Using Supercritical Fluid Technology (SFT) in Preparation of Tacrolimus Solid Dispersions.

Tacrolimus is an immunosuppressant agent that suffers from poor and variable bioavailability. This can be related to limited solubility and dissolution. The main objective of this study is to use SFT to prepare solid dispersions of tacrolimus in order to enhance its dissolution.

Drying Using Supercritical Fluid Technology as a Potential Method for Preparation of Chitosan Aerogel Microparticles.

Supercritical fluid technology offers several advantages in preparation of microparticles. These include uniformity in particle size, morphology, and drug distribution without degradation of the product. One of the recent advantages is preparation of porous aerogel carrier with proper aerodynamic properties.

Preparation and characterization of microemulsion formulations of nicotinic acid and its prodrugs for transdermal delivery.

At pharmacological doses, nicotinic acid has a lipid-regulating effect and is in use clinically for that purpose. However, despite of all features, its utility is strongly limited by several disadvantages such as, extensive hepatic metabolism and flushing. Transdermal delivery of nicotinic acid may, therefore, be the solution to reducing side effects associated with oral administration, and to maintaining constant therapeutic blood levels for longer duration.

The hydrolysis kinetics of monobasic and dibasic aminoalkyl esters of ketorolac.

Six aminoethyl and aminobutyl esters of ketorolac containing 1-methylpiperazine (MPE and MPB), N-acetylpiperazine (APE and APB) or morpholine (ME and MB), were synthesized and their hydrolysis kinetics were studied. The hydrolysis was studied at pH 1 to 9 (for MPE, APE and ME) and pH 1 to 8 (for MPB, APB and MB) in aqueous phosphate buffer (0.16 M) with ionic strength (0.

Chemical and in vitro enzymatic stability of newly synthesized celecoxib lipophilic and hydrophilic amides.

Five celecoxib (CXB) acylamide sodium salts, MP-CXB, Cy-CXB, Bz-CXB, CBz-CXB and FBz-CXB were synthesized and characterized. Two simple, fast and validated RP-HPLC methods were developed for simultaneous quantitative determination of the amides and celecoxib in aqueous and biological samples and LOD and LOQ were ≤13.6 and ≤40ng/mL, respectively.

Synthesis, characterization and in vitro hydrolysis of a gemfibrozil-nicotinic acid codrug for improvement of lipid profile.

Combination therapy of fibrates and nicotinic acid has been reported to be synergistic. Herein, we describe a covalent codrug of gemfibrozil (GEM) and nicotinic acid (NA) that was synthesized and characterized by (1)H NMR, (13)C NMR, FT-IR, MS analysis and elemental analysis. A validated HPLC method was developed that allows for the accurate quantitative determination of the codrug and its hydrolytic products that are formed during the in vitro chemical and enzymatic hydrolysis.

A promising codrug of nicotinic acid and ibuprofen for managing dyslipidemia. I: synthesis and in vitro evaluation.

Nicotinic acid is therapeutically the optimum antihyperlipidemic agent, yet its intolerable cutaneous flushing hinders its wide clinical implication. The codrug of nicotinic acid and ibuprofen (IBP) was synthesized in the aim of overcoming the troublesome side effect of nicotinic acid by blockade of prostaglandin synthesis through released IBP, thus enhance patient's compliance. The physico-chemical properties of codrug namely solubility, partition coefficient, and pKa were determined.

Validation of a simple and rapid HPLC method for determination of metronidazole in dermatological formulations.

A rapid and simple method using an isocratic high-pressure liquid chromatography (HPLC) and UV detection for the determination of metronidazole in dermatological formulations is presented. Metronidazole samples were extracted with a solution composed of 60% methanol and 40% mobile phase by a procedure that can be completed in less than 10 min. Subsequent separation and quantification was accomplished in less than 20 min using reversed-phase HPLC with isocratic elution with 0.

UVA is the major contributor to the photodegradation of tretinoin and isotretinoin: Implications for development of improved pharmaceutical formulations.

