PharmaForm, LLC, Austin, TX 78758, USA.
Drug Dev Ind Pharm. 2010 Feb;36(2):218-26. doi: 10.3109/03639040903271277.
This study investigated the effect of aqueous film coating on the recrystallization of guaifenesin from acrylic, hot-melt extruded matrix tablets.
After hot-melt extrusion, matrix tablets were film-coated with either hypromellose or ethylcellulose. The effects of the coating polymer, curing and storage conditions, polymer weight gain, and core guaifenesin concentration on guaifenesin recrystallization were investigated.
The presence of either film coating on the guaifenesin-containing tablets was found to prolong the onset time of drug crystallization. The coating polymer was the most important factor determining the delay in the onset of crystallization, with the more hydrophilic polymer, hypromellose, having a higher solubilization potential for the guaifenesin and delaying crystallization for longer period (3 or 6 months in tablets stored at 40 degrees C or 25 degrees C, respectively) than the more hydrophobic ethylcellulose, which displayed a lower solubilization potential for guaifenesin (crystal growth on tablets cured for 2 hours at 60 degrees C occurred within 3 weeks, whereas uncoated tablets displayed surface crystal growth after 30 minutes). Crystal morphology was also affected by the film coating. Elevated temperatures during both curing and storage, incomplete film coalescence, and high core drug concentrations all contributed to an earlier onset of crystal growth.
本研究考察了水膜包衣对丙烯酸热熔挤出基质片中小檗碱再结晶的影响。
热熔挤出后，用羟丙甲纤维素或乙基纤维素对基质片进行包衣。考察了包衣聚合物、固化和储存条件、聚合物增重以及核心小檗碱浓度对小檗碱再结晶的影响。
发现含有小檗碱的片剂表面的任何一种包衣都能延长药物结晶的起始时间。包衣聚合物是决定结晶起始延迟的最重要因素，亲水性更强的聚合物羟丙甲纤维素对小檗碱的溶解能力更高，因此结晶延迟时间更长（分别在 40°C 或 25°C 下储存 3 或 6 个月），而疏水性更强的乙基纤维素对小檗碱的溶解能力较低（在 60°C 下固化 2 小时的片剂上，结晶生长在 3 周内发生，而未包衣的片剂在 30 分钟后出现表面结晶生长）。包衣还会影响晶体形态。固化和储存过程中的高温、不完全的薄膜融合以及高芯药物浓度都会导致晶体生长更早开始。
