The purpose of this research was to prepare a pseudolatex transdermal delivery system for terbutaline sulfate and to evaluate the effect of pH and organic ester penetration enhancers on permeation kinetics of terbutaline sulfate through mice abdominal skin and human cadaver skin. An increase in the permeation flux by increasing pH was observed. The distribution coefficient of terbutaline sulfate between 1-octanol and buffers of different pH values was also pH-dependent. Furthermore, the change of the permeability coefficient with pH correlated well with the distribution coefficient by a 2-degree polynomial equation. The permeation profile and related kinetic parameters of terbutaline sulfate was determined in presence of 3 estertype permeation enhancers incorporated in the films, viz methyl laureate, isopropyl lanolate, and isopropyl myristate. Among the 3, the more pronounced enhancing effect was obtained with isopropyl myristate, regarding the permeation flux, permeability coefficient, and diffusion coefficient. This was attributed to solubility parameter of isopropyl myristate being closer to the solubility parameter of human skin, and such a pronounced enhancing effect was probably caused by its passage across the skin barrier through the lipid pathway.

Lincomycin hydrochloride is a systemic antibiotic, which is active against most common gram positive bacteria. It has proved to be excellent for infectious diseases like acne, anthrax, pneumonia, and also for the treatment of furunculosis, carbuncles, impetigo, burns and wounds, carrying to gram positive bacteria. Gels were prepared using carbopol 940 as gelling agent, and isopropyl myristate and dimethyl sulfoxide as permeation enhancer. The formulations were evaluated for drug content, viscosity, pH, extrudability, homogeneity, skin irritation test, spreadability, and gel strength. A formulation containing 1.5% carbopol with 10% isopropyl myristate, showed better in vitro skin permeation through abdominal mouse skin, and was found to be the best.

Extensive efforts have recently been focused on targeting a drug or delivery system in a particular region of the body for extended period of time, not only for local targeting of drugs but also for the better control of systemic drug delivery. The concept of periodontal drug delivery systems has fascinated many investigators to the possible use of various polymers, which can overcome various physiological barriers in long-term drug delivery, there by rendering the treatment more effective and safe for local disorders and systemic problems. Presence of a smooth and relatively immobile surface for placement of a bio-adhesive dosage form has made periodontal route more suitable for sustained delivery of therapeutic agents using bio-adhesive systems. Antibiotics, antiseptics and other poorly absorbable drugs can be successfully delivered via periodontium for the treatment of infectious periodontal diseases. The dosage forms include microparticles, microspheres, adhesive gels, adhesive films, adhesive creams and ointments. Bio-adhesive periodontal drug delivery system can also exert positive influence on drug effectiveness by keeping the drug in the region proximal to its absorption window and allow the targeting and localization of the drug at the specific site.

The objectives of the present research work are to improve the solubility and dissolution rate of bosentan. Solid dispersions of bosentan were prepared by fusion method by using two selected hydrophilic meltable carriers visà-vis gelucire 50/13 and poloxamer 188. Sylysia 350 was used as an adsorbent. Solid dispersions were evaluated for solubility, phase solubility, flowability, compressibility, Fourier transform infrared spectra (FT-IR), differential scanning calorimetry (DSC). Solubility studies showed 8 and 10 fold increase in solubility for gelucire 50/13 and poloxamer 188 based solid dispersions respectively. The Gibbs free energy ΔGtr° values were all negative for gelucire 50/13 (0, 0.1, 0.25, 0.5, 0.75, 1, 2, 4, 6, 8 and 10 % w/v) and poloxamer 188 (0, 0.1, 0.25, 0.5, 0.75 and 1 % w/v) indicating spontaneous nature of solubilisation. FT-IR and DSC spectra showed that drug and carriers are compatible with each other. Solid dispersions exhibiting highest solubility were compressed into immediate release tablets by using sodium starch glycolate as superdisintegrant. In vitro dissolution studies, exhibited more than 90 % drug dissolution in 1 h. Gelucire 50/13 and poloxamer 188 plays a significant role in enhancement of drug solubility and dissolution. The adsorbent, sylysia 350 may be used to impart good flow and compressibility to solid dispersions. Among the two carriers, poloxamer 188 exhibited better solubility and dissolution enhancement potential.

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