Recently, advances in pharmaceutical research is focused on new delivery systems utilizing new devices to achieve modification of delivery time, targeting, as well as improve the in vivo solubility and hence bioavailability of poorly soluble drugs. Lipid based drug delivery systems (LDDS) consists of diverse group of formulations, each consisting of varying functional and structural properties that are amenable to modifications achieved by varying the composition of lipid excipients and other additives. LDDS has evolved, overtime, from micro-to nano-scale enhancing the efficacy and therapeutic application of these systems. LDDS are accepted, proven, commercially viable strategies for formulating challenging pharmaceutical molecules and can be tailored to meet a wide range of product requirements. Generally, most lipid drug delivery systems used as drug carriers have high stability, high carrier capacity, feasibility of incorporating both hydrophilic and hydrophobic substances and feasibility of variable routes of administration, including oral, topical, parenteral and pulmonary routes. LDDS can also be designed to allow modified drug release from matrices. LDDS could be broadly grouped into four: solid lipid particulate dosage forms, emulsion based systems, solid lipid tablets, and vesicular systems. Modifications from these four types include: lipospheres, solid lipid nanoparticles (SLNs), nano structured lipid carriers (NLC), lipid drug conjugate nanoparticles (LDC), self emulsifying formulations (SEFs), pickering emulsions, dry emulsions, micro and nano-emulsions, solidified reverse micellar solution (SRMS) based tablets, liposomes, herbosomes, cryptosomes and transferosomes amongst others. This work exhaustively reviewed the advances in LDDS and also drew comparison between the different types based on history, methods of manufacture, applications, advantages and disadvantages.

Rifampicin-loaded SLMs could be used once daily for the treatment tuberculosis.

Gongronema latifolium-loaded SLMs exhibited a good hypoglycemic effect and could be used for the treatment of diabetes.

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The objectives of the present study were to formulate sustained release pyridoxine hydrochloride capsules and to study the effect of propylene glycol co-solvents on the in vitro properties of the capsules. All batches of formulations were made with fixed concentrations of binder-disintegrants, diluents and equal load of active pharmaceutical ingredient. The granules were prepared by wet granulation using propylene glycol water co-solvent as the wetting agent, sodium carboxymethylcellulose (SCMC) and maize starch were used as binder-disintegrant and kaolin was used as the diluents. The micromeritic properties of the granules were analysed by direct and indirect methods. The granules were encapsulated in hard gelatin capsule No. 1. The capsule weight uniformity, disintegration time and drug content were determined. In vitro dissolution test was performed in 0.1 N HCl, simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.2). The results showed that the particles size of granules ranged from 245 to 259 µm and had good flowability. The capsules complied with British Pharmacopoeia (BP) requirement for capsule weight uniformity. The drug content was within 90 to 110% of the average values. The results of in vitro drug release in SGF (pH, 1.2) showed that the release of pyridoxine hydrochloride was very slow and was significantly (P < 0.05) lower than the release in 0.1 N HCl and in SIF (pH, 7.2), respectively. Therefore, pyridoxine hydrochloride sustained release capsules could be formulated with kaolin as the diluent and propylene glycol co-solvent as the moistening agent in order to reduce the frequency of administration of this drug and improve patient compliance.

The purpose of this study was to evaluate the antioxidant properties of Vitis vinifera juice extract (grape) in rifampicin suspensions and to compare with that of ascorbic acid. Grape juice was extracted and used as antioxidant in both pure sample and commercial reconstituted samples of rifampicin. The rate of drug degradation was determined by spectroscopic method in a time dependent manner. Also, the antioxidant property of grape juice was compared with that of ascorbic acid. Phytochemical screening of the constituents in grape juice extract was carried out according to standard methods. The results revealed that rifampicin dispersions containing ascorbic acid (batches A1 to A5) showed significantly higher stability and had higher amount of drug remaining over time than the control (batch A6) containing no antioxidant (p < 0.05). However, the results revealed that grape fruit juice extract had higher antioxidant properties than the ascorbic acid (p < 0.05) in rifampicin dispersions. The results also indicated that increase in amount of both antioxidants significantly reduced the rate of drug degradation through oxidation, thereby causing a corresponding increase in the amount of rifampicin remaining over time. Grape juice extract contain alkaloids, carbohydrates, saponins, reducing sugars, steroids, tannins, proteins, flavonoids, resins, oils, terpenoids and acid compounds. Glycosides were however not found in the juice extract. Therefore, grape fruit juice extract could be used as a natural antioxidant in rifampicin suspensions.

Objective: To formulate extended release gentamicin-entrapped lipospheres using natural lipids from Irvingia wombolu (IWF) and Moringa oleifera seed (MO) popularly known as Ben oil. Methods: Different lipid combinations including IWF and Phospholipon 90H (P90H) and IWF and MO were employed in the formulation of lipospheres. The formulations were analysed for particle size, encapsulation efficiency (EE), pH stability and antimicrobial studies amongst other tests. Also the in vitro release properties were studied in Phosphate buffer pH 7.2. Results: High EE of up to 90 % were obtained for the various LM combinations. The pH was stable over 30 days and the formulations showed about 93 % release of gentamicin at 12 h. Lipospheres formulated with MO matrices showed synergism in the microbial inhibition than other formulations. Conclusion: Natural lipids from Irvingia wombolu and Moringa oleifera seed could be used in formulating oral extended release gentamicin lipospheres.

Purpose: To develop modified hard gelatin capsules (MHGCs) for colon-specific delivery of hydrogel-based piroxicam microparticles. Methods: Solvent evaporation technique was adopted for the microencapsulation of piroxicam using liquid paraffin (PL.MPs) and soybean oil (PS.MPs) which were subsequently encapsulated in MHGCs (water-impervious). Anti-inflammatory and in vitro dissolution studies were conducted on the unencapsulated microparticles (MPs). Furthermore, in vitro colon-specific sequential drug release from impervious capsules was carried out for 2 h at pH 1.2 and 3 h in 6.8, and ≥ 5 h in 7.4, to simulate drug release in the stomach, small intestine, and colon environment, respectively. Differential scanning calorimetry (DSC) analysis was also conducted on the formulations. Results: Edema inhibition of PL.MPs and PS.MPs were within the range of 51.0 – 64.0 and 58.0 – 69.0 %, respectively. In vitro colon-specific drug dissolution studies revealed absence, minimal, and highest amounts of drug release from MHGCs in pH 1.2, 6.8 and 7.4 media, respectively. Decreased crystallinity of the microparticles was indicated by a broad endothermic peak. Conclusion: The MHGCs hold promise as a potential alternative delivery system for hydrogel-based piroxicam microparticles designed for colon-targeted drug delivery. However, clinical development studies are required.