**4. Conclusion**

652 Advances in Crystallization Processes

C

The dissolution curves of pure carvedilol and its spherical crystals in 0.1 N HCl (pH 1.2) are shown in fig. 7. The release rate profiles were expressed as the percentage drug released vs. time. Table 4 shows % drug dissolved in 1h (DP60) and dissolution efficiency values at 30 min (DE30) for carvedilol and its spherical crystals. These values are tested statistically through one way ANOVA and are found significantly different (p<0.05) from pure carvedilol. As indicated carvedilol was dissolved more than 80% from spherical crystals CP681, CP1271 and CP1272 after 1h and more than 90% from spherical crystal CP682 while the pure CAR powder was just dissolved 34.37% at comparable time. The results revealed that the spherical crystals caused significant increase (P<0.05) in drug release compared to the pure drug. Enhancement in dissolution rate of spherical agglomerates as compared to pure drug may be due the presence of hydrophilic polymer, Poloxamer. The mechanism

**Sample Carvedilol Release after 1h Dissolution Efficiency at 30 min** 

CAR 34.37±0.19 20.56±0.09 CP681 83.42±0.25b 66.12±0.31b CP682 95.52±0.25b 70.63±1.38b CP1271 82.26±0.96b 65.90±0.14b CP1272 84.42±0.07b 67.39±0.39b

Fig. 6. SEM of (A) – Carvedilol, (B) – CP682, (C) – CP1272

**3.7 Dissolution rate studies** 

aMean ± SD, n = 3

bSignificantly different compared to carvedilol (*p* < 0.05). Table 4. Drug Release and Dissolution Efficiencya

CAR-poloxamer spherical crystals were prepared successfully by ESD method. The resultant crystals have the desired micromeritic properties, such as flowability and packability. In the present investigation Poloxamer F68 and Poloxamer F127 has significantly improved dissolution rate of carvedilol. However *in vivo* bioavailability studies are required to ensure whether, the results obtain in this investigation can be extrapolated to the *in vivo* conditions.
