It is now realized that the process of ocular drug and delivery requires a thorough understanding of various anatomical,phyysiological and metabolic features of the eye, in addition to the physico-chemical properties of the drug. Ocular drugs and delivery systems are currently undergoing a process of design optimization due to inherent physiological and anatomical constraints of the eye leading to problems associated with absorption efficiencies of topically applied drugs. Typically, 3 percent or less of the instilled drug in the solution dosage form into the percorneal area is actually absorbed across the cornea 1,3. The poor availability of ocular solution dosage forms therefore led to an intensive search for alternate forms delivery of drugs 4,5: (a) approaches to prolong the contact time of the drug with the corneal surface, and (b) approaches to epithelium or by modifications of chemical structure of the drug molecule. Chemical modifications of the active molecule is often found promising and necessary in order to overcome various problems of ocular drugs pertaining to their: (a)pharmacokinetic insufficiencies, (b) transportability, and (c) site specificity. In the recent years,some significant improvements have been made in this direction. The purpose of this article is to present a brief review of two novel chemical approaches of drug design, soft drugs and site-specific chemical delivery systems. A brief discussion on how these approaches have been utilized to design affective, selective and safe ocular drug delivery systems for the treatment of various pathological conditions and diseases affecting the eye, including treatment of glaucoma, ocular inflammations and infections is presented in this article.

Some new 1-alpha-aryloxypropionyl-3-methyl-5-pyrazolones (la-c) have been prepared. These on condensation with aromatic aldhydes yielded mono arylidene derivatives (LLa-i). All these compounds have been evaluated for their antifungal activity against A. niger and H. oryzae. Based on the screening data, a possible structure activity relationship has been discussed.

Pellets of indomethacin were prepared by dropping the suspension of indomethacin, in aqueous sodium alginate solution, into calcium chloride solution. The droplets instantaneously formed gelled spheres by lonotropic gelation. Pellets containing indomethacin were also prepared by solution layering technique and subsequently the drug loaded sugar pellets were coated with ethyl cellulose. Pellets were characterized by drug loading and in-vitro dissolution in phosphate buffer. The effects of formulation factors and process variables on the in-vitro dissolution rate are discussed. Goodness of fit test is used to establish the mechanism of indomethacin release from controlled release systems.

Shellac finds its application in Pharmaceutical industry because of its film forming and enteric properties. To modify its permeability and to prevent its hardening on keeping,various derivatives with polethylene glycol [SPEG], urea [SU], and thoiurea [STU] were prepared. Salicyclic acid granules were coated and evaluated for flow properties, moisture absorption and dissolution studies before and after aging. SPEG films were found to be most stable and could be used as aqueous film coating agents. Shellac urea resins could be used for controlled release of drug.

Amino Ketal derivates of benzoin and alpha-hydroxycyclohexyl phenyl ketone were prepared for evaluation of central anticholinergie and antiparkinsonian activity. Selected members of the series exhibited antitremorine potency with low orders of perpheral anticholinergic activity. The most potent tremorine antagoinst was tested against oxotremorine, an active metabolite of Tremorine and found to be in active. It is concluded that the compound probably act by preventing the in vivo conversion of tremorine to oxotremorine rather than by a central anticholinergic mechanism.

A new TLC Densitometric method for the quantitative estimation of a nonsteroidal anti-inflammatory agent curcumin in bulk drug samples, pharmaceutical dosage forms and in human serum has been worked out. The assay combines TLC on Silicagel 60 F254 with spot visualisation by single wavelength reflection mode, excitation 265 nm and emission UV D2 filter and densitometry. This communication describes a simple and quick TLC densitometric method for the estimation of curcumin in bulk drug samples, pharmaceutical dosage forms as well as in human serum.

The effects of exogenous supply of precursors, such as cholesterol, pregnenolone, L-ascorbic acid, shikimic acid, D-limonene, and squalene (50mg/1) on production of capsaicin in static cultures were observed. There were appreciable changes in capsaicin content due to treatment of 50 mg/1 of D-limonene (0.136 percent mg of capsaicin) and 100 mg/1 of L-ascorbic acid (0.169 mg of capsaicin). The capsaicin was detested only in the medium indicating its extracellular in-vitro accumulation. The precursors such as squalene, pregnenolone, and shikimic acid did not alter significantly the bioproduction pattern of capsaicin.

Flavone, its various methoxy derivatives and flavanone were investigated for their anti-inflammatory activity in carrageenin- induced paw edema in mice (acute) and cotton pellet granuloma in rats (chronic). In the acute study flavone,3,6,7, and 2,-methoxy flavones exhibited a dose related anti-inflammatory activity. However, compounds like flavanone, 5-and4'-methoxy flavones failed to show any anti-inflammatory response. In the chronic model, almost all the compounds except 4' - methoxy flavone exerted dose related anti-inflammatory effect. Thus a definite structure activity relationship could be observed in the anti-inflammatory activity of these compounds.

Some 2-azetidinone derivatives bearing 1,3,4-thiadiazole moiety have been synthesised by treating thiosemicarbazide with 2,4-dichlorophenoxy acetic acid in presence of phosphorus oxychloride, which resulted in product-1. This on treatment with aromatic aldehydes gave schiff's bases of thiadiazoles, product-II, which on further reaction with chloroacetyl chloride yielded the desired product (1 to 10 and 11 to 20). the structure of the products have been established by elemental analyses and spectral study. All the compounds have been evaluated for their antimicrobial activity against different microorganisms.

