Hygroscopicity Assessment Of Free Film: Film Analysis
3.6.2. Hygroscopicity assessment of free films
Free films were evaluated for hygroscopicity behavior to understand the contribution of lactose and sodium chloride on hygroscopicity, if any. It was found that HPMC SD and HPMC-LAC CP films were ‘moderately hygroscopic’ whereas HPMC-NaCl CP films were ‘very hygroscopic’. The percentage moisture content and classification of each sample as per Callahan et al. (Callahan et al., 1982; Murikipudi et al., 2013) has been listed in Table 5.
4. Discussion
In the present investigation, spray drying based co-processing was used for the generation of co-processed HPMC. HPMC co-processed products with lactose and sodium chloride exhibited better dispersibility over HPMC SD. Poor dispersibility of HPMC SD …show more content…
This pointed towards presence of a homogenous amorphous phase. However, it is reported that DSC is only able to differentiate domains that are above 30 nm in size. Calculation based on Hildebrand solubility parameters indicated miscible nature of HPMC and lactose as the difference between solubility parameter values (δ) was found to be 4.1 MPa1/2. Homogeneity of HPMC and lactose in HPMC-LAC CP was further confirmed by TEM and STEM analysis that can differentiate heterogeneous domains even in sub-nanometer range (least count < 1 nm). Thus, PXRD and MDSC data along with TEM and STEM images confirmed the formation of a uniformly dispersed phase in HPMC-LAC CP. Moreover, Williams et al. have already demonstrated sugar-induced suppression of polymer hydration due to destruction of intramolecular hydrogen bonding that restricts rapid hydration and swelling of polymer particles (Kabayama and Patterson, 1958; Williams et al., 2010a; Williams et al., 2009, 2010b). Hence, it can be concluded that the improvement in dispersion behavior of HPMC-LAC CP was predominantly due to molecular level …show more content…
HPMC was co-processed with various excipients using spray dryer. Amongst them, HPMC co-processed with lactose and sodium chloride exhibited maximum improvement in dispersibility. Sessile drop contact angle technique also provided supporting evidence by exhibiting improved immersional wetting of co-processed products. Further, different microscopic techniques like CLSM, TEM and STEM were employed to get deeper insights into the improved dispersion behavior and to investigate the underlying mechanisms. Improved dispersibility of co-processed products was attributed to molecular and/or particulate level interactions of polymeric chains with other excipients during co-processing. This led to alteration in swelling behavior and gel forming properties of HPMC. Based on dispersion behavior, hygroscopicity and mechanical properties of polymeric films, HPMC-LAC CP was found to be a better
Free films were evaluated for hygroscopicity behavior to understand the contribution of lactose and sodium chloride on hygroscopicity, if any. It was found that HPMC SD and HPMC-LAC CP films were ‘moderately hygroscopic’ whereas HPMC-NaCl CP films were ‘very hygroscopic’. The percentage moisture content and classification of each sample as per Callahan et al. (Callahan et al., 1982; Murikipudi et al., 2013) has been listed in Table 5.
4. Discussion
In the present investigation, spray drying based co-processing was used for the generation of co-processed HPMC. HPMC co-processed products with lactose and sodium chloride exhibited better dispersibility over HPMC SD. Poor dispersibility of HPMC SD …show more content…
This pointed towards presence of a homogenous amorphous phase. However, it is reported that DSC is only able to differentiate domains that are above 30 nm in size. Calculation based on Hildebrand solubility parameters indicated miscible nature of HPMC and lactose as the difference between solubility parameter values (δ) was found to be 4.1 MPa1/2. Homogeneity of HPMC and lactose in HPMC-LAC CP was further confirmed by TEM and STEM analysis that can differentiate heterogeneous domains even in sub-nanometer range (least count < 1 nm). Thus, PXRD and MDSC data along with TEM and STEM images confirmed the formation of a uniformly dispersed phase in HPMC-LAC CP. Moreover, Williams et al. have already demonstrated sugar-induced suppression of polymer hydration due to destruction of intramolecular hydrogen bonding that restricts rapid hydration and swelling of polymer particles (Kabayama and Patterson, 1958; Williams et al., 2010a; Williams et al., 2009, 2010b). Hence, it can be concluded that the improvement in dispersion behavior of HPMC-LAC CP was predominantly due to molecular level …show more content…
HPMC was co-processed with various excipients using spray dryer. Amongst them, HPMC co-processed with lactose and sodium chloride exhibited maximum improvement in dispersibility. Sessile drop contact angle technique also provided supporting evidence by exhibiting improved immersional wetting of co-processed products. Further, different microscopic techniques like CLSM, TEM and STEM were employed to get deeper insights into the improved dispersion behavior and to investigate the underlying mechanisms. Improved dispersibility of co-processed products was attributed to molecular and/or particulate level interactions of polymeric chains with other excipients during co-processing. This led to alteration in swelling behavior and gel forming properties of HPMC. Based on dispersion behavior, hygroscopicity and mechanical properties of polymeric films, HPMC-LAC CP was found to be a better