An oral route for drug administration is a more suitable route because of its ease of administration, pain avoidance, patient compliance, accommodation of various types of drug molecules, etc. But there are many factors affecting the oral absorption of the drugs. The main factor associated with oral absorption is drug solubility. Many new chemical molecules are poorly soluble in nature and can be included in BCS classes II and IV. For the administration of these drugs through the oral route, it was found that solubility is the rate limiting step. The low solubility of these drugs tends to cause precipitation in the gastrointestinaltract (GIT), affecting their bioavailability. Drug precipitation may be triggered by many factors such as insolubility of the drug in co-solvent, drug-excipient interactions, physiochemical properties of the drug, sudden change in the pH of the environment, incompatibility with the surfactant, etc. Precipitation of a drug may occur in two stages, formation of nucleation and crystal growth. To overcome precipitation, there are many strategies such as the use of polymers, the addition of surfactants, modulating drug loading and solubilizing capacity, change in the pH of the environment, etc. In this review, the causes of precipitation and diverse strategies of precipitation inhibition are critically reviewed.

中文翻译：

---

药物沉淀抑制的关键策略：以难溶性药物为重点的综述

口服给药途径具有易于给药、避免疼痛、患者依从性、适应各种类型药物分子等优点，是更合适的给药途径。但影响药物口服吸收的因素有很多。影响口服吸收的主要因素是药物溶解度。许多新的化学分子在自然界中溶解性差，可以列入 BCS II 类和 IV 类。对于通过口服途径给药这些药物，发现溶解度是限速步骤。这些药物的低溶解度往往会导致胃肠道 (GIT) 沉淀，从而影响它们的生物利用度。药物沉淀可能由许多因素引发，例如药物在共溶剂中的不溶性、药物-赋形剂相互作用、药物的理化性质、环境pH值的突然变化、与表面活性剂的不相容等。药物的沉淀可能发生在成核和晶体生长两个阶段。克服沉淀的策略有很多，如使用聚合物、添加表面活性剂、调节载药量和增溶能力、改变环境的pH值等。本文综述了沉淀的成因和多种沉淀策略抑制被严格审查。