Methyl, ethyl, and newly synthesized n-propyl, isopropyl, n- butyl, isobutyl, n-pentyl and isopentyl sinapates were prepared and their 13 C NMR and mass spectral data reported. Carrageenan-induced rat paw oedema model was used to evaluate the anti-inflammatory action of sinapic acid and its various esters. Isopentyle sinapate was found to be the most patent and methyl sinapate was noted to be the least effective among the tested compounds.

Rifampicin Nasal drops in various viscoelastic bases were prepared and evaluated for drug diffusion mucous binding property and medicament retention capacity on the muscol surface. Out of the seven bases studied sodium alginate base was found to possess ideal characterstics to immobilize the drug in the administered area.

A simple TLC densitometric estimation method for picroside-I and Kutkoside worked out in picroliv and its dosage forms are described. This method is simple and can be utilised to estimate five or more samples at the same time. The assay combines adsorption of Picroliv on silica gel 60 F254 plate and thin layer chromatography with spot visualization by spraying plate with ceric sulphate (1 percent solution in 2NH2SO4) and densitometry by absorption mode.

The unsaponitiable fraction of Pet. ether fraction of Tridax procumbens revealed the presence of campesterol, stigmasterol, and Beta-sitosterol by G.C.M.S. analysis.

The lipid fraction from Vicoa indica DC. (Cokpositae) was subjected to urea adduct formation method. The adduct was desintegrated and the residue chromatographed. GC-MS examination of the mixture obtained led to the identification of 16 n-alkanes and 9 n-alkanoic acid esters.

In a research programme designed towards the synthesis of new heterocylic systems from coumarin 1-3, our intrest developed in the possibility of synthesizing a sulphur heterocyylic system containing a triazolothiadiazole moiety at the 3rd position of coumarin system. We are able to synthesize such a system which forms the subject matter of the paper.

A study was conducted to determine the effect of pH on antimalarial compound N' -3' -Acetyl-4-5'-dihydro-2' -furanyl-N' -(6-methoxy, 8-quinolinyl)-1, 4-pentane diamine (80/53) [l]. Aqueous solutions of [l] were prepared in buffers of different pH values (2.2 to 8.6) at 25 +/- 2 degree. The order of reaction and degradation rate constant were computed by least square linear regression.

Methanol extract of the rhizomes of iris hookeriana led to the isolation of a stilbene glycoside, Piceid. The structure was established by spectroscopic and chemical methods.

Methotrexate was encapsulated in niosomes prepared by using Tweens and Spans. The size distribution, entrapment efficiency,pharmacokinetics and effect of tumor remission of mice transplanted with S-180 Sarcoma were evaluated. Nisomes prepared with Span 60 gave promising results.

Mannich base of P-nitrobenzamide was prepared using secondary aminesulphonamide. The synthesised product was identified by spectral technique i.e. IR and UV. The Mannich base was subjected to antimicrobial screening against various organisms using filter paper disc technique. The sensitivity of bacteria to antibacterial agent was tested against various concentration in mgs. The study revealed that synthesised Mannich base of p-nitrobenzamide was showing significant activity on bacteria as obtained on statistical calculations.

Liposomes were prepared by detergent dialysis method and 99m TCGHA, a radiopharmaceutical of choice for kidney imaging was entrapped in SUVs of different surface charges. The organ specificity of the agent with and without encapsulation in lipsomes was studied in experimental animals. Results obtained show that 99m TC-GHA entrapped SUV can be targetted to liver. These results were corroborated by scintigraphy studies. The effect of entrapping the agent in SUV on its half-life is discussed.

A spectrophotometric method for the estimation of Lysine hydrochloride and Glumatic acid based on their reaction with acetylacetone-formaldehyde reagent is reported. The resulting colored chromogenic species in solution is directly measured at their wavelength of maximum absorbance 415 nm. Beer's Law is obeyed in concentration range 10-60 mcg/ml of Lysine hydrochloride and 20-160 mcg/ml of glumatic acid. The proposed method is applied to analyse their pharmaceutical formulations. The results compare favourably with those obtained by official method.

Some new arylsulfonyl hydrazones undertaken by the condensaion of 2,5-dihydroxy-3-bromo-aceto/benzophenone with different arylsulfonyl hydrazines which were prepared by the reaction of arylsulfonyl chloride with hydrazine hydrate. The structures of the products has been supported by spectral data and elemental analyses. The products were screened for antimicrobial activity. The activity was compared with standard drugs at different concentration.

A reverse-phase HPLC assay procedure for the determination of sodium chromoglycate is described. The compound was chromatographed on a C-8 (Lichrosorb RP-8) column using a mobile phase consisting of methanol : 0.01 M K2HPO4 (3:7). Metronizadole was used as internal standard. The chromatographic system exhibited good precision (cv < 2 percent). The recovery of drug from formulation was quantitative (99-102).

A simple spectrophotometric method requiring no prior separation has been developed for the analysis of Salbutamol Sulphate and Bromhexine Hydrochloride in tablets.