An investigation of physicochemical properties of piroxicam liquisolid compacts.

The potential of liquisolid systems to improve the dissolution properties of a water-insoluble agent (piroxicam) was investigated. In this study, physicochemical properties of piroxicam liquisolid tablets, effect of aging, and type of the carrier were also investigated. To this end, several liquisolid tablets formulations containing various ratios of drug: solvent and different carriers were prepared.

Piroxicam nanoparticles for ocular delivery: physicochemical characterization and implementation in endotoxin-induced uveitis.

To investigate the anti-inflammatory impacts of piroxicam nanosuspension, in the current investigation, piroxicam:Eudragit RS100 nanoformulations were used to control inflammatory symptoms in the rabbits with endotoxin-induced uveitis (EIU). The nanoparticles of piroxicam:Eudragit RS100 was formulated using the solvent evaporation/extraction technique. The morphological and physicochemical characteristics of nanoparticles were studied using particle size analysis, X-ray crystallography, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).

Liquisolid technique for dissolution rate enhancement of a high dose water-insoluble drug (carbamazepine).

Different liquisolid formulations of carbamazepine were accomplished by dissolving the drug in the non-toxic hydrophilic liquids, and adsorbing the solution onto the surface of silica. In order to reduce the amounts of carrier and aerosil in liquisolid formulations, some additives namely polyvinylpyrrolidone (PVP), hydroxypropyle methylcellulose (HPMC) and polyethylene glycol (PEG 35000) were added to liquid medication to increase loading factor. The effects of various ratios of carrier to coating material, PVP concentration, effect of aging and type of the carrier on dissolution rate of liquisolid compacts were studied.

Liquisolid technique as a tool for enhancement of poorly water-soluble drugs and evaluation of their physicochemical properties.

The potential of liquisolid systems to improve the dissolution properties of a water-insoluble agent (indomethacin) was investigated. In this study, different formulations of liquisolid tablets using different co-solvents (non-volatile solvents) were prepared and the effect of aging on the dissolution behaviour of indomethacin liquisolid compacts was investigated. To evaluate any interaction between indomethacin and the other components in liquisolid formulations, X-ray powder diffraction (XPD) and differential scanning calorimetry (DSC) were used.

Preparation and characterization of solid dispersions of piroxicam with hydrophilic carriers.

The objective of this study was to improve the dissolution rate of a poor water soluble drug, piroxicam, by solid dispersion technique. Solid dispersions were prepared by three different methods depending on the type of carrier. The dissolution rate of piroxicam was markedly increased in solid dispersion of myrj 52, Eudragit E100 and mannitol.

The effect of terpene concentrations on the skin penetration of diclofenac sodium.

Terpenes and sesquiterpenes have been suggested as promising non-toxic, non-irritating transdermal penetration enhancers. This investigation aimed to study the effect of terpene concentration on the transdermal absorption of diclofenac sodium from ethanol:glycerin:phosphate buffer solution (60:10:30). Therefore, enhancing effects of various terpenes (menthone, limonenoxide, carvone, nerolidol and farnsol) with different concentrations (0.

QSPR models for the prediction of apparent volume of distribution.

An estimate of volume of distribution (V(d)) is of paramount importance both in drug choice as well as maintenance and loading dose calculations in therapeutics. It can also be used in the prediction of drug biological half life. This study employs quantitative structure-pharmacokinetic relationship (QSPR) techniques for the prediction of volume of distribution.

The microsponge delivery system of benzoyl peroxide: preparation, characterization and release studies.

Benzoyl peroxide (BPO) is commonly used in topical formulations for the treatment of acne and athletes foot. Skin irritation is a common side effect, and it has been shown that controlled release of BPO from a delivery system to the skin could reduce the side effect while reducing percutaneous absorption. Therefore, the aim of the present study was to produce ethylcellulose microparticles containing BPO which were able to control the release of BPO to the skin.

Mechanistic evaluation of the effect of thermal-treating on Eudragit RS matrices.

