Determination of capsaicin, dihydrocapsaicin, and capsanthin in Capsicum annuum from various habitats Determination of capsaicin, dihydrocapsaicin, and capsanthin in Capsicum annuum from various habitats Simultaneously determination of atropine sulphate,diphenhydramine hydrochloride, capsaicin and dihydrocapsaicin in pain-relieving plaster for arthritis by RP-HPLC