1. Allen LV, Popovich NG, Ansel HC. Pharmaceutical Dosage Forms and Drug Delivery Systems. Delhi, India: BI Pubication;2005;8:265.
2. N.K.Jain, Controlled and Novel drug delivery, 04 Edition, 236-237, 21.
3. S.P.Vyas and R.K.Khar, Targeted and Controlled drug delivery, 07 Edition, 418
4. Lachman LA, Liberman HA, Kanig JL. The Theory and Practice of Industrial Pharmacy. Mumbai, India: Varghese Publishng House;3:414-415.
5. Leon L, Herbert AL, Joseph LK. The Theory and Practice of Industrial Pharmacy. Varghese Publishing House 1990; 412-428.