Effect of methotrexate conjugated PAMAM dendrimers on the viability of MES-SA uterine cancer cells.

The aim of this work was to synthesize methotrexate (MTX)-polyamidoamine (PAMAM) dendritic nanoconjugates and to study their effect on cell viability in uterine sarcoma cells. The amide-bonded PAMAM dendrimer-MTX conjugates were prepared by conjugation between the amine-terminated G5 dendrimer and the carboxylic groups of the MTX using a dicyclohexylcarbodiimide coupling reaction. The formation of conjugates was evaluated by ultraviolet (UV) and (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy studies. The cell survival of MES-SA cells, a uterine sarcoma cell line, was evaluated in the presence of the dendrimer-MTX nanoconjugate, using appropriate controls. The UV and (1)H NMR study confirmed the formation of covalent bonds between the drug and the dendrimer. The cell viability study indicated that the nanoconjugates had significantly improved cell killing compared to the free MTX.

Recent Trends in Detection of Huntingtin and Preclinical Models of Huntington's Disease.

Huntington's disease is a genetically inherited neurodegenerative disease that is characterized by neuronal cell death in the brain. Molecular biology techniques to detect and quantify huntingtin protein in biological samples involve fluorescence imaging, western blotting, and PCR. Modified cell lines are widely used as models for Huntington's disease for preclinical screening of drugs to study their ability to suppress the expression of huntingtin. Although worm and fly species have been experimented on as models for Huntington's disease, the most successful animal models have been reported to be primates. This review critically analyses the molecular biology techniques for detection and quantitation of huntingtin and evaluates the various animal species for use as models for Huntington's disease.

RNAi-based therapies for Huntington's disease: delivery challenges and opportunities.

Huntington's disease (HD) is a polyglutamine neurodegenerative disease caused by a mutation in the HTT gene coding for the Huntingtin protein (HTT). Unfortunately, there is no cure for HD and there is also no known way to modify the disease progression. RNAi approaches offer the promise of a certain degree of control over the disease. However, there are several challenges in potential use of RNAi in the treatment of HD. This article will discuss the details of RNAi technology as applied to the treatment of HD, and novel approaches to overcome the drug delivery challenges.

Designing Paclitaxel drug delivery systems aimed at improved patient outcomes: current status and challenges.

Paclitaxel is one of the most widely used and effective antineoplastic agents derived from natural sources. It has a wide spectrum of antitumor activity, particularly against ovarian cancer, breast cancer, nonsmall cell lung cancer, head and neck tumors, Kaposi's sarcoma, and urologic malignancies. It is a highly lipophilic compound with a log P value of 3.96 and very poor aqueous solubility of less than 0.01 mg/mL. In addition, the compound lacks functional groups that are ionizable which could potentially lead to an increase in its solubility with the alteration in pH. Therefore, the delivery of paclitaxel is associated with substantial challenges. Until the introduction of Abraxane, only commercial formulation was solution of paclitaxel in cremophor, which caused severe side effects. However, in recent years, a number of approaches have been reported to solubilize paclitaxel using cosolvents and inclusion complexes. In addition, innovative approaches have been reported for passive targeting of tumors using nanoparticles, nanosuspensions, liposomes, emulsions, micelles, implants, pastes and gels. All approaches for delivery of improved therapeutic outcome have been discussed in this paper.

Late-night salivary cortisol in normal subjects and in patients with Cushing's syndrome.

BACKGROUND: Late-night salivary cortisol is used as a screening test for Cushing's syndrome (CS) in many European and American countries. However, its utility has not been studied in an Asian-Indian population. OBJECTIVE: To establish the reference range in Asian-Indians and to evaluate its usefulness in the diagnosis of CS. METHODS: Three groups of subjects were studied: normal subjects, patients with suspected CS, and patients with proven CS. All participants collected saliva at 23:00 h using a Salivette. Salivary cortisol was measured using an automated electrochemiluminescence assay. RESULTS: There were 56 normal subjects, 40 patients with suspected CS, and 30 with proven CS. Of the 40 with suspected CS, three were confirmed to have CS. The remaining 37 served as control patients. The 97.5th centile of the late-night salivary cortisol concentrations in normal subjects was 10.87 nmol/l. The mean+/-SD 23:00 h salivary cortisol concentration in control patients and those with confirmed CS was 3.21+/-2.36 nmol/l and 32.33+/-44.14 nmol/l, respectively. All the control patients and 30.3% (10/33) of patients with CS had a salivary cortisol concentration of <10.87 nmol/l. With the use of a receiver operating characteristic curve, a cut-off of 4.55 nmol/l gave a sensitivity of 93.9% and specificity of 81.1%. However, as this cut-off is less than the functional sensitivity of the assay, it may not be clinically applicable. CONCLUSIONS: The reference range for late-night salivary cortisol in our population was <10.87 nmol/l. With this cut-off, the sensitivity was 69.2% and specificity 100%. Even though this automated electrochemiluminescence assay is easy and quick to use, its clinical utility in measuring the low salivary cortisol concentrations needs further investigation.

