Dosage Form

pH modifiers are often used to promote drug solubility/ stability in dosage forms, but predicting the extent and duration of internal pH modification is difficult. Here, a noninvasive technique is developed for the spatial and temporal mapping of pH in a hydrated pharmaceutical pellet, within a pH range appropriate for microenvironmental pH control by weak acids. Confocal dual excitation imaging (Ex 488/Ex 568) of pellets containing a single, soluble, pH-sensitive fluorophore with cross-validation from a pH microelectrode. The technique was used to investigate the changing pH distribution in hydrating pellets containing two weak acids of differing solubility. The algorithm developed provided pH measurements over the range pH 3.5-5.5 with a typical accuracy of 0.1 pH units and with excellent correlation with pH microelectrode measurements. The method showed how pellets containing 25%w/w tartaric acid exhibited a rapid but transient fall in internal pH, in contrast to a slower more pr...

The prominent nitric oxide (NO) donor [Ru(terpy)(bdqi)NO](PF 6 ) 3 has been synthesized and evaluated with respect to noteworthy biological effects due to its NO photorelease, including vascular relaxation and melanoma cell culture toxicity. The potential for delivering NO in therapeutic quantities is tenable since the nitrosyl ruthenium complex (NRC) must first reach the "target tissue" and then release the NO upon stimulus. In this context, NRC-loaded lipid carriers were developed and characterized to further explore its topical administration for applications such as skin cancer treatment. NRC-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carriers were prepared via the microemulsification method, with average diameters of 275 ± 15 nm and 211 ± 31 nm and zeta potentials of −40.7 ± 10.4 mV and −50.0 ± 7.5 mV, respectively. In vitro kinetic studies of NRC release from nanoparticles showed sustained release of NRC from the lipid carriers and illustrated the influence of the release medium and the lyophilization process. Stability studies showed that NO is released from NRC as a function of temperature and time and due to skin contact. The encapsulation of NRC in SLN followed by its lyophilization, significantly improved the complex stability. Furthermore, of particular interest was the fact that in the NO photorelease study, the NO release from the NRC-loaded SLN was approximately twice that of just NRC in solution. NRC-loaded SLN performs well enough at releasing and protecting NO degradation in vitro that it is a promising carrier for topical delivery of NO.

To evaluate the efficacy and tolerability of once-daily extended release quetiapine fumarate (quetiapine XR) as monotherapy treatment for major depressive disorder (MDD). This 8-week (6-week active-treatment, randomized phase; 2-week posttreatment drug-discontinuation/tapering phase), multicenter, double-blind, randomized, parallel-group, placebo- and active-controlled, phase 3 study was conducted between April 2006 and May 2007. In total, 612 patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)-defined MDD were randomly assigned to quetiapine XR 150 mg/day or 300 mg/day, duloxetine 60 mg/day (active control), or placebo. The primary endpoint was the change from baseline to week 6 in Montgomery-Asberg Depression Rating Scale (MADRS) total score. At week 6, both doses of quetiapine XR (p < .001) and duloxetine (p < .01) significantly reduced mean MADRS total score versus placebo. A significant reduction was seen at week 1 with quetiapine XR 150 mg/day and 300 mg/day versus placebo (p < .01), but not with duloxetine. Response rates (>or= 50% reduction in MADRS total score) at week 6 were significantly higher for both doses of quetiapine XR (p < .01) and duloxetine (p < .05) versus placebo. Remission rates (MADRS score <or= 8) were significantly higher for quetiapine XR 300 mg/day and duloxetine versus placebo (p < .05), but not for quetiapine XR 150 mg/day. Hamilton Rating Scale for Depression, Hamilton Rating Scale for Anxiety, and Clinical Global Impressions-Severity of Illness total scores and the proportion of patients with Clinical Global Impressions-Improvement scores of 1 or 2 ("much/very much improved") were significantly improved with both doses of quetiapine XR and duloxetine versus placebo. The most common adverse events reported were dry mouth, sedation, and somnolence for quetiapine XR and nausea, headache, dizziness, and dry mouth for duloxetine. Quetiapine XR monotherapy (150 mg/day and 300 mg/day) is effective, with safety and tolerability consistent with the known profile of quetiapine XR, in the treatment of patients with MDD, with onset of symptom improvement demonstrated at week 1. clinicaltrials.gov Identifier: NCT00321490.

