Prolonged release drug delivery system of pilocarpine nitrate was made by optimizing thin layer film hydration method. Egg phosphatidylcholine and cholesterol were used to make multilamellar vesicles. Effects of charges over the vesicles were studied by incorporating dicetylphosphate and stearylamine. Various factors, which may affect the size, shape, encapsulation efficiency and release rate, were studied. Liposomes in the size range 0.2 to 1 µm were obtained by optimizing the process. Encapsulation efficiency of neutral, positive and negatively charged liposomes were found to be 32.5, 35.4 and 34.2 percent, respectively. In vitro drug release rate was studied on specially designed model. Biological response in terms of reduction in intraocular pressure was observed on rabbit eyes. Pilocarpine nitrate liposomes were lyophilized and stability studies were conducted.
Pilocarpine nitrate loaded egg albumin microspheres were prepared by thermal denaturation process in the size range of 1-12 μm. A series of batches were prepared to study factors, which may affect the size and entrapment efficiency of drug in microspheres and optimized the process. Drug loaded microspheres so obtained were evaluated for their size, entrapment efficiency, release rate and biological response. Electron photomicrographs were taken (8000X) to study the morphological characteristics of microspheres. The entrapment and encapsulation of pilocarpine after process optimization was found to be 82.63% and 62.5% respectively. In vitro dissolution rate studies revealed that the release of drug from the microspheres followed spherical matrix mechanism. Biological response of microspheric suspension was measured by reduction in intraocular pressure in albino rabbit eyes and compared with marketed eye drops. Various pharmacokinetic parameters viz. onset of action, duration of action, Tmax and AUC were studied. A measurable difference was found in the mean miotic response, duration and AUC of pilocarpine nitrate microspheric suspension.
Collagen is the principal structural protein present in the skin, tendon and bone of the vertebrate body. Ten different vertebrate collagens have been identified, of which the dominant collagen is type I. Interest in collagen as a biomaterial is due to its low immunogenicity and high biocompatibility. Collagen has diverse general and biomedical applications and is also a common constituent of many cosmetic and food products in the form of gelatin. This paper discusses the use of collagen in the fields of medicine and biotechnology, as well as in the cosmetic and pharmaceutical industry.
The bioavailability of drugs from conventional ophthalmic formulations is low. To optimize the therapy, sustained release ophthalmic dosage forms are warranted. Hydrogels such as sodium-carboxymethyl cellulose, hydroxypropylmethyl cellulose, Carbopol-940, Carbopol-941 and Lutrol-FC-127 increase the duration of action of various drugs. Gels containing pilocarpine were prepared and evaluated by measuring the intensity and duration of miotic response in albino rabbits. Carbopol-940 gels, being the best of those used, were studied further for the effect of its concentration and of additives (benzalkonium chloride, phenylmercuric nitrate, chlorbutol and disodium edetate), autoclaving at 121 degrees C for 30 min and irradiation with gamma rays (2.5 Mrad), on the end product.
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