**2.2.4 Powder X-ray diffraction studies**

644 Advances in Crystallization Processes

Carvedilol was supplied by Dr. Reddy's Laboratory, Hyderabad, India as a gift sample. Poloxamer F68 and F127 were supplied by Lupin Research Park, Pune, India. All other

Carvedilol (1.0 g) with poloxamer was dissolved in good solvent methanol (12.0 mL). The bridging liquid dichloromethane (2.0 mL) was added to it. The resulting solution was then poured dropwise in to the poor solvent distilled water (100 mL) containing Aerosil 200 Pharma (0.1 g). The mixture was stirred continuously for a period of 0.5 h using a controlled speed mechanical stirrer (Remi motors, India) at 1000 rpm. As the good solvent diffused into the poor solvent, droplets gradually solidified. Finally the coprecipitated microspheres of the drug-polymer were filtered through Whatman filter paper (No.1) and dried in desiccator at room temperature. The amount of poloxamers was altered to get desired microspheres.

**Composition/Parameters CP681 CP682 CP1271 CP1272**  CAR (g) 1.0 1.0 1.0 1.0 Methanol (ml) 12.0 12.0 12.0 12.0 DCM (ml) 2.0 2.0 2.0 2.0 Water (ml) 100 100 100 100 Poloxamer F68 (g) 1.5 3.0 -- -- Poloxamer F127 (g) -- -- 1.5 3.0 Aerosil 200 pharma (g) 0.1 0.1 0.1 0.1 Stirring speed (rpm) 1000 1000 1000 1000

The drug content study of agglomerates was determined by dissolving 100 mg of crystals in 3 ml methanol and diluting further with distilled water (100 ml) followed by measuring the absorbance of appropriately diluted solution spectrophotometrically (PharmaSpec UV-1700,

The FTIR spectra of powder CAR, and their agglomerates were recorded on an FTIR

DSC analysis was performed using a DSC 823 calorimeter (Mettler Toledo model) operated by STARe software. Samples of CAR and its agglomerates were sealed in an aluminium

**2. Materials and methods** 

chemicals used were of analytical grade.

The composition is given in Table 1.

Table 1. Composition of spherical crystals

UV-Vis spectrophotometer, Shimadzu) at 286 nm.

spectrophotometer (JASCO, FTIR V-430 Plus).

**2.2.3 Differential Scanning Calorimetry (DSC)** 

**2.2.2 Fourier Transform Infrared Spectroscopy (FTIR)** 

**2.2.1 Drug content study** 

**2.1 Materials** 

**2.2 Methods** 

Powder X-ray diffraction patterns (XRD) of the CAR and its spherical agglomerates were monitored with an x-ray diffractometer (Philips Analytical XRD) using copper as x-ray target, a voltage of 40 KV, a current of 25 mA and with 2.28970 Å wavelength. The samples were analyzed over 2θ range of 10.01-99.990 with scanning step size of 0.020 (2θ) and scan step time of 0.8 second.