Effect of microfluidization parameters on the physical properties of PEG-PLGA nanoparticles prepared using high pressure microfluidization.

The objective of this work was to develop uniformly distributed poly(ethylene glycol) grafted poly(lactide-co-glycolide) (PEG-PLGA) nanoparticles of mean size range approximately 100-200 nm using ethyl acetate as the solvent. In the multiple emulsion solvent evaporation method a high pressure microfluidization process was adopted to produce the W/O/W multiple emulsion. Non-toxic ethyl acetate was used to solubilize PEG-PLGA. The mean size of nanoparticles obtained was less than 180 nm. The particle size and size distribution were dependent on the microfluidization conditions applied. Mean particle size steadily increased from 121 nm at three passes to 172 nm at 20 passes of the microfluidizer, indicating that over-processing may be detrimental to PEG-PLGA nanoparticles prepared using this technique. There was no significant alteration of the PEG-PLGA matrix, as evidenced from the differential scanning calorimetric studies.

Effect of excipient and processing variables on adhesive properties and release profile of pentoxifylline from mucoadhesive tablets.

The bioavailability and onset of action of drugs with high first-pass metabolism can be significantly improved by administration via the sublingual route. The objective of this study was to evaluate the effect of polymer type and tablet compaction parameters on the adhesive properties and drug release profile from mucoadhesive sublingual tablet formulations. Pentoxifylline was selected as the model drug because it has poor oral bioavailability due to extensive first-pass metabolism. Two polymers known to possess mucoadhesive properties, carbomer and hydroxypropyl methyl cellulose (HPMC), were used to prepare the formulations. Tablets were prepared by using direct compression technique and evaluated for in vitro dissolution, drug-excipient interactions, and adhesive properties. In general, there was a decrease in the rate of drug release with an increase in the concentration of polymers. No drug-excipient interactions were evident from differential scanning calorimetry or high-performance liquid chromatography analysis. For the formulations containing HPMC, the force of mucoadhesion increased with an increase in the concentration of polymer; however, for carbomer formulations, no such correlation was observed. Force of mucoadhesion decreased as a function of hydration time in both of the polymers.

Development of mucoadhesive dosage forms of buprenorphine for sublingual drug delivery.

The development of mucoadhesive formulations of buprenorphine for intended sublingual usage in the treatment of drug addiction is described. The formulations include mucoadhesive polymer films, with or without plasticizers, and mucoadhesive polymer tablets, with or without excipients that enhance drug release and/or improve tablet compaction properties. The mucoadhesive polymers studied include carbomers such as Carbopol 934P, Carbopol 974P, and the polycarbophil Noveon AA-1, with excipients chosen from pregelatinized starch, lactose, glycerol, propylene glycol, and various molecular weights of polyethylene glycol. The development of plasticizer-containing mucoadhesive polymer films was feasible; however, these films failed to release their entire drug content within a reasonable period. Thus, they were not determined suitable for sublingual usage because of possible loss by ingestion during routine meal intakes. The mucoadhesive strength of tablet formulations containing Noveon AA-1 appears to be slightly superior to the Carbopol-containing tablets. However, the Carbopol 974P formulations exhibited superior drug dissolution profiles while providing adequate mucoadhesive strength. The tablet formulations containing Carbopol 974P as mucoadhesive polymer, lactose as drug release enhancer, and PEG 3350 as compaction enhancer exhibited the best results. Overall, the mucoadhesive tablet formulations exhibited superior results compared with the mucoadhesive film formulations.