Thermal treatment of acrylic matrices was recently introduced as a tool for prolonging the release of drug. Thermal treatment at temperatures above the T(g) of the polymer can decrease drug release rate. In this research we studied the mechanism of the effect of thermal treatment on Eudragit RS matrices.

The effect of type and concentration of vehicles on the dissolution rate of a poorly soluble drug (indomethacin) from liquisolid compacts.

Purpose: For poorly soluble, highly permeable (Class II) drugs, such as indomethacin, the rate of oral absorption is often controlled by the dissolution rate in the gastrointestinal tract. Therefore together with the permeability, the solubility and dissolution behaviour of a drug are key determinants of its oral bioavailability. The object of the present study is to increase dissolution rate of indomethacin using liquisolid compacts.

The influence of thermal treatment on the release behavior of diclofenac sodium from acrylic matrices.

The objective of this work was to investigate the effect of thermal treating on the release rate of diclofenac sodium from Eudragit RS and Eudragit RL matrices. Eudragit RS and RL are nonswelling polymers that have a low glass transition (Tg) temperature. The matrices were thermally treated at different temperatures (40, 50, 60, and 70 degrees C) for different periods of times (2, 5, and 24 h).

Enhancement of dissolution rate of piroxicam using liquisolid compacts.

Piroxicam is a poorly soluble, highly permeable drug and the rate of its oral absorption is often controlled by the dissolution rate in the gastrointestinal. The poor dissolution rate of water-insoluble drugs is still a major problem confronting the pharmaceutical industry. There are several techniques to enhance the dissolution of poorly soluble drugs.

In situ cross-linking of sodium alginate with calcium and aluminum ions to sustain the release of theophylline from polymeric matrices.

Small matrices of calcium alginate or aluminium alginate have been investigated as possible controlled release systems for drugs. The objective of the present study was to sustain the release of theophylline from alginate matrices using different concentrations of aluminium chloride and calcium chloride in presence and absence of HPMC. Tablets containing differing concentrations of aluminium and calcium chloride were produced and the release rate of theophylline was tested using the basket dissolution apparatus over 8 h.

The role of various surfactants on the release of salbutamol from suppositories.

Salbutamol is a selective beta(2)-adrenoreceptor agonist with different pharmacological effects. In this research because of the simplicity of suppository application in elderly and its higher plasma concentration than tablets as well as its particular indication in premature labour, salbutamol suppositories were prepared. The suppositories were formulated containing 10 mg of the drug and Witepsol H15, the oleaginous soluble base using melting method.

The effect of hydrophilic and lipophilic polymers and fillers on the release rate of atenolol from HPMC matrices.

The objective of this study is to investigate the effect of various polymers, and fillers, and their concentrations on the release rate of atenolol from polymeric matrices. Four polymers namely hydroxypropylmethylcellulose (HPMC), Eudragit RSPO, ethylcellulose (EC) and sodium carboxymethylcellulose (NaCMC) were used. The dissolution profiles showed that an increase in the concentration of HPMC and EC resulted in a reduction in the release rate of atenolol.

The effect of penetration enhancers on drug delivery through skin: a QSAR study.

Skin penetration enhancers are used to allow formulation of transdermal delivery systems for drugs that are otherwise insufficiently skin-permeable. A full understanding of the mode of action could be beneficial for the design of potent enhancers and for the choice of the enhancer to be used in the topical formulation of a special drug. In this study, the structural requirements of penetration enhancers have been investigated using the Quantitative Structure-Activity Relationship (QSAR) technique.

Physicochemical characterization of solid dispersions of indomethacin with PEG 6000, Myrj 52, lactose, sorbitol, dextrin, and Eudragit E100.

The purpose of this study was to prepare and characterize solid dispersions of indomethacin with polyethylene glycol (PEG) 6000, Myrj 52, Eudragit E100, and different carbohydrates such as lactose, mannitol, sorbitol, and dextrin. Indomethacin is a class II substance according to the Biopharmaceutics Classification System. It is a poorly water soluble antirheumatic agent.

Development and evaluation of buccoadhesive propranolol hydrochloride tablet formulations: effect of fillers.

