EVALUATION OF STABILITY OF ROPINIROLE HYDROCHLORIDE AND PRAMIPEXOLE DIHYDROCHLORIDE MICROSPHERES AT ACCELERATED CONDITION

Objective: The objective of the present work was to conduct accelerated stability study as per international council for harmonisation (ICH) guidelines and to establish shelf life of controlled release dosage form of ropinirole hydrochloride and pramipexole dihydrochloride microspheres for a period of 6 mo.Methods: Most optimized batch of ropinirole hydrochloride and pramipexole dihydrochloride (F12 and M12 respectively) were selected and subjected to exhaustive stability testing by keeping the sample in stability oven for a period of 3 and 6 mo. Various parameters like surface morphology, particle size, drug content, in vitro drug release and shelf life were evaluated at 3 and 6 mo period. The surface morphology of the formulated microspheres was determined by scanning electron microscopy (SEM). The particle size of the microspheres was estimated by optical microscopy method. The drug content was assayed by the help of ultra-violet spectrophotometer (UV). The in vitro drug release was performed by using Paddle II type dissolution apparatus and the filtrate was analyzed by UV spectrophotometer. The shelf life of the optimized microspheres was calculated by using the rate constant value of the zero-order reaction.Results: A minor change was recorded in average particle size of F12 and M12 microspheres after storage for 6 mo. For F12 and M12, initially the particle size was 130.00 µm and 128.92 µm respectively and after 6 mo it was found to be 130.92 µm and 128.99 µm respectively. There was no change in surface morphology of F12 and M12 microspheres after 6 mo of storage. The shape of microspheres remained spherical and smooth after 6 mo. An insignificant difference of drug content was recorded after 6 mo compared to the freshly prepared formulation. For F12 and M12, 94.50% and 93.77% of the drug was present initially and after 6 mo 94.45% and 93.72% of the drug was recorded. In vitro drug release was recorded after 6 mo for F12 and M12. Initially, 97.99% and 97.69% of the drug was released till 14th hour respectively for F12 and M12. After 6 mo, 98.23% and 97.99% of the drug was released respectively. The percentage residual drug content revealed that the degradation of microspheres was low. Considering the initial percentage residual drug content as 100%, 99.94% of the drug was recorded for both F12 and M12. The shelf life for F12 and M12 was found to be 10 y 52 d and 10 y 70 d respectively which were determined by the zero-order kinetic equation.Conclusion: A more or less similar surface morphology, particle size, drug content and percent of drug release before and after stability study confirmed the stability of F12 and M12 microspheres after storage for 6 mo and prove the efficacy of the microspheres in the site-specific delivery of drugs in Parkinson's disease

PREPARATION, CHARACTERISATION AND EVALUATION OF ROPINIROLE HYDROCHLORIDE LOADED CONTROLLED RELEASE MICROSPHERES USING SOLVENT EVAPORATION TECHNIQUE

Objective: The major objective of the research work was to design, characterise and evaluate controlled release microspheres of ropinirole hydrochloride by using non-aqueous solvent evaporation technique to facilitate the delivery of the drug at a predetermined rate for a specific period of time.Methods: Ropinirole hydrochloride microspheres were prepared by using different low-density polymers such as eudragit RL 100, eudragit RS 100 and ethylcellulose either alone or in combination with the help of non-aqueous solvent evaporation technique. All the formulated microparticles were subjected to various evaluation parameters such as particle size analysis, micrometric properties, drug entrapment efficiency, percentage drug loading, percentage yield and in vitro drug release study. The compatibility of the drug and polymers was confirmed by physical compatibility study, fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and x-ray diffraction study (XRD). The formation of the most optimized batch of the microsphere (F12) was confirmed by scanning electron microscopy (SEM), DSC, FTIR, and XRD. In vitro drug release study and in vitro drug release kinetics study of the formulated microspheres were also carried out.Results: Drug-polymer compatibility studies performed with the help of FTIR and DSC indicated that there were no interactions. Results revealed that non-aqueous solvent evaporation technique was a suitable technique for the preparation of microspheres as most of the formulations were discrete, free-flowing and spherical in shape with a good yield of 55.67% to 80.09%, percentage drug loading of 35.52% to 94.50% and percentage drug entrapment efficiency of 36.24% to 95.07%. Different drug-polymer ratios, as well as the combination of polymers, played a significant role in the variation of over-all characteristics of formulations. Based on the data of various evaluation parameters such as particle size analysis, percentage drug loading, percentage drug entrapment, percentage yield, rheological studies and in vitro drug release characteristics, formulation F12 was found to fulfil the criteria of ideal controlled release drug delivery system. F12 showed controlled release till the 14th hour (97.99%) and its in vitro release kinetics was best explained by zero-order kinetics and followed Korsemeyer-Pappas model (Non-Fickian mechanism). SEM of F12 revealed the formation of spherical structures. The FTIR study of F12 confirmed the stable nature of ropinirole in the drug-loaded microspheres. DSC and XRD patterns showed that ropinirole hydrochloride was dispersed at the molecular level in the polymer matrix.Conclusion: The controlled release microparticles were successfully prepared and from this study, it was concluded that the developed microspheres of ropinirole hydrochloride can be used for controlled drug release to improve the bioavailability and patient compliance and to maintain a constant drug level in the blood target tissue by releasing the drug in zero order pattern