Development and Characterization of Semi Interpenetrating Polymer Network Microspheres for Glaucoma Treatment

Abstract

ABSTRACT newlineTimolol maleate (TM) is used worldwide as a standard drug to reduce the intraocular pressure; it is a and#946;-adrenergic blocker and is non selective for and#946;-1 and and#946;-2 adrenergic receptors. It prevents the production of aqueous humour content and thus lowering the pressure in eye. Designing a new ocular dosage form for timolol maleate compels performing preformulation studies for drug. Therefore, the current aim of the study was to investigate some of the important physicochemical properties of timolol maleate which can help to select subsequent approaches during the development of novel semi-interpenetrating polymer network microspheres for ocular use. Preformulation studies of drug were carried out for identification (physical appearance, melting point and UV spectrophotometric analysis), solubility profile, lipophilicity (Partition coefficient), compatibility studies by Fourier transform infrared (FTIR) spectroscopy and thermal behaviour by differential scanning calorimetry (DSC). The melting point of timolol maleate was found to be 201±3and#9675;C. The log P value was found to be 1.41±0.12, from which it can be interpreted that drug is slightly hydrophobic in nature. The scanned and#955;max were found to be 298 nm. No significant changes were found when FTIR spectra of physical mixture compared with FTIR spectra of pure drug and excipients. This indicates absence of any possible interaction between the drug and excipients which confirms the identity and purity of drug. DSC thermogram of pure drug showed a sharp exothermic peak at 191.923ºC (area=68.890 mJ, delta H=22.963 J/g) indicating the crystal melting point of the drug. These results suggest that the timolol maleate serve as suitable candidate for ocular drug delivery system. newlineKeywords:Timolol maleate, Preformulation, ocular delivery, Spectrometric analysis, Compatibility newline