The buccal mucosa has been investigated for local and systemic delivery of therapeutic peptides and other drugs that are subjected to first-pass metabolism or are unstable within the rest of the gastrointestinal tract. Propranolol hydrochloride (propranolol HCl) is subjected to first-pass effect, therefore formulation of buccal-adhesive dosage form can circumvent this effect. The effect of lactose (a soluble excipient) and dicalcium phosphate (DCP) (an insoluble excipient) on dissolution rate, kinetic of release and adhesion force of buccal-adhesive tablets of propranolol HCl were evaluated.

The enhancement effect of surfactants on the penetration of lorazepam through rat skin.

Lorazepam is an anxiolytic, antidepressant agent, having suitable feature for transdermal delivery. The percutaneous permeation of lorazepam was investigated in rat skin after application of a water:propylene glycol (50:50%v/v). The enhancing effects of various surfactants (sodium lauryl sulfate (SLS), cetyltrimethylammonium bromide (CTAB), benzalkonium chloride or Tween 80) with different concentrations on the permeation of lorazepam were evaluated using Franz diffusion cells fitted with rat skins.

The effect of glycyrrhizin on the release rate and skin penetration of diclofenac sodium from topical formulations.

The influence of glycyrrhizin extracted from Glycyrrhiza glabra var. glandulifera (licorice roots) on the percutaneous absorption of diclofenac sodium from sodium carboxymethylcellulose (NaCMC) gels or oil-in-water (o/w) emulsion was investigated. Skin permeation experiments were carried out using excised abdominal rat skin.

Crystal modification of phenytoin using different solvents and crystallization conditions.

Phenytoin crystals having different types of habits, were prepared by recrystallization from ethanol and acetone solutions under different conditions (cooling rate or crystallization temperature, solvent evaporation and watering-out techniques). Scanning electron microscopy, X-ray powder diffractometry, FT-IR spectrometry and differential scanning calorimetry were used to investigate the physical characteristics of the crystals. The dissolution behavior and compaction properties of various batches of crystals were also studied.

The effect of various surfactants on the release rate of propranolol hydrochloride from hydroxypropylmethylcellulose (HPMC)-Eudragit matrices.

Hydrophilic and lipophilic polymers are widely used excipients to control the release rate of drugs from matrices. Researchers found that surfactants are able to control the release rate of drugs. The aim of the present investigation is to determine the effects of surfactant type, its concentration and the different ratios of surfactants on the release rate of highly soluble drug (propranolol HCl).

Thermal treating as a tool for sustained release of indomethacin from Eudragit RS and RL matrices.

Eudragit RS and RL are biocompatible non-swelling polymers that widely used in the preparation of sustained release drug delivery systems. In this study, the effect of thermal treating on the tensile strength of tablets and release of indomethacin from Eudragit RS and RL matrices were investigated. The results showed that thermal treating at 40 degrees C has no effect on the release of the drug, whereas heat-treating at temperatures higher than 50 or 60 degrees C decreases the release rate of indomethacin from Eudragit RS or RL, respectively.

Prediction of benzodiazepines solubility using different cosolvency models.

The solubility of four benzodiazepines (BZPs) including diazepam (DIZ), lorazepam (LRZ) clonazepam (CLZ), and chlordiazepoxide (CHZ) in water-cosolvent (ethanol propylene glycol and polyethylene glycol 200) binary systems were studied. In general, increasing the volume fraction of cosolvents resulted in an increase in the solubility of benzodiazepines. The mole fraction solubilities were fitted to the various cosolvency models, namely extended Hildebrand approach (EHA), excess free energy (EFE), combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K), general single model (GSM), mixture response surface (MR-S).

The effect of surfactants on the skin penetration of diazepam.

The percutaneous permeation of diazepam was investigated in rat skin after application of a water-propylene glycol (50:50% v/v) using a diffusion cell technique. The effect of various surfactants (sodium lauryl sulfate (SLS), cetyltrimethylammonium bromide (CTAB), benzalkonium chloride or Tween 80) with different concentrations on skin permeability were evaluated. Flux, K(p), lag time and enhancement ratios (ERs) of diazepam were measured over 10 h and compared with control sample (containing no surfactant).