Encrustation, a crust or hard coating on the surface of urinary stent & catheter, is developed due to the formation of biofilm caused by super saturation, adherence of micro bacteria and eventually deposition of mucoroteins, ions and crystals. Blockage of the stents & catheters causes reflux of urine thereby increasing renal pressure and ultimately damaging renal parenchymal tissues. El-Faqih et al has reported that encrustation occurs in 76.3% of stents left in place longer than 12 weeks. Urinary pH plays a role in the etiology of Stone formation and also for encrustation. The formation of various types of kidney stones is strongly influenced by urinary pH. An alkaline pH favors the crystallization of calcium- and phosphate-containing stones, whereas acidic urine pH promotes uric acid or cystine stones. pH/pKa of the drug reacted with different crystal forming chemicals on micro (replicated) environment  Drug schedules-Dried  aqueous extract of  Bryophyllum pinnatum and Crataeva nurvala taken for the study. Solubility is a function of pH. Maintenance of neutral pH increases aqueous solubility. pH of  Drug with different crystal forming element was between 7.5 to 7.6 .