Sustained release microspheres of ropinirole hydrochloride: Effect of process parameters

Abstract

Numerous carriers and encapsulation techniques have been evaluated for preparation of microcapsules with sustained-release properties. However, literature survey revealed that most of the drugs used were relatively water-insoluble. While water insoluble compounds have inherent sustained-release properties when incorporated in a polymer matrix and are relatively easy to encapsulate, preparation of sustained release microcapsules of water-soluble pharmaceuticals pose a great challenge (3). Among the various methods developed for formulation of microspheres, the solvent evaporation method has gained much attention due to its ease of fabrication without compromising the activity of the drug (4).Ropinirole hydrochloride is a selective non-ergoline dopamine D2 receptor agonist indicated for use in treating Parkinson's disease. It is a potent drug with a dose of 2 mg to be administered 3-4 times daily. It is a highly water-soluble drug (133 mg mL -1 ) with plasma half-life of 6 h (5). It is also soluble in dichloromethane (DCM), methanol, ethanol, etc. Results from efficacy and safety trials showed that adding extended release ropinirole to the patients on levodopa therapy reduced the amount of "off" time experienced by the An emulsion solvent evaporation method was employed to prepare microspheres of ropinirole hydrochloride, a highly water soluble drug, by using ethylcellulose and PEG with the help of 3 2 full factorial design. The microspheres were made by incorporating the drug in a polar organic solvent, which was emulsified using liquid paraffin as an external oil phase. Effects of various process parameters such as viscosity of the external phase, selection of the internal phase, surfactant selection and selection of stirring speed were studied. Microspheres were evaluated for product yield, encapsulation efficiency and particle size. Various drug/ethylcellulose ratios and PEG concentrations were assayed. In vitro dissolution profiles showed that ethylcellulose microspheres were able to control release of the drug for a period of 12 h.

Spray-dried alginate microparticles for potential intranasal delivery of ropinirole hydrochloride: development, characterization and histopathological evaluation

“…However, the exothermic peak was absent when the polymer to drug ratio was low. The sharp endothermic peak observed for RH (raw material) at 248.57 o C (∆H = 117.35 J/g) represents its melting point, and indicates the high crystallinity of the drug, as also shown in other studies (Avachat et al, 2011). However, as the polymer ratio in the A c c e p t e d M a n u s c r i p t formulation is increased, the sharpness of the drug's endothermic peak is decreased with a forward shift of the onset temperature of the endotherm (from 212.58 to 224.88 o C) ( Figure 8); this indicates partial loss of crystallinity of RH upon incorporation into the microspheres.…”

Some physico-chemical properties of Prunus armeniaca L. gum exudates

“…The molecular weight was measured by gel permeation chromatography (GPC) at 25 C , using A c c e p t e d M a n u s c r i p t 7 Consistency coefficient and flow behaviour index values were calculated using Power law model:…”

Enhancement of Hypolipidemic Effect of Atorvastatin Calcium via Floating Microspheres

“…The characteristics of surface and particle size of floating microspheres formulae were examined with an optical microscope (Seizz MC 63 C-Germany) (Avachat et al, 2011).…”