ObjectivesTo compare the efficacy, safety and tolerability of a novel rivastigmine transdermal patch with conventional rivastigmine capsules and placebo in patients with Alzheimer's disease (AD).To compare the efficacy, safety and tolerability of a novel rivastigmine transdermal patch with conventional rivastigmine capsules and placebo in patients with Alzheimer's disease (AD).MethodsIn this 24-week, multicenter, double-blind, double-dummy, placebo- and active-controlled trial, patients with probable AD were randomized to one of four treatment groups: 12 mg/day rivastigmine capsules; 10 cm2 (9.5 mg/24 h) rivastigmine patch; 20 cm2 (17.4 mg/24 h) rivastigmine patch; or placebo. Primary efficacy measures were the Alzheimer's Disease Assessment Scale—Cognitive subscale (ADAS-Cog) and Alzheimer's Disease Cooperative Study––Clinical Global Impression of Change (ADCS-CGIC).In this 24-week, multicenter, double-blind, double-dummy, placebo- and active-controlled trial, patients with probable AD were randomized to one of four treatment groups: 12 mg/day rivastigmine capsules; 10 cm2 (9.5 mg/24 h) rivastigmine patch; 20 cm2 (17.4 mg/24 h) rivastigmine patch; or placebo. Primary efficacy measures were the Alzheimer's Disease Assessment Scale—Cognitive subscale (ADAS-Cog) and Alzheimer's Disease Cooperative Study––Clinical Global Impression of Change (ADCS-CGIC).ResultsOne thousand one hundred and ninety five AD patients from 21 countries participated in the study. Treatment differences (vs placebo) on the ADAS-Cog at Week 24 in 10 cm2 patch, 20 cm2 patch and capsule groups were 1.6 (p = 0.005), 2.6 (p < 0.001) and 1.6 (p = 0.003). Treatment differences on the ADCS-CGIC were 0.3 (p = 0.01), 0.2 (p = 0.054) and 0.3 (p = 0.009). Comparison between the 10 cm2 patch and the capsule revealed non-inferiority. Rates of nausea in the 10 cm2 patch and capsule groups were 7.2% and 23.1%, respectively; rates of vomiting were 6.2% and 17.0%, respectively. Moderate or severe skin irritation occurred in ≤10% patients across the four patch sizes (5, 10, 15 and 20 cm2).One thousand one hundred and ninety five AD patients from 21 countries participated in the study. Treatment differences (vs placebo) on the ADAS-Cog at Week 24 in 10 cm2 patch, 20 cm2 patch and capsule groups were 1.6 (p = 0.005), 2.6 (p < 0.001) and 1.6 (p = 0.003). Treatment differences on the ADCS-CGIC were 0.3 (p = 0.01), 0.2 (p = 0.054) and 0.3 (p = 0.009). Comparison between the 10 cm2 patch and the capsule revealed non-inferiority. Rates of nausea in the 10 cm2 patch and capsule groups were 7.2% and 23.1%, respectively; rates of vomiting were 6.2% and 17.0%, respectively. Moderate or severe skin irritation occurred in ≤10% patients across the four patch sizes (5, 10, 15 and 20 cm2).ConclusionsThe target dose of 10 cm2 rivastigmine patch provides efficacy similar to the highest doses of capsules with a superior tolerability profile. The transdermal patch with rivastigmine may offer convenience important to many caregivers and patients. Copyright © 2007 John Wiley & Sons, Ltd.The target dose of 10 cm2 rivastigmine patch provides efficacy similar to the highest doses of capsules with a superior tolerability profile. The transdermal patch with rivastigmine may offer convenience important to many caregivers and patients. Copyright © 2007 John Wiley & Sons, Ltd.

Vitamin C exerts several functions on skin as collagen synthesis, depigmentant and antioxidant activity. Vitamin C is unstable in the presence of oxygen, luminosity, humidity, high temperatures and heavy metals, which presents a significant challenge to the development of cosmetic formulations. Therefore, the utilization of an effective antioxidant system is required to maintain the vitamin C stability. The purpose of this research work was to develop prototypes of cosmetic formulations, as O/W emulsion and extemporaneous aqueous gel, containing vitamin C and to evaluate the influence of sodium metabisulfite (SMB) and glutathione (GLT), as antioxidants, on the stability of the active substance. A HPLC stability-indicating method was developed and validated for this study and stability assays were performed in 90 and 26 days and storage conditions were 5.0 ± 0.5, 24 ± 2 and 40.0 ± 0.5 • C. The HPLC stability-indicating method showed linearity (r 2 > 0.99), specificity, R.S.D. < 1.22% and accuracy/recovery ranging from 95.46 to 101.54%. Preparations with SMB or GLT and the antioxidant-free presented results statistically distinct, demonstrating the necessity of the antioxidant system addition. O/W emulsions with SMB or GLT retained the vitamin C content >90.38% stored at 5.0 ± 0.5 and 24 ± 2 • C. For the aqueous gel with SMB or GLT, the active substance concentration was maintained >94.03%. Considering the vitamin C stability, the SMB and the GLT showed to be statistically adequate, as antioxidants, for the cosmetic formulations.