The chemical stability of tretinoin (RA) and isotretinoin (13RA) in ethanol and dermatological cream preparations exposed to solar simulated light (SSL), UVA, and visible light has been studied. Photostability was monitored by an HPLC method that allowed simultaneous analysis of RA and 13RA, thus allowing photodegradation due to isomerization to other retinoids and photolysis to non-retinoid products to be monitored. Both retinoids undergo both isomerization and photolysis following SSL, UVA and visible light exposure but RA is more sensitive to photodegradation than 13RA.

Formulation compatibility of myristyl nicotinate with drugs used to treat dermatological conditions involving an impaired skin barrier.

A number of dermatology conditions including skin photodamage, atopic dermatitis, and rosacea involve skin barrier impairment and first line therapies for these conditions including retinoids and steroids further impair skin barrier function. We have evaluated the compatibility of myristyl nicotinate, an agent that enhances skin barrier function, with drugs used to treat conditions where skin barrier impairment is present including photodamage (retinoic acid), atopic dermatitis (hydrocortisone, triamcinolone acetonide), rosacea (metronidazole), and seborrheic dermatitis (ketoconazole). Myristyl nicotinate was found to be compatible with each of the drugs examined when formulated together and also was shown to be photocompatible with retinoic acid.

Analysis and stability study of myristyl nicotinate in dermatological preparations by high-performance liquid chromatography.

Myristyl nicotinate is an ester prodrug under development for delivery of nicotinic acid to skin for treatment and prevention of conditions that involve skin barrier impairment such as chronic photodamage and atopic dermatitis or for mitigating skin barrier impairment that results from therapy such as retinoids or steroids. The formulation stability of myristyl nicotinate is crucial because even small amounts of free nicotinic acid cause skin flushing, an effect that is not harmful but would severely limit tolerability. We report here reversed-phase HPLC methods for the rapid analysis of myristyl nicotinate and nicotinic acid in dermatological preparations.

A rapid HPLC method for simultaneous determination of tretinoin and isotretinoin in dermatological formulations.

A rapid method using an isocratic high-pressure liquid chromatography and UV detection for determination of both all-trans retinoic acid (tretinoin) and 13-cis retinoic acid (isotretinoin) in dermatological preparations is presented. Tretinoin and isotretinoin samples were extracted with acetonitrile by a procedure that can be completed in less than 10 min. Subsequent separation and quantification of amounts as low as 10 pmol was accomplished in less than 15 min using reversed-phase HPLC with isocratic elution with 0.

In vitro and in vivo evaluation of glibenclamide in solid dispersion systems.

The purpose of this work is to improve the dissolution and bioavailability characteristics of glibenclamide as compared to Daonil tablets (Hoechst). Solid dispersions of glibenclamide in Gelucire 44/14 (Formula 1) and in polyethylene glycol 6000 (PEG 6000) (Formula 2) were prepared by fusion method. In vitro dissolution studies showed that the dispersing systems containing glibenclamide and Gelucire 44/ 14 or PEG 6000 gave faster dissolution rates than the reference product Daonil.

Determination of ketotifen in human plasma by LC-MS.

Analytical validation of a new liquid chromatographic-mass spectrometric (LC-MS) method for determination of total amount of ketotifen (unchanged and conjugated) in human plasma is presented. Pizotifen was used as an internal standard. An enzyme hydrolysis of conjugated ketotifen was conducted with a combination of beta-glucuronidase and aryl sulfatase.

Effect of microenvironment pH of swellable and erodable buffered matrices on the release characteristics of diclofenac sodium.

The aim of this work is to design pH-dependent swellable and erodable-buffered matrices and to study the effect of the microenvironment pH on the release pattern of diclofenac sodium. Buffered matrix tablets containing diclofenac sodium, physically mixed with hydrophilic polymer (hydroxypropyl methylcellulose [HPMC]) and pH-dependent solubility polymer (Eudragit L100-55) were prepared with different microenvironment pHs. The release of diclofenac sodium from the buffer matrices was studied in phosphate buffer solutions of pH 5.