaCD.

Development of a HPLC method for the determination of cyclosporin-A in rat blood and plasma using naproxen as an internal standard.

An isocratic reversed phase high-performance liquid chromatographic (HPLC) method with ultraviolet detection at 205 nm has been developed for the determination of cyclosporin-A (CyA) in rat blood and plasma. Naproxen was successfully used as an internal standard. Blood or plasma samples were pretreated by liquid-liquid extraction with diethyl ether.

Salbutamol sulfate suppositories: influence of formulation on physical parameters and stability.

Purpose: To prepare and evaluate a suppository dosage form of salbutamol sulfate. The prepared formulae with and without different concentrations of gels were tested for hardness, melting time, content uniformity, and drug release. The stability of some of the selected formulae was assessed.

Effect of Azone upon the in vivo antiviral efficacy of cidofovir or acyclovir topical formulations in treatment/prevention of cutaneous HSV-1 infections and its correlation with skin target site free drug concentration in hairless mice.

The purpose of this study is to examine the influence of Azone upon the skin target site free drug concentration (C(*)) and its correlation with the in vivo antiviral efficacies of cidofovir (HPMPC) and acyclovir (ACV) against HSV-1 infections. Formulations of HPMPC and ACV with or without Azone were used. The in vitro skin flux experiments were performed and the C(*) values were calculated.

Bioavailability assessment of oral coenzyme Q10 formulations in dogs.

The purpose of this investigation was to compare the bioavailability of three coenzyme Q10 (CoQ10) formulations in dogs using an open, randomized, multiple-dose crossover design. The formulations included a powder-filled capsule (A, control) and two soft gelatin formulations (Q-Gel as the water-miscible form of CoQ10, B and Q-Nol as the water-miscible form of ubiquinol, the reduced form of CoQ10, C). Formulations were evaluated in pairs, allowing a washout period of 14 days prior to crossing over.