Voriconazole is a broad spectrum agent used to treat serious fungal infections. Stability studies conducted so far refer to the stability of the injectable formulation in different solvents, packaging materials and on storage but studies on the inherent chemical stability of the drug are not available. The purpose of this study was to evaluate the stability of the drug under stress conditions, in solution and in the solid state; isolate and elucidate the structure of the major degradation product and evaluate the antifungal activity of the degradation products. The quantification of the drug after exposure to degradation conditions was studied by a validated LC method. Among the conditions tested, it was found that the drug is more rapidly degraded in an alkaline medium, exposure to UVC radiation (254 nm) and elevated temperatures (60°C). Degradation was greater under the first two conditions and in solution. Tablets exposed to UVC radiation for 14 days remained chemically and physically stable. For the isolation of the major degradation product, semi-preparative LC was employed and for the structural elucidation, spectroscopic techniques ( 1 H and 13 C NMR spectroscopy, IR spectroscopy and mass spectrometry) were used, and the major degradation product identified as 1-(2,4-difluorophenyl)-2-(1H-1,2,4-triazol-1-yl)-1-ethanone. The degraded samples were evaluated through microbiological assay and found to have no antifungal activity.

Directly compressed theophylline tablets, containing commercial xanthan (X) (Keltrol ® ) and a highly hydrophilic galactomannan (G) from the seeds of Mimosa scabrella (a brazilian leguminous tree called bracatinga) as release-controlling agents, were obtained. Gums were used at 4, 8, 12.5 and 25% (w/w), either alone or in mixture (X:G 1:1). During galactomannan extraction process, the biopolymer was dried in a scale up, by vacuum oven (VO) or spray dryer (SD). The in vitro drug release was evaluated at different time intervals during 8 h using apparatus 1 (USP 26) at 100 rpm. The pH of the dissolution medium (1.4) was changed to 4.0 and 6.8 after 2 and 3 h, respectively. Tablets containing G(SD) resulted in more uniform drug release than G(VO) ones, due to their smaller particle size. The drug release decreased with the increase of polymer concentration and all formulations at 25% w/w of gums showed excessive sustained release effect. The matrices made with alone X showed higher drug retention for all concentrations, compared with G matrices that released the drug too fast. The XG matrices were able to produce near zero-order drug release. The XG(SD) 8% tablets provided the required release rate (about 90% at the end of 8 h), with zero-order release kinetics. Tablets containing G(VO) in low concentration showed a complete erosion, while the others demonstrated fast hydration and swelling in contact with the dissolution medium. The release mechanism was a combination of difusion and relaxation. The relative importance of these two processes varied with matrix composition. The XG(SD) 8% matrix showed higher contribution of polymer relaxation.

Electrospun fiber mats are explored as drug delivery vehicles using tetracycline hydrochloride as a model drug. The mats were made either from poly(lactic acid) (PLA), poly(ethylene-co-vinyl acetate) (PEVA), or from a 50:50 blend of the two. The fibers were electrospun from chloroform solutions containing a small amount of methanol to solubilize the drug. The release of the tetracycline hydrochloride from these new drug delivery systems was followed by UV-VIS spectroscopy. ® Release profiles from the electrospun mats were compared to a commercially available drug delivery system, Actisite (Alza Corporation, Palo Alto, CA), as well as to cast films of the various formulations.

0 This paper reports interactions and possible incompatibilities in solid dispersions of hydrophobic drugs with hydrophilic carriers, with solubility parameters employed as a means of interpreting results. Systems containing ibuprofen (IB) and xylitol (XYL) in varying proportions and systems of IB with other sugars and a sugar polymer were produced using solvent evaporation and fusion methods. Additionally, bridging agents were employed with IB/XYL systems to facilitate the production of a solid dispersion. Results show that IB formed no interactions with any of the sugar carriers but interacted with all the bridging agents studied. The bridging agents were immiscible with XYL in the liquid state. Results of other reported drug/ carrier systems and those from the systems studied in this paper were interpreted using Hildebrand solubility parameters. A trend between differences in drug/carrier solubility parameters and immiscibility was identified with incompatibilities evidence when large solubility parameter differences exist between drug and carrier. It was concluded that Hildebrand parameters give an indication of possible incompatibilities between drugs and carriers in solid dispersions, but that the use of partial solubility parameters may provide a more accurate prediction of interactions in and between materials and could provide more accurate indications of potential incompatibilities.