Nonionic surfactant structure on the drug release, formulation and physical properties of ethylcellulose microspheres.

Evaluate the effects of nonionic surfactants Brij 58 and Tween 40 with different structures but similar hydrophilic lipophilic balances (HLBs) on theophylline (TH)-loaded ethylcellulose (EC) microspheres. Microspheres were formulated using ratios of the surfactants with matching HLB values but different chemical-structures at temperatures (22/35 °C) by hydrophobic solvent-emulsion evaporation. Particle size, GMD, drug loading, encapsulation efficiency and dissolution were evaluated.

Formulation parameters and release mechanism of theophylline loaded ethyl cellulose microspheres: effect of different dual surfactant ratios.

Altering the combined hydrophilic-lipophilic balance (CHLB), by varying the ratio of dual surfactants, on formulation parameters and in vitro drug release of ethyl cellulose microspheres was examined. Theophylline, a xanthine bronchodilator was used to model controlled release owing to its narrow therapeutic index. Microspheres were prepared using different ratios of dual surfactant in an emulsion-solvent evaporation process.

Transdermal permeation of novel n-acetyl-glucosamine/NSAIDs mutual prodrugs.

The current investigation reports skin permeation of three novel mutual prodrugs (MP) which couple n-acetyl-glucosamine with an NSAID, either ketoprofen or ibuprofen. They were evaluated for transdermal permeation using shed snakeskin, and to our knowledge represent the first MPs synthesized for this purpose, although they also could be used for subcutaneous delivery. MPs are defined as two active drug compounds usually connected by an ester linkage.

Accelerated dissolution testing for controlled release microspheres using the flow-through dissolution apparatus.

Theophylline controlled release capsules (THEO-24 CR) were used as a model system to evaluate accelerated dissolution tests for process and quality control and formulation development of controlled release formulations. Dissolution test acceleration was provided by increasing temperature, pH, flow rate, or adding surfactant. Electron microscope studies on the theophylline microspheres subsequent to each experiment showed that at pH values of 6.